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<meta charset="utf-8" />
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<meta name="viewport" content="width=device-width, initial-scale=1.0" />
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<title>Blog Blueprint — Flask Documentation (3.2.x)</title>
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<title>Application Setup — Flask Documentation (3.2.x)</title>
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<link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=6625fa76" />
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<link rel="stylesheet" type="text/css" href="../_static/flask.css?v=b87c8d14" />
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@ -15,8 +15,8 @@
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<link rel="icon" href="../_static/shortcut-icon.png"/>
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<link rel="index" title="Index" href="../genindex.html" />
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<link rel="search" title="Search" href="../search.html" />
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<link rel="next" title="Make the Project Installable" href="install.html" />
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<a href="../py-modindex.html" title="Python Module Index"
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>modules</a> |</li>
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<li class="right" >
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<a href="install.html" title="Make the Project Installable"
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<a href="database.html" title="Define and Access the Database"
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accesskey="N">next</a> |</li>
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<a href="layout.html" title="Project Layout"
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accesskey="P">previous</a> |</li>
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<li class="nav-item nav-item-0"><a href="../index.html">Flask Documentation (3.2.x)</a> »</li>
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<li class="nav-item nav-item-1"><a href="index.html" accesskey="U">Tutorial</a> »</li>
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<li class="nav-item nav-item-this"><a href="">Blog Blueprint</a></li>
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<li class="nav-item nav-item-this"><a href="">Application Setup</a></li>
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</ul>
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<div class="document">
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<div class="documentwrapper">
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<div class="bodywrapper">
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<div class="body" role="main">
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<section id="blog-blueprint">
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<h1>Blog Blueprint<a class="headerlink" href="#blog-blueprint" title="Link to this heading">¶</a></h1>
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<p>You’ll use the same techniques you learned about when writing the
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authentication blueprint to write the blog blueprint. The blog should
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list all posts, allow logged in users to create posts, and allow the
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author of a post to edit or delete it.</p>
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<p>As you implement each view, keep the development server running. As you
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save your changes, try going to the URL in your browser and testing them
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out.</p>
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<section id="the-blueprint">
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<h2>The Blueprint<a class="headerlink" href="#the-blueprint" title="Link to this heading">¶</a></h2>
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<p>Define the blueprint and register it in the application factory.</p>
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<div class="literal-block-wrapper docutils container" id="id1">
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<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/blog.py</span></code></span><a class="headerlink" href="#id1" title="Link to this code">¶</a></div>
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<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span><span class="w"> </span><span class="nn">flask</span><span class="w"> </span><span class="kn">import</span> <span class="p">(</span>
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<span class="n">Blueprint</span><span class="p">,</span> <span class="n">flash</span><span class="p">,</span> <span class="n">g</span><span class="p">,</span> <span class="n">redirect</span><span class="p">,</span> <span class="n">render_template</span><span class="p">,</span> <span class="n">request</span><span class="p">,</span> <span class="n">url_for</span>
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<span class="p">)</span>
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<span class="kn">from</span><span class="w"> </span><span class="nn">werkzeug.exceptions</span><span class="w"> </span><span class="kn">import</span> <span class="n">abort</span>
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<span class="kn">from</span><span class="w"> </span><span class="nn">flaskr.auth</span><span class="w"> </span><span class="kn">import</span> <span class="n">login_required</span>
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<span class="kn">from</span><span class="w"> </span><span class="nn">flaskr.db</span><span class="w"> </span><span class="kn">import</span> <span class="n">get_db</span>
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<span class="n">bp</span> <span class="o">=</span> <span class="n">Blueprint</span><span class="p">(</span><span class="s1">'blog'</span><span class="p">,</span> <span class="vm">__name__</span><span class="p">)</span>
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<section id="application-setup">
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<h1>Application Setup<a class="headerlink" href="#application-setup" title="Link to this heading">¶</a></h1>
|
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<p>A Flask application is an instance of the <a class="reference internal" href="../api.html#flask.Flask" title="flask.Flask"><code class="xref py py-class docutils literal notranslate"><span class="pre">Flask</span></code></a> class.
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Everything about the application, such as configuration and URLs, will
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||||
be registered with this class.</p>
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<p>The most straightforward way to create a Flask application is to create
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a global <a class="reference internal" href="../api.html#flask.Flask" title="flask.Flask"><code class="xref py py-class docutils literal notranslate"><span class="pre">Flask</span></code></a> instance directly at the top of your code, like
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how the “Hello, World!” example did on the previous page. While this is
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simple and useful in some cases, it can cause some tricky issues as the
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||||
project grows.</p>
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||||
<p>Instead of creating a <a class="reference internal" href="../api.html#flask.Flask" title="flask.Flask"><code class="xref py py-class docutils literal notranslate"><span class="pre">Flask</span></code></a> instance globally, you will create
|
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it inside a function. This function is known as the <em>application
