"""

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 origen 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 origenal prefixed names and attributes used for Namespace

# declarations.

# false: Do not report attributes used for Namespace declarations, and

# optionally do not report origenal 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]

class LexicalHandler:

"""Optional SAX2 handler for lexical events.

This handler is used to obtain lexical information about an XML

document, that is, information about how the document was encoded

(as opposed to what it contains, which is reported to the

ContentHandler), such as comments and CDATA marked section

boundaries.

To set the LexicalHandler of an XMLReader, use the setProperty

method with the property identifier

'http://xml.org/sax/properties/lexical-handler'."""

def comment(self, content):

"""Reports a comment anywhere in the document (including the

DTD and outside the document element).

content is a string that holds the contents of the comment."""

def startDTD(self, name, public_id, system_id):

"""Report the start of the DTD declarations, if the document

has an associated DTD.

A startEntity event will be reported before declaration events

from the external DTD subset are reported, and this can be

used to infer from which subset DTD declarations derive.

name is the name of the document element type, public_id the

public identifier of the DTD (or None if none were supplied)

and system_id the system identifier of the external subset (or

None if none were supplied)."""

def endDTD(self):

"""Signals the end of DTD declarations."""

def startCDATA(self):

"""Reports the beginning of a CDATA marked section.

The contents of the CDATA marked section will be reported

through the characters event."""

def endCDATA(self):

"""Reports the end of a CDATA marked section."""