Difference between revisions of "HTML Module"

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This [[Module Library|XQuery Module]] provides functions for converting HTML to XML. The input will only be converted if [http://home.ccil.org/~cowan/XML/tagsoup/ TagSoup] is included in the classpath (see [[Parsers#HTML Parser|HTML Parsing]] for more details).
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This [[Module Library|XQuery Module]] provides functions for converting HTML to XML. Conversion will only take place if TagSoup is included in the classpath (see [[Parsers#HTML Parser|HTML Parsing]] for more details).
  
 
=Conventions=
 
=Conventions=
  
All functions in this module are assigned to the {{Code|http://basex.org/modules/html}} namespace, which is statically bound to the {{Code|html}} prefix.<br/>
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All functions and errors in this module are assigned to the <code><nowiki>http://basex.org/modules/html</nowiki></code> namespace, which is statically bound to the {{Code|html}} prefix.<br/>
All errors are assigned to the {{Code|http://basex.org/errors}} namespace, which is statically bound to the {{Code|bxerr}} prefix.
 
  
 
=Functions=
 
=Functions=
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{| width='100%'
 
{| width='100%'
 
|-
 
|-
| width='90' | '''Signatures'''
+
| width='120' | '''Signatures'''
 
|{{Code|'''html:parser'''() as xs:string}}<br />
 
|{{Code|'''html:parser'''() as xs:string}}<br />
 
|-
 
|-
Line 20: Line 19:
  
 
==html:parse==
 
==html:parse==
 +
 
{| width='100%'
 
{| width='100%'
 
|-
 
|-
| width='90' | '''Signatures'''
+
| width='120' | '''Signatures'''
|{{Func|html:parse|$input as xs:anyAtomicType|document-node()}}<br />{{Func|html:parse|$input as xs:anyAtomicType, $options as item()|document-node()}}<br />
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|{{Func|html:parse|$input as xs:anyAtomicType|document-node()}}<br />{{Func|html:parse|$input as xs:anyAtomicType, $options as map(*)?|document-node()}}<br />
 
|-
 
|-
 
| '''Summary'''
 
| '''Summary'''
|Converts the HTML document specified by {{Code|$input}} to XML, and returns a document node. The input may either be a string or a binary item (xs:hexBinary, xs:base64Binary). If the input is passed on in its binary representation, the HTML parser will try to automatically choose the correct encoding.<br/>The {{Code|$options}} argument can be used to set [[Parsers#TagSoup Options|TagSoup options]]. It can be specified<br />
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|Converts the HTML document specified by {{Code|$input}} to XML and returns a document node:<br/>
* as children of an {{Code|<html:options/>}} element; e.g.:
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* The input may either be a string or a binary item (xs:hexBinary, xs:base64Binary).
<pre class="brush:xml">
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* If the input is passed on in its binary representation, the HTML parser will try to automatically choose the correct encoding.
<html:options>
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  <html:key1 value='value1'/>
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The {{Code|$options}} argument can be used to set [[Parsers#Options|TagSoup Options]].
  ...
 
</html:options>
 
</pre>
 
* as map, which contains all key/value pairs:
 
<pre class="brush:xml">
 
map { "key1" := "value1", ... }
 
</pre>
 
 
|-
 
|-
 
| '''Errors'''
 
| '''Errors'''
|{{Error|BXHL0001|#Errors}} the input cannot be converted to XML.
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|{{Error|parse|#Errors}} the input cannot be converted to XML.
 +
|}
 +
 
 +
==html:doc==
 +
 
 +
{{Mark|Introduced with BaseX 9.4:}}
 +
 
 +
{| width='100%'
 
|-
 
|-
| '''Examples'''
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| width='120' | '''Signatures'''
|
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|{{Func|html:doc|$uri as xs:string?|document-node()?}}<br />{{Func|html:doc|$uri as xs:string?, $options as map(*)?|document-node()?}}<br />
* {{Code|html:parse("<html></html>")}} returns {{Code|<html/>}}
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|-
* <code><nowiki>html:parse("<a href='ok.html'/>", map { 'nons' := true() })</nowiki></code> creates an XML document without namespaces. It returns:
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| '''Summary'''
<pre class="brush:xml">
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|Fetches the HTML document referred to by the given {{Code|$uri}}, converts it to XML and returns a document node. The {{Code|$options}} argument can be used to set [[Parsers#Options|TagSoup Options]].
<html>
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|-
 +
| '''Errors'''
 +
|{{Error|parse|#Errors}} the input cannot be converted to XML.
 +
|}
 +
 
 +
=Examples=
 +
 
 +
===Basic Example===
 +
 
 +
The following query converts the specified string to an XML document node.
 +
 
 +
;Query:
 +
<syntaxhighlight lang="xquery">
 +
html:parse("<html>")
 +
</syntaxhighlight>
 +
 
 +
;Result:
 +
<syntaxhighlight lang="xml">
 +
<html xmlns="http://www.w3.org/1999/xhtml"/>
 +
</syntaxhighlight>
 +
 
 +
===Specifying Options===
 +
 
 +
The next query creates an XML document with namespaces:
 +
 
 +
;Query:
 +
<syntaxhighlight lang="xquery">
 +
html:parse("<a href='ok.html'/>", map { 'nons': false() })
 +
</syntaxhighlight>
 +
 