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factory</em>. Any configuration, registration, and other setup the
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application needs will happen inside the function, then the application
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will be returned.</p>
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<section id="the-application-factory">
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<h2>The Application Factory<a class="headerlink" href="#the-application-factory" title="Link to this heading">¶</a></h2>
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<p>It’s time to start coding! Create the <code class="docutils literal notranslate"><span class="pre">flaskr</span></code> directory and add the
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<code class="docutils literal notranslate"><span class="pre">__init__.py</span></code> file. The <code class="docutils literal notranslate"><span class="pre">__init__.py</span></code> serves double duty: it will
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contain the application factory, and it tells Python that the <code class="docutils literal notranslate"><span class="pre">flaskr</span></code>
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directory should be treated as a package.</p>
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<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>$ mkdir flaskr
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</pre></div>
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</div>
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</div>
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<p>Import and register the blueprint from the factory using
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<a class="reference internal" href="../api.html#flask.Flask.register_blueprint" title="flask.Flask.register_blueprint"><code class="xref py py-meth docutils literal notranslate"><span class="pre">app.register_blueprint()</span></code></a>. Place the
|
||||
new code at the end of the factory function before returning the app.</p>
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<div class="literal-block-wrapper docutils container" id="id2">
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||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/__init__.py</span></code></span><a class="headerlink" href="#id2" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">create_app</span><span class="p">():</span>
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<span class="n">app</span> <span class="o">=</span> <span class="o">...</span>
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||||
<span class="c1"># existing code omitted</span>
|
||||
<div class="literal-block-wrapper docutils container" id="id1">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/__init__.py</span></code></span><a class="headerlink" href="#id1" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">os</span>
|
||||
|
||||
<span class="kn">from</span><span class="w"> </span><span class="nn">.</span><span class="w"> </span><span class="kn">import</span> <span class="n">blog</span>
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<span class="n">app</span><span class="o">.</span><span class="n">register_blueprint</span><span class="p">(</span><span class="n">blog</span><span class="o">.</span><span class="n">bp</span><span class="p">)</span>
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<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span><span class="s1">'/'</span><span class="p">,</span> <span class="n">endpoint</span><span class="o">=</span><span class="s1">'index'</span><span class="p">)</span>
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<span class="kn">from</span><span class="w"> </span><span class="nn">flask</span><span class="w"> </span><span class="kn">import</span> <span class="n">Flask</span>
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||||
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<span class="k">def</span><span class="w"> </span><span class="nf">create_app</span><span class="p">(</span><span class="n">test_config</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span>
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<span class="c1"># create and configure the app</span>
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<span class="n">app</span> <span class="o">=</span> <span class="n">Flask</span><span class="p">(</span><span class="vm">__name__</span><span class="p">,</span> <span class="n">instance_relative_config</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
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<span class="n">app</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">from_mapping</span><span class="p">(</span>
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<span class="n">SECRET_KEY</span><span class="o">=</span><span class="s1">'dev'</span><span class="p">,</span>
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<span class="n">DATABASE</span><span class="o">=</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">app</span><span class="o">.</span><span class="n">instance_path</span><span class="p">,</span> <span class="s1">'flaskr.sqlite'</span><span class="p">),</span>
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<span class="p">)</span>
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<span class="k">if</span> <span class="n">test_config</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
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<span class="c1"># load the instance config, if it exists, when not testing</span>
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<span class="n">app</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">from_pyfile</span><span class="p">(</span><span class="s1">'config.py'</span><span class="p">,</span> <span class="n">silent</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
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<span class="k">else</span><span class="p">:</span>
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<span class="c1"># load the test config if passed in</span>
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||||
<span class="n">app</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">from_mapping</span><span class="p">(</span><span class="n">test_config</span><span class="p">)</span>
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<span class="c1"># ensure the instance folder exists</span>
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<span class="k">try</span><span class="p">:</span>
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<span class="n">os</span><span class="o">.</span><span class="n">makedirs</span><span class="p">(</span><span class="n">app</span><span class="o">.</span><span class="n">instance_path</span><span class="p">)</span>
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<span class="k">except</span> <span class="ne">OSError</span><span class="p">:</span>
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<span class="k">pass</span>
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<span class="c1"># a simple page that says hello</span>
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<span class="nd">@app</span><span class="o">.</span><span class="n">route</span><span class="p">(</span><span class="s1">'/hello'</span><span class="p">)</span>
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<span class="k">def</span><span class="w"> </span><span class="nf">hello</span><span class="p">():</span>
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<span class="k">return</span> <span class="s1">'Hello, World!'</span>
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<span class="k">return</span> <span class="n">app</span>
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</pre></div>
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</div>
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</div>
