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Diffstat (limited to 'Lib/xml/sax/handler.py')
| -rw-r--r-- | Lib/xml/sax/handler.py | 342 |
1 files changed, 342 insertions, 0 deletions
diff --git a/Lib/xml/sax/handler.py b/Lib/xml/sax/handler.py new file mode 100644 index 0000000..f9e91b6 --- /dev/null +++ b/Lib/xml/sax/handler.py @@ -0,0 +1,342 @@ +""" +This module contains the core classes of version 2.0 of SAX for Python. +This file provides only default classes with absolutely minimum +functionality, from which drivers and applications can be subclassed. + +Many of these classes are empty and are included only as documentation +of the interfaces. + +$Id$ +""" + +version = '2.0beta' + +#============================================================================ +# +# HANDLER INTERFACES +# +#============================================================================ + +# ===== ERRORHANDLER ===== + +class ErrorHandler: + """Basic interface for SAX error handlers. + + If you create an object that implements this interface, then + register the object with your XMLReader, the parser will call the + methods in your object to report all warnings and errors. There + are three levels of errors available: warnings, (possibly) + recoverable errors, and unrecoverable errors. All methods take a + SAXParseException as the only parameter.""" + + def error(self, exception): + "Handle a recoverable error." + raise exception + + def fatalError(self, exception): + "Handle a non-recoverable error." + raise exception + + def warning(self, exception): + "Handle a warning." + print exception + + +# ===== CONTENTHANDLER ===== + +class ContentHandler: + """Interface for receiving logical document content events. + + This is the main callback interface in SAX, and the one most + important to applications. The order of events in this interface + mirrors the order of the information in the document.""" + + def __init__(self): + self._locator = None + + def setDocumentLocator(self, locator): + """Called by the parser to give the application a locator for + locating the origin of document events. + + SAX parsers are strongly encouraged (though not absolutely + required) to supply a locator: if it does so, it must supply + the locator to the application by invoking this method before + invoking any of the other methods in the DocumentHandler + interface. + + The locator allows the application to determine the end + position of any document-related event, even if the parser is + not reporting an error. Typically, the application will use + this information for reporting its own errors (such as + character content that does not match an application's + business rules). The information returned by the locator is + probably not sufficient for use with a search engine. + + Note that the locator will return correct information only + during the invocation of the events in this interface. The + application should not attempt to use it at any other time.""" + self._locator = locator + + def startDocument(self): + """Receive notification of the beginning of a document. + + The SAX parser will invoke this method only once, before any + other methods in this interface or in DTDHandler (except for + setDocumentLocator).""" + + def endDocument(self): + """Receive notification of the end of a document. + + The SAX parser will invoke this method only once, and it will + be the last method invoked during the parse. The parser shall + not invoke this method until it has either abandoned parsing + (because of an unrecoverable error) or reached the end of + input.""" + + def startPrefixMapping(self, prefix, uri): + """Begin the scope of a prefix-URI Namespace mapping. + + The information from this event is not necessary for normal + Namespace processing: the SAX XML reader will automatically + replace prefixes for element and attribute names when the + http://xml.org/sax/features/namespaces feature is true (the + default). + + There are cases, however, when applications need to use + prefixes in character data or in attribute values, where they + cannot safely be expanded automatically; the + start/endPrefixMapping event supplies the information to the + application to expand prefixes in those contexts itself, if + necessary. + + Note that start/endPrefixMapping events are not guaranteed to + be properly nested relative to each-other: all + startPrefixMapping events will occur before the corresponding + startElement event, and all endPrefixMapping events will occur + after the corresponding endElement event, but their order is + not guaranteed.""" + + def endPrefixMapping(self, prefix): + """End the scope of a prefix-URI mapping. + + See startPrefixMapping for details. This event will always + occur after the corresponding endElement event, but the order + of endPrefixMapping events is not otherwise guaranteed.""" + + def startElement(self, name, attrs): + """Signals the start of an element in non-namespace mode. + + The name parameter contains the raw XML 1.0 name of the + element type as a string and the attrs parameter holds an + instance of the Attributes class containing the attributes of + the element.""" + + def endElement(self, name): + """Signals the end of an element in non-namespace mode. + + The name parameter contains the name of the element type, just + as with the startElement event.""" + + def startElementNS(self, name, qname, attrs): + """Signals the start of an element in namespace mode. + + The name parameter contains the name of the element type as a + (uri, localname) tuple, the qname parameter the raw XML 1.0 + name used in the source document, and the attrs parameter + holds an instance of the Attributes class containing the + attributes of the element. + + The uri part of the name tuple is None for elements which have + no namespace.""" + + def endElementNS(self, name, qname): + """Signals the end of an element in namespace mode. + + The name parameter contains the name of the element type, just + as with the startElementNS event.""" + + def characters(self, content): + """Receive notification of character data. + + The Parser will call this method to report each chunk of + character data. SAX parsers may return all contiguous + character data in a single chunk, or they may split it into + several chunks; however, all of the characters in any single + event must come from the same external entity so that the + Locator provides useful information.""" + + def ignorableWhitespace(self, whitespace): + """Receive notification of ignorable whitespace in element content. + + Validating Parsers must use this method to report each chunk + of ignorable whitespace (see the W3C XML 