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<div class="section" id="basics">
<span id="id1"></span><h1><a class="toc-backref" href="#id4">Basics</a><a class="headerlink" href="#basics" title="Permalink to this headline">¶</a></h1>
<p>The following sections will drive you through the basics of
a CherryPy application, introducing some essential concepts.</p>
<div class="contents topic" id="contents">
<p class="topic-title first">Contents</p>
<ul class="simple">
<li><a class="reference internal" href="#basics" id="id4">Basics</a><ul>
<li><a class="reference internal" href="#the-one-minute-application-example" id="id5">The one-minute application example</a></li>
<li><a class="reference internal" href="#hosting-one-or-more-applications" id="id6">Hosting one or more applications</a><ul>
<li><a class="reference internal" href="#single-application" id="id7">Single application</a></li>
<li><a class="reference internal" href="#multiple-applications" id="id8">Multiple applications</a></li>
</ul>
</li>
<li><a class="reference internal" href="#logging" id="id9">Logging</a><ul>
<li><a class="reference internal" href="#disable-logging" id="id10">Disable logging</a></li>
<li><a class="reference internal" href="#play-along-with-your-other-loggers" id="id11">Play along with your other loggers</a></li>
</ul>
</li>
<li><a class="reference internal" href="#configuring" id="id12">Configuring</a><ul>
<li><a class="reference internal" href="#global-server-configuration" id="id13">Global server configuration</a></li>
<li><a class="reference internal" href="#per-application-configuration" id="id14">Per-application configuration</a></li>
<li><a class="reference internal" href="#additional-application-settings" id="id15">Additional application settings</a></li>
</ul>
</li>
<li><a class="reference internal" href="#cookies" id="id16">Cookies</a></li>
<li><a class="reference internal" href="#using-sessions" id="id17">Using sessions</a><ul>
<li><a class="reference internal" href="#filesystem-backend" id="id18">Filesystem backend</a></li>
<li><a class="reference internal" href="#memcached-backend" id="id19">Memcached backend</a></li>
<li><a class="reference internal" href="#other-backends" id="id20">Other backends</a></li>
</ul>
</li>
<li><a class="reference internal" href="#static-content-serving" id="id21">Static content serving</a><ul>
<li><a class="reference internal" href="#serving-a-single-file" id="id22">Serving a single file</a></li>
<li><a class="reference internal" href="#serving-a-whole-directory" id="id23">Serving a whole directory</a></li>
<li><a class="reference internal" href="#specifying-an-index-file" id="id24">Specifying an index file</a></li>
<li><a class="reference internal" href="#allow-files-downloading" id="id25">Allow files downloading</a></li>
</ul>
</li>
<li><a class="reference internal" href="#dealing-with-json" id="id26">Dealing with JSON</a><ul>
<li><a class="reference internal" href="#decoding-request" id="id27">Decoding request</a></li>
<li><a class="reference internal" href="#encoding-response" id="id28">Encoding response</a></li>
</ul>
</li>
<li><a class="reference internal" href="#authentication" id="id29">Authentication</a><ul>
<li><a class="reference internal" href="#basic" id="id30">Basic</a></li>
<li><a class="reference internal" href="#digest" id="id31">Digest</a></li>
</ul>
</li>
<li><a class="reference internal" href="#favicon" id="id32">Favicon</a></li>
</ul>
</li>
</ul>
</div>
<div class="section" id="the-one-minute-application-example">
<h2><a class="toc-backref" href="#id5">The one-minute application example</a><a class="headerlink" href="#the-one-minute-application-example" title="Permalink to this headline">¶</a></h2>
<p>The most basic application you can write with CherryPy
involves almost all its core concepts.</p>
<div class="highlight-python"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre>1
2
3
4
5
6
7
8
9</pre></div></td><td class="code"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">cherrypy</span>
<span class="k">class</span> <span class="nc">Root</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s2">"Hello World!"</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">Root</span><span class="p">(),</span> <span class="s1">'/'</span><span class="p">)</span>
</pre></div>
</td></tr></table></div>
<p>First and foremost, for most tasks, you will never need more than
a single import statement as demonstrated in line 1.</p>
<p>Before discussing the meat, let’s jump to line 9 which shows,
how to host your application with the CherryPy application server
and serve it with its builtin HTTP server at the <cite>‘/’</cite> path.
All in one single line. Not bad.</p>
<p>Let’s now step back to the actual application. Even though CherryPy
does not mandate it, most of the time your applications
will be written as Python classes. Methods of those classes will
be called by CherryPy to respond to client requests. However,
CherryPy needs to be aware that a method can be used that way, we
say the method needs to be <a class="reference internal" href="glossary.html#term-exposed"><span class="xref std std-term">exposed</span></a>. This is precisely
what the <code class="xref py py-func docutils literal"><span class="pre">cherrypy.expose()</span></code> decorator does in line 4.</p>
<p>Save the snippet in a file named <cite>myapp.py</cite> and run your first
CherryPy application:</p>
<div class="highlight-bash"><div class="highlight"><pre><span></span>$ python myapp.py
</pre></div>
</div>
<p>Then point your browser at <a class="reference external" href="http://127.0.0.1:8080">http://127.0.0.1:8080</a>. Tada!</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>CherryPy is a small framework that focuses on one single task:
take a HTTP request and locate the most appropriate
Python function or method that match the request’s URL.
Unlike other well-known frameworks, CherryPy does not
provide a built-in support for database access, HTML
templating or any other middleware nifty features.</p>
<p>In a nutshell, once CherryPy has found and called an
<a class="reference internal" href="glossary.html#term-exposed"><span class="xref std std-term">exposed</span></a> method, it is up to you, as a developer, to
provide the tools to implement your application’s logic.</p>
<p class="last">CherryPy takes the opinion that you, the developer, know best.</p>
</div>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">The previous example demonstrated the simplicty of the
CherryPy interface but, your application will likely
contain a few other bits and pieces: static service,
more complex structure, database access, etc.
