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diff --git a/app/static/doc/flask-docs/patterns/urlprocessors.html b/app/static/doc/flask-docs/patterns/urlprocessors.html new file mode 100644 index 0000000..8e50e36 --- /dev/null +++ b/app/static/doc/flask-docs/patterns/urlprocessors.html @@ -0,0 +1,237 @@ + +<!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>Using URL Processors — 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="Deploying with Distribute" href="distribute.html" /> + <link rel="prev" title="Application Dispatching" href="appdispatch.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="distribute.html" title="Deploying with Distribute" + accesskey="N">next</a> |</li> + <li class="right" > + <a href="appdispatch.html" title="Application Dispatching" + 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="using-url-processors"> +<h1>Using URL Processors<a class="headerlink" href="#using-url-processors" title="Permalink to this headline">¶</a></h1> +<p class="versionadded"> +<span class="versionmodified">New in version 0.7.</span></p> +<p>Flask 0.7 introduces the concept of URL processors. The idea is that you +might have a bunch of resources with common parts in the URL that you +don’t always explicitly want to provide. For instance you might have a +bunch of URLs that have the language code in it but you don’t want to have +to handle it in every single function yourself.</p> +<p>URL processors are especially helpful when combined with blueprints. We +will handle both application specific URL processors here as well as +blueprint specifics.</p> +<div class="section" id="internationalized-application-urls"> +<h2>Internationalized Application URLs<a class="headerlink" href="#internationalized-application-urls" title="Permalink to this headline">¶</a></h2> +<p>Consider an application like this:</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">Flask</span><span class="p">,</span> <span class="n">g</span> + +<span class="n">app</span> <span class="o">=</span> <span class="n">Flask</span><span class="p">(</span><span class="n">__name__</span><span class="p">)</span> + +<span class="nd">@app.route</span><span class="p">(</span><span class="s">'/<lang_code>/'</span><span class="p">)</span> +<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="n">lang_code</span><span class="p">):</span> + <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span> <span class="o">=</span> <span class="n">lang_code</span> + <span class="o">...</span> + +<span class="nd">@app.route</span><span class="p">(</span><span class="s">'/<lang_code>/about'</span><span class="p">)</span> +<span class="k">def</span> <span class="nf">about</span><span class="p">(</span><span class="n">lang_code</span><span class="p">):</span> + <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span> <span class="o">=</span> <span class="n">lang_code</span> + <span class="o">...</span> +</pre></div> +</div> +<p>This is an awful lot of repetition as you have to handle the language code +setting 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 yourself in every single function. +Sure, a decorator could be used to simplify this, but if you want to +generate URLs from one function to another you would have to still provide +the language code explicitly which can be annoying.</p> +<p>For the latter, this is where <a class="reference internal" href="../api.html#flask.Flask.url_defaults" title="flask.Flask.url_defaults"><tt class="xref py py-func docutils literal"><span class="pre">url_defaults()</span></tt></a> functions +come in. They can automatically inject values into a call for +<a class="reference internal" href="../api.html#flask.url_for" title="flask.url_for"><tt class="xref py py-func docutils literal"><span class="pre">url_for()</span></tt></a> automatically. The code below checks if the +language code is not yet in the dictionary of URL values and if the +endpoint wants a value named <tt class="docutils literal"><span class="pre">'lang_code'</span></tt>:</p> +<div class="highlight-python"><div class="highlight"><pre><span class="nd">@app.url_defaults</span> +<span class="k">def</span> <span class="nf">add_language_code</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="n">values</span><span class="p">):</span> + <span class="k">if</span> <span class="s">'lang_code'</span> <span class="ow">in</span> <span class="n">values</span> <span class="ow">or</span> <span class="ow">not</span> <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span><span class="p">:</span> + <span class="k">return</span> + <span class="k">if</span> <span class="n">app</span><span class="o">.</span><span class="n">url_map</span><span class="o">.</span><span class="n">is_endpoint_expecting</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="s">'lang_code'</span><span class="p">):</span> + <span class="n">values</span><span class="p">[</span><span class="s">'lang_code'</span><span class="p">]</span> <span class="o">=</span> <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span> +</pre></div> +</div> +<p>The method <a class="reference external" href="http://werkzeug.pocoo.org/docs/routing/#werkzeug.routing.Map.is_endpoint_expecting" title="(in Werkzeug v0.7)"><tt class="xref py py-meth docutils literal"><span class="pre">is_endpoint_expecting()</span></tt></a> of the URL +map can be used to figure out if it would make sense to provide a language +code for the given endpoint.