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<!DOCTYPE html>
<html lang="en" data-content_root="../">
<html lang="en" data-content_root="./">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Templates &#8212; Flask Documentation (3.2.x)</title>
<link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=6625fa76" />
<link rel="stylesheet" type="text/css" href="../_static/flask.css?v=b87c8d14" />
<script src="../_static/documentation_options.js?v=56528222"></script>
<script src="../_static/doctools.js?v=9bcbadda"></script>
<script src="../_static/sphinx_highlight.js?v=dc90522c"></script>
<script data-project="flask" data-version="3.2.x" src="../_static/describe_version.js?v=fa7f30d0"></script>
<link rel="icon" href="../_static/shortcut-icon.png"/>
<link rel="index" title="Index" href="../genindex.html" />
<link rel="search" title="Search" href="../search.html" />
<link rel="next" title="Static Files" href="static.html" />
<link rel="prev" title="Blueprints and Views" href="views.html" />
<title>Class-based Views &#8212; Flask Documentation (3.2.x)</title>
<link rel="stylesheet" type="text/css" href="_static/pygments.css?v=6625fa76" />
<link rel="stylesheet" type="text/css" href="_static/flask.css?v=b87c8d14" />
<script src="_static/documentation_options.js?v=56528222"></script>
<script src="_static/doctools.js?v=9bcbadda"></script>
<script src="_static/sphinx_highlight.js?v=dc90522c"></script>
<script data-project="flask" data-version="3.2.x" src="_static/describe_version.js?v=fa7f30d0"></script>
<link rel="icon" href="_static/shortcut-icon.png"/>
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
<link rel="next" title="Application Structure and Lifecycle" href="lifecycle.html" />
<link rel="prev" title="Signals" href="signals.html" />
</head><body>
<div class="related" role="navigation" aria-label="Related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python Module Index"
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
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accesskey="N">next</a> |</li>
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accesskey="P">previous</a> |</li>
<li class="nav-item nav-item-0"><a href="../index.html">Flask Documentation (3.2.x)</a> &#187;</li>
<li class="nav-item nav-item-1"><a href="index.html" accesskey="U">Tutorial</a> &#187;</li>
<li class="nav-item nav-item-this"><a href="">Templates</a></li>
<li class="nav-item nav-item-0"><a href="index.html">Flask Documentation (3.2.x)</a> &#187;</li>
<li class="nav-item nav-item-this"><a href="">Class-based Views</a></li>
</ul>
</div>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<section id="templates">
<h1>Templates<a class="headerlink" href="#templates" title="Link to this heading"></a></h1>
<p>You’ve written the authentication views for your application, but if
you’re running the server and try to go to any of the URLs, you’ll see a
<code class="docutils literal notranslate"><span class="pre">TemplateNotFound</span></code> error. That’s because the views are calling
<a class="reference internal" href="../api.html#flask.render_template" title="flask.render_template"><code class="xref py py-func docutils literal notranslate"><span class="pre">render_template()</span></code></a>, but you haven’t written the templates yet.
The template files will be stored in the <code class="docutils literal notranslate"><span class="pre">templates</span></code> directory inside
the <code class="docutils literal notranslate"><span class="pre">flaskr</span></code> package.</p>
<p>Templates are files that contain static data as well as placeholders
for dynamic data. A template is rendered with specific data to produce a
final document. Flask uses the <a class="reference external" href="https://jinja.palletsprojects.com/templates/">Jinja</a> template library to render
templates.</p>
<p>In your application, you will use templates to render <a class="reference external" href="https://developer.mozilla.org/docs/Web/HTML">HTML</a> which
will display in the user’s browser. In Flask, Jinja is configured to
<em>autoescape</em> any data that is rendered in HTML templates. This means
that it’s safe to render user input; any characters they’ve entered that
could mess with the HTML, such as <code class="docutils literal notranslate"><span class="pre">&lt;</span></code> and <code class="docutils literal notranslate"><span class="pre">&gt;</span></code> will be <em>escaped</em> with
<em>safe</em> values that look the same in the browser but don’t cause unwanted
effects.</p>
<p>Jinja looks and behaves mostly like Python. Special delimiters are used
to distinguish Jinja syntax from the static data in the template.
