OwlCyberSecurity - MANAGER
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<!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="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>20.5. urllib — Open arbitrary resources by URL — Python 2.7.18 documentation</title> <link rel="stylesheet" href="../_static/classic.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 2.7.18 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="20.6. urllib2 — extensible library for opening URLs" href="urllib2.html" /> <link rel="prev" title="20.4. wsgiref — WSGI Utilities and Reference Implementation" href="wsgiref.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="file:///usr/share/doc/python2.7/html/library/urllib.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head><body> <div id="outdated-warning" style="padding: .5em; text-align: center; background-color: #FFBABA; color: #6A0E0E;"> This document is for an old version of Python that is <a href="https://devguide.python.org/devcycle/#end-of-life-branches">no longer supported</a>. 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Internet Protocols and Support</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-urllib"> <span id="urllib-open-arbitrary-resources-by-url"></span><h1>20.5. <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> — Open arbitrary resources by URL<a class="headerlink" href="#module-urllib" title="Permalink to this headline">¶</a></h1> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">The <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> module has been split into parts and renamed in Python 3 to <code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib.request</span></code>, <code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib.parse</span></code>, and <code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib.error</span></code>. The <a class="reference internal" href="../glossary.html#term-2to3"><span class="xref std std-term">2to3</span></a> tool will automatically adapt imports when converting your sources to Python 3. Also note that the <code class="xref py py-func docutils literal notranslate"><span class="pre">urllib.request.urlopen()</span></code> function in Python 3 is equivalent to <a class="reference internal" href="urllib2.html#urllib2.urlopen" title="urllib2.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urllib2.urlopen()</span></code></a> and that <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urllib.urlopen()</span></code></a> has been removed.</p> </div> <p id="index-0">This module provides a high-level interface for fetching data across the World Wide Web. In particular, the <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> function is similar to the built-in function <a class="reference internal" href="functions.html#open" title="open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a>, but accepts Universal Resource Locators (URLs) instead of filenames. Some restrictions apply — it can only open URLs for reading, and no seek operations are available.</p> <div class="admonition seealso"> <p class="first admonition-title">See also</p> <p class="last">The <a class="reference external" href="http://docs.python-requests.org/">Requests package</a> is recommended for a higher-level HTTP client interface.</p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.7.9: </span>For HTTPS URIs, <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> performs all the neccessary certificate and hostname checks by default.</p> </div> <div class="admonition warning"> <p class="first admonition-title">Warning</p> <p class="last">For Python versions earlier than 2.7.9, urllib does not attempt to validate the server certificates of HTTPS URIs. Use at your own risk!</p> </div> <div class="section" id="high-level-interface"> <h2>20.5.1. High-level interface<a class="headerlink" href="#high-level-interface" title="Permalink to this headline">¶</a></h2> <dl class="function"> <dt id="urllib.urlopen"> <code class="descclassname">urllib.</code><code class="descname">urlopen</code><span class="sig-paren">(</span><em>url</em><span class="optional">[</span>, <em>data</em><span class="optional">[</span>, <em>proxies</em><span class="optional">[</span>, <em>context</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.urlopen" title="Permalink to this definition">¶</a></dt> <dd><p>Open a network object denoted by a URL for reading. If the URL does not have a scheme identifier, or if it has <code class="file docutils literal notranslate"><span class="pre">file:</span></code> as its scheme identifier, this opens a local file (without <a class="reference internal" href="../glossary.html#term-universal-newlines"><span class="xref std std-term">universal newlines</span></a>); otherwise it opens a socket to a server somewhere on the network. If the connection cannot be made the <a class="reference internal" href="exceptions.html#exceptions.IOError" title="exceptions.IOError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IOError</span></code></a> exception is raised. If all went well, a file-like object is returned. This supports the following methods: <code class="xref py py-meth docutils literal notranslate"><span class="pre">read()</span></code>, <a class="reference internal" href="readline.html#module-readline" title="readline: GNU readline support for Python. (Unix)"><code class="xref py py-meth docutils literal notranslate"><span class="pre">readline()</span></code></a>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">readlines()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">fileno()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">info()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">getcode()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">geturl()</span></code>. It also has proper support for the <a class="reference internal" href="../glossary.html#term-iterator"><span class="xref std std-term">iterator</span></a> protocol. One caveat: the <code class="xref py py-meth docutils literal notranslate"><span class="pre">read()</span></code> method, if the size argument is omitted or negative, may not read until the end of the data stream; there is no good way to determine that the entire stream from a socket has been read in the general case.</p> <p>Except for the <code class="xref py py-meth docutils literal notranslate"><span class="pre">info()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">getcode()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">geturl()</span></code> methods, these methods have the same interface as for file objects — see section <a class="reference internal" href="stdtypes.html#bltin-file-objects"><span class="std std-ref">File Objects</span></a> in this manual. (It is not a built-in file object, however, so it can’t be used at those few places where a true built-in file object is required.)