 +
;Result:
 +
<syntaxhighlight lang="xml">
 +
<html xmlns="http://www.w3.org/1999/xhtml">
 
   <body>
 
   <body>
 
     <a shape="rect" href="ok.html"/>
 
     <a shape="rect" href="ok.html"/>
 
   </body>
 
   </body>
 
</html>
 
</html>
</pre>
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</syntaxhighlight>
* <code><nowiki>html:parse(fetch:content-binary("http://en.wikipedia.org"))</nowiki></code> returns an XML representation of the English Wikipedia main page. The input is passed on its binary representation such that the HTML parser can automatically detect the correct encoding.
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|}
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===Parsing Binary Input===
 +
 
 +
If the input encoding is unknown, the data to be processed can be passed on in its binary representation.
 +
The HTML parser will automatically try to detect the correct encoding:
 +
 
 +
;Query:
 +
<syntaxhighlight lang="xquery">
 +
html:parse(fetch:binary("https://en.wikipedia.org"))
 +
</syntaxhighlight>
 +
 
 +
;Result:
 +
<syntaxhighlight lang="xml">
 +
<html xmlns="http://www.w3.org/1999/xhtml" class="client-nojs" dir="ltr" lang="en">
 +
  <head>
 +
    <title>Wikipedia, the free encyclopedia</title>
 +
    <meta charset="UTF-8"/>
 +
    ...
 +
</syntaxhighlight>
  
 
=Errors=
 
=Errors=
  
{| width='100%' class="wikitable" width="100%"
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{| class="wikitable" width="100%"
! width="5%"|Code
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! width="110"|Code
! width="95%"|Description
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|Description
 
|-
 
|-
|{{Code|BXHL0001}}
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|{{Code|parse}}
 
|The input cannot be converted to XML.
 
|The input cannot be converted to XML.
 
|}
 
|}
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=Changelog=
 
=Changelog=
  
The module was introduced with Version 7.5.1.
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;Version 9.4
 +
 
 +
* Added: [[#html:doc|html:doc]]
 +
 
 +
;Version 9.0
 +
 
 +
* Updated: error codes updated; errors now use the module namespace
  
[[Category:XQuery]]
+
The module was introduced with Version 7.6.

Revision as of 12:58, 3 April 2020

This XQuery Module provides functions for converting HTML to XML. Conversion will only take place if TagSoup is included in the classpath (see HTML Parsing for more details).

Conventions

All functions and errors in this module are assigned to the http://basex.org/modules/html namespace, which is statically bound to the html prefix.

Functions

html:parser

Signatures html:parser() as xs:string
Summary Returns the name of the applied HTML parser (currently: TagSoup). If an empty string is returned, TagSoup was not found in the classpath, and the input will be treated as well-formed XML.

html:parse

Signatures html:parse($input as xs:anyAtomicType) as document-node()
html:parse($input as xs:anyAtomicType, $options as map(*)?) as document-node()
Summary Converts the HTML document specified by $input to XML and returns a document node:
  • The input may either be a string or a binary item (xs:hexBinary, xs:base64Binary).
  • If the input is passed on in its binary representation, the HTML parser will try to automatically choose the correct encoding.

The $options argument can be used to set TagSoup Options.

Errors parse: the input cannot be converted to XML.

html:doc

Template:Mark

Signatures html:doc($uri as xs:string?) as document-node()?
html:doc($uri as xs:string?, $options as map(*)?) as document-node()?
Summary Fetches the HTML document referred to by the given $uri, converts it to XML and returns a document node. The $options argument can be used to set TagSoup Options.
Errors parse: the input cannot be converted to XML.

Examples

Basic Example

The following query converts the specified string to an XML document node.

Query

<syntaxhighlight lang="xquery"> html:parse("<html>") </syntaxhighlight>

Result

<syntaxhighlight lang="xml"> <html xmlns="http://www.w3.org/1999/xhtml"/> </syntaxhighlight>

Specifying Options

The next query creates an XML document with namespaces:

Query

<syntaxhighlight lang="xquery"> html:parse("<a href='ok.html'/>", map { 'nons': false() }) </syntaxhighlight>

Result

<syntaxhighlight lang="xml"> <html xmlns="http://www.w3.org/1999/xhtml">

 <body>
   <a shape="rect" href="ok.html"/>
 </body>

</html> </syntaxhighlight>

Parsing Binary Input

If the input encoding is unknown, the data to be processed can be passed on in its binary representation. The HTML parser will automatically try to detect the correct encoding:

Query

<syntaxhighlight lang="xquery"> html:parse(fetch:binary("https://en.wikipedia.org")) </syntaxhighlight>

Result

<syntaxhighlight lang="xml"> <html xmlns="http://www.w3.org/1999/xhtml" class="client-nojs" dir="ltr" lang="en">

 <head>
   <title>Wikipedia, the free encyclopedia</title>
   <meta charset="UTF-8"/>
   ...

</syntaxhighlight>

Errors

Code Description
parse The input cannot be converted to XML.

Changelog

Version 9.4
Version 9.0
  • Updated: error codes updated; errors now use the module namespace

The module was introduced with Version 7.6.