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<p>Unlike the auth blueprint, the blog blueprint does not have a
|
||||
<code class="docutils literal notranslate"><span class="pre">url_prefix</span></code>. So the <code class="docutils literal notranslate"><span class="pre">index</span></code> view will be at <code class="docutils literal notranslate"><span class="pre">/</span></code>, the <code class="docutils literal notranslate"><span class="pre">create</span></code>
|
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view at <code class="docutils literal notranslate"><span class="pre">/create</span></code>, and so on. The blog is the main feature of Flaskr,
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so it makes sense that the blog index will be the main index.</p>
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<p>However, the endpoint for the <code class="docutils literal notranslate"><span class="pre">index</span></code> view defined below will be
|
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<code class="docutils literal notranslate"><span class="pre">blog.index</span></code>. Some of the authentication views referred to a plain
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<code class="docutils literal notranslate"><span class="pre">index</span></code> endpoint. <a class="reference internal" href="../api.html#flask.Flask.add_url_rule" title="flask.Flask.add_url_rule"><code class="xref py py-meth docutils literal notranslate"><span class="pre">app.add_url_rule()</span></code></a>
|
||||
associates the endpoint name <code class="docutils literal notranslate"><span class="pre">'index'</span></code> with the <code class="docutils literal notranslate"><span class="pre">/</span></code> url so that
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||||
<code class="docutils literal notranslate"><span class="pre">url_for('index')</span></code> or <code class="docutils literal notranslate"><span class="pre">url_for('blog.index')</span></code> will both work,
|
||||
generating the same <code class="docutils literal notranslate"><span class="pre">/</span></code> URL either way.</p>
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<p>In another application you might give the blog blueprint a
|
||||
<code class="docutils literal notranslate"><span class="pre">url_prefix</span></code> and define a separate <code class="docutils literal notranslate"><span class="pre">index</span></code> view in the application
|
||||
factory, similar to the <code class="docutils literal notranslate"><span class="pre">hello</span></code> view. Then the <code class="docutils literal notranslate"><span class="pre">index</span></code> and
|
||||
<code class="docutils literal notranslate"><span class="pre">blog.index</span></code> endpoints and URLs would be different.</p>
|
||||
<p><code class="docutils literal notranslate"><span class="pre">create_app</span></code> is the application factory function. You’ll add to it
|
||||
later in the tutorial, but it already does a lot.</p>
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<ol class="arabic simple">
|
||||
<li><p><code class="docutils literal notranslate"><span class="pre">app</span> <span class="pre">=</span> <span class="pre">Flask(__name__,</span> <span class="pre">instance_relative_config=True)</span></code> creates the
|
||||
<a class="reference internal" href="../api.html#flask.Flask" title="flask.Flask"><code class="xref py py-class docutils literal notranslate"><span class="pre">Flask</span></code></a> instance.</p>
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||||
<ul class="simple">
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||||
<li><p><code class="docutils literal notranslate"><span class="pre">__name__</span></code> is the name of the current Python module. The app
|
||||
needs to know where it’s located to set up some paths, and
|
||||
<code class="docutils literal notranslate"><span class="pre">__name__</span></code> is a convenient way to tell it that.</p></li>
|
||||
<li><p><code class="docutils literal notranslate"><span class="pre">instance_relative_config=True</span></code> tells the app that
|
||||
configuration files are relative to the
|
||||
<a class="reference internal" href="../config.html#instance-folders"><span class="std std-ref">instance folder</span></a>. The instance folder
|
||||
is located outside the <code class="docutils literal notranslate"><span class="pre">flaskr</span></code> package and can hold local
|
||||
data that shouldn’t be committed to version control, such as
|
||||
configuration secrets and the database file.</p></li>
|
||||
</ul>
|
||||
</li>
|
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<li><p><a class="reference internal" href="../api.html#flask.Config.from_mapping" title="flask.Config.from_mapping"><code class="xref py py-meth docutils literal notranslate"><span class="pre">app.config.from_mapping()</span></code></a> sets
|
||||
some default configuration that the app will use:</p>
|
||||
<ul class="simple">
|
||||
<li><p><a class="reference internal" href="../config.html#SECRET_KEY" title="SECRET_KEY"><code class="xref py py-data docutils literal notranslate"><span class="pre">SECRET_KEY</span></code></a> is used by Flask and extensions to keep data
|
||||
safe. It’s set to <code class="docutils literal notranslate"><span class="pre">'dev'</span></code> to provide a convenient value
|
||||
during development, but it should be overridden with a random
|
||||
value when deploying.</p></li>
|
||||
<li><p><code class="docutils literal notranslate"><span class="pre">DATABASE</span></code> is the path where the SQLite database file will be
|
||||
saved. It’s under
|
||||
<a class="reference internal" href="../api.html#flask.Flask.instance_path" title="flask.Flask.instance_path"><code class="xref py py-attr docutils literal notranslate"><span class="pre">app.instance_path</span></code></a>, which is the
|
||||
path that Flask has chosen for the instance folder. You’ll learn
|
||||
more about the database in the next section.</p></li>
|
||||
</ul>
|
||||
</li>
|
||||
<li><p><a class="reference internal" href="../api.html#flask.Config.from_pyfile" title="flask.Config.from_pyfile"><code class="xref py py-meth docutils literal notranslate"><span class="pre">app.config.from_pyfile()</span></code></a> overrides
|
||||
the default configuration with values taken from the <code class="docutils literal notranslate"><span class="pre">config.py</span></code>
|
||||
file in the instance folder if it exists. For example, when
|
||||
deploying, this can be used to set a real <code class="docutils literal notranslate"><span class="pre">SECRET_KEY</span></code>.</p>
|
||||
<ul class="simple">
|
||||
<li><p><code class="docutils literal notranslate"><span class="pre">test_config</span></code> can also be passed to the factory, and will be
|
||||
used instead of the instance configuration. This is so the tests
|
||||
you’ll write later in the tutorial can be configured
|
||||
independently of any development values you have configured.</p></li>
|
||||
</ul>
|
||||
</li>
|
||||
<li><p><a class="reference external" href="https://docs.python.org/3/library/os.html#os.makedirs" title="(in Python v3.13)"><code class="xref py py-func docutils literal notranslate"><span class="pre">os.makedirs()</span></code></a> ensures that
|
||||
<a class="reference internal" href="../api.html#flask.Flask.instance_path" title="flask.Flask.instance_path"><code class="xref py py-attr docutils literal notranslate"><span class="pre">app.instance_path</span></code></a> exists. Flask
|
||||
doesn’t create the instance folder automatically, but it needs to be
|
||||
created because your project will create the SQLite database file
|
||||
there.</p></li>
|
||||
<li><p><a class="reference internal" href="../api.html#flask.Flask.route" title="flask.Flask.route"><code class="xref py py-meth docutils literal notranslate"><span class="pre">@app.route()</span></code></a> creates a simple route so you can
|
||||
see the application working before getting into the rest of the
|
||||
tutorial. It creates a connection between the URL <code class="docutils literal notranslate"><span class="pre">/hello</span></code> and a