</p> <p id="index-1">The <code class="xref py py-meth docutils literal notranslate"><span class="pre">info()</span></code> method returns an instance of the class <a class="reference internal" href="mimetools.html#mimetools.Message" title="mimetools.Message"><code class="xref py py-class docutils literal notranslate"><span class="pre">mimetools.Message</span></code></a> containing meta-information associated with the URL. When the method is HTTP, these headers are those returned by the server at the head of the retrieved HTML page (including Content-Length and Content-Type). When the method is FTP, a Content-Length header will be present if (as is now usual) the server passed back a file length in response to the FTP retrieval request. A Content-Type header will be present if the MIME type can be guessed. When the method is local-file, returned headers will include a Date representing the file’s last-modified time, a Content-Length giving file size, and a Content-Type containing a guess at the file’s type. See also the description of the <a class="reference internal" href="mimetools.html#module-mimetools" title="mimetools: Tools for parsing MIME-style message bodies. (deprecated)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">mimetools</span></code></a> module.</p> <p>The <code class="xref py py-meth docutils literal notranslate"><span class="pre">geturl()</span></code> method returns the real URL of the page. In some cases, the HTTP server redirects a client to another URL. The <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> function handles this transparently, but in some cases the caller needs to know which URL the client was redirected to. The <code class="xref py py-meth docutils literal notranslate"><span class="pre">geturl()</span></code> method can be used to get at this redirected URL.</p> <p>The <code class="xref py py-meth docutils literal notranslate"><span class="pre">getcode()</span></code> method returns the HTTP status code that was sent with the response, or <code class="docutils literal notranslate"><span class="pre">None</span></code> if the URL is no HTTP URL.</p> <p>If the <em>url</em> uses the <code class="file docutils literal notranslate"><span class="pre">http:</span></code> scheme identifier, the optional <em>data</em> argument may be given to specify a <code class="docutils literal notranslate"><span class="pre">POST</span></code> request (normally the request type is <code class="docutils literal notranslate"><span class="pre">GET</span></code>). The <em>data</em> argument must be in standard <em class="mimetype">application/x-www-form-urlencoded</em> format; see the <a class="reference internal" href="#urllib.urlencode" title="urllib.urlencode"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlencode()</span></code></a> function below.</p> <p>The <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> function works transparently with proxies which do not require authentication. In a Unix or Windows environment, set the <span class="target" id="index-2"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">http_proxy</span></code>, or <span class="target" id="index-3"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">ftp_proxy</span></code> environment variables to a URL that identifies the proxy server before starting the Python interpreter. For example (the <code class="docutils literal notranslate"><span class="pre">'%'</span></code> is the command prompt):</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="o">%</span> <span class="n">http_proxy</span><span class="o">=</span><span class="s2">"http://www.someproxy.com:3128"</span> <span class="o">%</span> <span class="n">export</span> <span class="n">http_proxy</span> <span class="o">%</span> <span class="n">python</span> <span class="o">...</span> </pre></div> </div> <p>The <span class="target" id="index-4"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">no_proxy</span></code> environment variable can be used to specify hosts which shouldn’t be reached via proxy; if set, it should be a comma-separated list of hostname suffixes, optionally with <code class="docutils literal notranslate"><span class="pre">:port</span></code> appended, for example <code class="docutils literal notranslate"><span class="pre">cern.ch,ncsa.uiuc.edu,some.host:8080</span></code>.</p> <p>In a Windows environment, if no proxy environment variables are set, proxy settings are obtained from the registry’s Internet Settings section.</p> <p id="index-5">In a Mac OS X environment, <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> will retrieve proxy information from the OS X System Configuration Framework, which can be managed with Network System Preferences panel.</p> <p>Alternatively, the optional <em>proxies</em> argument may be used to explicitly specify proxies. It must be a dictionary mapping scheme names to proxy URLs, where an empty dictionary causes no proxies to be used, and <code class="docutils literal notranslate"><span class="pre">None</span></code> (the default value) causes environmental proxy settings to be used as discussed above. For example:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="c1"># Use http://www.someproxy.com:3128 for HTTP proxying</span> <span class="n">proxies</span> <span class="o">=</span> <span class="p">{</span><span class="s1">'http'</span><span class="p">:</span> <span class="s1">'http://www.someproxy.com:3128'</span><span class="p">}</span> <span class="n">filehandle</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="n">some_url</span><span class="p">,</span> <span class="n">proxies</span><span class="o">=</span><span class="n">proxies</span><span class="p">)</span> <span class="c1"># Don't use any proxies</span> <span class="n">filehandle</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="n">some_url</span><span class="p">,</span> <span class="n">proxies</span><span class="o">=</span><span class="p">{})</span> <span class="c1"># Use proxies from environment - both versions are equivalent</span> <span class="n">filehandle</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="n">some_url</span><span class="p">,</span> <span class="n">proxies</span><span class="o">=</span><span class="kc">None</span><span class="p">)</span> <span class="n">filehandle</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="n">some_url</span><span class="p">)</span> </pre></div> </div> <p>Proxies which require authentication for use are not currently supported; this is considered an implementation limitation.