This will be developed in the tutorial section.</p>
</div>
<p>CherryPy is a minimal framework but not a bare one, it comes
with a few basic tools to cover common usages that you would
expect.</p>
</div>
<div class="section" id="hosting-one-or-more-applications">
<h2><a class="toc-backref" href="#id6">Hosting one or more applications</a><a class="headerlink" href="#hosting-one-or-more-applications" title="Permalink to this headline">¶</a></h2>
<p>A web application needs an HTTP server to be accessed to. CherryPy
provides its own, production ready, HTTP server. There are two
ways to host an application with it. The simple one and the almost-as-simple one.</p>
<div class="section" id="single-application">
<h3><a class="toc-backref" href="#id7">Single application</a><a class="headerlink" href="#single-application" title="Permalink to this headline">¶</a></h3>
<p>The most straightforward way is to use <code class="xref py py-func docutils literal"><span class="pre">cherrypy.quickstart()</span></code>
function. It takes at least one argument, the instance of the
application to host. Two other settings are optionals. First, the
base path at which the application will be accessible from. Second,
a config dictionary or file to configure your application.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">Blog</span><span class="p">())</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">Blog</span><span class="p">(),</span> <span class="s1">'/blog'</span><span class="p">)</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">Blog</span><span class="p">(),</span> <span class="s1">'/blog'</span><span class="p">,</span> <span class="p">{</span><span class="s1">'/'</span><span class="p">:</span> <span class="p">{</span><span class="s1">'tools.gzip.on'</span><span class="p">:</span> <span class="bp">True</span><span class="p">}})</span>
</pre></div>
</div>
<p>The first one means that your application will be available at
<a class="reference external" href="http://hostname:port/">http://hostname:port/</a> whereas the other two will make your blog
application available at <a class="reference external" href="http://hostname:port/blog">http://hostname:port/blog</a>. In addition,
the last one provides specific settings for the application.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Notice in the third case how the settings are still
relative to the application, not where it is made available at,
hence the <cite>{‘/’: … }</cite> rather than a <cite>{‘/blog’: … }</cite></p>
</div>
</div>
<div class="section" id="multiple-applications">
<h3><a class="toc-backref" href="#id8">Multiple applications</a><a class="headerlink" href="#multiple-applications" title="Permalink to this headline">¶</a></h3>
<p>The <code class="xref py py-func docutils literal"><span class="pre">cherrypy.quickstart()</span></code> approach is fine for a single application,
but lacks the capacity to host several applications with the server.
To achieve this, one must use the <code class="xref py py-meth docutils literal"><span class="pre">cherrypy.tree.mount</span></code>
function as follows:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">tree</span><span class="o">.</span><span class="n">mount</span><span class="p">(</span><span class="n">Blog</span><span class="p">(),</span> <span class="s1">'/blog'</span><span class="p">,</span> <span class="n">blog_conf</span><span class="p">)</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">tree</span><span class="o">.</span><span class="n">mount</span><span class="p">(</span><span class="n">Forum</span><span class="p">(),</span> <span class="s1">'/forum'</span><span class="p">,</span> <span class="n">forum_conf</span><span class="p">)</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">engine</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">engine</span><span class="o">.</span><span class="n">block</span><span class="p">()</span>
</pre></div>
</div>
<p>Essentially, <code class="xref py py-meth docutils literal"><span class="pre">cherrypy.tree.mount</span></code>
takes the same parameters as <code class="xref py py-func docutils literal"><span class="pre">cherrypy.quickstart()</span></code>: an <a class="reference internal" href="glossary.html#term-application"><span class="xref std std-term">application</span></a>,
a hosting path segment and a configuration. The last two lines
are simply starting application server.</p>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p><code class="xref py py-func docutils literal"><span class="pre">cherrypy.quickstart()</span></code> and <code class="xref py py-meth docutils literal"><span class="pre">cherrypy.tree.mount</span></code>
are not exclusive. For instance, the previous lines can be written as:</p>
<div class="last highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">tree</span><span class="o">.</span><span class="n">mount</span><span class="p">(</span><span class="n">Blog</span><span class="p">(),</span> <span class="s1">'/blog'</span><span class="p">,</span> <span class="n">blog_conf</span><span class="p">)</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">Forum</span><span class="p">(),</span> <span class="s1">'/forum'</span><span class="p">,</span> <span class="n">forum_conf</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">You can also <a class="reference internal" href="advanced.html#hostwsgiapp"><span class="std std-ref">host foreign WSGI application</span></a>.</p>
</div>
</div>
</div>
<div class="section" id="logging">
<h2><a class="toc-backref" href="#id9">Logging</a><a class="headerlink" href="#logging" title="Permalink to this headline">¶</a></h2>
<p>Logging is an important task in any application. CherryPy will
log all incoming requests as well as protocol errors.</p>
<p>To do so, CherryPy manages two loggers:</p>
<ul class="simple">
<li>an access one that logs every incoming requests</li>
<li>an application/error log that traces errors or other application-level messages</li>
</ul>
<p>Your application may leverage that second logger by calling
<code class="xref py py-func docutils literal"><span class="pre">cherrypy.log()</span></code>.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">"hello there"</span><span class="p">)</span>
</pre></div>
</div>
<p>You can also log an exception:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">try</span><span class="p">:</span>
<span class="o">...</span>
<span class="k">except</span><span class="p">:</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">"kaboom!"</span><span class="p">,</span> <span class="n">traceback</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
</pre></div>