|
||||
function that returns a response, the string <code class="docutils literal notranslate"><span class="pre">'Hello,</span> <span class="pre">World!'</span></code> in
|
||||
this case.</p></li>
|
||||
</ol>
|
||||
</section>
|
||||
<section id="index">
|
||||
<h2>Index<a class="headerlink" href="#index" title="Link to this heading">¶</a></h2>
|
||||
<p>The index will show all of the posts, most recent first. A <code class="docutils literal notranslate"><span class="pre">JOIN</span></code> is
|
||||
used so that the author information from the <code class="docutils literal notranslate"><span class="pre">user</span></code> table is
|
||||
available in the result.</p>
|
||||
<div class="literal-block-wrapper docutils container" id="id3">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/blog.py</span></code></span><a class="headerlink" href="#id3" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="nd">@bp</span><span class="o">.</span><span class="n">route</span><span class="p">(</span><span class="s1">'/'</span><span class="p">)</span>
|
||||
<span class="k">def</span><span class="w"> </span><span class="nf">index</span><span class="p">():</span>
|
||||
<span class="n">db</span> <span class="o">=</span> <span class="n">get_db</span><span class="p">()</span>
|
||||
<span class="n">posts</span> <span class="o">=</span> <span class="n">db</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span>
|
||||
<span class="s1">'SELECT p.id, title, body, created, author_id, username'</span>
|
||||
<span class="s1">' FROM post p JOIN user u ON p.author_id = u.id'</span>
|
||||
<span class="s1">' ORDER BY created DESC'</span>
|
||||
<span class="p">)</span><span class="o">.</span><span class="n">fetchall</span><span class="p">()</span>
|
||||
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="s1">'blog/index.html'</span><span class="p">,</span> <span class="n">posts</span><span class="o">=</span><span class="n">posts</span><span class="p">)</span>
|
||||
<section id="run-the-application">
|
||||
<h2>Run The Application<a class="headerlink" href="#run-the-application" title="Link to this heading">¶</a></h2>
|
||||
<p>Now you can run your application using the <code class="docutils literal notranslate"><span class="pre">flask</span></code> command. From the
|
||||
terminal, tell Flask where to find your application, then run it in
|
||||
debug mode. Remember, you should still be in the top-level
|
||||
<code class="docutils literal notranslate"><span class="pre">flask-tutorial</span></code> directory, not the <code class="docutils literal notranslate"><span class="pre">flaskr</span></code> package.</p>
|
||||
<p>Debug mode shows an interactive debugger whenever a page raises an
|
||||
exception, and restarts the server whenever you make changes to the
|
||||
code. You can leave it running and just reload the browser page as you
|
||||
follow the tutorial.</p>
|
||||
<div class="highlight-text notranslate"><div class="highlight"><pre><span></span>$ flask --app flaskr run --debug
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
<div class="literal-block-wrapper docutils container" id="id4">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/templates/blog/index.html</span></code></span><a class="headerlink" href="#id4" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-html+jinja notranslate"><div class="highlight"><pre><span></span><span class="cp">{%</span> <span class="k">extends</span> <span class="s1">'base.html'</span> <span class="cp">%}</span>
|
||||
|
||||
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">header</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">h1</span><span class="p">></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}</span>Posts<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="p"></</span><span class="nt">h1</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">if</span> <span class="nv">g.user</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">a</span> <span class="na">class</span><span class="o">=</span><span class="s">"action"</span> <span class="na">href</span><span class="o">=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">url_for</span><span class="o">(</span><span class="s1">'blog.create'</span><span class="o">)</span> <span class="cp">}}</span><span class="s">"</span><span class="p">></span>New<span class="p"></</span><span class="nt">a</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span>
|
||||
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
|
||||
|
||||
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">content</span> <span class="cp">%}</span>
|
||||
<span class="cp">{%</span> <span class="k">for</span> <span class="nv">post</span> <span class="k">in</span> <span class="nv">posts</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">article</span> <span class="na">class</span><span class="o">=</span><span class="s">"post"</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">header</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">div</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">h1</span><span class="p">></span><span class="cp">{{</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'title'</span><span class="o">]</span> <span class="cp">}}</span><span class="p"></</span><span class="nt">h1</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">"about"</span><span class="p">></span>by <span class="cp">{{</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'username'</span><span class="o">]</span> <span class="cp">}}</span> on <span class="cp">{{</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'created'</span><span class="o">]</span><span class="nv">.strftime</span><span class="o">(</span><span class="s1">'%Y-%m-%d'</span><span class="o">)</span> <span class="cp">}}</span><span class="p"></</span><span class="nt">div</span><span class="p">></span>
|
||||
<span class="p"></</span><span class="nt">div</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">if</span> <span class="nv">g.user</span><span class="o">[</span><span class="s1">'id'</span><span class="o">]</span> <span class="o">==</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'author_id'</span><span class="o">]</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">a</span> <span class="na">class</span><span class="o">=</span><span class="s">"action"</span> <span class="na">href</span><span class="o">=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">url_for</span><span class="o">(</span><span class="s1">'blog.update'</span><span class="o">,</span> <span class="nv">id</span><span class="o">=</span><span class="nv">post</span><span class="o">[</span><span class="s1">'id'</span><span class="o">])</span> <span class="cp">}}</span><span class="s">"</span><span class="p">></span>Edit<span class="p"></</span><span class="nt">a</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span>
|
||||
<span class="p"></</span><span class="nt">header</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">p</span> <span class="na">class</span><span class="o">=</span><span class="s">"body"</span><span class="p">></span><span class="cp">{{</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'body'</span><span class="o">]</span> <span class="cp">}}</span><span class="p"></</span><span class="nt">p</span><span class="p">></span>
|
||||
<span class="p"></</span><span class="nt">article</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">if</span> <span class="k">not</span> <span class="nb">loop</span><span class="nv">.last</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">hr</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span>
|
||||
<span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span>
|
||||
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
|
||||
<p>You’ll see output similar to this:</p>
|
||||
<div class="highlight-text notranslate"><div class="highlight"><pre><span></span>* Serving Flask app "flaskr"
|
||||
* Debug mode: on
|
||||
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
|
||||
* Restarting with stat
|
||||
* Debugger is active!
