<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8" /> <title>mailcap — Mailcap file handling — Python 3.7.4 documentation</title> <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></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> <script type="text/javascript" src="../_static/language_data.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.7.4 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="mailbox — Manipulate mailboxes in various formats" href="mailbox.html" /> <link rel="prev" title="json — JSON encoder and decoder" href="json.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/library/mailcap.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> <script type="text/javascript" src="../_static/switchers.js"></script> <style> @media only screen { table.full-width-table { width: 100%; } } </style> </head><body> <div class="related" role="navigation" aria-label="related navigation"> <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="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="mailbox.html" title="mailbox — Manipulate mailboxes in various formats" accesskey="N">next</a> |</li> <li class="right" > <a href="json.html" title="json — JSON encoder and decoder" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <span class="language_switcher_placeholder">en</span> <span class="version_switcher_placeholder">3.7.4</span> <a href="../index.html">Documentation </a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="netdata.html" accesskey="U">Internet Data Handling</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" 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> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-mailcap"> <span id="mailcap-mailcap-file-handling"></span><h1><a class="reference internal" href="#module-mailcap" title="mailcap: Mailcap file handling."><code class="xref py py-mod docutils literal notranslate"><span class="pre">mailcap</span></code></a> — Mailcap file handling<a class="headerlink" href="#module-mailcap" title="Permalink to this headline">¶</a></h1> <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.7/Lib/mailcap.py">Lib/mailcap.py</a></p> <hr class="docutils" /> <p>Mailcap files are used to configure how MIME-aware applications such as mail readers and Web browsers react to files with different MIME types. (The name “mailcap” is derived from the phrase “mail capability”.) For example, a mailcap file might contain a line like <code class="docutils literal notranslate"><span class="pre">video/mpeg;</span> <span class="pre">xmpeg</span> <span class="pre">%s</span></code>. Then, if the user encounters an email message or Web document with the MIME type <em class="mimetype">video/mpeg</em>, <code class="docutils literal notranslate"><span class="pre">%s</span></code> will be replaced by a filename (usually one belonging to a temporary file) and the <strong class="program">xmpeg</strong> program can be automatically started to view the file.</p> <p>The mailcap format is documented in <span class="target" id="index-0"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc1524.html"><strong>RFC 1524</strong></a>, “A User Agent Configuration Mechanism For Multimedia Mail Format Information,” but is not an Internet standard. However, mailcap files are supported on most Unix systems.</p> <dl class="function"> <dt id="mailcap.findmatch"> <code class="descclassname">mailcap.</code><code class="descname">findmatch</code><span class="sig-paren">(</span><em>caps</em>, <em>MIMEtype</em>, <em>key='view'</em>, <em>filename='/dev/null'</em>, <em>plist=[]</em><span class="sig-paren">)</span><a class="headerlink" href="#mailcap.findmatch" title="Permalink to this definition">¶</a></dt> <dd><p>Return a 2-tuple; the first element is a string containing the command line to be executed (which can be passed to <a class="reference internal" href="os.html#os.system" title="os.system"><code class="xref py py-func docutils literal notranslate"><span class="pre">os.system()</span></code></a>), and the second element is the mailcap entry for a given MIME type. If no matching MIME type can be found, <code class="docutils literal notranslate"><span class="pre">(None,</span> <span class="pre">None)</span></code> is returned.</p> <p><em>key</em> is the name of the field desired, which represents the type of activity to be performed; the default value is ‘view’, since in the most common case you simply want to view the body of the MIME-typed data. Other possible values might be ‘compose’ and ‘edit’, if you wanted to create a new body of the given MIME type or alter the existing body data. See <span class="target" id="index-1"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc1524.html"><strong>RFC 1524</strong></a> for a complete list of these fields.</p> <p><em>filename</em> is the filename to be substituted for <code class="docutils literal notranslate"><span class="pre">%s</span></code> in the command line; the default value is <code class="docutils literal notranslate"><span class="pre">'/dev/null'</span></code> which is almost certainly not what you want, so usually you’ll override it by specifying a filename.