</p> <p>The <em>context</em> parameter may be set to a <a class="reference internal" href="ssl.html#ssl.SSLContext" title="ssl.SSLContext"><code class="xref py py-class docutils literal notranslate"><span class="pre">ssl.SSLContext</span></code></a> instance to configure the SSL settings that are used if <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> makes a HTTPS connection.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.3: </span>Added the <em>proxies</em> support.</p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.6: </span>Added <code class="xref py py-meth docutils literal notranslate"><span class="pre">getcode()</span></code> to returned object and support for the <span class="target" id="index-6"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">no_proxy</span></code> environment variable.</p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.7.9: </span>The <em>context</em> parameter was added. All the neccessary certificate and hostname checks are done by default.</p> </div> <div class="deprecated"> <p><span class="versionmodified">Deprecated since version 2.6: </span>The <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> function has been removed in Python 3 in favor of <a class="reference internal" href="urllib2.html#urllib2.urlopen" title="urllib2.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urllib2.urlopen()</span></code></a>.</p> </div> </dd></dl> <dl class="function"> <dt id="urllib.urlretrieve"> <code class="descclassname">urllib.</code><code class="descname">urlretrieve</code><span class="sig-paren">(</span><em>url</em><span class="optional">[</span>, <em>filename</em><span class="optional">[</span>, <em>reporthook</em><span class="optional">[</span>, <em>data</em><span class="optional">[</span>, <em>context</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.urlretrieve" title="Permalink to this definition">¶</a></dt> <dd><p>Copy a network object denoted by a URL to a local file, if necessary. If the URL points to a local file, or a valid cached copy of the object exists, the object is not copied. Return a tuple <code class="docutils literal notranslate"><span class="pre">(filename,</span> <span class="pre">headers)</span></code> where <em>filename</em> is the local file name under which the object can be found, and <em>headers</em> is whatever the <code class="xref py py-meth docutils literal notranslate"><span class="pre">info()</span></code> method of the object returned by <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> returned (for a remote object, possibly cached). Exceptions are the same as for <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a>.</p> <p>The second argument, if present, specifies the file location to copy to (if absent, the location will be a tempfile with a generated name). The third argument, if present, is a callable that will be called once on establishment of the network connection and once after each block read thereafter. The callable will be passed three arguments; a count of blocks transferred so far, a block size in bytes, and the total size of the file. The third argument may be <code class="docutils literal notranslate"><span class="pre">-1</span></code> on older FTP servers which do not return a file size in response to a retrieval request.</p> <p>If the <em>url</em> uses the <code class="file docutils literal notranslate"><span class="pre">http:</span></code> scheme identifier, the optional <em>data</em> argument may be given to specify a <code class="docutils literal notranslate"><span class="pre">POST</span></code> request (normally the request type is <code class="docutils literal notranslate"><span class="pre">GET</span></code>). The <em>data</em> argument must in standard <em class="mimetype">application/x-www-form-urlencoded</em> format; see the <a class="reference internal" href="#urllib.urlencode" title="urllib.urlencode"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlencode()</span></code></a> function below.</p> <p>The <em>context</em> parameter may be set to a <a class="reference internal" href="ssl.html#ssl.SSLContext" title="ssl.SSLContext"><code class="xref py py-class docutils literal notranslate"><span class="pre">ssl.SSLContext</span></code></a> instance to configure the SSL settings that are used if <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> makes a HTTPS connection.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.5: </span><a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> will raise <a class="reference internal" href="#urllib.ContentTooShortError" title="urllib.ContentTooShortError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ContentTooShortError</span></code></a> when it detects that the amount of data available was less than the expected amount (which is the size reported by a <em>Content-Length</em> header). This can occur, for example, when the download is interrupted.</p> <p>The <em>Content-Length</em> is treated as a lower bound: if there’s more data to read, <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> reads more data, but if less data is available, it raises the exception.</p> <p>You can still retrieve the downloaded data in this case, it is stored in the <code class="xref py py-attr docutils literal notranslate"><span class="pre">content</span></code> attribute of the exception instance.</p> <p>If no <em>Content-Length</em> header was supplied, <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> can not check the size of the data it has downloaded, and just returns it. In this case you just have to assume that the download was successful.</p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.7.9: </span>The <em>context</em> parameter was added. All the neccessary certificate and hostname checks are done by default.</p> </div> </dd></dl> <dl class="data"> <dt id="urllib._urlopener"> <code class="descclassname">urllib.