Difference between revisions of "Fetch Module"
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| '''Summary''' | | '''Summary''' | ||
− | |Fetches the resource referred to by the given {{Code|$uri}} and returns it as document node | + | |Fetches the resource referred to by the given {{Code|$uri}} and returns it as document node.<br/>The {{Code|$options}} argument can be used to change the parsing behavior. Allowed options are all [[Options#Parsing|parsing]] and [[Options#XML Parsing|XML parsing]] options in lower case.<br/>The function is different to <code>fn:doc</code> in various aspects: |
+ | * As it is non-deterministic, a new document node will be created by each call of this function. | ||
+ | * A document created by this function will be garbage-collected as soon as it is not referenced anymore. | ||
+ | * URIs will not be resolved against existing databases. As a result, it will not trigger any locks (see [[Transaction Management#Limitations|limitations of database locking]] for more details). | ||
|- | |- | ||
| '''Errors''' | | '''Errors''' |
Revision as of 09:26, 21 May 2019
This XQuery Module provides simple functions to fetch the content of resources identified by URIs. Resources can be stored locally or remotely and e.g. use the file://
or http://
scheme. If more control over HTTP requests is required, the HTTP Module can be used. With the HTML Module, retrieved HTML documents can be converted to XML.
Contents
Conventions
All functions and errors in this module are assigned to the http://basex.org/modules/fetch
namespace, which is statically bound to the fetch
prefix.
URI arguments can point be URLs or point to local files. Relative file paths will be resolved against the current working directory (for more details, have a look at the File Module).
Functions
fetch:binary
Signatures | fetch:binary($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 $uri and returns it as lazy xs:string item:
|
Errors | open : the URI could not be resolved, or the resource could not be retrieved.encoding : the specified encoding is not supported, or unknown.
|
Examples |
|
fetch:xml
Signatures | fetch:xml($uri as xs:string) as document-node() fetch:xml($uri as xs:string, $options as map(*)?) as document-node()
|
Summary | Fetches the resource referred to by the given $uri and returns it as document node.The $options argument can be used to change the parsing behavior. Allowed options are all parsing and XML parsing options in lower case.The function is different to fn:doc in various aspects:
|
Errors | open : the URI could not be resolved, or the resource could not be retrieved.
|
Examples |
fetch:xml("http://en.wikipedia.org", map { 'chop': true() })
fetch:xml(file:base-dir() || "example.xml")
fetch:xml( 'http://basex.org/', map { 'parser': 'html', 'htmlparser': map { 'nons': false() } } ) |
fetch:xml-binary
Signatures | fetch:xml-binary($data as xs:base64Binary) as document-node() fetch:xml-binary($data as xs:base64Binary, $options as map(*)?) as document-node()
|
Summary | Parses binary $data and returns it as document node.In contrast to fn:parse-xml, which expects an XQuery string, the input of this function can be arbitrarily encoded. The encoding will be derived from the XML declaration or (in case of UTF16 or UTF32) from the first bytes of the input. The $options argument can be used to change the parsing behavior. Allowed options are all parsing and XML parsing options in lower case.
|
Examples |
fetch:xml-binary(file:read-binary('doc.xml'))
fetch:xml-binary(convert:string-to-base64( "<?xml version='1.0' encoding='CP1252'?><xml>touché</xml>", "CP1252" ))
fetch:xml-binary(convert:string-to-base64("<xml/>", "UTF16")) |
fetch:content-type
Signatures | fetch:content-type($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 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.