Anything between <code class="docutils literal notranslate"><span class="pre">{{</span></code> and <code class="docutils literal notranslate"><span class="pre">}}</span></code> is an expression that will be output
to the final document. <code class="docutils literal notranslate"><span class="pre">{%</span></code> and <code class="docutils literal notranslate"><span class="pre">%}</span></code> denotes a control flow
statement like <code class="docutils literal notranslate"><span class="pre">if</span></code> and <code class="docutils literal notranslate"><span class="pre">for</span></code>. Unlike Python, blocks are denoted
by start and end tags rather than indentation since static text within
a block could change indentation.</p>
<section id="the-base-layout">
<h2>The Base Layout<a class="headerlink" href="#the-base-layout" title="Link to this heading"></a></h2>
<p>Each page in the application will have the same basic layout around a
different body. Instead of writing the entire HTML structure in each
template, each template will <em>extend</em> a base template and override
specific sections.</p>
<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/templates/base.html</span></code></span><a class="headerlink" href="#id1" title="Link to this code"></a></div>
<div class="highlight-html+jinja notranslate"><div class="highlight"><pre><span></span><span class="cp">&lt;!doctype html&gt;</span>
<span class="p">&lt;</span><span class="nt">title</span><span class="p">&gt;</span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}{%</span> <span class="k">endblock</span> <span class="cp">%}</span> - Flaskr<span class="p">&lt;/</span><span class="nt">title</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">link</span> <span class="na">rel</span><span class="o">=</span><span class="s">&quot;stylesheet&quot;</span> <span class="na">href</span><span class="o">=</span><span class="s">&quot;</span><span class="cp">{{</span> <span class="nv">url_for</span><span class="o">(</span><span class="s1">&#39;static&#39;</span><span class="o">,</span> <span class="nv">filename</span><span class="o">=</span><span class="s1">&#39;style.css&#39;</span><span class="o">)</span> <span class="cp">}}</span><span class="s">&quot;</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">nav</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">h1</span><span class="p">&gt;</span>Flaskr<span class="p">&lt;/</span><span class="nt">h1</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">ul</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">if</span> <span class="nv">g.user</span> <span class="cp">%}</span>
<span class="p">&lt;</span><span class="nt">li</span><span class="p">&gt;&lt;</span><span class="nt">span</span><span class="p">&gt;</span><span class="cp">{{</span> <span class="nv">g.user</span><span class="o">[</span><span class="s1">&#39;username&#39;</span><span class="o">]</span> <span class="cp">}}</span><span class="p">&lt;/</span><span class="nt">span</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">li</span><span class="p">&gt;&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&quot;</span><span class="cp">{{</span> <span class="nv">url_for</span><span class="o">(</span><span class="s1">&#39;auth.logout&#39;</span><span class="o">)</span> <span class="cp">}}</span><span class="s">&quot;</span><span class="p">&gt;</span>Log Out<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">else</span> <span class="cp">%}</span>
<span class="p">&lt;</span><span class="nt">li</span><span class="p">&gt;&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&quot;</span><span class="cp">{{</span> <span class="nv">url_for</span><span class="o">(</span><span class="s1">&#39;auth.register&#39;</span><span class="o">)</span> <span class="cp">}}</span><span class="s">&quot;</span><span class="p">&gt;</span>Register<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">li</span><span class="p">&gt;&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&quot;</span><span class="cp">{{</span> <span class="nv">url_for</span><span class="o">(</span><span class="s1">&#39;auth.login&#39;</span><span class="o">)</span> <span class="cp">}}</span><span class="s">&quot;</span><span class="p">&gt;</span>Log In<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span>
<span class="p">&lt;/</span><span class="nt">ul</span><span class="p">&gt;</span>
<span class="p">&lt;/</span><span class="nt">nav</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">section</span> <span class="na">class</span><span class="o">=</span><span class="s">&quot;content&quot;</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">header</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">header</span> <span class="cp">%}{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
<span class="p">&lt;/</span><span class="nt">header</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">for</span> <span class="nv">message</span> <span class="k">in</span> <span class="nv">get_flashed_messages</span><span class="o">()</span> <span class="cp">%}</span>
<span class="p">&lt;</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">&quot;flash&quot;</span><span class="p">&gt;</span><span class="cp">{{</span> <span class="nv">message</span> <span class="cp">}}</span><span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">endfor</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="k">endblock</span> <span class="cp">%}</span>
<span class="p">&lt;/</span><span class="nt">section</span><span class="p">&gt;</span>
<section id="class-based-views">
<h1>Class-based Views<a class="headerlink" href="#class-based-views" title="Link to this heading"></a></h1>
<p>This page introduces using the <a class="reference internal" href="api.html#flask.views.View" title="flask.views.View"><code class="xref py py-class docutils literal notranslate"><span class="pre">View</span></code></a> and <a class="reference internal" href="api.html#flask.views.MethodView" title="flask.views.MethodView"><code class="xref py py-class docutils literal notranslate"><span class="pre">MethodView</span></code></a>
classes to write class-based views.</p>
<p>A class-based view is a class that acts as a view function. Because it
is a class, different instances of the class can be created with
different arguments, to change the behavior of the view. This is also
known as generic, reusable, or pluggable views.</p>
<p>An example of where this is useful is defining a class that creates an
API based on the database model it is initialized with.</p>
<p>For more complex API behavior and customization, look into the various
API extensions for Flask.</p>
<section id="basic-reusable-view">
