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diff --git a/app/static/doc/flask-docs/patterns/deferredcallbacks.html b/app/static/doc/flask-docs/patterns/deferredcallbacks.html deleted file mode 100644 index 32b6b79..0000000 --- a/app/static/doc/flask-docs/patterns/deferredcallbacks.html +++ /dev/null @@ -1,180 +0,0 @@ - -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" - "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> - - -<html xmlns="http://www.w3.org/1999/xhtml"> - <head> - <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> - - <title>Deferred Request Callbacks — Flask 0.8 documentation</title> - - <link rel="stylesheet" href="../_static/flasky.css" type="text/css" /> - <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> - - <script type="text/javascript"> - var DOCUMENTATION_OPTIONS = { - URL_ROOT: '../', - VERSION: '0.8', - COLLAPSE_INDEX: false, - FILE_SUFFIX: '.html', - HAS_SOURCE: true - }; - </script> - <script type="text/javascript" src="../_static/jquery.js"></script> - <script type="text/javascript" src="../_static/underscore.js"></script> - <script type="text/javascript" src="../_static/doctools.js"></script> - <link rel="top" title="Flask 0.8 documentation" href="../index.html" /> - <link rel="up" title="Patterns for Flask" href="index.html" /> - <link rel="next" title="Deployment Options" href="../deploying/index.html" /> - <link rel="prev" title="Streaming Contents" href="streaming.html" /> - - - <link rel="apple-touch-icon" href="../_static/touch-icon.png" /> - - <link media="only screen and (max-device-width: 480px)" href="../_static/small_flask.css" type= "text/css" rel="stylesheet" /> - - </head> - <body> - <div class="related"> - <h3>Navigation</h3> - <ul> - <li class="right" style="margin-right: 10px"> - <a href="../genindex.html" title="General Index" - accesskey="I">index</a></li> - <li class="right" > - <a href="../deploying/index.html" title="Deployment Options" - accesskey="N">next</a> |</li> - <li class="right" > - <a href="streaming.html" title="Streaming Contents" - accesskey="P">previous</a> |</li> - <li><a href="../index.html">Flask 0.8 documentation</a> »</li> - <li><a href="index.html" accesskey="U">Patterns for Flask</a> »</li> - </ul> - </div> - - <div class="document"> - <div class="documentwrapper"> - <div class="bodywrapper"> - <div class="body"> - - <div class="section" id="deferred-request-callbacks"> -<span id="deferred-callbacks"></span><h1>Deferred Request Callbacks<a class="headerlink" href="#deferred-request-callbacks" title="Permalink to this headline">¶</a></h1> -<p>One of the design principles of Flask is that response objects are created -and passed down a chain of potential callbacks that can modify them or -replace them. When the request handling starts, there is no response -object yet. It is created as necessary either by a view function or by -some other component in the system.</p> -<p>But what happens if you want to modify the response at a point where the -response does not exist yet? A common example for that would be a -before-request function that wants to set a cookie on the response object.</p> -<p>One way is to avoid the situation. Very often that is possible. For -instance you can try to move that logic into an after-request callback -instead. Sometimes however moving that code there is just not a very -pleasant experience or makes code look very awkward.</p> -<p>As an alternative possibility you can attach a bunch of callback functions -to the <a class="reference internal" href="../api.html#flask.g" title="flask.g"><tt class="xref py py-data docutils literal"><span class="pre">g</span></tt></a> object and call then at the end of the request. -This way you can defer code execution from anywhere in the application.</p> -<div class="section" id="the-decorator"> -<h2>The Decorator<a class="headerlink" href="#the-decorator" title="Permalink to this headline">¶</a></h2> -<p>The following decorator is the key. It registers a function on a list on -the <a class="reference internal" href="../api.html#flask.g" title="flask.g"><tt class="xref py py-data docutils literal"><span class="pre">g</span></tt></a> object:</p> -<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">flask</span> <span class="kn">import</span> <span class="n">g</span> - -<span class="k">def</span> <span class="nf">after_this_request</span><span class="p">(</span><span class="n">f</span><span class="p">):</span> - <span class="k">if</span> <span class="ow">not</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">g</span><span class="p">,</span> <span class="s">'after_request_callbacks'</span><span class="p">):</span> - <span class="n">g</span><span class="o">.</span><span class="n">after_request_callbacks</span> <span class="o">=</span> <span class="p">[]</span> - <span class="n">g</span><span class="o">.