</code><code class="descname">_urlopener</code><a class="headerlink" href="#urllib._urlopener" title="Permalink to this definition">¶</a></dt> <dd><p>The public functions <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> and <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> create an instance of the <a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a> class and use it to perform their requested actions. To override this functionality, programmers can create a subclass of <a class="reference internal" href="#urllib.URLopener" title="urllib.URLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">URLopener</span></code></a> or <a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a>, then assign an instance of that class to the <code class="docutils literal notranslate"><span class="pre">urllib._urlopener</span></code> variable before calling the desired function. For example, applications may want to specify a different <em class="mailheader">User-Agent</em> header than <a class="reference internal" href="#urllib.URLopener" title="urllib.URLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">URLopener</span></code></a> defines. This can be accomplished with the following code:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">urllib</span> <span class="k">class</span> <span class="nc">AppURLopener</span><span class="p">(</span><span class="n">urllib</span><span class="o">.</span><span class="n">FancyURLopener</span><span class="p">):</span> <span class="n">version</span> <span class="o">=</span> <span class="s2">"App/1.7"</span> <span class="n">urllib</span><span class="o">.</span><span class="n">_urlopener</span> <span class="o">=</span> <span class="n">AppURLopener</span><span class="p">()</span> </pre></div> </div> </dd></dl> <dl class="function"> <dt id="urllib.urlcleanup"> <code class="descclassname">urllib.</code><code class="descname">urlcleanup</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.urlcleanup" title="Permalink to this definition">¶</a></dt> <dd><p>Clear the cache that may have been built up by previous calls to <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a>.</p> </dd></dl> </div> <div class="section" id="utility-functions"> <h2>20.5.2. Utility functions<a class="headerlink" href="#utility-functions" title="Permalink to this headline">¶</a></h2> <dl class="function"> <dt id="urllib.quote"> <code class="descclassname">urllib.</code><code class="descname">quote</code><span class="sig-paren">(</span><em>string</em><span class="optional">[</span>, <em>safe</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.quote" title="Permalink to this definition">¶</a></dt> <dd><p>Replace special characters in <em>string</em> using the <code class="docutils literal notranslate"><span class="pre">%xx</span></code> escape. Letters, digits, and the characters <code class="docutils literal notranslate"><span class="pre">'_.-'</span></code> are never quoted. By default, this function is intended for quoting the path section of the URL. The optional <em>safe</em> parameter specifies additional characters that should not be quoted — its default value is <code class="docutils literal notranslate"><span class="pre">'/'</span></code>.</p> <p>Example: <code class="docutils literal notranslate"><span class="pre">quote('/~connolly/')</span></code> yields <code class="docutils literal notranslate"><span class="pre">'/%7econnolly/'</span></code>.</p> </dd></dl> <dl class="function"> <dt id="urllib.quote_plus"> <code class="descclassname">urllib.</code><code class="descname">quote_plus</code><span class="sig-paren">(</span><em>string</em><span class="optional">[</span>, <em>safe</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.quote_plus" title="Permalink to this definition">¶</a></dt> <dd><p>Like <a class="reference internal" href="#urllib.quote" title="urllib.quote"><code class="xref py py-func docutils literal notranslate"><span class="pre">quote()</span></code></a>, but also replaces spaces by plus signs, as required for quoting HTML form values when building up a query string to go into a URL. Plus signs in the original string are escaped unless they are included in <em>safe</em>. It also does not have <em>safe</em> default to <code class="docutils literal notranslate"><span class="pre">'/'</span></code>.</p> </dd></dl> <dl class="function"> <dt id="urllib.unquote"> <code class="descclassname">urllib.</code><code class="descname">unquote</code><span class="sig-paren">(</span><em>string</em><span class="sig-paren">)</span><a class="headerlink" href="#urllib.unquote" title="Permalink to this definition">¶</a></dt> <dd><p>Replace <code class="docutils literal notranslate"><span class="pre">%xx</span></code> escapes by their single-character equivalent.</p> <p>Example: <code class="docutils literal notranslate"><span class="pre">unquote('/%7Econnolly/')</span></code> yields <code class="docutils literal notranslate"><span class="pre">'/~connolly/'</span></code>.</p> </dd></dl> <dl class="function"> <dt id="urllib.unquote_plus"> <code class="descclassname">urllib.</code><code class="descname">unquote_plus</code><span class="sig-paren">(</span><em>string</em><span class="sig-paren">)</span><a class="headerlink" href="#urllib.unquote_plus" title="Permalink to this definition">¶</a></dt> <dd><p>Like <a class="reference internal" href="#urllib.unquote" title="urllib.unquote"><code class="xref py py-func docutils literal notranslate"><span class="pre">unquote()</span></code></a>, but also replaces plus signs by spaces, as required for unquoting HTML form values.</p> </dd></dl> <dl class="function"> <dt id="urllib.urlencode"> <code class="descclassname">urllib.</code><code class="descname">urlencode</code><span class="sig-paren">(</span><em>query</em><span class="optional">[</span>, <em>doseq</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.urlencode" title="Permalink to this definition">¶</a></dt> <dd><p>Convert a mapping object or a sequence of two-element tuples to a “percent-encoded” string, suitable to pass to <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> above as the optional <em>data</em> argument. This is useful to pass a dictionary of form fields to a <code class="docutils literal notranslate"><span class="pre">POST</span></code> request. The resulting string is a series of <code class="docutils literal notranslate"><span class="pre">key=value</span></code> pairs separated by <code class="docutils literal notranslate"><span class="pre">'&'</span></code> characters, where both <em>key</em> and <em>value</em> are quoted using <a class="reference internal" href="#urllib.quote_plus" title="urllib.quote_plus"><code class="xref py py-func docutils literal notranslate"><span class="pre">quote_plus()</span></code></a> above. When a sequence of two-element tuples is used as the <em>query</em> argument, the first element of each tuple is a key and the second is a value. The value element in itself can be a sequence and in that case, if the optional parameter <em>doseq</em> is evaluates to <code class="docutils literal notranslate"><span class="pre">True</span></code>, individual <code class="docutils literal notranslate"><span class="pre">key=value</span></code> pairs separated by <code class="docutils literal notranslate"><span class="pre">'&'</span></code> are generated for each element of the value sequence for the key. The order of parameters in the encoded string will match the order of parameter tuples in the sequence. The <a class="reference internal" href="urlparse.html#module-urlparse" title="urlparse: Parse URLs into or assemble them from components."