<h2>Basic Reusable View<a class="headerlink" href="#basic-reusable-view" title="Link to this heading"></a></h2>
<p>Let’s walk through an example converting a view function to a view
class. We start with a view function that queries a list of users then
renders a template to show the list.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="nd">@app</span><span class="o">.</span><span class="n">route</span><span class="p">(</span><span class="s2">&quot;/users/&quot;</span><span class="p">)</span>
<span class="k">def</span><span class="w"> </span><span class="nf">user_list</span><span class="p">():</span>
<span class="n">users</span> <span class="o">=</span> <span class="n">User</span><span class="o">.</span><span class="n">query</span><span class="o">.</span><span class="n">all</span><span class="p">()</span>
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="s2">&quot;users.html&quot;</span><span class="p">,</span> <span class="n">users</span><span class="o">=</span><span class="n">users</span><span class="p">)</span>
</pre></div>
</div>
</div>
<p><a class="reference internal" href="../api.html#flask.g" title="flask.g"><code class="xref py py-data docutils literal notranslate"><span class="pre">g</span></code></a> is automatically available in templates. Based on if
<code class="docutils literal notranslate"><span class="pre">g.user</span></code> is set (from <code class="docutils literal notranslate"><span class="pre">load_logged_in_user</span></code>), either the username
and a log out link are displayed, or links to register and log in
are displayed. <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> is also automatically available, and is
used to generate URLs to views instead of writing them out manually.</p>
<p>After the page title, and before the content, the template loops over
each message returned by <a class="reference internal" href="../api.html#flask.get_flashed_messages" title="flask.get_flashed_messages"><code class="xref py py-func docutils literal notranslate"><span class="pre">get_flashed_messages()</span></code></a>. You used
<a class="reference internal" href="../api.html#flask.flash" title="flask.flash"><code class="xref py py-func docutils literal notranslate"><span class="pre">flash()</span></code></a> in the views to show error messages, and this is the code
that will display them.</p>
<p>There are three blocks defined here that will be overridden in the other
templates:</p>
<ol class="arabic simple">
<li><p><code class="docutils literal notranslate"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">title</span> <span class="pre">%}</span></code> will change the title displayed in the
browser’s tab and window title.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">header</span> <span class="pre">%}</span></code> is similar to <code class="docutils literal notranslate"><span class="pre">title</span></code> but will change the
title displayed on the page.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">content</span> <span class="pre">%}</span></code> is where the content of each page goes, such
as the login form or a blog post.</p></li>
</ol>
<p>The base template is directly in the <code class="docutils literal notranslate"><span class="pre">templates</span></code> directory. To keep
the others organized, the templates for a blueprint will be placed in a
directory with the same name as the blueprint.</p>
</section>
<section id="register">
<h2>Register<a class="headerlink" href="#register" title="Link to this heading"></a></h2>
<div class="literal-block-wrapper docutils container" id="id2">
<div class="code-block-caption"><span class="caption-text"><code class="docutils literal notranslate"><span class="pre">flaskr/templates/auth/register.html</span></code></span><a class="headerlink" href="#id2" 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">&#39;base.html&#39;</span> <span class="cp">%}</span>
<p>This works for the user model, but let’s say you also had more models
that needed list pages. You’d need to write another view function for
each model, even though the only thing that would change is the model
and template name.</p>
<p>Instead, you can write a <a class="reference internal" href="api.html#flask.views.View" title="flask.views.View"><code class="xref py py-class docutils literal notranslate"><span class="pre">View</span></code></a> subclass that will query a model
and render a template. As the first step, we’ll convert the view to a
class without any customization.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span><span class="w"> </span><span class="nn">flask.views</span><span class="w"> </span><span class="kn">import</span> <span class="n">View</span>
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">header</span> <span class="cp">%}</span>
<span class="p">&lt;</span><span class="nt">h1</span><span class="p">&gt;</span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}</span>Register<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="p">&lt;/</span><span class="nt">h1</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
<span class="k">class</span><span class="w"> </span><span class="nc">UserList</span><span class="p">(</span><span class="n">View</span><span class="p">):</span>
<span class="k">def</span><span class="w"> </span><span class="nf">dispatch_request</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">users</span> <span class="o">=</span> <span class="n">User</span><span class="o">.</span><span class="n">query</span><span class="o">.</span><span class="n">all</span><span class="p">()</span>
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="s2">&quot;users.html&quot;</span><span class="p">,</span> <span class="n">objects</span><span class="o">=</span><span class="n">users</span><span class="p">)</span>
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">content</span> <span class="cp">%}</span>
<span class="p">&lt;</span><span class="nt">form</span> <span class="na">method</span><span class="o">=</span><span class="s">&quot;post&quot;</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">&quot;username&quot;</span><span class="p">&gt;</span>Username<span class="p">&lt;/</span><span class="nt">label</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">input</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;username&quot;</span> <span class="na">id</span><span class="o">=</span><span class="s">&quot;username&quot;</span> <span class="na">required</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">&quot;password&quot;</span><span class="p">&gt;</span>Password<span class="p">&lt;/</span><span class="nt">label</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;password&quot;</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;password&quot;</span> <span class="na">id</span><span class="o">=</span><span class="s">&quot;password&quot;</span> <span class="na">required</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;submit&quot;</span> <span class="na">value</span><span class="o">=</span><span class="s">&quot;Register&quot;</span><span class="p">&gt;</span>
