4Suite™ API Documentation

# ► Module Ft.Xml.Xslt.Processor

XSLT processing engine

    Copyright 2005 Fourthought, Inc. (USA).
    Detailed license and copyright information: http://4suite.org/COPYRIGHT
    Project home, documentation, distributions: http://4suite.org/

Classes: Processor |  |  |  | Globals: DEFAULT_ENCODING, EMPTY_NAMESPACE, XSLT_IMT

## Classes

class Processor(object)
  An XSLT processing engine (4XSLT).

      Typical usage:

      from Ft.Lib.Uri import OsPathToUri
      from Ft.Xml import InputSource
      from Ft.Xml.Xslt import Processor
      # this is just one of several ways to create InputSources
      styuri = OsPathToUri('/absolute/path/to/stylesheet.xslt')
      srcuri = OsPathToUri('/absolute/path/to/doc.xml')
      STY = InputSource.DefaultFactory.fromUri(styuri)
      SRC = InputSource.DefaultFactory.fromUri(srcuri)
      proc = Processor.Processor()
      proc.appendStylesheet(STY)
      result = proc.run(SRC)

      Optional constructor arguments are:

        stylesheetAltUris: a list of alternative base URIs to use when
          resolving relative hrefs in xsl:import/xsl:include instructions.
          These URIs are only tried when the standard XSLT behavior of
          using the base URI of the xsl:import/include element itself
          fails to result in retrieval of a document.

        documentReader: an object that will be used to parse XML source
          documents (not stylesheets). It defaults to
          Ft.Xml.Domlette.NonvalidatingReader, but it can be any object
          that has a parse() method that returns a DOM or Domlette tree.

        implementation: a DOM implementation instance that will be used
          by the processor to create new source tree nodes, such as when
          generating result tree fragments or duplicating the source tree
          when runNode(node, preserveSrc=1) is called. Defaults to
          Ft.Xml.Domlette.implementation. Needs to have a
          createRootNode() method.

      See the run() and runNode() methods for additional runtime options.

      Important instance attributes:

        .extensionParams: a dictionary that allows one to attach
          additional metadata to a processor instance. We use this
          to make invocation-specific data like HTTP query args and
          logfile handles available to XSLT extension functions & elements
          when invoking the processor via the repository's HTTP server.

        .inputSourceFactory: InputSource factory instance used when
          obtaining source documents. Defaults to
          Ft.Xml.InputSource.DefaultFactory.

        .mediaPref: the preferred/target media, for the purpose of
          picking from multiple xml-stylesheet processing instructions.
          Defaults to None. If set to a string, xml-stylesheet PIs
          without that string in their 'media' pseudo-attribute will be
          ignored.

        .msgPrefix and .msgSuffix: strings emitted before and after
          xsl:message output.

        .stylesheet: the complete stylesheet tree.

  ### Methods

  __init__(self, stylesheetAltUris=None, documentReader=None, implementation=None, stylesheetIncPaths=None)
    Overrides: __init__ from class object
  addHandler(self, outputParams, stream)
    Intended to be used by XSLT instruction implementations only.

        Sets up the processor to start processing subsequently
        generated content with an output writer wrapper that first
        determines which XSLT output method is going to be used (i.e.,
        by looking at the output parameters or waiting to see if an
        'html' element is the first new node generated), then replaces
        itself with the appropriate writer instance.

        outputParams is an Ft.Xml.Xslt.OutputParameters instance.

        stream will be passed on to the constructor of the real writer.

  appendStylesheet(self, iSrc)
    Append a stylesheet from an InputSource.

        This method establishes the stylesheet that the processor will use to
        do the transformation. If a stylesheet has already been appended, then
        this method is equivalent to having, in an outer "shell" stylesheet,
        an xsl:import for the most recently appended stylesheet followed by an
        xsl:import for the stylesheet accessible via the given InputSource.

  appendStylesheetInstance(self, instance, refUri='')
    Append an "instant" ("compiled") stylesheet, which is a pickled Ft.Xml.Xslt.Stylesheet.Stylesheet object that has had its setup() method called already. Such an instance can be obtained from another processor, p, as p.stylesheet.root, which you can then pickle, save to disk, and reuse in a new processor via this method.

        This method establishes the stylesheet that the processor will use to
        do the transformation. If a stylesheet has already been appended, then
        this method is equivalent to having an xsl:import of the new stylesheet
        in the most recently appended stylesheet.