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urlparse</span></code></a> module provides the functions <code class="xref py py-func docutils literal notranslate"><span class="pre">parse_qs()</span></code> and <code class="xref py py-func docutils literal notranslate"><span class="pre">parse_qsl()</span></code> which are used to parse query strings into Python data structures.</p> </dd></dl> <dl class="function"> <dt id="urllib.pathname2url"> <code class="descclassname">urllib.</code><code class="descname">pathname2url</code><span class="sig-paren">(</span><em>path</em><span class="sig-paren">)</span><a class="headerlink" href="#urllib.pathname2url" title="Permalink to this definition">¶</a></dt> <dd><p>Convert the pathname <em>path</em> from the local syntax for a path to the form used in the path component of a URL. This does not produce a complete URL. The return value will already be quoted using the <a class="reference internal" href="#urllib.quote" title="urllib.quote"><code class="xref py py-func docutils literal notranslate"><span class="pre">quote()</span></code></a> function.</p> </dd></dl> <dl class="function"> <dt id="urllib.url2pathname"> <code class="descclassname">urllib.</code><code class="descname">url2pathname</code><span class="sig-paren">(</span><em>path</em><span class="sig-paren">)</span><a class="headerlink" href="#urllib.url2pathname" title="Permalink to this definition">¶</a></dt> <dd><p>Convert the path component <em>path</em> from a percent-encoded URL to the local syntax for a path. This does not accept a complete URL. This function uses <a class="reference internal" href="#urllib.unquote" title="urllib.unquote"><code class="xref py py-func docutils literal notranslate"><span class="pre">unquote()</span></code></a> to decode <em>path</em>.</p> </dd></dl> <dl class="function"> <dt id="urllib.getproxies"> <code class="descclassname">urllib.</code><code class="descname">getproxies</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.getproxies" title="Permalink to this definition">¶</a></dt> <dd><p>This helper function returns a dictionary of scheme to proxy server URL mappings. It scans the environment for variables named <code class="docutils literal notranslate"><span class="pre"><scheme>_proxy</span></code>, in case insensitive way, for all operating systems first, and when it cannot find it, looks for proxy information from Mac OSX System Configuration for Mac OS X and Windows Systems Registry for Windows. If both lowercase and uppercase environment variables exist (and disagree), lowercase is preferred.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">If the environment variable <code class="docutils literal notranslate"><span class="pre">REQUEST_METHOD</span></code> is set, which usually indicates your script is running in a CGI environment, the environment variable <code class="docutils literal notranslate"><span class="pre">HTTP_PROXY</span></code> (uppercase <code class="docutils literal notranslate"><span class="pre">_PROXY</span></code>) will be ignored. This is because that variable can be injected by a client using the “Proxy:” HTTP header. If you need to use an HTTP proxy in a CGI environment, either use <code class="docutils literal notranslate"><span class="pre">ProxyHandler</span></code> explicitly, or make sure the variable name is in lowercase (or at least the <code class="docutils literal notranslate"><span class="pre">_proxy</span></code> suffix).</p> </div> </dd></dl> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">urllib also exposes certain utility functions like splittype, splithost and others parsing URL into various components. But it is recommended to use <a class="reference internal" href="urlparse.html#module-urlparse" title="urlparse: Parse URLs into or assemble them from components."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urlparse</span></code></a> for parsing URLs rather than using these functions directly. Python 3 does not expose these helper functions from <code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib.parse</span></code> module.</p> </div> </div> <div class="section" id="url-opener-objects"> <h2>20.5.3. URL Opener objects<a class="headerlink" href="#url-opener-objects" title="Permalink to this headline">¶</a></h2> <dl class="class"> <dt id="urllib.URLopener"> <em class="property">class </em><code class="descclassname">urllib.</code><code class="descname">URLopener</code><span class="sig-paren">(</span><span class="optional">[</span><em>proxies</em><span class="optional">[</span>, <em>context</em><span class="optional">[</span>, <em>**x509</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.URLopener" title="Permalink to this definition">¶</a></dt> <dd><p>Base class for opening and reading URLs. Unless you need to support opening objects using schemes other than <code class="file docutils literal notranslate"><span class="pre">http:</span></code>, <code class="file docutils literal notranslate"><span class="pre">ftp:</span></code>, or <code class="file docutils literal notranslate"><span class="pre">file:</span></code>, you probably want to use <a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a>.</p> <p>By default, the <a class="reference internal" href="#urllib.URLopener" title="urllib.URLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">URLopener</span></code></a> class sends a <em class="mailheader">User-Agent</em> header of <code class="docutils literal notranslate"><span class="pre">urllib/VVV</span></code>, where <em>VVV</em> is the <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> version number. Applications can define their own <em class="mailheader">User-Agent</em> header by subclassing <a class="reference internal" href="#urllib.URLopener" title="urllib.URLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">URLopener</span></code></a> or <a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a> and setting the class attribute <a class="reference internal" href="#urllib.URLopener.version" title="urllib.URLopener.version"><code class="xref py py-attr docutils literal notranslate"><span class="pre">version</span></code></a> to an appropriate string value in the subclass definition.