<span class="p">&lt;/</span><span class="nt">form</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span><span class="s2">&quot;/users/&quot;</span><span class="p">,</span> <span class="n">view_func</span><span class="o">=</span><span class="n">UserList</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="s2">&quot;user_list&quot;</span><span class="p">))</span>
</pre></div>
</div>
<p>The <a class="reference internal" href="api.html#flask.views.View.dispatch_request" title="flask.views.View.dispatch_request"><code class="xref py py-meth docutils literal notranslate"><span class="pre">View.dispatch_request()</span></code></a> method is the equivalent of the view
function. Calling <a class="reference internal" href="api.html#flask.views.View.as_view" title="flask.views.View.as_view"><code class="xref py py-meth docutils literal notranslate"><span class="pre">View.as_view()</span></code></a> method will create a view
function that can be registered on the app with its
<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">add_url_rule()</span></code></a> method. The first argument to
<code class="docutils literal notranslate"><span class="pre">as_view</span></code> is the name to use to refer to the view with
<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>.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>You can’t decorate the class with <code class="docutils literal notranslate"><span class="pre">&#64;app.route()</span></code> the way you’d
do with a basic view function.</p>
</div>
<p><code class="docutils literal notranslate"><span class="pre">{%</span> <span class="pre">extends</span> <span class="pre">'base.html'</span> <span class="pre">%}</span></code> tells Jinja that this template should
replace the blocks from the base template. All the rendered content must
appear inside <code class="docutils literal notranslate"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">%}</span></code> tags that override blocks from the base
template.</p>
<p>A useful pattern used here is to place <code class="docutils literal notranslate"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">title</span> <span class="pre">%}</span></code> inside
<code class="docutils literal notranslate"><span class="pre">{%</span> <span class="pre">block</span> <span class="pre">header</span> <span class="pre">%}</span></code>. This will set the title block and then output
the value of it into the header block, so that both the window and page
share the same title without writing it twice.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">input</span></code> tags are using the <code class="docutils literal notranslate"><span class="pre">required</span></code> attribute here. This tells
the browser not to submit the form until those fields are filled in. If
the user is using an older browser that doesn’t support that attribute,
or if they are using something besides a browser to make requests, you
still want to validate the data in the Flask view. It’s important to
always fully validate the data on the server, even if the client does
some validation as well.</p>
</section>
<section id="log-in">
<h2>Log In<a class="headerlink" href="#log-in" title="Link to this heading"></a></h2>
<p>This is identical to the register template except for the title and
submit button.</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/templates/auth/login.html</span></code></span><a class="headerlink" href="#id3" 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">&#39;base.html&#39;</span> <span class="cp">%}</span>
<p>Next, we need to be able to register the same view class for different
models and templates, to make it more useful than the original function.
The class will take two arguments, the model and template, and store
them on <code class="docutils literal notranslate"><span class="pre">self</span></code>. Then <code class="docutils literal notranslate"><span class="pre">dispatch_request</span></code> can reference these instead
of hard-coded values.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span><span class="w"> </span><span class="nc">ListView</span><span class="p">(</span><span class="n">View</span><span class="p">):</span>
<span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">,</span> <span class="n">template</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span>
<span class="bp">self</span><span class="o">.</span><span class="n">template</span> <span class="o">=</span> <span class="n">template</span>
<span class="cp">{%</span> <span class="k">block</span> <span class="nv">header</span> <span class="cp">%}</span>
<span class="p">&lt;</span><span class="nt">h1</span><span class="p">&gt;</span><span class="cp">{%</span> <span class="k">block</span> <span class="nv">title</span> <span class="cp">%}</span>Log In<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span><span class="p">&lt;/</span><span class="nt">h1</span><span class="p">&gt;</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">&lt;</span><span class="nt">form</span> <span class="na">method</span><span class="o">=</span><span class="s">&quot;post&quot;</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">&quot;username&quot;</span><span class="p">&gt;</span>Username<span class="p">&lt;/</span><span class="nt">label</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">input</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;username&quot;</span> <span class="na">id</span><span class="o">=</span><span class="s">&quot;username&quot;</span> <span class="na">required</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">label</span> <span class="na">for</span><span class="o">=</span><span class="s">&quot;password&quot;</span><span class="p">&gt;</span>Password<span class="p">&lt;/</span><span class="nt">label</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;password&quot;</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;password&quot;</span> <span class="na">id</span><span class="o">=</span><span class="s">&quot;password&quot;</span> <span class="na">required</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;submit&quot;</span> <span class="na">value</span><span class="o">=</span><span class="s">&quot;Log In&quot;</span><span class="p">&gt;</span>