|
||||
* Debugger PIN: nnn-nnn-nnn
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
<p>When a user is logged in, the <code class="docutils literal notranslate"><span class="pre">header</span></code> block adds a link to the
|
||||
<code class="docutils literal notranslate"><span class="pre">create</span></code> view. When the user is the author of a post, they’ll see an
|
||||
“Edit” link to the <code class="docutils literal notranslate"><span class="pre">update</span></code> view for that post. <code class="docutils literal notranslate"><span class="pre">loop.last</span></code> is a
|
||||
special variable available inside <a class="reference external" href="https://jinja.palletsprojects.com/templates/#for">Jinja for loops</a>. It’s used to
|
||||
display a line after each post except the last one, to visually separate
|
||||
them.</p>
|
||||
</section>
|
||||
<section id="create">
|
||||
<h2>Create<a class="headerlink" href="#create" title="Link to this heading">¶</a></h2>
|
||||
<p>The <code class="docutils literal notranslate"><span class="pre">create</span></code> view works the same as the auth <code class="docutils literal notranslate"><span class="pre">register</span></code> view. Either
|
||||
the form is displayed, or the posted data is validated and the post is
|
||||
added to the database or an error is shown.</p>
|
||||
<p>The <code class="docutils literal notranslate"><span class="pre">login_required</span></code> decorator you wrote earlier is used on the blog
|
||||
views. A user must be logged in to visit these views, otherwise they
|
||||
will be redirected to the login page.</p>
|
||||
<div class="literal-block-wrapper docutils container" id="id5">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/blog.py</span></code></span><a class="headerlink" href="#id5" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="nd">@bp</span><span class="o">.</span><span class="n">route</span><span class="p">(</span><span class="s1">'/create'</span><span class="p">,</span> <span class="n">methods</span><span class="o">=</span><span class="p">(</span><span class="s1">'GET'</span><span class="p">,</span> <span class="s1">'POST'</span><span class="p">))</span>
|
||||
<span class="nd">@login_required</span>
|
||||
<span class="k">def</span><span class="w"> </span><span class="nf">create</span><span class="p">():</span>
|
||||
<span class="k">if</span> <span class="n">request</span><span class="o">.</span><span class="n">method</span> <span class="o">==</span> <span class="s1">'POST'</span><span class="p">:</span>
|
||||
<span class="n">title</span> <span class="o">=</span> <span class="n">request</span><span class="o">.</span><span class="n">form</span><span class="p">[</span><span class="s1">'title'</span><span class="p">]</span>
|
||||
<span class="n">body</span> <span class="o">=</span> <span class="n">request</span><span class="o">.</span><span class="n">form</span><span class="p">[</span><span class="s1">'body'</span><span class="p">]</span>
|
||||
<span class="n">error</span> <span class="o">=</span> <span class="kc">None</span>
|
||||
|
||||
<span class="k">if</span> <span class="ow">not</span> <span class="n">title</span><span class="p">:</span>
|
||||
<span class="n">error</span> <span class="o">=</span> <span class="s1">'Title is required.'</span>
|
||||
|
||||
<span class="k">if</span> <span class="n">error</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
|
||||
<span class="n">flash</span><span class="p">(</span><span class="n">error</span><span class="p">)</span>
|
||||
<span class="k">else</span><span class="p">:</span>
|
||||
<span class="n">db</span> <span class="o">=</span> <span class="n">get_db</span><span class="p">()</span>
|
||||
<span class="n">db</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span>
|
||||
<span class="s1">'INSERT INTO post (title, body, author_id)'</span>
|
||||
<span class="s1">' VALUES (?, ?, ?)'</span><span class="p">,</span>
|
||||
<span class="p">(</span><span class="n">title</span><span class="p">,</span> <span class="n">body</span><span class="p">,</span> <span class="n">g</span><span class="o">.</span><span class="n">user</span><span class="p">[</span><span class="s1">'id'</span><span class="p">])</span>
|
||||
<span class="p">)</span>
|
||||
<span class="n">db</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
|
||||
<span class="k">return</span> <span class="n">redirect</span><span class="p">(</span><span class="n">url_for</span><span class="p">(</span><span class="s1">'blog.index'</span><span class="p">))</span>
|
||||
|
||||
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="s1">'blog/create.html'</span><span class="p">)</span>
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
<div class="literal-block-wrapper docutils container" id="id6">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/templates/blog/create.html</span></code></span><a class="headerlink" href="#id6" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-html+jinja notranslate"><div class="highlight"><pre><span></span><span class="cp">{%</span> <span class="k">extends</span> <span class="s1">'base.html'</span> <span class="cp">%}</span>
|
||||
|
||||
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">header</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">h1</span><span class="p">></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}</span>New Post<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="p"></</span><span class="nt">h1</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
|
||||
|
||||
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">content</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">form</span> <span class="na">method</span><span class="o">=</span><span class="s">"post"</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">"title"</span><span class="p">></span>Title<span class="p"></</span><span class="nt">label</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">input</span> <span class="na">name</span><span class="o">=</span><span class="s">"title"</span> <span class="na">id</span><span class="o">=</span><span class="s">"title"</span> <span class="na">value</span><span class="o">=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">request.form</span><span class="o">[</span><span class="s1">'title'</span><span class="o">]</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">required</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">"body"</span><span class="p">></span>Body<span class="p"></</span><span class="nt">label</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">textarea</span> <span class="na">name</span><span class="o">=</span><span class="s">"body"</span> <span class="na">id</span><span class="o">=</span><span class="s">"body"</span><span class="p">></span><span class="cp">{{</span> <span class="nv">request.form</span><span class="o">[</span><span class="s1">'body'</span><span class="o">]</span> <span class="cp">}}</span><span class="p"></</span><span class="nt">textarea</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">"submit"</span> <span class="na">value</span><span class="o">=</span><span class="s">"Save"</span><span class="p">></span>
|
||||
<span class="p"></</span><span class="nt">form</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
</section>
|
||||
<section id="update">
|
||||
<h2>Update<a class="headerlink" href="#update" title="Link to this heading">¶</a></h2>
|
||||
