Difference between revisions of "Fetch Module"
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|} | |} | ||
− | ==fetch: | + | ==fetch:doc== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func|fetch: | + | |{{Func|fetch:doc|$uri as xs:string|document-node()}}<br/>{{Func|fetch:doc|$uri as xs:string, $options as map(*)?|document-node()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Fetches the resource referred to by the given {{Code|$uri}} and returns it as document node.<br/>The {{Code|$options}} argument can be used to change the parsing behavior. Allowed options are all [[Options#Parsing|parsing]] and [[Options#XML Parsing|XML parsing]] options in lower case.<br/>The function | + | |Fetches the resource referred to by the given {{Code|$uri}} and returns it as a document node.<br/>The {{Code|$options}} argument can be used to change the parsing behavior. Allowed options are all [[Options#Parsing|parsing]] and [[Options#XML Parsing|XML parsing]] options in lower case.<br/>The function differs from {{Code|fn:doc}} in various aspects: |
− | * | + | * It is ''non-deterministic'', i.e., a new document node will be created by each call of this function. |
* A document created by this function will be garbage-collected as soon as it is not referenced anymore. | * A document created by this function will be garbage-collected as soon as it is not referenced anymore. | ||
* URIs will not be resolved against existing databases. As a result, it will not trigger any locks (see [[Transaction Management#Limitations|limitations of database locking]] for more details). | * URIs will not be resolved against existing databases. As a result, it will not trigger any locks (see [[Transaction Management#Limitations|limitations of database locking]] for more details). | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * Retrieve an XML representation of the English Wikipedia main HTML page | + | * Retrieve an XML representation of the English Wikipedia main HTML page with whitespace stripped: |
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | fetch: | + | fetch:doc("http://en.wikipedia.org", map { 'stripws': true() }) |
− | |||
− | |||
− | |||
− | |||
</syntaxhighlight> | </syntaxhighlight> | ||
* Return a web page as XML, preserve namespaces: | * Return a web page as XML, preserve namespaces: | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | fetch: | + | fetch:doc( |
'http://basex.org/', | 'http://basex.org/', | ||
map { | map { | ||
Line 88: | Line 84: | ||
|} | |} | ||
− | ==fetch: | + | ==fetch:binary-doc== |
{| width='100%' | {| width='100%' | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func|fetch: | + | |{{Func|fetch:binary-doc|$input as xs:anyAtomicType|document-node()}}<br/>{{Func|fetch:binary-doc|$data as xs:anyAtomicType, $options as map(*)?|document-node()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | | | + | |Converts the specified {{Code|$input}} ({{Code|xs:base64Binary}}, {{Code|xs:hexBinary}}) to XML and returns it as a document node.<br/>In contrast to {{Code|fn:parse-xml}}, which expects a string, the input can be arbitrarily encoded. The encoding will be derived from the XML declaration or (in case of UTF-16 or UTF-32) from the first bytes of the input.<br/>The {{Code|$options}} argument can be used to change the parsing behavior. Allowed options are all [[Options#Parsing|parsing]] and [[Options#XML Parsing|XML parsing]] options in lower case. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
Line 102: | Line 98: | ||
* Retrieves file input as binary data and parses it as XML: | * Retrieves file input as binary data and parses it as XML: | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | fetch: | + | fetch:binary-doc(file:read-binary('doc.xml')) |
</syntaxhighlight> | </syntaxhighlight> | ||
* Encodes a string as CP1252 and parses it as XML. The input and the string {{Code|touché}} will be correctly decoded because of the XML declaration: | * Encodes a string as CP1252 and parses it as XML. The input and the string {{Code|touché}} will be correctly decoded because of the XML declaration: | ||
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | fetch: | + | fetch:binary-doc(convert:string-to-base64( |
"<?xml version='1.0' encoding='CP1252'?><xml>touché</xml>", | "<?xml version='1.0' encoding='CP1252'?><xml>touché</xml>", | ||
"CP1252" | "CP1252" | ||
)) | )) | ||
</syntaxhighlight> | </syntaxhighlight> | ||
− | * Encodes a string as | + | * Encodes a string as UTF-16 and parses it as XML. The document will be correctly decoded, as the first bytes of the data indicate that the input must be UTF-16: |
<syntaxhighlight lang="xquery"> | <syntaxhighlight lang="xquery"> | ||
− | fetch: | + | fetch:binary-doc(convert:string-to-base64("<xml/>", "UTF16")) |
</syntaxhighlight> | </syntaxhighlight> | ||
|} | |} | ||
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=Changelog= | =Changelog= | ||
+ | |||
+ | ;Version 10.0 | ||
+ | * Updated: {{Function||fetch:doc}} renamed (before: {{Code|fetch:xml}}). | ||
+ | * Updated: {{Function||fetch:binary-doc}} renamed (before: {{Code|fetch:xml-binary}}). | ||
;Version 9.0 | ;Version 9.0 | ||
− | + | * Added: {{Code|fetch:xml-binary}} | |
− | * Added: {{ | ||
* Updated: error codes updated; errors now use the module namespace | * Updated: error codes updated; errors now use the module namespace | ||
;Version 8.5 | ;Version 8.5 | ||
− | |||
* Updated: {{Function||fetch:text}}: <code>$fallback</code> argument added. | * Updated: {{Function||fetch:text}}: <code>$fallback</code> argument added. | ||
;Version 8.0 | ;Version 8.0 | ||
− | + | * Added: {{Code|fetch:xml}} | |
− | * Added: {{ | ||
The module was introduced with Version 7.6. | The module was introduced with Version 7.6. |
Revision as of 10:30, 20 July 2022
This XQuery Module provides simple functions to fetch the content of resources identified by URIs. Resources can be stored locally or remotely and e.g. use the file://
or http://
scheme. If more control over HTTP requests is required, the HTTP Client Module can be used. With the HTML Module, retrieved HTML documents can be converted to XML.