<span class="p">&lt;/</span><span class="nt">form</span><span class="p">&gt;</span>
<span class="cp">{%</span> <span class="k">endblock</span> <span class="cp">%}</span>
<span class="k">def</span><span class="w"> </span><span class="nf">dispatch_request</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">items</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">query</span><span class="o">.</span><span class="n">all</span><span class="p">()</span>
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">template</span><span class="p">,</span> <span class="n">items</span><span class="o">=</span><span class="n">items</span><span class="p">)</span>
</pre></div>
</div>
<p>Remember, we create the view function with <code class="docutils literal notranslate"><span class="pre">View.as_view()</span></code> instead of
creating the class directly. Any extra arguments passed to <code class="docutils literal notranslate"><span class="pre">as_view</span></code>
are then passed when creating the class. Now we can register the same
view to handle multiple models.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span>
<span class="s2">&quot;/users/&quot;</span><span class="p">,</span>
<span class="n">view_func</span><span class="o">=</span><span class="n">ListView</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="s2">&quot;user_list&quot;</span><span class="p">,</span> <span class="n">User</span><span class="p">,</span> <span class="s2">&quot;users.html&quot;</span><span class="p">),</span>
<span class="p">)</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span>
<span class="s2">&quot;/stories/&quot;</span><span class="p">,</span>
<span class="n">view_func</span><span class="o">=</span><span class="n">ListView</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="s2">&quot;story_list&quot;</span><span class="p">,</span> <span class="n">Story</span><span class="p">,</span> <span class="s2">&quot;stories.html&quot;</span><span class="p">),</span>
<span class="p">)</span>
</pre></div>
</div>
</section>
<section id="register-a-user">
<h2>Register A User<a class="headerlink" href="#register-a-user" title="Link to this heading"></a></h2>
<p>Now that the authentication templates are written, you can register a
user. Make sure the server is still running (<code class="docutils literal notranslate"><span class="pre">flask</span> <span class="pre">run</span></code> if it’s not),
then go to <a class="reference external" href="http://127.0.0.1:5000/auth/register">http://127.0.0.1:5000/auth/register</a>.</p>
<p>Try clicking the “Register” button without filling out the form and see
that the browser shows an error message. Try removing the <code class="docutils literal notranslate"><span class="pre">required</span></code>
attributes from the <code class="docutils literal notranslate"><span class="pre">register.html</span></code> template and click “Register”
again. Instead of the browser showing an error, the page will reload and
the error from <a class="reference internal" href="../api.html#flask.flash" title="flask.flash"><code class="xref py py-func docutils literal notranslate"><span class="pre">flash()</span></code></a> in the view will be shown.</p>
<p>Fill out a username and password and you’ll be redirected to the login
page. Try entering an incorrect username, or the correct username and
incorrect password. If you log in you’ll get an error because there’s
no <code class="docutils literal notranslate"><span class="pre">index</span></code> view to redirect to yet.</p>
<p>Continue to <a class="reference internal" href="static.html"><span class="doc">Static Files</span></a>.</p>
<section id="url-variables">
<h2>URL Variables<a class="headerlink" href="#url-variables" title="Link to this heading"></a></h2>
<p>Any variables captured by the URL are passed as keyword arguments to the
<code class="docutils literal notranslate"><span class="pre">dispatch_request</span></code> method, as they would be for a regular view
function.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span><span class="w"> </span><span class="nc">DetailView</span><span class="p">(</span><span class="n">View</span><span class="p">):</span>
<span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span>
<span class="bp">self</span><span class="o">.</span><span class="n">template</span> <span class="o">=</span> <span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">model</span><span class="o">.</span><span class="vm">__name__</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span><span class="si">}</span><span class="s2">/detail.html&quot;</span>
<span class="k">def</span><span class="w"> </span><span class="nf">dispatch_request</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="nb">id</span><span class="p">)</span>
<span class="n">item</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">query</span><span class="o">.</span><span class="n">get_or_404</span><span class="p">(</span><span class="nb">id</span><span class="p">)</span>
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">template</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="n">item</span><span class="p">)</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span>
<span class="s2">&quot;/users/&lt;int:id&gt;&quot;</span><span class="p">,</span>
<span class="n">view_func</span><span class="o">=</span><span class="n">DetailView</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="s2">&quot;user_detail&quot;</span><span class="p">,</span> <span class="n">User</span><span class="p">)</span>
<span class="p">)</span>
</pre></div>
</div>
</section>
<section id="view-lifetime-and-self">
<h2>View Lifetime and <code class="docutils literal notranslate"><span class="pre">self</span></code><a class="headerlink" href="#view-lifetime-and-self" title="Link to this heading"></a></h2>
<p>By default, a new instance of the view class is created every time a
request is handled. This means that it is safe to write other data to
<code class="docutils literal notranslate"><span class="pre">self</span></code> during the request, since the next request will not see it,
unlike other forms of global state.</p>
<p>However, if your view class needs to do a lot of complex initialization,
doing it for every request is unnecessary and can be inefficient. To
avoid this, set <a class="reference internal" href="api.html#flask.views.View.init_every_request" title="flask.views.View.init_every_request"><code class="xref py py-attr docutils literal notranslate"><span class="pre">View.init_every_request</span></code></a> to <code class="docutils literal notranslate"><span class="pre">False</span></code>, which will