</span><span class="n">after_request_callbacks</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">f</span><span class="p">)</span> - <span class="k">return</span> <span class="n">f</span> -</pre></div> -</div> -</div> -<div class="section" id="calling-the-deferred"> -<h2>Calling the Deferred<a class="headerlink" href="#calling-the-deferred" title="Permalink to this headline">¶</a></h2> -<p>Now you can use the <cite>after_this_request</cite> decorator to mark a function to -be called at the end of the request. But we still need to call them. For -this the following function needs to be registered as -<a class="reference internal" href="../api.html#flask.Flask.after_request" title="flask.Flask.after_request"><tt class="xref py py-meth docutils literal"><span class="pre">after_request()</span></tt></a> callback:</p> -<div class="highlight-python"><div class="highlight"><pre><span class="nd">@app.after_request</span> -<span class="k">def</span> <span class="nf">call_after_request_callbacks</span><span class="p">(</span><span class="n">response</span><span class="p">):</span> - <span class="k">for</span> <span class="n">callback</span> <span class="ow">in</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">g</span><span class="p">,</span> <span class="s">'after_request_callbacks'</span><span class="p">,</span> <span class="p">()):</span> - <span class="n">response</span> <span class="o">=</span> <span class="n">callback</span><span class="p">(</span><span class="n">response</span><span class="p">)</span> - <span class="k">return</span> <span class="n">response</span> -</pre></div> -</div> -</div> -<div class="section" id="a-practical-example"> -<h2>A Practical Example<a class="headerlink" href="#a-practical-example" title="Permalink to this headline">¶</a></h2> -<p>Now we can easily at any point in time register a function to be called at -the end of this particular request. For example you can remember the -current language of the user in a cookie in the before-request function:</p> -<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">flask</span> <span class="kn">import</span> <span class="n">request</span> - -<span class="nd">@app.before_request</span> -<span class="k">def</span> <span class="nf">detect_user_language</span><span class="p">():</span> - <span class="n">language</span> <span class="o">=</span> <span class="n">request</span><span class="o">.</span><span class="n">cookies</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s">'user_lang'</span><span class="p">)</span> - <span class="k">if</span> <span class="n">language</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span> - <span class="n">language</span> <span class="o">=</span> <span class="n">guess_language_from_request</span><span class="p">()</span> - <span class="nd">@after_this_request</span> - <span class="k">def</span> <span class="nf">remember_language</span><span class="p">(</span><span class="n">response</span><span class="p">):</span> - <span class="n">response</span><span class="o">.</span><span class="n">set_cookie</span><span class="p">(</span><span class="s">'user_lang'</span><span class="p">,</span> <span class="n">language</span><span class="p">)</span> - <span class="n">g</span><span class="o">.</span><span class="n">language</span> <span class="o">=</span> <span class="n">language</span> -</pre></div> -</div> -</div> -</div> - - - </div> - </div> - </div> - <div class="sphinxsidebar"> - <div class="sphinxsidebarwrapper"><p class="logo"><a href="../index.html"> - <img class="logo" src="../_static/flask.png" alt="Logo"/> -</a></p> - <h3><a href="../index.html">Table Of Contents</a></h3> - <ul> -<li><a class="reference internal" href="#">Deferred Request Callbacks</a><ul> -<li><a class="reference internal" href="#the-decorator">The Decorator</a></li> -<li><a class="reference internal" href="#calling-the-deferred">Calling the Deferred</a></li> -<li><a class="reference internal" href="#a-practical-example">A Practical Example</a></li> -</ul> -</li> -</ul> -<h3>Related Topics</h3> -<ul> - <li><a href="../index.html">Documentation overview</a><ul> - <li><a href="index.html">Patterns for Flask</a><ul> - <li>Previous: <a href="streaming.html" title="previous chapter">Streaming Contents</a></li> - <li>Next: <a href="../deploying/index.html" title="next chapter">Deployment Options</a></li> - </ul></li> - </ul></li> -</ul> - <h3>This Page</h3> - <ul class="this-page-menu"> - <li><a href="../_sources/patterns/deferredcallbacks.txt" - rel="nofollow">Show Source</a></li> - </ul> -<div id="searchbox" style="display: none"> - <h3>Quick search</h3> - <form class="search" action="../search.html" method="get"> - <input type="text" name="q" /> - <input type="submit" value="Go" /> - <input type="hidden" name="check_keywords" value="yes" /> - <input type="hidden" name="area" value="default" /> - </form> - <p class="searchtip" style="font-size: 90%"> - Enter search terms or a module, class or function name. - </p> -</div> -<script type="text/javascript">$('#searchbox').show(0);</script> - </div> - </div> - <div class="clearer"></div> - </div> - <div class="footer"> - © Copyright 2010, Armin Ronacher. - Created using <a href="http://sphinx.pocoo.org/">Sphinx</a>. - </div> - </body> -</html>
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