1.0 recommendation, + section 2.10): non-validating parsers may also use this method + if they are capable of parsing and using content models. + + SAX parsers may return all contiguous whitespace in a single + chunk, or they may split it into several chunks; however, all + of the characters in any single event must come from the same + external entity, so that the Locator provides useful + information.""" + + def processingInstruction(self, target, data): + """Receive notification of a processing instruction. + + The Parser will invoke this method once for each processing + instruction found: note that processing instructions may occur + before or after the main document element. + + A SAX parser should never report an XML declaration (XML 1.0, + section 2.8) or a text declaration (XML 1.0, section 4.3.1) + using this method.""" + + def skippedEntity(self, name): + """Receive notification of a skipped entity. + + The Parser will invoke this method once for each entity + skipped. Non-validating processors may skip entities if they + have not seen the declarations (because, for example, the + entity was declared in an external DTD subset). All processors + may skip external entities, depending on the values of the + http://xml.org/sax/features/external-general-entities and the + http://xml.org/sax/features/external-parameter-entities + properties.""" + + +# ===== DTDHandler ===== + +class DTDHandler: + """Handle DTD events. + + This interface specifies only those DTD events required for basic + parsing (unparsed entities and attributes).""" + + def notationDecl(self, name, publicId, systemId): + "Handle a notation declaration event." + + def unparsedEntityDecl(self, name, publicId, systemId, ndata): + "Handle an unparsed entity declaration event." + + +# ===== ENTITYRESOLVER ===== + +class EntityResolver: + """Basic interface for resolving entities. If you create an object + implementing this interface, then register the object with your + Parser, the parser will call the method in your object to + resolve all external entities. Note that DefaultHandler implements + this interface with the default behaviour.""" + + def resolveEntity(self, publicId, systemId): + """Resolve the system identifier of an entity and return either + the system identifier to read from as a string, or an InputSource + to read from.""" + return systemId + + +#============================================================================ +# +# CORE FEATURES +# +#============================================================================ + +feature_namespaces = "http://xml.org/sax/features/namespaces" +# true: Perform Namespace processing (default). +# false: Optionally do not perform Namespace processing +# (implies namespace-prefixes). +# access: (parsing) read-only; (not parsing) read/write + +feature_namespace_prefixes = "http://xml.org/sax/features/namespace-prefixes" +# true: Report the original prefixed names and attributes used for Namespace +# declarations. +# false: Do not report attributes used for Namespace declarations, and +# optionally do not report original prefixed names (default). +# access: (parsing) read-only; (not parsing) read/write + +feature_string_interning = "http://xml.org/sax/features/string-interning" +# true: All element names, prefixes, attribute names, Namespace URIs, and +# local names are interned using the built-in intern function. +# false: Names are not necessarily interned, although they may be (default). +# access: (parsing) read-only; (not parsing) read/write + +feature_validation = "http://xml.org/sax/features/validation" +# true: Report all validation errors (implies external-general-entities and +# external-parameter-entities). +# false: Do not report validation errors. +# access: (parsing) read-only; (not parsing) read/write + +feature_external_ges = "http://xml.org/sax/features/external-general-entities" +# true: Include all external general (text) entities. +# false: Do not include external general entities. +# access: (parsing) read-only; (not parsing) read/write + +feature_external_pes = "http://xml.org/sax/features/external-parameter-entities" +# true: Include all external parameter entities, including the external +# DTD subset. +# false: Do not include any external parameter entities, even the external +# DTD subset. +# access: (parsing) read-only; (not parsing) read/write + +all_features = [feature_namespaces, + feature_namespace_prefixes, + feature_string_interning, + feature_validation, + feature_external_ges, + feature_external_pes] + + +#============================================================================ +# +# CORE PROPERTIES +# +#============================================================================ + +property_lexical_handler = "http://xml.org/sax/properties/lexical-handler" +# data type: xml.sax.sax2lib.LexicalHandler +# description: An optional extension handler for lexical events like comments. +# access: read/write + +property_declaration_handler = "http://xml.org/sax/properties/declaration-handler" +# data type: xml.sax.sax2lib.DeclHandler +# description: An optional extension handler for DTD-related events other +# than notations and unparsed entities. +# access: read/write + +property_dom_node = "http://xml.org/sax/properties/dom-node" +# data type: org.w3c.dom.Node +# description: When parsing, the current DOM node being visited if this is +# a DOM iterator; when not parsing, the root DOM node for +# iteration. +# access: (parsing) read-only; (not parsing) read/write + +property_xml_string = "http://xml.org/sax/properties/xml-string" +# data type: String +# description: The literal string of characters that was the source for +# the current event. +# access: read-only + +property_encoding = "http://www.python.org/sax/properties/encoding" +# data type: String +# description: The name of the encoding to assume for input data. +# access: write: set the encoding, e.g. established by a higher-level +# protocol. May change during parsing (e.g. after +# processing a META tag) +# read: return the current encoding (possibly established through +# auto-detection. +# initial value: UTF-8 +# + +property_interning_dict = "http://www.python.org/sax/properties/interning-dict" +# data type: Dictionary +# description: The dictionary used to intern common strings in the document +# access: write: Request that the parser uses a specific dictionary, to +# allow interning across different documents +# read: return the current interning dictionary, or None +# + +all_properties = [property_lexical_handler, + property_dom_node, + property_declaration_handler, + property_xml_string, + property_encoding, + property_interning_dict] |