<p>Both the <code class="docutils literal notranslate"><span class="pre">update</span></code> and <code class="docutils literal notranslate"><span class="pre">delete</span></code> views will need to fetch a <code class="docutils literal notranslate"><span class="pre">post</span></code>
|
||||
by <code class="docutils literal notranslate"><span class="pre">id</span></code> and check if the author matches the logged in user. To avoid
|
||||
duplicating code, you can write a function to get the <code class="docutils literal notranslate"><span class="pre">post</span></code> and call
|
||||
it from each view.</p>
|
||||
<div class="literal-block-wrapper docutils container" id="id7">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/blog.py</span></code></span><a class="headerlink" href="#id7" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">get_post</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="n">check_author</span><span class="o">=</span><span class="kc">True</span><span class="p">):</span>
|
||||
<span class="n">post</span> <span class="o">=</span> <span class="n">get_db</span><span class="p">()</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span>
|
||||
<span class="s1">'SELECT p.id, title, body, created, author_id, username'</span>
|
||||
<span class="s1">' FROM post p JOIN user u ON p.author_id = u.id'</span>
|
||||
<span class="s1">' WHERE p.id = ?'</span><span class="p">,</span>
|
||||
<span class="p">(</span><span class="nb">id</span><span class="p">,)</span>
|
||||
<span class="p">)</span><span class="o">.</span><span class="n">fetchone</span><span class="p">()</span>
|
||||
|
||||
<span class="k">if</span> <span class="n">post</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
|
||||
<span class="n">abort</span><span class="p">(</span><span class="mi">404</span><span class="p">,</span> <span class="sa">f</span><span class="s2">"Post id </span><span class="si">{</span><span class="nb">id</span><span class="si">}</span><span class="s2"> doesn't exist."</span><span class="p">)</span>
|
||||
|
||||
<span class="k">if</span> <span class="n">check_author</span> <span class="ow">and</span> <span class="n">post</span><span class="p">[</span><span class="s1">'author_id'</span><span class="p">]</span> <span class="o">!=</span> <span class="n">g</span><span class="o">.</span><span class="n">user</span><span class="p">[</span><span class="s1">'id'</span><span class="p">]:</span>
|
||||
<span class="n">abort</span><span class="p">(</span><span class="mi">403</span><span class="p">)</span>
|
||||
|
||||
<span class="k">return</span> <span class="n">post</span>
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
<p><a class="reference internal" href="../api.html#flask.abort" title="flask.abort"><code class="xref py py-func docutils literal notranslate"><span class="pre">abort()</span></code></a> will raise a special exception that returns an HTTP status
|
||||
code. It takes an optional message to show with the error, otherwise a
|
||||
default message is used. <code class="docutils literal notranslate"><span class="pre">404</span></code> means “Not Found”, and <code class="docutils literal notranslate"><span class="pre">403</span></code> means
|
||||
“Forbidden”. (<code class="docutils literal notranslate"><span class="pre">401</span></code> means “Unauthorized”, but you redirect to the
|
||||
login page instead of returning that status.)</p>
|
||||
<p>The <code class="docutils literal notranslate"><span class="pre">check_author</span></code> argument is defined so that the function can be
|
||||
used to get a <code class="docutils literal notranslate"><span class="pre">post</span></code> without checking the author. This would be useful
|
||||
if you wrote a view to show an individual post on a page, where the user
|
||||
doesn’t matter because they’re not modifying the post.</p>
|
||||
<div class="literal-block-wrapper docutils container" id="id8">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/blog.py</span></code></span><a class="headerlink" href="#id8" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="nd">@bp</span><span class="o">.</span><span class="n">route</span><span class="p">(</span><span class="s1">'/<int:id>/update'</span><span class="p">,</span> <span class="n">methods</span><span class="o">=</span><span class="p">(</span><span class="s1">'GET'</span><span class="p">,</span> <span class="s1">'POST'</span><span class="p">))</span>
|
||||
<span class="nd">@login_required</span>
|
||||
<span class="k">def</span><span class="w"> </span><span class="nf">update</span><span class="p">(</span><span class="nb">id</span><span class="p">):</span>
|
||||
<span class="n">post</span> <span class="o">=</span> <span class="n">get_post</span><span class="p">(</span><span class="nb">id</span><span class="p">)</span>
|
||||
|
||||
<span class="k">if</span> <span class="n">request</span><span class="o">.</span><span class="n">method</span> <span class="o">==</span> <span class="s1">'POST'</span><span class="p">:</span>
|
||||
<span class="n">title</span> <span class="o">=</span> <span class="n">request</span><span class="o">.</span><span class="n">form</span><span class="p">[</span><span class="s1">'title'</span><span class="p">]</span>
|
||||
<span class="n">body</span> <span class="o">=</span> <span class="n">request</span><span class="o">.</span><span class="n">form</span><span class="p">[</span><span class="s1">'body'</span><span class="p">]</span>
|
||||
<span class="n">error</span> <span class="o">=</span> <span class="kc">None</span>
|
||||
|
||||
<span class="k">if</span> <span class="ow">not</span> <span class="n">title</span><span class="p">:</span>
|
||||
<span class="n">error</span> <span class="o">=</span> <span class="s1">'Title is required.'</span>
|
||||
|
||||
<span class="k">if</span> <span class="n">error</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
|
||||
<span class="n">flash</span><span class="p">(</span><span class="n">error</span><span class="p">)</span>
|
||||
<span class="k">else</span><span class="p">:</span>
|
||||
<span class="n">db</span> <span class="o">=</span> <span class="n">get_db</span><span class="p">()</span>
|
||||
<span class="n">db</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span>
|
||||
<span class="s1">'UPDATE post SET title = ?, body = ?'</span>
|
||||
<span class="s1">' WHERE id = ?'</span><span class="p">,</span>
|
||||
<span class="p">(</span><span class="n">title</span><span class="p">,</span> <span class="n">body</span><span class="p">,</span> <span class="nb">id</span><span class="p">)</span>
|
||||
<span class="p">)</span>
|
||||
<span class="n">db</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
|
||||
<span class="k">return</span> <span class="n">redirect</span><span class="p">(</span><span class="n">url_for</span><span class="p">(</span><span class="s1">'blog.index'</span><span class="p">))</span>
|
||||
|
||||
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="s1">'blog/update.html'</span><span class="p">,</span> <span class="n">post</span><span class="o">=</span><span class="n">post</span><span class="p">)</span>
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
<p>Unlike the views you’ve written so far, the <code class="docutils literal notranslate"><span class="pre">update</span></code> function takes
|
||||
an argument, <code class="docutils literal notranslate"><span class="pre">id</span></code>. That corresponds to the <code class="docutils literal notranslate"><span class="pre"><int:id></span></code> in the route.