</div>
<p>Both logs are writing to files identified by the following keys
in your configuration:</p>
<ul class="simple">
<li><code class="docutils literal"><span class="pre">log.access_file</span></code> for incoming requests using the
<a class="reference external" href="http://en.wikipedia.org/wiki/Common_Log_Format">common log format</a></li>
<li><code class="docutils literal"><span class="pre">log.error_file</span></code> for the other log</li>
</ul>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">Refer to the <code class="xref py py-mod docutils literal"><span class="pre">cherrypy._cplogging</span></code> module for more
details about CherryPy’s logging architecture.</p>
</div>
<div class="section" id="disable-logging">
<h3><a class="toc-backref" href="#id10">Disable logging</a><a class="headerlink" href="#disable-logging" title="Permalink to this headline">¶</a></h3>
<p>You may be interested in disabling either logs.</p>
<p>To disable file logging, simply set a en empty string to the
<code class="docutils literal"><span class="pre">log.access_file</span></code> or <code class="docutils literal"><span class="pre">log.error_file</span></code> keys in your
<a class="reference internal" href="#globalsettings"><span class="std std-ref">global configuration</span></a>.</p>
<p>To disable, console logging, set <code class="docutils literal"><span class="pre">log.screen</span></code> to <cite>False</cite>.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">update</span><span class="p">({</span><span class="s1">'log.screen'</span><span class="p">:</span> <span class="bp">False</span><span class="p">,</span>
<span class="s1">'log.access_file'</span><span class="p">:</span> <span class="s1">''</span><span class="p">,</span>
<span class="s1">'log.error_file'</span><span class="p">:</span> <span class="s1">''</span><span class="p">})</span>
</pre></div>
</div>
</div>
<div class="section" id="play-along-with-your-other-loggers">
<h3><a class="toc-backref" href="#id11">Play along with your other loggers</a><a class="headerlink" href="#play-along-with-your-other-loggers" title="Permalink to this headline">¶</a></h3>
<p>Your application may obviously already use the <code class="xref py py-mod docutils literal"><span class="pre">logging</span></code>
module to trace application level messages. Below is a simple
example on setting it up.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">logging</span>
<span class="kn">import</span> <span class="nn">logging.config</span>
<span class="kn">import</span> <span class="nn">cherrypy</span>
<span class="n">logger</span> <span class="o">=</span> <span class="n">logging</span><span class="o">.</span><span class="n">getLogger</span><span class="p">()</span>
<span class="n">db_logger</span> <span class="o">=</span> <span class="n">logging</span><span class="o">.</span><span class="n">getLogger</span><span class="p">(</span><span class="s1">'db'</span><span class="p">)</span>
<span class="n">LOG_CONF</span> <span class="o">=</span> <span class="p">{</span>
<span class="s1">'version'</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span>
<span class="s1">'formatters'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'void'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'format'</span><span class="p">:</span> <span class="s1">''</span>
<span class="p">},</span>
<span class="s1">'standard'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'format'</span><span class="p">:</span> <span class="s1">'</span><span class="si">%(asctime)s</span><span class="s1"> [</span><span class="si">%(levelname)s</span><span class="s1">] </span><span class="si">%(name)s</span><span class="s1">: </span><span class="si">%(message)s</span><span class="s1">'</span>
<span class="p">},</span>
<span class="p">},</span>
<span class="s1">'handlers'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'default'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'level'</span><span class="p">:</span><span class="s1">'INFO'</span><span class="p">,</span>
<span class="s1">'class'</span><span class="p">:</span><span class="s1">'logging.StreamHandler'</span><span class="p">,</span>
<span class="s1">'formatter'</span><span class="p">:</span> <span class="s1">'standard'</span><span class="p">,</span>
<span class="s1">'stream'</span><span class="p">:</span> <span class="s1">'ext://sys.stdout'</span>
<span class="p">},</span>
<span class="s1">'cherrypy_console'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'level'</span><span class="p">:</span><span class="s1">'INFO'</span><span class="p">,</span>
<span class="s1">'class'</span><span class="p">:</span><span class="s1">'logging.StreamHandler'</span><span class="p">,</span>
<span class="s1">'formatter'</span><span class="p">:</span> <span class="s1">'void'</span><span class="p">,</span>
<span class="s1">'stream'</span><span class="p">:</span> <span class="s1">'ext://sys.stdout'</span>
<span class="p">},</span>
<span class="s1">'cherrypy_access'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'level'</span><span class="p">:</span><span class="s1">'INFO'</span><span class="p">,</span>
<span class="s1">'class'</span><span class="p">:</span> <span class="s1">'logging.handlers.RotatingFileHandler'</span><span class="p">,</span>
<span class="s1">'formatter'</span><span class="p">:</span> <span class="s1">'void'</span><span class="p">,</span>
<span class="s1">'filename'</span><span class="p">:</span> <span class="s1">'access.log'</span><span class="p">,</span>
<span class="s1">'maxBytes'</span><span class="p">:</span> <span class="mi">10485760</span><span class="p">,</span>
<span class="s1">'backupCount'</span><span class="p">:</span> <span class="mi">20</span><span class="p">,</span>
<span class="s1">'encoding'</span><span class="p">:</span> <span class="s1">'utf8'</span>
<span class="p">},</span>
<span class="s1">'cherrypy_error'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'level'</span><span class="p">:</span><span class="s1">'INFO'</span><span class="p">,</span>
<span class="s1">'class'</span><span class="p">:</span> <span class="s1">'logging.handlers.RotatingFileHandler'</span><span class="p">,</span>
<span class="s1">'formatter'</span><span class="p">:</span> <span class="s1">'void'</span><span class="p">,</span>
<span class="s1">'filename'</span><span class="p">:</span> <span class="s1">'errors.log'</span><span class="p">,</span>
<span class="s1">'maxBytes'</span><span class="p">:</span> <span class="mi">10485760</span><span class="p">,</span>
<span class="s1">'backupCount'</span><span class="p">:</span> <span class="mi">20</span><span class="p">,</span>