Contents
Conventions
All functions and errors in this module are assigned to the http://basex.org/modules/fetch
namespace, which is statically bound to the fetch
prefix.
URI arguments can point be URLs or point to local files. Relative file paths will be resolved against the current working directory (for more details, have a look at the File Module).
Functions
fetch:binary
Signatures | fetch:binary($uri as xs:string) as xs:base64Binary |
Summary | Fetches the resource referred to by the given URI and returns it as lazy xs:base64Binary item.
|
Errors | open : the URI could not be resolved, or the resource could not be retrieved.
|
Examples |
|
fetch:text
Signatures | fetch:text($uri as xs:string) as xs:string fetch:text($uri as xs:string, $encoding as xs:string) as xs:string fetch:text($uri as xs:string, $encoding as xs:string, $fallback as xs:boolean) as xs:string |
Summary | Fetches the resource referred to by the given $uri and returns it as lazy xs:string item:
|
Errors | open : the URI could not be resolved, or the resource could not be retrieved.encoding : the specified encoding is not supported, or unknown.
|
Examples |
|
fetch:doc
Signatures | fetch:doc($uri as xs:string) as document-node() fetch:doc($uri as xs:string, $options as map(*)?) as document-node()
|
Summary | Fetches the resource referred to by the given $uri and returns it as a document node.The $options argument can be used to change the parsing behavior. Allowed options are all parsing and XML parsing options in lower case.The function differs from fn:doc in various aspects:
|
Errors | open : the URI could not be resolved, or the resource could not be retrieved.
|
Examples |
<syntaxhighlight lang="xquery"> fetch:doc("http://en.wikipedia.org", map { 'stripws': true() }) </syntaxhighlight>
<syntaxhighlight lang="xquery"> fetch:doc( 'http://basex.org/', map { 'parser': 'html', 'htmlparser': map { 'nons': false() } } ) </syntaxhighlight> |
fetch:binary-doc
Signatures | fetch:binary-doc($input as xs:anyAtomicType) as document-node() fetch:binary-doc($data as xs:anyAtomicType, $options as map(*)?) as document-node()
|
Summary | Converts the specified $input (xs:base64Binary , xs:hexBinary ) to XML and returns it as a document node.In contrast to fn:parse-xml , which expects a string, the input can be arbitrarily encoded. The encoding will be derived from the XML declaration or (in case of UTF-16 or UTF-32) from the first bytes of the input.The $options argument can be used to change the parsing behavior. Allowed options are all parsing and XML parsing options in lower case.
|
Examples |
<syntaxhighlight lang="xquery"> fetch:binary-doc(file:read-binary('doc.xml')) </syntaxhighlight>
<syntaxhighlight lang="xquery"> fetch:binary-doc(convert:string-to-base64( "<?xml version='1.0' encoding='CP1252'?><xml>touché</xml>", "CP1252" )) </syntaxhighlight>
<syntaxhighlight lang="xquery"> fetch:binary-doc(convert:string-to-base64("<xml/>", "UTF16")) </syntaxhighlight> |
fetch:content-type
Signatures | fetch:content-type($uri as xs:string) as xs:string |
Summary | Returns the content-type (also called mime-type) of the resource specified by $uri :
|
Errors | open : the URI could not be resolved, or the resource could not be retrieved.
|
Examples |
|
Errors
Code | Description |
---|---|
encoding
|
The specified encoding is not supported, or unknown. |
open
|
The URI could not be resolved, or the resource could not be retrieved. |
Changelog
- Version 10.0
- Updated:
fetch:doc
renamed (before:fetch:xml
). - Updated:
fetch:binary-doc
renamed (before:fetch:xml-binary
).
- Version 9.0
- Added:
fetch:xml-binary
- Updated: error codes updated; errors now use the module namespace
- Version 8.5
- Updated:
fetch:text
:$fallback
argument added.
- Version 8.0
- Added:
fetch:xml
The module was introduced with Version 7.6.