|
||||
A real URL will look like <code class="docutils literal notranslate"><span class="pre">/1/update</span></code>. Flask will capture the <code class="docutils literal notranslate"><span class="pre">1</span></code>,
|
||||
ensure it’s an <a class="reference external" href="https://docs.python.org/3/library/functions.html#int" title="(in Python v3.13)"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a>, and pass it as the <code class="docutils literal notranslate"><span class="pre">id</span></code> argument. If you
|
||||
don’t specify <code class="docutils literal notranslate"><span class="pre">int:</span></code> and instead do <code class="docutils literal notranslate"><span class="pre"><id></span></code>, it will be a string.
|
||||
To generate a URL to the update page, <a class="reference internal" href="../api.html#flask.url_for" title="flask.url_for"><code class="xref py py-func docutils literal notranslate"><span class="pre">url_for()</span></code></a> needs to be passed
|
||||
the <code class="docutils literal notranslate"><span class="pre">id</span></code> so it knows what to fill in:
|
||||
<code class="docutils literal notranslate"><span class="pre">url_for('blog.update',</span> <span class="pre">id=post['id'])</span></code>. This is also in the
|
||||
<code class="docutils literal notranslate"><span class="pre">index.html</span></code> file above.</p>
|
||||
<p>The <code class="docutils literal notranslate"><span class="pre">create</span></code> and <code class="docutils literal notranslate"><span class="pre">update</span></code> views look very similar. The main
|
||||
difference is that the <code class="docutils literal notranslate"><span class="pre">update</span></code> view uses a <code class="docutils literal notranslate"><span class="pre">post</span></code> object and an
|
||||
<code class="docutils literal notranslate"><span class="pre">UPDATE</span></code> query instead of an <code class="docutils literal notranslate"><span class="pre">INSERT</span></code>. With some clever refactoring,
|
||||
you could use one view and template for both actions, but for the
|
||||
tutorial it’s clearer to keep them separate.</p>
|
||||
<div class="literal-block-wrapper docutils container" id="id9">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/templates/blog/update.html</span></code></span><a class="headerlink" href="#id9" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-html+jinja notranslate"><div class="highlight"><pre><span></span><span class="cp">{%</span> <span class="k">extends</span> <span class="s1">'base.html'</span> <span class="cp">%}</span>
|
||||
|
||||
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">header</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">h1</span><span class="p">></span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}</span>Edit "<span class="cp">{{</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'title'</span><span class="o">]</span> <span class="cp">}}</span>"<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="p"></</span><span class="nt">h1</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
|
||||
|
||||
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">content</span> <span class="cp">%}</span>
|
||||
<span class="p"><</span><span class="nt">form</span> <span class="na">method</span><span class="o">=</span><span class="s">"post"</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">"title"</span><span class="p">></span>Title<span class="p"></</span><span class="nt">label</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">input</span> <span class="na">name</span><span class="o">=</span><span class="s">"title"</span> <span class="na">id</span><span class="o">=</span><span class="s">"title"</span>
|
||||
<span class="na">value</span><span class="o">=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">request.form</span><span class="o">[</span><span class="s1">'title'</span><span class="o">]</span> <span class="k">or</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'title'</span><span class="o">]</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">required</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">"body"</span><span class="p">></span>Body<span class="p"></</span><span class="nt">label</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">textarea</span> <span class="na">name</span><span class="o">=</span><span class="s">"body"</span> <span class="na">id</span><span class="o">=</span><span class="s">"body"</span><span class="p">></span><span class="cp">{{</span> <span class="nv">request.form</span><span class="o">[</span><span class="s1">'body'</span><span class="o">]</span> <span class="k">or</span> <span class="nv">post</span><span class="o">[</span><span class="s1">'body'</span><span class="o">]</span> <span class="cp">}}</span><span class="p"></</span><span class="nt">textarea</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">"submit"</span> <span class="na">value</span><span class="o">=</span><span class="s">"Save"</span><span class="p">></span>
|
||||
<span class="p"></</span><span class="nt">form</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">hr</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">form</span> <span class="na">action</span><span class="o">=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">url_for</span><span class="o">(</span><span class="s1">'blog.delete'</span><span class="o">,</span> <span class="nv">id</span><span class="o">=</span><span class="nv">post</span><span class="o">[</span><span class="s1">'id'</span><span class="o">])</span> <span class="cp">}}</span><span class="s">"</span> <span class="na">method</span><span class="o">=</span><span class="s">"post"</span><span class="p">></span>
|
||||
<span class="p"><</span><span class="nt">input</span> <span class="na">class</span><span class="o">=</span><span class="s">"danger"</span> <span class="na">type</span><span class="o">=</span><span class="s">"submit"</span> <span class="na">value</span><span class="o">=</span><span class="s">"Delete"</span> <span class="na">onclick</span><span class="o">=</span><span class="s">"return confirm('Are you sure?');"</span><span class="p">></span>
|
||||
<span class="p"></</span><span class="nt">form</span><span class="p">></span>
|
||||
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
<p>This template has two forms. The first posts the edited data to the
|
||||
current page (<code class="docutils literal notranslate"><span class="pre">/<id>/update</span></code>). The other form contains only a button
|
||||
and specifies an <code class="docutils literal notranslate"><span class="pre">action</span></code> attribute that posts to the delete view