<span class="s1">'encoding'</span><span class="p">:</span> <span class="s1">'utf8'</span>
<span class="p">},</span>
<span class="p">},</span>
<span class="s1">'loggers'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">''</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'handlers'</span><span class="p">:</span> <span class="p">[</span><span class="s1">'default'</span><span class="p">],</span>
<span class="s1">'level'</span><span class="p">:</span> <span class="s1">'INFO'</span>
<span class="p">},</span>
<span class="s1">'db'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'handlers'</span><span class="p">:</span> <span class="p">[</span><span class="s1">'default'</span><span class="p">],</span>
<span class="s1">'level'</span><span class="p">:</span> <span class="s1">'INFO'</span> <span class="p">,</span>
<span class="s1">'propagate'</span><span class="p">:</span> <span class="bp">False</span>
<span class="p">},</span>
<span class="s1">'cherrypy.access'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'handlers'</span><span class="p">:</span> <span class="p">[</span><span class="s1">'cherrypy_access'</span><span class="p">],</span>
<span class="s1">'level'</span><span class="p">:</span> <span class="s1">'INFO'</span><span class="p">,</span>
<span class="s1">'propagate'</span><span class="p">:</span> <span class="bp">False</span>
<span class="p">},</span>
<span class="s1">'cherrypy.error'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'handlers'</span><span class="p">:</span> <span class="p">[</span><span class="s1">'cherrypy_console'</span><span class="p">,</span> <span class="s1">'cherrypy_error'</span><span class="p">],</span>
<span class="s1">'level'</span><span class="p">:</span> <span class="s1">'INFO'</span><span class="p">,</span>
<span class="s1">'propagate'</span><span class="p">:</span> <span class="bp">False</span>
<span class="p">},</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="k">class</span> <span class="nc">Root</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">logger</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s2">"boom"</span><span class="p">)</span>
<span class="n">db_logger</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s2">"bam"</span><span class="p">)</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">"bang"</span><span class="p">)</span>
<span class="k">return</span> <span class="s2">"hello world"</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">update</span><span class="p">({</span><span class="s1">'log.screen'</span><span class="p">:</span> <span class="bp">False</span><span class="p">,</span>
<span class="s1">'log.access_file'</span><span class="p">:</span> <span class="s1">''</span><span class="p">,</span>
<span class="s1">'log.error_file'</span><span class="p">:</span> <span class="s1">''</span><span class="p">})</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">engine</span><span class="o">.</span><span class="n">unsubscribe</span><span class="p">(</span><span class="s1">'graceful'</span><span class="p">,</span> <span class="n">cherrypy</span><span class="o">.</span><span class="n">log</span><span class="o">.</span><span class="n">reopen_files</span><span class="p">)</span>
<span class="n">logging</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">dictConfig</span><span class="p">(</span><span class="n">LOG_CONF</span><span class="p">)</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">Root</span><span class="p">())</span>
</pre></div>
</div>
<p>In this snippet, we create a <a class="reference external" href="https://docs.python.org/2/library/logging.config.html#logging.config.dictConfig">configuration dictionary</a>
that we pass on to the <code class="docutils literal"><span class="pre">logging</span></code> module to configure
our loggers:</p>
<blockquote>
<div><ul class="simple">
<li>the default root logger is associated to a single stream handler</li>
<li>a logger for the db backend with also a single stream handler</li>
</ul>
</div></blockquote>
<p>In addition, we re-configure the CherryPy loggers:</p>
<blockquote>
<div><ul class="simple">
<li>the top-level <code class="docutils literal"><span class="pre">cherrypy.access</span></code> logger to log requests into a file</li>
<li>the <code class="docutils literal"><span class="pre">cherrypy.error</span></code> logger to log everything else into a file
and to the console</li>
</ul>
</div></blockquote>
<p>We also prevent CherryPy from trying to open its log files when
the autoreloader kicks in. This is not strictly required since we do not
even let CherryPy open them in the first place. But, this avoids
wasting time on something useless.</p>
</div>
</div>
<div class="section" id="configuring">
<span id="config"></span><h2><a class="toc-backref" href="#id12">Configuring</a><a class="headerlink" href="#configuring" title="Permalink to this headline">¶</a></h2>
<p>CherryPy comes with a fine-grained configuration mechanism and
settings can be set at various levels.</p>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">Once you have the reviewed the basics, please refer
to the <a class="reference internal" href="config.html#configindepth"><span class="std std-ref">in-depth discussion</span></a>
around configuration.</p>
</div>
<div class="section" id="global-server-configuration">
<span id="globalsettings"></span><h3><a class="toc-backref" href="#id13">Global server configuration</a><a class="headerlink" href="#global-server-configuration" title="Permalink to this headline">¶</a></h3>
<p>To configure the HTTP and application servers,
use the <code class="xref py py-meth docutils literal"><span class="pre">cherrypy.config.update()</span></code>
method.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">update</span><span class="p">({</span><span class="s1">'server.socket_port'</span><span class="p">:</span> <span class="mi">9090</span><span class="p">})</span>
</pre></div>
</div>
<p>The <code class="xref py py-mod docutils literal"><span class="pre">cherrypy.config</span></code> object is a dictionary and the
update method merges the passed dictionary into it.</p>
<p>You can also pass a file instead (assuming a <cite>server.conf</cite>
file):</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[global]</span>
<span class="na">server.socket_port: 9090</span>
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="s2">"server.conf"</span><span class="p">)</span>
</pre></div>
</div>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last"><code class="xref py py-meth docutils literal"><span class="pre">cherrypy.config.update()</span></code>
is not meant to be used to configure the application.