</p> +<p>The reverse of that function are +<a class="reference internal" href="../api.html#flask.Flask.url_value_preprocessor" title="flask.Flask.url_value_preprocessor"><tt class="xref py py-meth docutils literal"><span class="pre">url_value_preprocessor()</span></tt></a>s. They are executed right +after the request was matched and can execute code based on the URL +values. The idea is that they pull information out of the values +dictionary and put it somewhere else:</p> +<div class="highlight-python"><div class="highlight"><pre><span class="nd">@app.url_value_preprocessor</span> +<span class="k">def</span> <span class="nf">pull_lang_code</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="n">values</span><span class="p">):</span> + <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span> <span class="o">=</span> <span class="n">values</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s">'lang_code'</span><span class="p">,</span> <span class="bp">None</span><span class="p">)</span> +</pre></div> +</div> +<p>That way you no longer have to do the <cite>lang_code</cite> assigment to +<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> in every function. You can further improve that by +writing your own decorator that prefixes URLs with the language code, but +the more beautiful solution is using a blueprint. Once the +<tt class="docutils literal"><span class="pre">'lang_code'</span></tt> is popped from the values dictionary and it will no longer +be forwarded to the view function reducing the code to this:</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">Flask</span><span class="p">,</span> <span class="n">g</span> + +<span class="n">app</span> <span class="o">=</span> <span class="n">Flask</span><span class="p">(</span><span class="n">__name__</span><span class="p">)</span> + +<span class="nd">@app.url_defaults</span> +<span class="k">def</span> <span class="nf">add_language_code</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="n">values</span><span class="p">):</span> + <span class="k">if</span> <span class="s">'lang_code'</span> <span class="ow">in</span> <span class="n">values</span> <span class="ow">or</span> <span class="ow">not</span> <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span><span class="p">:</span> + <span class="k">return</span> + <span class="k">if</span> <span class="n">app</span><span class="o">.</span><span class="n">url_map</span><span class="o">.</span><span class="n">is_endpoint_expecting</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="s">'lang_code'</span><span class="p">):</span> + <span class="n">values</span><span class="p">[</span><span class="s">'lang_code'</span><span class="p">]</span> <span class="o">=</span> <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span> + +<span class="nd">@app.url_value_preprocessor</span> +<span class="k">def</span> <span class="nf">pull_lang_code</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="n">values</span><span class="p">):</span> + <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span> <span class="o">=</span> <span class="n">values</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s">'lang_code'</span><span class="p">,</span> <span class="bp">None</span><span class="p">)</span> + +<span class="nd">@app.route</span><span class="p">(</span><span class="s">'/<lang_code>/'</span><span class="p">)</span> +<span class="k">def</span> <span class="nf">index</span><span class="p">():</span> + <span class="o">...</span> + +<span class="nd">@app.route</span><span class="p">(</span><span class="s">'/<lang_code>/about'</span><span class="p">)</span> +<span class="k">def</span> <span class="nf">about</span><span class="p">():</span> + <span class="o">...</span> +</pre></div> +</div> +</div> +<div class="section" id="internationalized-blueprint-urls"> +<h2>Internationalized Blueprint URLs<a class="headerlink" href="#internationalized-blueprint-urls" title="Permalink to this headline">¶</a></h2> +<p>Because blueprints can automatically prefix all URLs with a common string +it’s easy to automatically do that for every function. Furthermore +blueprints can have per-blueprint URL processors which removes a whole lot +of logic from the <a class="reference internal" href="../api.html#flask.Flask.url_defaults" title="flask.Flask.url_defaults"><tt class="xref py py-meth docutils literal"><span class="pre">url_defaults()</span></tt></a> function because it no +longer has to check if the URL is really interested in a <tt class="docutils literal"><span class="pre">'lang_code'</span></tt> +parameter:</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">Blueprint</span><span class="p">,</span> <span class="n">g</span> + +<span class="n">bp</span> <span class="o">=</span> <span class="n">Blueprint</span><span class="p">(</span><span class="s">'frontend'</span><span class="p">,</span> <span class="n">__name__</span><span class="p">,</span> <span class="n">url_prefix</span><span class="o">=</span><span class="s">'/<lang_code>'</span><span class="p">)</span> + +<span class="nd">@bp.url_defaults</span> +<span class="k">def</span> <span class="nf">add_language_code</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="n">values</span><span class="p">):</span> + <span class="n">values</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s">'lang_code'</span><span class="p">,</span> <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span><span class="p">)</span> + +<span class="nd">@bp.url_value_preprocessor</span> +<span class="k">def</span> <span class="nf">pull_lang_code</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="n">values</span><span class="p">):</span> + <span class="n">g</span><span class="o">.</span><span class="n">lang_code</span> <span class="o">=</span> <span class="n">values</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="s">'lang_code'</span><span class="p">)</span> + +<span class="nd">@bp.route</span><span class="p">(</span><span class="s">'/'</span><span class="p">)</span> +<span class="k">def</span> <span class="nf">index</span><span class="p">():</span> + <span class="o">...</span> + +<span class="nd">@bp.route</span><span class="p">(</span><span class="s">'/about'</span><span class="p">)</span> +<span class="k">def</span> <span class="nf">about</span><span class="p">():</span> + <span class="o">...</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="#">Using URL Processors</a><ul> +<li><a class="reference internal" href="#internationalized-application-urls">Internationalized Application URLs</a></li> +<li><a class="reference internal" href="#internationalized-blueprint-urls">Internationalized Blueprint URLs</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="appdispatch.html" title="previous chapter">Application Dispatching</a></li> + <li>Next: <a href="distribute.html" title="next chapter">Deploying with Distribute</a></li> + </ul></li> + </ul></li> +</ul> + <h3>This Page</h3> + <ul class="this-page-menu"> + <li><a href="../_sources/patterns/urlprocessors.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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