</p> <p>The optional <em>proxies</em> parameter should be a dictionary mapping scheme names to proxy URLs, where an empty dictionary turns proxies off completely. Its default value is <code class="docutils literal notranslate"><span class="pre">None</span></code>, in which case environmental proxy settings will be used if present, as discussed in the definition of <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a>, above.</p> <p>The <em>context</em> parameter may be a <a class="reference internal" href="ssl.html#ssl.SSLContext" title="ssl.SSLContext"><code class="xref py py-class docutils literal notranslate"><span class="pre">ssl.SSLContext</span></code></a> instance. If given, it defines the SSL settings the opener uses to make HTTPS connections.</p> <p>Additional keyword parameters, collected in <em>x509</em>, may be used for authentication of the client when using the <code class="file docutils literal notranslate"><span class="pre">https:</span></code> scheme. The keywords <em>key_file</em> and <em>cert_file</em> are supported to provide an SSL key and certificate; both are needed to support client authentication.</p> <p><a class="reference internal" href="#urllib.URLopener" title="urllib.URLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">URLopener</span></code></a> objects will raise an <a class="reference internal" href="exceptions.html#exceptions.IOError" title="exceptions.IOError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IOError</span></code></a> exception if the server returns an error code.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.7.9: </span>The <em>context</em> parameter was added. All the neccessary certificate and hostname checks are done by default.</p> </div> <dl class="method"> <dt id="urllib.URLopener.open"> <code class="descname">open</code><span class="sig-paren">(</span><em>fullurl</em><span class="optional">[</span>, <em>data</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.URLopener.open" title="Permalink to this definition">¶</a></dt> <dd><p>Open <em>fullurl</em> using the appropriate protocol. This method sets up cache and proxy information, then calls the appropriate open method with its input arguments. If the scheme is not recognized, <a class="reference internal" href="#urllib.URLopener.open_unknown" title="urllib.URLopener.open_unknown"><code class="xref py py-meth docutils literal notranslate"><span class="pre">open_unknown()</span></code></a> is called. The <em>data</em> argument has the same meaning as the <em>data</em> argument of <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a>.</p> </dd></dl> <dl class="method"> <dt id="urllib.URLopener.open_unknown"> <code class="descname">open_unknown</code><span class="sig-paren">(</span><em>fullurl</em><span class="optional">[</span>, <em>data</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.URLopener.open_unknown" title="Permalink to this definition">¶</a></dt> <dd><p>Overridable interface to open unknown URL types.</p> </dd></dl> <dl class="method"> <dt id="urllib.URLopener.retrieve"> <code class="descname">retrieve</code><span class="sig-paren">(</span><em>url</em><span class="optional">[</span>, <em>filename</em><span class="optional">[</span>, <em>reporthook</em><span class="optional">[</span>, <em>data</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.URLopener.retrieve" title="Permalink to this definition">¶</a></dt> <dd><p>Retrieves the contents of <em>url</em> and places it in <em>filename</em>. The return value is a tuple consisting of a local filename and either a <a class="reference internal" href="mimetools.html#mimetools.Message" title="mimetools.Message"><code class="xref py py-class docutils literal notranslate"><span class="pre">mimetools.Message</span></code></a> object containing the response headers (for remote URLs) or <code class="docutils literal notranslate"><span class="pre">None</span></code> (for local URLs). The caller must then open and read the contents of <em>filename</em>. If <em>filename</em> is not given and the URL refers to a local file, the input filename is returned. If the URL is non-local and <em>filename</em> is not given, the filename is the output of <a class="reference internal" href="tempfile.html#tempfile.mktemp" title="tempfile.mktemp"><code class="xref py py-func docutils literal notranslate"><span class="pre">tempfile.mktemp()</span></code></a> with a suffix that matches the suffix of the last path component of the input URL. If <em>reporthook</em> is given, it must be a function accepting three numeric parameters. It will be called after each chunk of data is read from the network. <em>reporthook</em> is ignored for local URLs.</p> <p>If the <em>url</em> uses the <code class="file docutils literal notranslate"><span class="pre">http:</span></code> scheme identifier, the optional <em>data</em> argument may be given to specify a <code class="docutils literal notranslate"><span class="pre">POST</span></code> request (normally the request type is <code class="docutils literal notranslate"><span class="pre">GET</span></code>). The <em>data</em> argument must in standard <em class="mimetype">application/x-www-form-urlencoded</em> format; see the <a class="reference internal" href="#urllib.urlencode" title="urllib.urlencode"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlencode()</span></code></a> function below.</p> </dd></dl> <dl class="attribute"> <dt id="urllib.URLopener.version"> <code class="descname">version</code><a class="headerlink" href="#urllib.URLopener.version" title="Permalink to this definition">¶</a></dt> <dd><p>Variable that specifies the user agent of the opener object. To get <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> to tell servers that it is a particular user agent, set this in a subclass as a class variable or in the constructor before calling the base constructor.</p> </dd></dl> </dd></dl> <dl class="class"> <dt id="urllib.FancyURLopener"> <em class="property">class </em><code class="descclassname">urllib.</code><code class="descname">FancyURLopener</code><span class="sig-paren">(</span><em>...