It is a common mistake. It is used to configure the server and engine.</p>
</div>
</div>
<div class="section" id="per-application-configuration">
<span id="perappconf"></span><h3><a class="toc-backref" href="#id14">Per-application configuration</a><a class="headerlink" href="#per-application-configuration" title="Permalink to this headline">¶</a></h3>
<p>To configure your application, pass in a dictionary or a file
when you associate your application to the server.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">myapp</span><span class="p">,</span> <span class="s1">'/'</span><span class="p">,</span> <span class="p">{</span><span class="s1">'/'</span><span class="p">:</span> <span class="p">{</span><span class="s1">'tools.gzip.on'</span><span class="p">:</span> <span class="bp">True</span><span class="p">}})</span>
</pre></div>
</div>
<p>or via a file (called <cite>app.conf</cite> for instance):</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/]</span>
<span class="na">tools.gzip.on: True</span>
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">myapp</span><span class="p">,</span> <span class="s1">'/'</span><span class="p">,</span> <span class="s2">"app.conf"</span><span class="p">)</span>
</pre></div>
</div>
<p>Although, you can define most of your configuration in a global
fashion, it is sometimes convenient to define them
where they are applied in the code.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Root</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="nd">@cherrypy.tools.gzip</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s2">"hello world!"</span>
</pre></div>
</div>
<p>A variant notation to the above:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Root</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s2">"hello world!"</span>
<span class="n">index</span><span class="o">.</span><span class="n">_cp_config</span> <span class="o">=</span> <span class="p">{</span><span class="s1">'tools.gzip.on'</span><span class="p">:</span> <span class="bp">True</span><span class="p">}</span>
</pre></div>
</div>
<p>Both methods have the same effect so pick the one
that suits your style best.</p>
</div>
<div class="section" id="additional-application-settings">
<h3><a class="toc-backref" href="#id15">Additional application settings</a><a class="headerlink" href="#additional-application-settings" title="Permalink to this headline">¶</a></h3>
<p>You can add settings that are not specific to a request URL
and retrieve them from your page handler as follows:</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/]</span>
<span class="na">tools.gzip.on: True</span>
<span class="k">[googleapi]</span>
<span class="na">key</span> <span class="o">=</span> <span class="s">"..."</span>
<span class="na">appid</span> <span class="o">=</span> <span class="s">"..."</span>
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Root</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">google_appid</span> <span class="o">=</span> <span class="n">cherrypy</span><span class="o">.</span><span class="n">request</span><span class="o">.</span><span class="n">app</span><span class="o">.</span><span class="n">config</span><span class="p">[</span><span class="s1">'googleapi'</span><span class="p">][</span><span class="s1">'appid'</span><span class="p">]</span>
<span class="k">return</span> <span class="s2">"hello world!"</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">Root</span><span class="p">(),</span> <span class="s1">'/'</span><span class="p">,</span> <span class="s2">"app.conf"</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
<div class="section" id="cookies">
<h2><a class="toc-backref" href="#id16">Cookies</a><a class="headerlink" href="#cookies" title="Permalink to this headline">¶</a></h2>
<p>CherryPy uses the <code class="xref py py-mod docutils literal"><span class="pre">Cookie</span></code> module from python and in particular the
<code class="xref py py-class docutils literal"><span class="pre">Cookie.SimpleCookie</span></code> object type to handle cookies.</p>
<ul class="simple">
<li>To send a cookie to a browser, set <code class="docutils literal"><span class="pre">cherrypy.response.cookie[key]</span> <span class="pre">=</span> <span class="pre">value</span></code>.</li>
<li>To retrieve a cookie sent by a browser, use <code class="docutils literal"><span class="pre">cherrypy.request.cookie[key]</span></code>.</li>
<li>To delete a cookie (on the client side), you must <em>send</em> the cookie with its
expiration time set to <cite>0</cite>:</li>
</ul>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">response</span><span class="o">.</span><span class="n">cookie</span><span class="p">[</span><span class="n">key</span><span class="p">]</span> <span class="o">=</span> <span class="n">value</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">response</span><span class="o">.</span><span class="n">cookie</span><span class="p">[</span><span class="n">key</span><span class="p">][</span><span class="s1">'expires'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
</pre></div>
</div>
<p>It’s important to understand that the request cookies are <strong>not</strong> automatically
copied to the response cookies. Clients will send the same cookies on every
request, and therefore <code class="docutils literal"><span class="pre">cherrypy.request.cookie</span></code> should be populated each
time. But the server doesn’t need to send the same cookies with every response;
therefore, <code class="docutils literal"><span class="pre">cherrypy.response.cookie</span></code> will usually be empty. When you wish
to “delete” (expire) a cookie, therefore, you must set
<code class="docutils literal"><span class="pre">cherrypy.response.cookie[key]</span> <span class="pre">=</span> <span class="pre">value</span></code> first, and then set its <code class="docutils literal"><span class="pre">expires</span></code>
attribute to 0.</p>
<p>Extended example:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">cherrypy</span>
<span class="k">class</span> <span class="nc">MyCookieApp</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">set</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">cookie</span> <span class="o">=</span> <span class="n">cherrypy</span><span class="o">.</span><span class="n">response</span><span class="o">.</span><span class="n">cookie</span>
<span class="n">cookie</span><span class="p">[</span><span class="s1">'cookieName'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'cookieValue'</span>
<span class="n">cookie</span><span class="p">[</span><span class="s1">'cookieName'</span><span class="p">][</span><span class="s1">'path'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'/'</span>
<span class="n">cookie</span><span class="p">[</span><span class="s1">'cookieName'</span><span class="p">][</span><span class="s1">'max-age'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">3600</span>
<span class="n">cookie</span><span class="p">[</span><span class="s1">'cookieName'</span><span class="p">][</span><span class="s1">'version'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">1</span>
<span class="k">return</span> <span class="s2">"<html><body>Hello, I just sent you a cookie</body></html>"</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">read</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">cookie</span> <span class="o">=</span> <span class="n">cherrypy</span><span class="o">.</span><span class="n">request</span><span class="o">.</span><span class="n">cookie</span>
<span class="n">res</span> <span class="o">=</span> <span class="s2">"""<html><body>Hi, you sent me </span><span class="si">%s</span><span class="s2"> cookies.<br /></span>
<span class="s2"> Here is a list of cookie names/values:<br />"""</span> <span class="o">%</span> <span class="nb">len</span><span class="p">(</span><span class="n">cookie</span><span class="p">)</span>
<span class="k">for</span> <span class="n">name</span> <span class="ow">in</span> <span class="n">cookie</span><span class="o">.</span><span class="n">keys</span><span class="p">():</span>
<span class="n">res</span> <span class="o">+=</span> <span class="s2">"name: </span><span class="si">%s</span><span class="s2">, value: </span><span class="si">%s</span><span class="s2"><br>"</span> <span class="o">%</span> <span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="n">cookie</span><span class="p">[</span><span class="n">name</span><span class="p">]</span><span class="o">.</span><span class="n">value</span><span class="p">)</span>