        An exception will be raised if the same stylesheet is appended more
        than once, just as if the same stylesheet were imported more than once.

        refUri is the base URI to assume for the stylesheet. It defaults to
        the base URI of the root node of the original stylesheet document with
        the highest import precedence.

        Note: Using the instant stylesheet tends to be less efficient than
        using the original document and appendStylesheet(), unless the
        stylesheet is large and complex, like DocBook XSL.

  appendStylesheetNode(self, node, refUri='', factory=None)
    Append a stylesheet given as a DOM or Domlette Document node.

        This method establishes the stylesheet that the processor will use to
        do the transformation. If a stylesheet has already been appended, then
        this method is equivalent to having an xsl:import of the new stylesheet
        in the most recently appended stylesheet.

        An exception will be raised if the same stylesheet is appended more
        than once, just as if the same stylesheet were imported more than once.

        refUri is the base URI to assume for the stylesheet. It defaults to
        the base URI of the given node.

        The given InputSourceFactory will be used in order to read external
        entities. It defaults to Ft.Xml.InputSource.DefaultFactory.

  applyTemplates(self, context, params=None)
    Intended to be used by XSLT instruction implementations only.

        Implements the xsl:apply-templates instruction by attempting to
        let the stylesheet apply its own template for the given context.
        If the stylesheet does not have a matching template, the
        built-in templates are invoked.

        context is an XsltContext instance. params is a dictionary of
        parameters being passed in, defaulting to None.

  execute(self, node, docInputSource, ignorePis=0, topLevelParams=None, writer=None, outputStream=None)
    Warning: do not call this method directly unless you know what you're doing. If unsure, you probably want the runNode method.

        Runs the stylesheet processor against the given XML DOM node with the
        stylesheets that have been registered. It does not mutate the source.
        If writer is given, it is used in place of the default output method
        decisions for choosing the proper writer.

  getDocumentReader(self)
    Returns the reader used for source document input sources.
  getStripElements(self)
  getStylesheetReader(self)
    Returns the reader used for stylesheet document input sources.
  messageControl(self, suppress)
    Controls whether the processor emits warnings and xsl:message messages. Call with suppress=1 to suppress such output.
  output(self)
  popResult(self)
    Intended to be used by XSLT instruction implementations only.

        Ends temporary output writing that was started with
        pushResultString(), pushResultTree(), or pushResult(), and
        returns the result.

  pushResult(self, handler=None)
    Intended to be used by XSLT instruction implementations only.

        Sets up the processor to start processing subsequently
        generated content with a new output writer (the given handler
        of SAX-like output events).

  pushResultString(self)
    Intended to be used by XSLT instruction implementations only.

        Sets up the processor to start processing subsequently
        generated content with an output writer that buffers the text
        from text events and keeps track of whether non-text events
        occurred. This is used by the implementations of XSLT
        instructions such as xsl:attribute.

  pushResultTree(self, baseUri, implementation=None)
    Intended to be used by XSLT instruction implementations only.

        Sets up the processor to start processing subsequently
        generated content with a new output writer that produces
        a separate document. The new document will have the given
        baseUri as its URI. This is used to generate result tree
        fragments.

        Allows specifying an alternative DOM implementation for the
        creation of the new document.

  registerExtensionElement(self, namespace, localName, klass)
    Register a single extension element.

        For example, implement your own extension element as a subclass
        of Ft.Xml.Xslt.XsltElement. To make the element available to the
        Processor, call this method, passing in the namespace URI and
        local name of the element, and a direct reference to the class
        that implements the extension.

        See also registerExtensionModules().

  registerExtensionFunction(self, namespace, localName, function)
    Register a single extension function.

        For example, implement your own extension function as a Python
        function that takes an Ft.Xml.XPath.Context.Context instance as
        its first argument. Then, to make the function available to the
        Processor, call this method, passing in the namespace URI and
        local name of the function, and a direct reference to the Python
        function that implements the extension.

        See also registerExtensionModules().

  registerExtensionModules(self, moduleList)
    Registers a list of Python modules that have public ExtFunctions and/or ExtElements dictionaries.

        In a Python module that contains extension implementations,
        define a dictionary named ExtFunctions that, for each extension
        function or element, maps a (namespace-URI, xpath-function-name)
        tuple to a direct reference to the Python function that
        implements the extension. To make the function available to the
        Processor, call this method, passing in ['your.module.name'].