only create one instance of the class and use it for every request. In
this case, writing to <code class="docutils literal notranslate"><span class="pre">self</span></code> is not safe. If you need to store data
during the request, use <a class="reference internal" href="api.html#flask.g" title="flask.g"><code class="xref py py-data docutils literal notranslate"><span class="pre">g</span></code></a> instead.</p>
<p>In the <code class="docutils literal notranslate"><span class="pre">ListView</span></code> example, nothing writes to <code class="docutils literal notranslate"><span class="pre">self</span></code> during the
request, so it is more efficient to create a single instance.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span><span class="w"> </span><span class="nc">ListView</span><span class="p">(</span><span class="n">View</span><span class="p">):</span>
<span class="n">init_every_request</span> <span class="o">=</span> <span class="kc">False</span>
<span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">,</span> <span class="n">template</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span>
<span class="bp">self</span><span class="o">.</span><span class="n">template</span> <span class="o">=</span> <span class="n">template</span>
<span class="k">def</span><span class="w"> </span><span class="nf">dispatch_request</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">items</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">query</span><span class="o">.</span><span class="n">all</span><span class="p">()</span>
<span class="k">return</span> <span class="n">render_template</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">template</span><span class="p">,</span> <span class="n">items</span><span class="o">=</span><span class="n">items</span><span class="p">)</span>
</pre></div>
</div>
<p>Different instances will still be created each for each <code class="docutils literal notranslate"><span class="pre">as_view</span></code>
call, but not for each request to those views.</p>
</section>
<section id="view-decorators">
<h2>View Decorators<a class="headerlink" href="#view-decorators" title="Link to this heading"></a></h2>
<p>The view class itself is not the view function. View decorators need to
be applied to the view function returned by <code class="docutils literal notranslate"><span class="pre">as_view</span></code>, not the class
itself. Set <a class="reference internal" href="api.html#flask.views.View.decorators" title="flask.views.View.decorators"><code class="xref py py-attr docutils literal notranslate"><span class="pre">View.decorators</span></code></a> to a list of decorators to apply.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span><span class="w"> </span><span class="nc">UserList</span><span class="p">(</span><span class="n">View</span><span class="p">):</span>
<span class="n">decorators</span> <span class="o">=</span> <span class="p">[</span><span class="n">cache</span><span class="p">(</span><span class="n">minutes</span><span class="o">=</span><span class="mi">2</span><span class="p">),</span> <span class="n">login_required</span><span class="p">]</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span><span class="s1">&#39;/users/&#39;</span><span class="p">,</span> <span class="n">view_func</span><span class="o">=</span><span class="n">UserList</span><span class="o">.</span><span class="n">as_view</span><span class="p">())</span>
</pre></div>
</div>
<p>If you didn’t set <code class="docutils literal notranslate"><span class="pre">decorators</span></code>, you could apply them manually instead.
This is equivalent to:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">view</span> <span class="o">=</span> <span class="n">UserList</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="s2">&quot;users_list&quot;</span><span class="p">)</span>
<span class="n">view</span> <span class="o">=</span> <span class="n">cache</span><span class="p">(</span><span class="n">minutes</span><span class="o">=</span><span class="mi">2</span><span class="p">)(</span><span class="n">view</span><span class="p">)</span>
<span class="n">view</span> <span class="o">=</span> <span class="n">login_required</span><span class="p">(</span><span class="n">view</span><span class="p">)</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span><span class="s1">&#39;/users/&#39;</span><span class="p">,</span> <span class="n">view_func</span><span class="o">=</span><span class="n">view</span><span class="p">)</span>
</pre></div>
</div>
<p>Keep in mind that order matters. If you’re used to <code class="docutils literal notranslate"><span class="pre">&#64;decorator</span></code> style,
this is equivalent to:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="nd">@app</span><span class="o">.</span><span class="n">route</span><span class="p">(</span><span class="s2">&quot;/users/&quot;</span><span class="p">)</span>
<span class="nd">@login_required</span>
<span class="nd">@cache</span><span class="p">(</span><span class="n">minutes</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span>
<span class="k">def</span><span class="w"> </span><span class="nf">user_list</span><span class="p">():</span>
<span class="o">...</span>
</pre></div>
</div>
</section>
<section id="method-hints">
<h2>Method Hints<a class="headerlink" href="#method-hints" title="Link to this heading"></a></h2>
<p>A common pattern is to register a view with <code class="docutils literal notranslate"><span class="pre">methods=[&quot;GET&quot;,</span> <span class="pre">&quot;POST&quot;]</span></code>,
then check <code class="docutils literal notranslate"><span class="pre">request.method</span> <span class="pre">==</span> <span class="pre">&quot;POST&quot;</span></code> to decide what to do. Setting
<a class="reference internal" href="api.html#flask.views.View.methods" title="flask.views.View.methods"><code class="xref py py-attr docutils literal notranslate"><span class="pre">View.methods</span></code></a> is equivalent to passing the list of methods to
<code class="docutils literal notranslate"><span class="pre">add_url_rule</span></code> or <code class="docutils literal notranslate"><span class="pre">route</span></code>.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span><span class="w"> </span><span class="nc">MyView</span><span class="p">(</span><span class="n">View</span><span class="p">):</span>
<span class="n">methods</span> <span class="o">=</span> <span class="p">[</span><span class="s2">&quot;GET&quot;</span><span class="p">,</span> <span class="s2">&quot;POST&quot;</span><span class="p">]</span>