<span class="k">return</span> <span class="n">res</span> <span class="o">+</span> <span class="s2">"</body></html>"</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">MyCookieApp</span><span class="p">(),</span> <span class="s1">'/cookie'</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="using-sessions">
<span id="basicsession"></span><h2><a class="toc-backref" href="#id17">Using sessions</a><a class="headerlink" href="#using-sessions" title="Permalink to this headline">¶</a></h2>
<p>Sessions are one of the most common mechanism used by developers to
identify users and synchronize their activity. By default, CherryPy
does not activate sessions because it is not a mandatory feature
to have, to enable it simply add the following settings in your
configuration:</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/]</span>
<span class="na">tools.sessions.on: True</span>
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">myapp</span><span class="p">,</span> <span class="s1">'/'</span><span class="p">,</span> <span class="s2">"app.conf"</span><span class="p">)</span>
</pre></div>
</div>
<p>Sessions are, by default, stored in RAM so, if you restart your server
all of your current sessions will be lost. You can store them in memcached
or on the filesystem instead.</p>
<p>Using sessions in your applications is done as follows:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">cherrypy</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">if</span> <span class="s1">'count'</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">cherrypy</span><span class="o">.</span><span class="n">session</span><span class="p">:</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">session</span><span class="p">[</span><span class="s1">'count'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">session</span><span class="p">[</span><span class="s1">'count'</span><span class="p">]</span> <span class="o">+=</span> <span class="mi">1</span>
</pre></div>
</div>
<p>In this snippet, everytime the the index page handler is called,
the current user’s session has its <cite>‘count’</cite> key incremented by <cite>1</cite>.</p>
<p>CherryPy knows which session to use by inspecting the cookie
sent alongside the request. This cookie contains the session
identifier used by CherryPy to load the user’s session from
the storage.</p>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">Refer to the <code class="xref py py-mod docutils literal"><span class="pre">cherrypy.lib.sessions</span></code> module for more
details about the session interface and implementation.
Notably you will learn about sessions expiration.</p>
</div>
<div class="section" id="filesystem-backend">
<h3><a class="toc-backref" href="#id18">Filesystem backend</a><a class="headerlink" href="#filesystem-backend" title="Permalink to this headline">¶</a></h3>
<p>Using a filesystem is a simple to not lose your sessions
between reboots. Each session is saved in its own file within
the given directory.</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/]</span>
<span class="na">tools.sessions.on: True</span>
<span class="na">tools.sessions.storage_class</span> <span class="o">=</span> <span class="s">cherrypy.lib.sessions.FileSession</span>
<span class="na">tools.sessions.storage_path</span> <span class="o">=</span> <span class="s">"/some/directory"</span>
</pre></div>
</div>
</div>
<div class="section" id="memcached-backend">
<h3><a class="toc-backref" href="#id19">Memcached backend</a><a class="headerlink" href="#memcached-backend" title="Permalink to this headline">¶</a></h3>
<p><a class="reference external" href="http://memcached.org/">Memcached</a> is a popular key-store on top of your RAM,
it is distributed and a good choice if you want to
share sessions outside of the process running CherryPy.</p>
<p>Requires that the Python
<a class="reference external" href="https://pypi.org/project/memcached">memcached</a>
package is installed, which may be indicated by installing
<code class="docutils literal"><span class="pre">cherrypy[memcached_session]</span></code>.</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/]</span>
<span class="na">tools.sessions.on: True</span>
<span class="na">tools.sessions.storage_class</span> <span class="o">=</span> <span class="s">cherrypy.lib.sessions.MemcachedSession</span>
</pre></div>
</div>
</div>
<div class="section" id="other-backends">
<span id="staticontent"></span><h3><a class="toc-backref" href="#id20">Other backends</a><a class="headerlink" href="#other-backends" title="Permalink to this headline">¶</a></h3>
<p>Any other library may implement a session backend. Simply subclass
<code class="docutils literal"><span class="pre">cherrypy.lib.sessions.Session</span></code> and indicate that subclass as
<code class="docutils literal"><span class="pre">tools.sessions.storage_class</span></code>.</p>
</div>
</div>
<div class="section" id="static-content-serving">
<h2><a class="toc-backref" href="#id21">Static content serving</a><a class="headerlink" href="#static-content-serving" title="Permalink to this headline">¶</a></h2>
<p>CherryPy can serve your static content such as images, javascript and
CSS resources, etc.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>CherryPy uses the <code class="xref py py-mod docutils literal"><span class="pre">mimetypes</span></code> module to determine the
best content-type to serve a particular resource. If the choice
is not valid, you can simply set more media-types as follows:</p>
<div class="last highlight-python"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">mimetypes</span>
<span class="n">mimetypes</span><span class="o">.</span><span class="n">types_map</span><span class="p">[</span><span class="s1">'.csv'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'text/csv'</span>
</pre></div>
</div>
</div>
<div class="section" id="serving-a-single-file">
<h3><a class="toc-backref" href="#id22">Serving a single file</a><a class="headerlink" href="#serving-a-single-file" title="Permalink to this headline">¶</a></h3>
<p>You can serve a single file as follows:</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/style.css]</span>
<span class="na">tools.staticfile.on</span> <span class="o">=</span> <span class="s">True</span>
<span class="na">tools.staticfile.filename</span> <span class="o">=</span> <span class="s">"/home/site/style.css"</span>
</pre></div>
</div>
<p>CherryPy will automatically respond to URLs such as
<cite>http://hostname/style.css</cite>.</p>
</div>
<div class="section" id="serving-a-whole-directory">
<h3><a class="toc-backref" href="#id23">Serving a whole directory</a><a class="headerlink" href="#serving-a-whole-directory" title="Permalink to this headline">¶</a></h3>
<p>Serving a whole directory is similar to a single file:</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/static]</span>
<span class="na">tools.staticdir.on</span> <span class="o">=</span> <span class="s">True</span>
<span class="na">tools.staticdir.dir</span> <span class="o">=</span> <span class="s">"/home/site/static"</span>
</pre></div>
</div>
<p>Assuming you have a file at <cite>static/js/my.js</cite>,
CherryPy will automatically respond to URLs such as
<cite>http://hostname/static/js/my.js</cite>.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>CherryPy always requires the absolute path to the files or directories
it will serve. If you have several static sections to configure
but located in the same root directory, you can use the following
shortcut:</p>
<div class="last highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/]</span>
<span class="na">tools.staticdir.root</span> <span class="o">=</span> <span class="s">"/home/site"</span>
<span class="k">[/static]</span>
<span class="na">tools.staticdir.on</span> <span class="o">=</span> <span class="s">True</span>
<span class="na">tools.staticdir.dir</span> <span class="o">=</span> <span class="s">"static"</span>
</pre></div>
</div>
</div>
</div>
<div class="section" id="specifying-an-index-file">
<h3><a class="toc-backref" href="#id24">Specifying an index file</a><a class="headerlink" href="#specifying-an-index-file" title="Permalink to this headline">¶</a></h3>
<p>By default, CherryPy will respond to the root of a static
directory with an 404 error indicating the path ‘/’ was not found.
