phoenix_title wx.html.HtmlParser

Classes derived from this handle the generic parsing of HTML documents: it scans the document and divide it into blocks of tags (where one block consists of beginning and ending tag and of text between these two tags).

It is independent from wx.html.HtmlWindow and can be used as stand-alone parser.

It uses system of tag handlers to parse the HTML document. Tag handlers are not statically shared by all instances but are created for each wx.html.HtmlParser instance. The reason is that the handler may contain document-specific temporary data used during parsing (e.g. complicated structures like tables).

Typically the user calls only the wx.html.HtmlParser.Parse method.

See also

Cells and Containers, Tag Handlers, wx.html.HtmlTag


class_hierarchy Class Hierarchy

Inheritance diagram for class HtmlParser:

sub_classes Known Subclasses

wx.html.HtmlWinParser


method_summary Methods Summary

__init__

Constructor.

AddTag

This may (and may not) be overwritten in derived class.

AddTagHandler

Adds handler to the internal list ( hash table) of handlers.

DoParsing

Parses the whole m_Source.

DoneParser

This must be called after DoParsing .

GetFS

Returns pointer to the file system.

GetProduct

Returns product of parsing.

GetSource

Returns pointer to the source being parsed.

InitParser

Setups the parser for parsing the source string.

OpenURL

Opens given URL and returns wx.FSFile object that can be used to read data from it.

Parse

Proceeds parsing of the document.

PopTagHandler

Restores parser’s state before last call to PushTagHandler .

PushTagHandler

Forces the handler to handle additional tags (not returned by wx.html.HtmlTagHandler.GetSupportedTags ).

SetFS

Sets the virtual file system that will be used to request additional files.

StopParsing

Call this function to interrupt parsing from a tag handler.


property_summary Properties Summary

FS

See GetFS and SetFS

Product

See GetProduct

Source

See GetSource


api Class API

class wx.html.HtmlParser(object)

Possible constructors:

HtmlParser()

Classes derived from this handle the generic parsing of HTML documents: it scans the document and divide it into blocks of tags (where one block consists of beginning and ending tag and of text between these two tags).


Methods

__init__(self)

Constructor.



AddTag(self, tag)

This may (and may not) be overwritten in derived class.

This method is called each time new tag is about to be added. tag contains information about the tag. (See wx.html.HtmlTag for details.)

Default ( wx.html.HtmlParser) behaviour is this: first it finds a handler capable of handling this tag and then it calls handler’s HandleTag() method.

Parameters:

tag (wx.html.HtmlTag) –



AddTagHandler(self, handler)

Adds handler to the internal list ( hash table) of handlers.

This method should not be called directly by user but rather by derived class’ constructor.

This adds the handler to this instance of wx.html.HtmlParser, not to all objects of this class! (Static front-end to AddTagHandler is provided by wx.html.HtmlWinParser).

All handlers are deleted on object deletion.

Parameters:

handler (wx.html.HtmlTagHandler) –



DoParsing(self)

Parses the whole m_Source.



DoneParser(self)

This must be called after DoParsing .



GetFS(self)

Returns pointer to the file system.

Because each tag handler has reference to it is parent parser it can easily request the file by calling:

f = self.Parser.GetFS().OpenFile("image.jpg")
Return type:

FileSystem



GetProduct(self)

Returns product of parsing.

Returned value is result of parsing of the document.

The type of this result depends on internal representation in derived parser (but it must be derived from Object!). See wx.html.HtmlWinParser for details.

Return type:

Object



GetSource(self)

Returns pointer to the source being parsed.

Return type:

string



InitParser(self, source)

Setups the parser for parsing the source string.

(Should be overridden in derived class)

Parameters:

source (string) –



OpenURL(self, type, url)

Opens given URL and returns wx.FSFile object that can be used to read data from it.

This method may return None in one of two cases: either the URL doesn’t point to any valid resource or the URL is blocked by overridden implementation of OpenURL in derived class.

Parameters:
  • type (HtmlURLType) – Indicates type of the resource. Is one of:

    • wx.html.HTML_URL_PAGE: Opening a HTML page.

    • wx.html.HTML_URL_IMAGE: Opening an image.

    • wx.html.HTML_URL_OTHER: Opening a resource that doesn’t fall into any other category.

  • url (string) – URL being opened.

Return type:

FSFile

Note

Always use this method in tag handlers instead of GetFS .OpenFile() because it can block the URL and is thus more secure. Default behaviour is to call wx.html.HtmlWindow.OnOpeningURL of the associated wx.html.HtmlWindow object (which may decide to block the URL or redirect it to another one),if there’s any, and always open the URL if the parser is not used with wx.html.HtmlWindow. Returned wx.FSFile object is not guaranteed to point to url, it might have been redirected!



Parse(self, source)

Proceeds parsing of the document.

This is end-user method. You can simply call it when you need to obtain parsed output (which is parser-specific).

The method does these things:

You shouldn’t use InitParser , DoParsing , GetProduct or DoneParser directly.

Parameters:

source (string) –

Return type:

Object



PopTagHandler(self)

Restores parser’s state before last call to PushTagHandler .



PushTagHandler(self, handler, tags)

Forces the handler to handle additional tags (not returned by wx.html.HtmlTagHandler.GetSupportedTags ).

The handler should already be added to this parser.

Parameters:
  • handler (wx.html.HtmlTagHandler) – the handler

  • tags (string) – List of tags (in same format as GetSupportedTags()’s return value). The parser will redirect these tags to handler (until call to PopTagHandler ).

Imagine you want to parse following pseudo-html structure:

<myitems>
    <param name="one" value="1">
    <param name="two" value="2">
</myitems>

<execute>
    <param program="text.exe">
</execute>

It is obvious that you cannot use only one tag handler for <param> tag. Instead you must use context-sensitive handlers for <param> inside <myitems> and <param> inside <execute>. This is the preferred solution:

# some code in HandleTag for "MYITEMS"...

self.Parser.PushTagHandler(self, "PARAM")
self.ParseInner(tag)
self.Parser.PopTagHandler()

# back to working on "MYITEMS"...


SetFS(self, fs)

Sets the virtual file system that will be used to request additional files.

(For example IMG tag handler requests wx.FSFile with the image data.)

Parameters:

fs (wx.FileSystem) –



StopParsing(self)

Call this function to interrupt parsing from a tag handler.

No more tags will be parsed afterward. This function may only be called from Parse or any function called by it (i.e. from tag handlers).


Properties

FS

See GetFS and SetFS



Product

See GetProduct



Source

See GetSource