</em><span class="sig-paren">)</span><a class="headerlink" href="#urllib.FancyURLopener" title="Permalink to this definition">¶</a></dt> <dd><p><a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a> subclasses <a class="reference internal" href="#urllib.URLopener" title="urllib.URLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">URLopener</span></code></a> providing default handling for the following HTTP response codes: 301, 302, 303, 307 and 401. For the 30x response codes listed above, the <em class="mailheader">Location</em> header is used to fetch the actual URL. For 401 response codes (authentication required), basic HTTP authentication is performed. For the 30x response codes, recursion is bounded by the value of the <em>maxtries</em> attribute, which defaults to 10.</p> <p>For all other response codes, the method <code class="xref py py-meth docutils literal notranslate"><span class="pre">http_error_default()</span></code> is called which you can override in subclasses to handle the error appropriately.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">According to the letter of <span class="target" id="index-7"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc2616.html"><strong>RFC 2616</strong></a>, 301 and 302 responses to POST requests must not be automatically redirected without confirmation by the user. In reality, browsers do allow automatic redirection of these responses, changing the POST to a GET, and <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> reproduces this behaviour.</p> </div> <p>The parameters to the constructor are the same as those for <a class="reference internal" href="#urllib.URLopener" title="urllib.URLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">URLopener</span></code></a>.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">When performing basic authentication, a <a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a> instance calls its <a class="reference internal" href="#urllib.FancyURLopener.prompt_user_passwd" title="urllib.FancyURLopener.prompt_user_passwd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">prompt_user_passwd()</span></code></a> method. The default implementation asks the users for the required information on the controlling terminal. A subclass may override this method to support more appropriate behavior if needed.</p> </div> <p>The <a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a> class offers one additional method that should be overloaded to provide the appropriate behavior:</p> <dl class="method"> <dt id="urllib.FancyURLopener.prompt_user_passwd"> <code class="descname">prompt_user_passwd</code><span class="sig-paren">(</span><em>host</em>, <em>realm</em><span class="sig-paren">)</span><a class="headerlink" href="#urllib.FancyURLopener.prompt_user_passwd" title="Permalink to this definition">¶</a></dt> <dd><p>Return information needed to authenticate the user at the given host in the specified security realm. The return value should be a tuple, <code class="docutils literal notranslate"><span class="pre">(user,</span> <span class="pre">password)</span></code>, which can be used for basic authentication.</p> <p>The implementation prompts for this information on the terminal; an application should override this method to use an appropriate interaction model in the local environment.</p> </dd></dl> </dd></dl> <dl class="exception"> <dt id="urllib.ContentTooShortError"> <em class="property">exception </em><code class="descclassname">urllib.</code><code class="descname">ContentTooShortError</code><span class="sig-paren">(</span><em>msg</em><span class="optional">[</span>, <em>content</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#urllib.ContentTooShortError" title="Permalink to this definition">¶</a></dt> <dd><p>This exception is raised when the <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> function detects that the amount of the downloaded data is less than the expected amount (given by the <em>Content-Length</em> header). The <code class="xref py py-attr docutils literal notranslate"><span class="pre">content</span></code> attribute stores the downloaded (and supposedly truncated) data.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 2.5.</span></p> </div> </dd></dl> </div> <div class="section" id="urllib-restrictions"> <h2>20.5.4. <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> Restrictions<a class="headerlink" href="#urllib-restrictions" title="Permalink to this headline">¶</a></h2> <blockquote> <div></div></blockquote> <ul id="index-8"> <li><p class="first">Currently, only the following protocols are supported: HTTP, (versions 0.9 and 1.0), FTP, and local files.</p> </li> <li><p class="first">The caching feature of <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> has been disabled until I find the time to hack proper processing of Expiration time headers.</p> </li> <li><p class="first">There should be a function to query whether a particular URL is in the cache.</p> </li> <li><p class="first">For backward compatibility, if a URL appears to point to a local file but the file can’t be opened, the URL is re-interpreted using the FTP protocol. This can sometimes cause confusing error messages.</p> </li> <li><p class="first">The <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> and <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> functions can cause arbitrarily long delays while waiting for a network connection to be set up. This means that it is difficult to build an interactive Web client using these functions without using threads.</p> </li> <li id="index-9"><p class="first">The data returned by <a class="reference internal" href="#urllib.urlopen" title="urllib.urlopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlopen()</span></code></a> or <a class="reference internal" href="#urllib.urlretrieve" title="urllib.urlretrieve"><code class="xref py py-func docutils literal notranslate"><span class="pre">urlretrieve()</span></code></a> is the raw data returned by the server. This may be binary data (such as an image), plain text or (for example) HTML. The HTTP protocol provides type information in the reply header, which can be inspected by looking at the <em class="mailheader">Content-Type</em> header. If the returned data is HTML, you can use the module <a class="reference internal" href="htmllib.html#module-htmllib" title="htmllib: A parser for HTML documents. (deprecated)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">htmllib</span></code></a> to parse it.