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HTML
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<li class="nav-item nav-item-this"><a href="">Working with the Shell</a></li>
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<section id="working-with-the-shell">
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<h1>Working with the Shell<a class="headerlink" href="#working-with-the-shell" title="Link to this heading">¶</a></h1>
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<details class="changelog">
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<summary>Changelog</summary><div class="versionadded">
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<p><span class="versionmodified added">Added in version 0.3.</span></p>
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</div>
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</details><p>One of the reasons everybody loves Python is the interactive shell. It
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basically allows you to execute Python commands in real time and
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immediately get results back. Flask itself does not come with an
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interactive shell, because it does not require any specific setup upfront,
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just import your application and start playing around.</p>
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<p>There are however some handy helpers to make playing around in the shell a
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more pleasant experience. The main issue with interactive console
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sessions is that you’re not triggering a request like a browser does which
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means that <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>, <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> and others are not
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available. But the code you want to test might depend on them, so what
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can you do?</p>
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<p>This is where some helper functions come in handy. Keep in mind however
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that these functions are not only there for interactive shell usage, but
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also for unit testing and other situations that require a faked request
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context.</p>
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<p>Generally it’s recommended that you read <a class="reference internal" href="reqcontext.html"><span class="doc">The Request Context</span></a> first.</p>
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<section id="command-line-interface">
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<h2>Command Line Interface<a class="headerlink" href="#command-line-interface" title="Link to this heading">¶</a></h2>
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<p>Starting with Flask 0.11 the recommended way to work with the shell is the
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<code class="docutils literal notranslate"><span class="pre">flask</span> <span class="pre">shell</span></code> command which does a lot of this automatically for you.
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For instance the shell is automatically initialized with a loaded
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application context.</p>
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<p>For more information see <a class="reference internal" href="cli.html"><span class="doc">Command Line Interface</span></a>.</p>
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</section>
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<section id="creating-a-request-context">
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<h2>Creating a Request Context<a class="headerlink" href="#creating-a-request-context" title="Link to this heading">¶</a></h2>
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<p>The easiest way to create a proper request context from the shell is by
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using the <a class="reference internal" href="api.html#flask.Flask.test_request_context" title="flask.Flask.test_request_context"><code class="xref py py-attr docutils literal notranslate"><span class="pre">test_request_context</span></code></a> method which creates
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us a <a class="reference internal" href="api.html#flask.ctx.RequestContext" title="flask.ctx.RequestContext"><code class="xref py py-class docutils literal notranslate"><span class="pre">RequestContext</span></code></a>:</p>
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<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">ctx</span> <span class="o">=</span> <span class="n">app</span><span class="o">.</span><span class="n">test_request_context</span><span class="p">()</span>
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</pre></div>
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</div>
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<p>Normally you would use the <code class="docutils literal notranslate"><span class="pre">with</span></code> statement to make this request object
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active, but in the shell it’s easier to use the
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<code class="xref py py-meth docutils literal notranslate"><span class="pre">push()</span></code> and
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<a class="reference internal" href="api.html#flask.ctx.RequestContext.pop" title="flask.ctx.RequestContext.pop"><code class="xref py py-meth docutils literal notranslate"><span class="pre">pop()</span></code></a> methods by hand:</p>
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<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">ctx</span><span class="o">.</span><span class="n">push</span><span class="p">()</span>
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</pre></div>
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</div>
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<p>From that point onwards you can work with the request object until you
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call <code class="code docutils literal notranslate"><span class="pre">pop</span></code>:</p>
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<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">ctx</span><span class="o">.</span><span class="n">pop</span><span class="p">()</span>
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</pre></div>
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</div>
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</section>
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<section id="firing-before-after-request">
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<h2>Firing Before/After Request<a class="headerlink" href="#firing-before-after-request" title="Link to this heading">¶</a></h2>
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<p>By just creating a request context, you still don’t have run the code that
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is normally run before a request. This might result in your database
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being unavailable if you are connecting to the database in a
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before-request callback or the current user not being stored on the
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<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> object etc.</p>
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<p>This however can easily be done yourself. Just call
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<a class="reference internal" href="api.html#flask.Flask.preprocess_request" title="flask.Flask.preprocess_request"><code class="xref py py-meth docutils literal notranslate"><span class="pre">preprocess_request()</span></code></a>:</p>
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<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">ctx</span> <span class="o">=</span> <span class="n">app</span><span class="o">.</span><span class="n">test_request_context</span><span class="p">()</span>
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<span class="gp">>>> </span><span class="n">ctx</span><span class="o">.</span><span class="n">push</span><span class="p">()</span>
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<span class="gp">>>> </span><span class="n">app</span><span class="o">.</span><span class="n">preprocess_request</span><span class="p">()</span>
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</pre></div>
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</div>
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<p>Keep in mind that the <a class="reference internal" href="api.html#flask.Flask.preprocess_request" title="flask.Flask.preprocess_request"><code class="xref py py-meth docutils literal notranslate"><span class="pre">preprocess_request()</span></code></a> function
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might return a response object, in that case just ignore it.</p>
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<p>To shutdown a request, you need to trick a bit before the after request
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functions (triggered by <a class="reference internal" href="api.html#flask.Flask.process_response" title="flask.Flask.process_response"><code class="xref py py-meth docutils literal notranslate"><span class="pre">process_response()</span></code></a>) operate on
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a response object:</p>
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<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">app</span><span class="o">.</span><span class="n">process_response</span><span class="p">(</span><span class="n">app</span><span class="o">.</span><span class="n">response_class</span><span class="p">())</span>
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<span class="go"><Response 0 bytes [200 OK]></span>
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<span class="gp">>>> </span><span class="n">ctx</span><span class="o">.</span><span class="n">pop</span><span class="p">()</span>
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</pre></div>
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</div>
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<p>The functions registered as <a class="reference internal" href="api.html#flask.Flask.teardown_request" title="flask.Flask.teardown_request"><code class="xref py py-meth docutils literal notranslate"><span class="pre">teardown_request()</span></code></a> are
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automatically called when the context is popped. So this is the perfect
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place to automatically tear down resources that were needed by the request
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context (such as database connections).</p>
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</section>
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<section id="further-improving-the-shell-experience">
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<h2>Further Improving the Shell Experience<a class="headerlink" href="#further-improving-the-shell-experience" title="Link to this heading">¶</a></h2>
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<p>If you like the idea of experimenting in a shell, create yourself a module
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with stuff you want to star import into your interactive session. There
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you could also define some more helper methods for common things such as
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initializing the database, dropping tables etc.</p>
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<p>Just put them into a module (like <code class="code docutils literal notranslate"><span class="pre">shelltools</span></code>) and import from there:</p>
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<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">from</span><span class="w"> </span><span class="nn">shelltools</span><span class="w"> </span><span class="kn">import</span> <span class="o">*</span>
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</pre></div>
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</div>
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</section>
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</section>
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<h3>Contents</h3>
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<ul>
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<li><a class="reference internal" href="#">Working with the Shell</a><ul>
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<li><a class="reference internal" href="#command-line-interface">Command Line Interface</a></li>
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<li><a class="reference internal" href="#creating-a-request-context">Creating a Request Context</a></li>
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<li><a class="reference internal" href="#firing-before-after-request">Firing Before/After Request</a></li>
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<li><a class="reference internal" href="#further-improving-the-shell-experience">Further Improving the Shell Experience</a></li>
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