<span class="k">def</span><span class="w"> </span><span class="nf">dispatch_request</span><span class="p">(</span><span class="bp">self</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="s2">&quot;POST&quot;</span><span class="p">:</span>
<span class="o">...</span>
<span class="o">...</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span><span class="s1">&#39;/my-view&#39;</span><span class="p">,</span> <span class="n">view_func</span><span class="o">=</span><span class="n">MyView</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="s1">&#39;my-view&#39;</span><span class="p">))</span>
</pre></div>
</div>
<p>This is equivalent to the following, except further subclasses can
inherit or change the methods.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span>
<span class="s2">&quot;/my-view&quot;</span><span class="p">,</span>
<span class="n">view_func</span><span class="o">=</span><span class="n">MyView</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="s2">&quot;my-view&quot;</span><span class="p">),</span>
<span class="n">methods</span><span class="o">=</span><span class="p">[</span><span class="s2">&quot;GET&quot;</span><span class="p">,</span> <span class="s2">&quot;POST&quot;</span><span class="p">],</span>
<span class="p">)</span>
</pre></div>
</div>
</section>
<section id="method-dispatching-and-apis">
<h2>Method Dispatching and APIs<a class="headerlink" href="#method-dispatching-and-apis" title="Link to this heading"></a></h2>
<p>For APIs it can be helpful to use a different function for each HTTP
method. <a class="reference internal" href="api.html#flask.views.MethodView" title="flask.views.MethodView"><code class="xref py py-class docutils literal notranslate"><span class="pre">MethodView</span></code></a> extends the basic <a class="reference internal" href="api.html#flask.views.View" title="flask.views.View"><code class="xref py py-class docutils literal notranslate"><span class="pre">View</span></code></a> to dispatch
to different methods of the class based on the request method. Each HTTP
method maps to a method of the class with the same (lowercase) name.</p>
<p><a class="reference internal" href="api.html#flask.views.MethodView" title="flask.views.MethodView"><code class="xref py py-class docutils literal notranslate"><span class="pre">MethodView</span></code></a> automatically sets <a class="reference internal" href="api.html#flask.views.View.methods" title="flask.views.View.methods"><code class="xref py py-attr docutils literal notranslate"><span class="pre">View.methods</span></code></a> based on the
methods defined by the class. It even knows how to handle subclasses
that override or define other methods.</p>
<p>We can make a generic <code class="docutils literal notranslate"><span class="pre">ItemAPI</span></code> class that provides get (detail),
patch (edit), and delete methods for a given model. A <code class="docutils literal notranslate"><span class="pre">GroupAPI</span></code> can
provide get (list) and post (create) methods.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span><span class="w"> </span><span class="nn">flask.views</span><span class="w"> </span><span class="kn">import</span> <span class="n">MethodView</span>
<span class="k">class</span><span class="w"> </span><span class="nc">ItemAPI</span><span class="p">(</span><span class="n">MethodView</span><span class="p">):</span>
<span class="n">init_every_request</span> <span class="o">=</span> <span class="kc">False</span>
<span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span>
<span class="bp">self</span><span class="o">.</span><span class="n">validator</span> <span class="o">=</span> <span class="n">generate_validator</span><span class="p">(</span><span class="n">model</span><span class="p">)</span>
<span class="k">def</span><span class="w"> </span><span class="nf">_get_item</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="nb">id</span><span class="p">):</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">query</span><span class="o">.</span><span class="n">get_or_404</span><span class="p">(</span><span class="nb">id</span><span class="p">)</span>
<span class="k">def</span><span class="w"> </span><span class="nf">get</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="nb">id</span><span class="p">):</span>
<span class="n">item</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_get_item</span><span class="p">(</span><span class="nb">id</span><span class="p">)</span>
<span class="k">return</span> <span class="n">jsonify</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">to_json</span><span class="p">())</span>
<span class="k">def</span><span class="w"> </span><span class="nf">patch</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="nb">id</span><span class="p">):</span>
<span class="n">item</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_get_item</span><span class="p">(</span><span class="nb">id</span><span class="p">)</span>
<span class="n">errors</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">validator</span><span class="o">.</span><span class="n">validate</span><span class="p">(</span><span class="n">item</span><span class="p">,</span> <span class="n">request</span><span class="o">.</span><span class="n">json</span><span class="p">)</span>
<span class="k">if</span> <span class="n">errors</span><span class="p">:</span>
<span class="k">return</span> <span class="n">jsonify</span><span class="p">(</span><span class="n">errors</span><span class="p">),</span> <span class="mi">400</span>
<span class="n">item</span><span class="o">.</span><span class="n">update_from_json</span><span class="p">(</span><span class="n">request</span><span class="o">.</span><span class="n">json</span><span class="p">)</span>
<span class="n">db</span><span class="o">.</span><span class="n">session</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="k">return</span> <span class="n">jsonify</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">to_json</span><span class="p">())</span>
<span class="k">def</span><span class="w"> </span><span class="nf">delete</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="nb">id</span><span class="p">):</span>
<span class="n">item</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_get_item</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">session</span><span class="o">.</span><span class="n">delete</span><span class="p">(</span><span class="n">item</span><span class="p">)</span>
<span class="n">db</span><span class="o">.</span><span class="n">session</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="k">return</span> <span class="s2">&quot;&quot;</span><span class="p">,</span> <span class="mi">204</span>