</p> </li> <li id="index-10"><p class="first">The code handling the FTP protocol cannot differentiate between a file and a directory. This can lead to unexpected behavior when attempting to read a URL that points to a file that is not accessible. If the URL ends in a <code class="docutils literal notranslate"><span class="pre">/</span></code>, it is assumed to refer to a directory and will be handled accordingly. But if an attempt to read a file leads to a 550 error (meaning the URL cannot be found or is not accessible, often for permission reasons), then the path is treated as a directory in order to handle the case when a directory is specified by a URL but the trailing <code class="docutils literal notranslate"><span class="pre">/</span></code> has been left off. This can cause misleading results when you try to fetch a file whose read permissions make it inaccessible; the FTP code will try to read it, fail with a 550 error, and then perform a directory listing for the unreadable file. If fine-grained control is needed, consider using the <a class="reference internal" href="ftplib.html#module-ftplib" title="ftplib: FTP protocol client (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">ftplib</span></code></a> module, subclassing <a class="reference internal" href="#urllib.FancyURLopener" title="urllib.FancyURLopener"><code class="xref py py-class docutils literal notranslate"><span class="pre">FancyURLopener</span></code></a>, or changing <em>_urlopener</em> to meet your needs.</p> </li> <li><p class="first">This module does not support the use of proxies which require authentication. This may be implemented in the future.</p> </li> <li id="index-11"><p class="first">Although the <a class="reference internal" href="#module-urllib" title="urllib: Open an arbitrary network resource by URL (requires sockets)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urllib</span></code></a> module contains (undocumented) routines to parse and unparse URL strings, the recommended interface for URL manipulation is in module <a class="reference internal" href="urlparse.html#module-urlparse" title="urlparse: Parse URLs into or assemble them from components."><code class="xref py py-mod docutils literal notranslate"><span class="pre">urlparse</span></code></a>.</p> </li> </ul> </div> <div class="section" id="examples"> <span id="urllib-examples"></span><h2>20.5.5. Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h2> <p>Here is an example session that uses the <code class="docutils literal notranslate"><span class="pre">GET</span></code> method to retrieve a URL containing parameters:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">urllib</span> <span class="gp">>>> </span><span class="n">params</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlencode</span><span class="p">({</span><span class="s1">'spam'</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> <span class="s1">'eggs'</span><span class="p">:</span> <span class="mi">2</span><span class="p">,</span> <span class="s1">'bacon'</span><span class="p">:</span> <span class="mi">0</span><span class="p">})</span> <span class="gp">>>> </span><span class="n">f</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="s2">"http://www.musi-cal.com/cgi-bin/query?</span><span class="si">%s</span><span class="s2">"</span> <span class="o">%</span> <span class="n">params</span><span class="p">)</span> <span class="gp">>>> </span><span class="nb">print</span> <span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">()</span> </pre></div> </div> <p>The following example uses the <code class="docutils literal notranslate"><span class="pre">POST</span></code> method instead:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">urllib</span> <span class="gp">>>> </span><span class="n">params</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlencode</span><span class="p">({</span><span class="s1">'spam'</span><span class="p">:</span> <span class="mi">1</span><span class="p">,</span> <span class="s1">'eggs'</span><span class="p">:</span> <span class="mi">2</span><span class="p">,</span> <span class="s1">'bacon'</span><span class="p">:</span> <span class="mi">0</span><span class="p">})</span> <span class="gp">>>> </span><span class="n">f</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">urlopen</span><span class="p">(</span><span class="s2">"http://www.musi-cal.com/cgi-bin/query"</span><span class="p">,</span> <span class="n">params</span><span class="p">)</span> <span class="gp">>>> </span><span class="nb">print</span> <span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">()</span> </pre></div> </div> <p>The following example uses an explicitly specified HTTP proxy, overriding environment settings:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">urllib</span> <span class="gp">>>> </span><span class="n">proxies</span> <span class="o">=</span> <span class="p">{</span><span class="s1">'http'</span><span class="p">:</span> <span class="s1">'http://proxy.example.com:8080/'</span><span class="p">}</span> <span class="gp">>>> </span><span class="n">opener</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">FancyURLopener</span><span class="p">(</span><span class="n">proxies</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">f</span> <span class="o">=</span> <span class="n">opener</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s2">"http://www.python.org"</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">()</span> </pre></div> </div> <p>The following example uses no proxies at all, overriding environment settings:</p> <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">urllib</span> <span class="gp">>>> </span><span class="n">opener</span> <span class="o">=</span> <span class="n">urllib</span><span class="o">.</span><span class="n">FancyURLopener</span><span class="p">({})</span> <span class="gp">>>> </span><span class="n">f</span> <span class="o">=</span> <span class="n">opener</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s2">"http://www.python.org/"</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">f</span><span class="o">.</span><span class="n">read</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="../contents.html">Table of Contents</a></h3> <ul> <li><a class="reference internal" href="#">20.5. <code class="docutils literal notranslate"><span class="pre">urllib</span></code> — Open arbitrary resources by URL</a><ul> <li><a class="reference internal" href="#high-level-interface">20.5.1. High-level interface</a></li> <li><a class="reference internal" href="#utility-functions">20.5.2. Utility functions</a></li> <li><a class="reference internal" href="#url-opener-objects">20.5.3. URL Opener objects</a></li> <li><a class="reference internal" href="#urllib-restrictions">20.5.4. <code class="docutils literal notranslate"><span class="pre">urllib</span></code> Restrictions</a></li> <li><a class="reference internal" href="#examples">20.5.5. 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