To specify an index file, you can use the following:</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/static]</span>
<span class="na">tools.staticdir.on</span> <span class="o">=</span> <span class="s">True</span>
<span class="na">tools.staticdir.dir</span> <span class="o">=</span> <span class="s">"/home/site/static"</span>
<span class="na">tools.staticdir.index</span> <span class="o">=</span> <span class="s">"index.html"</span>
</pre></div>
</div>
<p>Assuming you have a file at <cite>static/index.html</cite>,
CherryPy will automatically respond to URLs such as
<cite>http://hostname/static/</cite> by returning its contents.</p>
</div>
<div class="section" id="allow-files-downloading">
<h3><a class="toc-backref" href="#id25">Allow files downloading</a><a class="headerlink" href="#allow-files-downloading" title="Permalink to this headline">¶</a></h3>
<p>Using <code class="docutils literal"><span class="pre">"application/x-download"</span></code> response content-type,
you can tell a browser that a resource should be downloaded
onto the user’s machine rather than displayed.</p>
<p>You could for instance write a page handler as follows:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">cherrypy.lib.static</span> <span class="kn">import</span> <span class="n">serve_file</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">download</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">filepath</span><span class="p">):</span>
<span class="k">return</span> <span class="n">serve_file</span><span class="p">(</span><span class="n">filepath</span><span class="p">,</span> <span class="s2">"application/x-download"</span><span class="p">,</span> <span class="s2">"attachment"</span><span class="p">)</span>
</pre></div>
</div>
<p>Assuming the filepath is a valid path on your machine, the
response would be considered as a downloadable content by
the browser.</p>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">The above page handler is a security risk on its own since any file
of the server could be accessed (if the user running the
server had permissions on them).</p>
</div>
</div>
</div>
<div class="section" id="dealing-with-json">
<h2><a class="toc-backref" href="#id26">Dealing with JSON</a><a class="headerlink" href="#dealing-with-json" title="Permalink to this headline">¶</a></h2>
<p>CherryPy has built-in support for JSON encoding and decoding
of the request and/or response.</p>
<div class="section" id="decoding-request">
<h3><a class="toc-backref" href="#id27">Decoding request</a><a class="headerlink" href="#decoding-request" title="Permalink to this headline">¶</a></h3>
<p>To automatically decode the content of a request using JSON:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Root</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="nd">@cherrypy.tools.json_in</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">data</span> <span class="o">=</span> <span class="n">cherrypy</span><span class="o">.</span><span class="n">request</span><span class="o">.</span><span class="n">json</span>
</pre></div>
</div>
<p>The <cite>json</cite> attribute attached to the request contains
the decoded content.</p>
</div>
<div class="section" id="encoding-response">
<h3><a class="toc-backref" href="#id28">Encoding response</a><a class="headerlink" href="#encoding-response" title="Permalink to this headline">¶</a></h3>
<p>To automatically encode the content of a response using JSON:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Root</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="nd">@cherrypy.tools.json_out</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="p">{</span><span class="s1">'key'</span><span class="p">:</span> <span class="s1">'value'</span><span class="p">}</span>
</pre></div>
</div>
<p>CherryPy will encode any content returned by your page handler
using JSON. Not all type of objects may natively be
encoded.</p>
</div>
</div>
<div class="section" id="authentication">
<h2><a class="toc-backref" href="#id29">Authentication</a><a class="headerlink" href="#authentication" title="Permalink to this headline">¶</a></h2>
<p>CherryPy provides support for two very simple authentication mechanisms,
both described in <span class="target" id="index-0"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc2617.html"><strong>RFC 2617</strong></a>: Basic and Digest. They are most commonly
known to trigger a browser’s popup asking users their name
and password.</p>
<div class="section" id="basic">
<h3><a class="toc-backref" href="#id30">Basic</a><a class="headerlink" href="#basic" title="Permalink to this headline">¶</a></h3>
<p>Basic authentication is the simplest form of authentication however
it is not a secure one as the user’s credentials are embedded into
the request. We advise against using it unless you are running on
SSL or within a closed network.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">cherrypy.lib</span> <span class="kn">import</span> <span class="n">auth_basic</span>
<span class="n">USERS</span> <span class="o">=</span> <span class="p">{</span><span class="s1">'jon'</span><span class="p">:</span> <span class="s1">'secret'</span><span class="p">}</span>
<span class="k">def</span> <span class="nf">validate_password</span><span class="p">(</span><span class="n">realm</span><span class="p">,</span> <span class="n">username</span><span class="p">,</span> <span class="n">password</span><span class="p">):</span>
<span class="k">if</span> <span class="n">username</span> <span class="ow">in</span> <span class="n">USERS</span> <span class="ow">and</span> <span class="n">USERS</span><span class="p">[</span><span class="n">username</span><span class="p">]</span> <span class="o">==</span> <span class="n">password</span><span class="p">:</span>
<span class="k">return</span> <span class="bp">True</span>
<span class="k">return</span> <span class="bp">False</span>
<span class="n">conf</span> <span class="o">=</span> <span class="p">{</span>
<span class="s1">'/protected/area'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'tools.auth_basic.on'</span><span class="p">:</span> <span class="bp">True</span><span class="p">,</span>
<span class="s1">'tools.auth_basic.realm'</span><span class="p">:</span> <span class="s1">'localhost'</span><span class="p">,</span>