|
||||
instead. The button uses some JavaScript to show a confirmation dialog
|
||||
before submitting.</p>
|
||||
<p>The pattern <code class="docutils literal notranslate"><span class="pre">{{</span> <span class="pre">request.form['title']</span> <span class="pre">or</span> <span class="pre">post['title']</span> <span class="pre">}}</span></code> is used to
|
||||
choose what data appears in the form. When the form hasn’t been
|
||||
submitted, the original <code class="docutils literal notranslate"><span class="pre">post</span></code> data appears, but if invalid form data
|
||||
was posted you want to display that so the user can fix the error, so
|
||||
<code class="docutils literal notranslate"><span class="pre">request.form</span></code> is used instead. <a class="reference internal" href="../api.html#flask.request" title="flask.request"><code class="xref py py-data docutils literal notranslate"><span class="pre">request</span></code></a> is another variable
|
||||
that’s automatically available in templates.</p>
|
||||
</section>
|
||||
<section id="delete">
|
||||
<h2>Delete<a class="headerlink" href="#delete" title="Link to this heading">¶</a></h2>
|
||||
<p>The delete view doesn’t have its own template, the delete button is part
|
||||
of <code class="docutils literal notranslate"><span class="pre">update.html</span></code> and posts to the <code class="docutils literal notranslate"><span class="pre">/<id>/delete</span></code> URL. Since there
|
||||
is no template, it will only handle the <code class="docutils literal notranslate"><span class="pre">POST</span></code> method and then redirect
|
||||
to the <code class="docutils literal notranslate"><span class="pre">index</span></code> view.</p>
|
||||
<div class="literal-block-wrapper docutils container" id="id10">
|
||||
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/blog.py</span></code></span><a class="headerlink" href="#id10" title="Link to this code">¶</a></div>
|
||||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="nd">@bp</span><span class="o">.</span><span class="n">route</span><span class="p">(</span><span class="s1">'/<int:id>/delete'</span><span class="p">,</span> <span class="n">methods</span><span class="o">=</span><span class="p">(</span><span class="s1">'POST'</span><span class="p">,))</span>
|
||||
<span class="nd">@login_required</span>
|
||||
<span class="k">def</span><span class="w"> </span><span class="nf">delete</span><span class="p">(</span><span class="nb">id</span><span class="p">):</span>
|
||||
<span class="n">get_post</span><span class="p">(</span><span class="nb">id</span><span class="p">)</span>
|
||||
<span class="n">db</span> <span class="o">=</span> <span class="n">get_db</span><span class="p">()</span>
|
||||
<span class="n">db</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="s1">'DELETE FROM post WHERE id = ?'</span><span class="p">,</span> <span class="p">(</span><span class="nb">id</span><span class="p">,))</span>
|
||||
<span class="n">db</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
|
||||
<span class="k">return</span> <span class="n">redirect</span><span class="p">(</span><span class="n">url_for</span><span class="p">(</span><span class="s1">'blog.index'</span><span class="p">))</span>
|
||||
</pre></div>
|
||||
</div>
|
||||
</div>
|
||||
<p>Congratulations, you’ve now finished writing your application! Take some
|
||||
time to try out everything in the browser. However, there’s still more
|
||||
to do before the project is complete.</p>
|
||||
<p>Continue to <a class="reference internal" href="install.html"><span class="doc">Make the Project Installable</span></a>.</p>
|
||||
<p>Visit <a class="reference external" href="http://127.0.0.1:5000/hello">http://127.0.0.1:5000/hello</a> in a browser and you should see the
|
||||
“Hello, World!” message. Congratulations, you’re now running your Flask
|
||||
web application!</p>
|
||||
<p>If another program is already using port 5000, you’ll see
|
||||
<code class="docutils literal notranslate"><span class="pre">OSError:</span> <span class="pre">[Errno</span> <span class="pre">98]</span></code> or <code class="docutils literal notranslate"><span class="pre">OSError:</span> <span class="pre">[WinError</span> <span class="pre">10013]</span></code> when the
|
||||
server tries to start. See <a class="reference internal" href="../server.html#address-already-in-use"><span class="std std-ref">Address already in use</span></a> for how to
|
||||
handle that.</p>
|
||||
<p>Continue to <a class="reference internal" href="database.html"><span class="doc">Define and Access the Database</span></a>.</p>
|
||||
</section>
|
||||
</section>
|
||||
|
||||
|
|
@ -370,21 +200,18 @@ to do before the project is complete.</p>
|
|||
<span id="sidebar-top"></span>
|
||||
<div class="sphinxsidebar" role="navigation" aria-label="Main">
|
||||
<div class="sphinxsidebarwrapper">
|
||||
|
||||
|
||||
|
||||
|
||||
<p class="logo"><a href="../index.html">
|
||||
<img class="logo" src="../_static/flask-vertical.png" alt="Logo of Flask"/>
|
||||
</a></p>
|
||||
|
||||
|
||||
|
||||
<h3>Contents</h3>
|
||||
<ul>
|
||||
<li><a class="reference internal" href="#">Blog Blueprint</a><ul>
|
||||
<li><a class="reference internal" href="#the-blueprint">The Blueprint</a></li>
|
||||
<li><a class="reference internal" href="#index">Index</a></li>
|
||||
<li><a class="reference internal" href="#create">Create</a></li>
|
||||
<li><a class="reference internal" href="#update">Update</a></li>
|
||||
<li><a class="reference internal" href="#delete">Delete</a></li>
|
||||
<li><a class="reference internal" href="#">Application Setup</a><ul>
|
||||
<li><a class="reference internal" href="#the-application-factory">The Application Factory</a></li>
|
||||
<li><a class="reference internal" href="#run-the-application">Run The Application</a></li>
|
||||
</ul>
|
||||
</li>
|
||||
</ul>
|
||||
|
|
@ -394,8 +221,8 @@ to do before the project is complete.</p>
|
|||
<ul>
|
||||
<li><a href="index.html">Tutorial</a>
|
||||
<ul>
|
||||
<li>Previous: <a href="static.html" title="previous chapter">Static Files</a>
|
||||
<li>Next: <a href="install.html" title="next chapter">Make the Project Installable</a></ul>
|
||||
<li>Previous: <a href="layout.html" title="previous chapter">Project Layout</a>
|
||||
<li>Next: <a href="database.html" title="next chapter">Define and Access the Database</a></ul>
|
||||
</li>
|
||||
</ul>
|
||||
</li>
|
||||
|
|
@ -419,4 +246,4 @@ to do before the project is complete.</p>
|
|||
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 8.1.3.
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
</html>
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue