path: root/devdocs/python~3.12/library%2Fxml.sax.html

 <span id="xml-sax-support-for-sax2-parsers"></span><h1>xml.sax — Support for SAX2 parsers</h1> <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.12/Lib/xml/sax/__init__.py">Lib/xml/sax/__init__.py</a></p>  <p>The <a class="reference internal" href="#module-xml.sax" title="xml.sax: Package containing SAX2 base classes and convenience functions."><code>xml.sax</code></a> package provides a number of modules which implement the Simple API for XML (SAX) interface for Python. The package itself provides the SAX exceptions and the convenience functions which will be most used by users of the SAX API.</p> <div class="admonition warning"> <p class="admonition-title">Warning</p> <p>The <a class="reference internal" href="#module-xml.sax" title="xml.sax: Package containing SAX2 base classes and convenience functions."><code>xml.sax</code></a> module is not secure against maliciously constructed data. If you need to parse untrusted or unauthenticated data see <a class="reference internal" href="xml#xml-vulnerabilities"><span class="std std-ref">XML vulnerabilities</span></a>.</p> </div> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.7.1: </span>The SAX parser no longer processes general external entities by default to increase security. Before, the parser created network connections to fetch remote files or loaded local files from the file system for DTD and entities. The feature can be enabled again with method <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.XMLReader.setFeature" title="xml.sax.xmlreader.XMLReader.setFeature"><code>setFeature()</code></a> on the parser object and argument <a class="reference internal" href="xml.sax.handler#xml.sax.handler.feature_external_ges" title="xml.sax.handler.feature_external_ges"><code>feature_external_ges</code></a>.</p> </div> <p>The convenience functions are:</p> <dl class="py function"> <dt class="sig sig-object py" id="xml.sax.make_parser">
<code>xml.sax.make_parser(parser_list=[])</code> </dt> <dd>
<p>Create and return a SAX <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.XMLReader" title="xml.sax.xmlreader.XMLReader"><code>XMLReader</code></a> object. The first parser found will be used. If <em>parser_list</em> is provided, it must be an iterable of strings which name modules that have a function named <code>create_parser()</code>. Modules listed in <em>parser_list</em> will be used before modules in the default list of parsers.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.8: </span>The <em>parser_list</em> argument can be any iterable, not just a list.</p> </div> </dd>
</dl> <dl class="py function"> <dt class="sig sig-object py" id="xml.sax.parse">
<code>xml.sax.parse(filename_or_stream, handler, error_handler=handler.ErrorHandler())</code> </dt> <dd>
<p>Create a SAX parser and use it to parse a document. The document, passed in as <em>filename_or_stream</em>, can be a filename or a file object. The <em>handler</em> parameter needs to be a SAX <a class="reference internal" href="xml.sax.handler#xml.sax.handler.ContentHandler" title="xml.sax.handler.ContentHandler"><code>ContentHandler</code></a> instance. If <em>error_handler</em> is given, it must be a SAX <a class="reference internal" href="xml.sax.handler#xml.sax.handler.ErrorHandler" title="xml.sax.handler.ErrorHandler"><code>ErrorHandler</code></a> instance; if omitted, <a class="reference internal" href="#xml.sax.SAXParseException" title="xml.sax.SAXParseException"><code>SAXParseException</code></a> will be raised on all errors. There is no return value; all work must be done by the <em>handler</em> passed in.</p> </dd>
</dl> <dl class="py function"> <dt class="sig sig-object py" id="xml.sax.parseString">
<code>xml.sax.parseString(string, handler, error_handler=handler.ErrorHandler())</code> </dt> <dd>
<p>Similar to <a class="reference internal" href="#xml.sax.parse" title="xml.sax.parse"><code>parse()</code></a>, but parses from a buffer <em>string</em> received as a parameter. <em>string</em> must be a <a class="reference internal" href="stdtypes#str" title="str"><code>str</code></a> instance or a <a class="reference internal" href="../glossary#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a>.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.5: </span>Added support of <a class="reference internal" href="stdtypes#str" title="str"><code>str</code></a> instances.</p> </div> </dd>
</dl> <p>A typical SAX application uses three kinds of objects: readers, handlers and input sources. “Reader” in this context is another term for parser, i.e. some piece of code that reads the bytes or characters from the input source, and produces a sequence of events. The events then get distributed to the handler objects, i.e. the reader invokes a method on the handler. A SAX application must therefore obtain a reader object, create or open the input sources, create the handlers, and connect these objects all together. As the final step of preparation, the reader is called to parse the input. During parsing, methods on the handler objects are called based on structural and syntactic events from the input data.</p> <p>For these objects, only the interfaces are relevant; they are normally not instantiated by the application itself. Since Python does not have an explicit notion of interface, they are formally introduced as classes, but applications may use implementations which do not inherit from the provided classes. The <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.InputSource" title="xml.sax.xmlreader.InputSource"><code>InputSource</code></a>, <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.Locator" title="xml.sax.xmlreader.Locator"><code>Locator</code></a>, <code>Attributes</code>, <code>AttributesNS</code>, and <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.XMLReader" title="xml.sax.xmlreader.XMLReader"><code>XMLReader</code></a> interfaces are defined in the module <a class="reference internal" href="xml.sax.reader#module-xml.sax.xmlreader" title="xml.sax.xmlreader: Interface which SAX-compliant XML parsers must implement."><code>xml.sax.xmlreader</code></a>. The handler interfaces are defined in <a class="reference internal" href="xml.sax.handler#module-xml.sax.handler" title="xml.sax.handler: Base classes for SAX event handlers."><code>xml.sax.handler</code></a>. For convenience, <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.InputSource" title="xml.sax.xmlreader.InputSource"><code>InputSource</code></a> (which is often instantiated directly) and the handler classes are also available from <a class="reference internal" href="#module-xml.sax" title="xml.sax: Package containing SAX2 base classes and convenience functions."><code>xml.sax</code></a>. These interfaces are described below.</p> <p>In addition to these classes, <a class="reference internal" href="#module-xml.sax" title="xml.sax: Package containing SAX2 base classes and convenience functions."><code>xml.sax</code></a> provides the following exception classes.</p> <dl class="py exception"> <dt class="sig sig-object py" id="xml.sax.SAXException">
<code>exception xml.sax.SAXException(msg, exception=None)</code> </dt> <dd>
<p>Encapsulate an XML error or warning. This class can contain basic error or warning information from either the XML parser or the application: it can be subclassed to provide additional functionality or to add localization. Note that although the handlers defined in the <a class="reference internal" href="xml.sax.handler#xml.sax.handler.ErrorHandler" title="xml.sax.handler.ErrorHandler"><code>ErrorHandler</code></a> interface receive instances of this exception, it is not required to actually raise the exception — it is also useful as a container for information.</p> <p>When instantiated, <em>msg</em> should be a human-readable description of the error. The optional <em>exception</em> parameter, if given, should be <code>None</code> or an exception that was caught by the parsing code and is being passed along as information.</p> <p>This is the base class for the other SAX exception classes.</p> </dd>
</dl> <dl class="py exception"> <dt class="sig sig-object py" id="xml.sax.SAXParseException">
<code>exception xml.sax.SAXParseException(msg, exception, locator)</code> </dt> <dd>
<p>Subclass of <a class="reference internal" href="#xml.sax.SAXException" title="xml.sax.SAXException"><code>SAXException</code></a> raised on parse errors. Instances of this class are passed to the methods of the SAX <a class="reference internal" href="xml.sax.handler#xml.sax.handler.ErrorHandler" title="xml.sax.handler.ErrorHandler"><code>ErrorHandler</code></a> interface to provide information about the parse error. This class supports the SAX <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.Locator" title="xml.sax.xmlreader.Locator"><code>Locator</code></a> interface as well as the <a class="reference internal" href="#xml.sax.SAXException" title="xml.sax.SAXException"><code>SAXException</code></a> interface.</p> </dd>
</dl> <dl class="py exception"> <dt class="sig sig-object py" id="xml.sax.SAXNotRecognizedException">
<code>exception xml.sax.SAXNotRecognizedException(msg, exception=None)</code> </dt> <dd>
<p>Subclass of <a class="reference internal" href="#xml.sax.SAXException" title="xml.sax.SAXException"><code>SAXException</code></a> raised when a SAX <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.XMLReader" title="xml.sax.xmlreader.XMLReader"><code>XMLReader</code></a> is confronted with an unrecognized feature or property. SAX applications and extensions may use this class for similar purposes.</p> </dd>
</dl> <dl class="py exception"> <dt class="sig sig-object py" id="xml.sax.SAXNotSupportedException">
<code>exception xml.sax.SAXNotSupportedException(msg, exception=None)</code> </dt> <dd>
<p>Subclass of <a class="reference internal" href="#xml.sax.SAXException" title="xml.sax.SAXException"><code>SAXException</code></a> raised when a SAX <a class="reference internal" href="xml.sax.reader#xml.sax.xmlreader.XMLReader" title="xml.sax.xmlreader.XMLReader"><code>XMLReader</code></a> is asked to enable a feature that is not supported, or to set a property to a value that the implementation does not support. SAX applications and extensions may use this class for similar purposes.</p> </dd>
</dl> <div class="admonition seealso"> <p class="admonition-title">See also</p> <dl class="simple"> <dt><a class="reference external" href="http://www.saxproject.org/">SAX: The Simple API for XML</a></dt>
<dd>
<p>This site is the focal point for the definition of the SAX API. It provides a Java implementation and online documentation. Links to implementations and historical information are also available.</p> </dd> <dt>
<code>Module</code> <a class="reference internal" href="xml.sax.handler#module-xml.sax.handler" title="xml.sax.handler: Base classes for SAX event handlers."><code>xml.sax.handler</code></a>
</dt>
<dd>
<p>Definitions of the interfaces for application-provided objects.</p> </dd> <dt>
<code>Module</code> <a class="reference internal" href="xml.sax.utils#module-xml.sax.saxutils" title="xml.sax.saxutils: Convenience functions and classes for use with SAX."><code>xml.sax.saxutils</code></a>
</dt>
<dd>
<p>Convenience functions for use in SAX applications.</p> </dd> <dt>
<code>Module</code> <a class="reference internal" href="xml.sax.reader#module-xml.sax.xmlreader" title="xml.sax.xmlreader: Interface which SAX-compliant XML parsers must implement."><code>xml.sax.xmlreader</code></a>
</dt>
<dd>
<p>Definitions of the interfaces for parser-provided objects.</p> </dd> </dl> </div> <section id="saxexception-objects"> <span id="sax-exception-objects"></span><h2>SAXException Objects</h2> <p>The <a class="reference internal" href="#xml.sax.SAXException" title="xml.sax.SAXException"><code>SAXException</code></a> exception class supports the following methods:</p> <dl class="py method"> <dt class="sig sig-object py" id="xml.sax.SAXException.getMessage">
<code>SAXException.getMessage()</code> </dt> <dd>
<p>Return a human-readable message describing the error condition.</p> </dd>
</dl> <dl class="py method"> <dt class="sig sig-object py" id="xml.sax.SAXException.getException">
<code>SAXException.getException()</code> </dt> <dd>
<p>Return an encapsulated exception object, or <code>None</code>.</p> </dd>
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