<span class="k">class</span><span class="w"> </span><span class="nc">GroupAPI</span><span class="p">(</span><span class="n">MethodView</span><span class="p">):</span>
<span class="n">init_every_request</span> <span class="o">=</span> <span class="kc">False</span>
<span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span>
<span class="bp">self</span><span class="o">.</span><span class="n">validator</span> <span class="o">=</span> <span class="n">generate_validator</span><span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="n">create</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="k">def</span><span class="w"> </span><span class="nf">get</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">items</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">query</span><span class="o">.</span><span class="n">all</span><span class="p">()</span>
<span class="k">return</span> <span class="n">jsonify</span><span class="p">([</span><span class="n">item</span><span class="o">.</span><span class="n">to_json</span><span class="p">()</span> <span class="k">for</span> <span class="n">item</span> <span class="ow">in</span> <span class="n">items</span><span class="p">])</span>
<span class="k">def</span><span class="w"> </span><span class="nf">post</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">errors</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">validator</span><span class="o">.</span><span class="n">validate</span><span class="p">(</span><span class="n">request</span><span class="o">.</span><span class="n">json</span><span class="p">)</span>
<span class="k">if</span> <span class="n">errors</span><span class="p">:</span>
<span class="k">return</span> <span class="n">jsonify</span><span class="p">(</span><span class="n">errors</span><span class="p">),</span> <span class="mi">400</span>
<span class="n">db</span><span class="o">.</span><span class="n">session</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">from_json</span><span class="p">(</span><span class="n">request</span><span class="o">.</span><span class="n">json</span><span class="p">))</span>
<span class="n">db</span><span class="o">.</span><span class="n">session</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="k">return</span> <span class="n">jsonify</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">to_json</span><span class="p">())</span>
<span class="k">def</span><span class="w"> </span><span class="nf">register_api</span><span class="p">(</span><span class="n">app</span><span class="p">,</span> <span class="n">model</span><span class="p">,</span> <span class="n">name</span><span class="p">):</span>
<span class="n">item</span> <span class="o">=</span> <span class="n">ItemAPI</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s2">-item&quot;</span><span class="p">,</span> <span class="n">model</span><span class="p">)</span>
<span class="n">group</span> <span class="o">=</span> <span class="n">GroupAPI</span><span class="o">.</span><span class="n">as_view</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s2">-group&quot;</span><span class="p">,</span> <span class="n">model</span><span class="p">)</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;/</span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s2">/&lt;int:id&gt;&quot;</span><span class="p">,</span> <span class="n">view_func</span><span class="o">=</span><span class="n">item</span><span class="p">)</span>
<span class="n">app</span><span class="o">.</span><span class="n">add_url_rule</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;/</span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s2">/&quot;</span><span class="p">,</span> <span class="n">view_func</span><span class="o">=</span><span class="n">group</span><span class="p">)</span>
<span class="n">register_api</span><span class="p">(</span><span class="n">app</span><span class="p">,</span> <span class="n">User</span><span class="p">,</span> <span class="s2">&quot;users&quot;</span><span class="p">)</span>
<span class="n">register_api</span><span class="p">(</span><span class="n">app</span><span class="p">,</span> <span class="n">Story</span><span class="p">,</span> <span class="s2">&quot;stories&quot;</span><span class="p">)</span>
</pre></div>
</div>
<p>This produces the following views, a standard REST API!</p>
<table class="docutils align-default">
<tbody>
<tr class="row-odd"><td><p>URL</p></td>
<td><p>Method</p></td>
<td><p>Description</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">/users/</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">GET</span></code></p></td>
<td><p>List all users</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">/users/</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">POST</span></code></p></td>
<td><p>Create a new user</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">/users/&lt;id&gt;</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">GET</span></code></p></td>
<td><p>Show a single user</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">/users/&lt;id&gt;</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">PATCH</span></code></p></td>
<td><p>Update a user</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">/users/&lt;id&gt;</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">DELETE</span></code></p></td>
<td><p>Delete a user</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">/stories/</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">GET</span></code></p></td>
<td><p>List all stories</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">/stories/</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">POST</span></code></p></td>
<td><p>Create a new story</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">/stories/&lt;id&gt;</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">GET</span></code></p></td>
<td><p>Show a single story</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">/stories/&lt;id&gt;</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">PATCH</span></code></p></td>
<td><p>Update a story</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">/stories/&lt;id&gt;</span></code></p></td>
<td><p><code class="docutils literal notranslate"><span class="pre">DELETE</span></code></p></td>
<td><p>Delete a story</p></td>
</tr>
</tbody>
</table>
</section>
</section>
@ -217,39 +366,38 @@ no <code class="docutils literal notranslate"><span class="pre">index</span></co
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<h3>Contents</h3>
<ul>
<li><a class="reference internal" href="#">Templates</a><ul>
<li><a class="reference internal" href="#the-base-layout">The Base Layout</a></li>
<li><a class="reference internal" href="#register">Register</a></li>
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