<span class="s1">'tools.auth_basic.checkpassword'</span><span class="p">:</span> <span class="n">validate_password</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">myapp</span><span class="p">,</span> <span class="s1">'/'</span><span class="p">,</span> <span class="n">conf</span><span class="p">)</span>
</pre></div>
</div>
<p>Simply put, you have to provide a function that will
be called by CherryPy passing the username and password
decoded from the request.</p>
<p>The function can read its data from any source it has to: a file,
a database, memory, etc.</p>
</div>
<div class="section" id="digest">
<h3><a class="toc-backref" href="#id31">Digest</a><a class="headerlink" href="#digest" title="Permalink to this headline">¶</a></h3>
<p>Digest authentication differs by the fact the credentials
are not carried on by the request so it’s a little more secure
than basic.</p>
<p>CherryPy’s digest support has a similar interface to the
basic one explained above.</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">cherrypy.lib</span> <span class="kn">import</span> <span class="n">auth_digest</span>
<span class="n">USERS</span> <span class="o">=</span> <span class="p">{</span><span class="s1">'jon'</span><span class="p">:</span> <span class="s1">'secret'</span><span class="p">}</span>
<span class="n">conf</span> <span class="o">=</span> <span class="p">{</span>
<span class="s1">'/protected/area'</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'tools.auth_digest.on'</span><span class="p">:</span> <span class="bp">True</span><span class="p">,</span>
<span class="s1">'tools.auth_digest.realm'</span><span class="p">:</span> <span class="s1">'localhost'</span><span class="p">,</span>
<span class="s1">'tools.auth_digest.get_ha1'</span><span class="p">:</span> <span class="n">auth_digest</span><span class="o">.</span><span class="n">get_ha1_dict_plain</span><span class="p">(</span><span class="n">USERS</span><span class="p">),</span>
<span class="s1">'tools.auth_digest.key'</span><span class="p">:</span> <span class="s1">'a565c27146791cfb'</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">myapp</span><span class="p">,</span> <span class="s1">'/'</span><span class="p">,</span> <span class="n">conf</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
<div class="section" id="favicon">
<h2><a class="toc-backref" href="#id32">Favicon</a><a class="headerlink" href="#favicon" title="Permalink to this headline">¶</a></h2>
<p>CherryPy serves its own sweet red cherrypy as the default
<a class="reference external" href="http://en.wikipedia.org/wiki/Favicon">favicon</a> using the static file
tool. You can serve your own favicon as follows:</p>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">cherrypy</span>
<span class="k">class</span> <span class="nc">HelloWorld</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s2">"Hello World!"</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">HelloWorld</span><span class="p">(),</span> <span class="s1">'/'</span><span class="p">,</span>
<span class="p">{</span>
<span class="s1">'/favicon.ico'</span><span class="p">:</span>
<span class="p">{</span>
<span class="s1">'tools.staticfile.on'</span><span class="p">:</span> <span class="bp">True</span><span class="p">,</span>
<span class="s1">'tools.staticfile.filename'</span><span class="p">:</span> <span class="s1">'/path/to/myfavicon.ico'</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="p">)</span>
</pre></div>
</div>
<p>Please refer to the <a class="reference internal" href="#staticontent"><span class="std std-ref">static serving</span></a> section
for more details.</p>
<p>You can also use a file to configure it:</p>
<div class="highlight-ini"><div class="highlight"><pre><span></span><span class="k">[/favicon.ico]</span>
<span class="na">tools.staticfile.on: True</span>
<span class="na">tools.staticfile.filename: "/path/to/myfavicon.ico"</span>
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">cherrypy</span>
<span class="k">class</span> <span class="nc">HelloWorld</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="nd">@cherrypy.expose</span>
<span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s2">"Hello World!"</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="n">cherrypy</span><span class="o">.</span><span class="n">quickstart</span><span class="p">(</span><span class="n">HelloWorld</span><span class="p">(),</span> <span class="s1">'/'</span><span class="p">,</span> <span class="n">app</span><span class="o">.</span><span class="n">conf</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Basics</a><ul>
<li><a class="reference internal" href="#the-one-minute-application-example">The one-minute application example</a></li>
<li><a class="reference internal" href="#hosting-one-or-more-applications">Hosting one or more applications</a><ul>
<li><a class="reference internal" href="#single-application">Single application</a></li>
<li><a class="reference internal" href="#multiple-applications">Multiple applications</a></li>
</ul>
</li>
<li><a class="reference internal" href="#logging">Logging</a><ul>
<li><a class="reference internal" href="#disable-logging">Disable logging</a></li>
<li><a class="reference internal" href="#play-along-with-your-other-loggers">Play along with your other loggers</a></li>
</ul>
</li>
<li><a class="reference internal" href="#configuring">Configuring</a><ul>
<li><a class="reference internal" href="#global-server-configuration">Global server configuration</a></li>
<li><a class="reference internal" href="#per-application-configuration">Per-application configuration</a></li>
<li><a class="reference internal" href="#additional-application-settings">Additional application settings</a></li>
</ul>
</li>
<li><a class="reference internal" href="#cookies">Cookies</a></li>
<li><a class="reference internal" href="#using-sessions">Using sessions</a><ul>
<li><a class="reference internal" href="#filesystem-backend">Filesystem backend</a></li>
<li><a class="reference internal" href="#memcached-backend">Memcached backend</a></li>
<li><a class="reference internal" href="#other-backends">Other backends</a></li>
</ul>
</li>
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