</p> <p><em>plist</em> can be a list containing named parameters; the default value is simply an empty list. Each entry in the list must be a string containing the parameter name, an equals sign (<code class="docutils literal notranslate"><span class="pre">'='</span></code>), and the parameter’s value. Mailcap entries can contain named parameters like <code class="docutils literal notranslate"><span class="pre">%{foo}</span></code>, which will be replaced by the value of the parameter named ‘foo’. For example, if the command line <code class="docutils literal notranslate"><span class="pre">showpartial</span> <span class="pre">%{id}</span> <span class="pre">%{number}</span> <span class="pre">%{total}</span></code> was in a mailcap file, and <em>plist</em> was set to <code class="docutils literal notranslate"><span class="pre">['id=1',</span> <span class="pre">'number=2',</span> <span class="pre">'total=3']</span></code>, the resulting command line would be <code class="docutils literal notranslate"><span class="pre">'showpartial</span> <span class="pre">1</span> <span class="pre">2</span> <span class="pre">3'</span></code>.</p> <p>In a mailcap file, the “test” field can optionally be specified to test some external condition (such as the machine architecture, or the window system in use) to determine whether or not the mailcap line applies. <a class="reference internal" href="#mailcap.findmatch" title="mailcap.findmatch"><code class="xref py py-func docutils literal notranslate"><span class="pre">findmatch()</span></code></a> will automatically check such conditions and skip the entry if the check fails.</p> </dd></dl> <dl class="function"> <dt id="mailcap.getcaps"> <code class="descclassname">mailcap.</code><code class="descname">getcaps</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#mailcap.getcaps" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a dictionary mapping MIME types to a list of mailcap file entries. This dictionary must be passed to the <a class="reference internal" href="#mailcap.findmatch" title="mailcap.findmatch"><code class="xref py py-func docutils literal notranslate"><span class="pre">findmatch()</span></code></a> function. An entry is stored as a list of dictionaries, but it shouldn’t be necessary to know the details of this representation.</p> <p>The information is derived from all of the mailcap files found on the system. Settings in the user’s mailcap file <code class="file docutils literal notranslate"><span class="pre">$HOME/.mailcap</span></code> will override settings in the system mailcap files <code class="file docutils literal notranslate"><span class="pre">/etc/mailcap</span></code>, <code class="file docutils literal notranslate"><span class="pre">/usr/etc/mailcap</span></code>, and <code class="file docutils literal notranslate"><span class="pre">/usr/local/etc/mailcap</span></code>.</p> </dd></dl> <p>An example usage:</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">mailcap</span> <span class="gp">>>> </span><span class="n">d</span> <span class="o">=</span> <span class="n">mailcap</span><span class="o">.</span><span class="n">getcaps</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">mailcap</span><span class="o">.</span><span class="n">findmatch</span><span class="p">(</span><span class="n">d</span><span class="p">,</span> <span class="s1">'video/mpeg'</span><span class="p">,</span> <span class="n">filename</span><span class="o">=</span><span class="s1">'tmp1223'</span><span class="p">)</span> <span class="go">('xmpeg tmp1223', {'view': 'xmpeg %s'})</span> </pre></div> </div> </div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="json.html" title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">json</span></code> — JSON encoder and decoder</a></p> <h4>Next topic</h4> <p class="topless"><a href="mailbox.html" title="next chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">mailbox</span></code> — Manipulate mailboxes in various formats</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/3.7/Doc/library/mailcap.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </div> </div> <div class="clearer"></div> </div> <div class="related" role="navigation" aria-label="related navigation"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="mailbox.html" title="mailbox — Manipulate mailboxes in various formats" >next</a> |</li> <li class="right" > <a href="json.html" title="json — JSON encoder and decoder" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <span class="language_switcher_placeholder">en</span> <span class="version_switcher_placeholder">3.7.4</span> <a href="../index.html">Documentation </a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="netdata.html" >Internet Data Handling</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" 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> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 2001-2019, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="https://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Jul 13, 2019. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.0.1. </div> </body> </html>