        See Ft.Xml.Xslt.Exslt.*, Ft.Xml.Xslt.BuiltInExtFunctions and
        BuiltInExtElements for working examples of extension modules.

  removeHandler(self)
    Intended to be used by XSLT instruction implementations only.

        Deletes the most recently added output writer.

  reset(self)
    Returns the processor to a state where it can be used to do a new transformation with a new stylesheet. Deletes the current stylesheet tree, and may do other cleanup.
  run(self, iSrc, ignorePis=0, topLevelParams=None, writer=None, outputStream=None)
    Transform a source document as given via an InputSource.

        Assumes that either the Processor instance has already had
        stylesheets appended (via appendStylesheet(), for example), or
        the source document contains xml-stylesheet processing
        instructions that are not being ignored.

        The ignorePis flag, if set, will cause xml-stylesheet
        processing instructions in the source document to be ignored.

        The topLevelParams argument is an optional dictionary of
        stylesheet parameters, the keys of which may be given as
        strings if they have no namespace, or as (uri, localname)
        tuples otherwise.

        The optional writer argument is a SAX-like event handler that
        is an Ft.Xml.Xslt.NullWriter subclass. The default writer is
        either an Ft.Xml.Xslt.XmlWriter, HtmlWriter or PlainTextWriter,
        depending on the stylesheet(s).

        The optional outputStream argument is a Python file-like object
        to be used as the destination for the writer's output.

  runNode(self, node, sourceUri=None, ignorePis=0, topLevelParams=None, writer=None, outputStream=None, preserveSrc=0, docInputSource=None)
    Transform a source document as given via a Domlette document node.

        Use Ft.Xml.Domlette.ConvertDocument() to create a Domlette
        from some other type of DOM.

        Assumes that either the Processor instance has already had
        stylesheets appended (via appendStylesheet(), for example), or
        the source document contains xml-stylesheet processing
        instructions that are not being ignored.

        sourceUri - The absolute URI of the document
        entity that the node represents, and should be explicitly
        provided, even if it is available from the node itself.

        ignorePis - (flag) If set, will cause xml-stylesheet
        processing instructions in the source document to be ignored.

        topLevelParams - optional dictionary of
        stylesheet parameters, the keys of which may be given as
        strings if they have no namespace, or as (uri, localname)
        tuples otherwise.

        writer - optional SAX-like event handler that
        is an Ft.Xml.Xslt.NullWriter subclass. The default writer is
        either an Ft.Xml.Xslt.XmlWriter, HtmlWriter or PlainTextWriter,
        depending on the stylesheet(s).

        outputStream - optional Python file-like object
        to be used as the destination for the writer's output.

        preserveSrc - (flag) If set signals that the source DOM should not be
        mutated, as would normally happen when honoring XSLT whitespace
        stripping requirements. Setting preserveSrc results in the
        creation of a copy of the source DOM.

        isrc - optional input source used strictly for further resolution
        relative the given DOM

  setDocumentReader(self, docReader)
    Sets the reader used for source document input sources.

        The reader can be anything with a parse() interface that
        returns a DOM tree. It is normally
        Ft.Xml.Domlette.NonvalidatingReader or whatever was specified in
        the Processor constructor. This method is sometimes used to set
        the reader to Domlette.ValidatingReader.

  setStylesheetReader(self, reader)
    Sets the reader used for stylesheet document input sources.

        It is normally an instance of
        Ft.Xml.Xslt.StylesheetReader.StylesheetReader

  warning(self, message)
    Emits a warning via Python's warnings framework, unless warnings are suppressed (see messageControl()).

        Used, for example, to announce that built-in templates are being
        invoked with params.

  xslMessage(self, msg)
    Intended to be used by XSLT instruction implementations only.

        Used by xsl:message to emit a message to sys.stderr, unless such
        messages are suppressed (see messageControl()). Uses the
        msgPrefix & msgSuffix instance attributes.

  ### Methods inherited from class object

  __delattr__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __str__

  ### Members

  __dict__ = <attribute '__dict__' of 'Processor' objects>
  __weakref__ = <attribute '__weakref__' of 'Processor' objects>
  writer = <property object>

  ### Members inherited from class object

  __class__

## Globals

DEFAULT_ENCODING = 'US-ASCII'
EMPTY_NAMESPACE = None
XSLT_IMT = ['application/xslt+xml', 'application/xslt', 'text/xml', 'application/xml']