Difference between revisions of "HTTP Client Module"
(32 intermediate revisions by 2 users not shown) | |||
Line 1: | Line 1: | ||
− | This [[Module Library|XQuery Module]] contains a single function to send HTTP requests and handle HTTP responses. The function {{Code|send-request}} is based on the [http://expath.org/spec/http-client EXPath HTTP Client Module]: | + | This [[Module Library|XQuery Module]] contains a single function to send HTTP requests and handle HTTP responses. The function {{Code|send-request}} is based on the [http://expath.org/spec/http-client EXPath HTTP Client Module]. It gives full control over the available request and response parameters. For simple GET requests, the [[Fetch Module]] may be sufficient. |
+ | |||
+ | If <code><http:header name="Accept-Encoding" value="gzip"/></code> is specified and if the addressed web server provides support for the {{Code|gzip}} compression algorithm, the response will automatically be decompressed. | ||
=Conventions= | =Conventions= | ||
− | All functions in this module are assigned to the | + | All functions in this module are assigned to the <code><nowiki>http://expath.org/ns/http-client</nowiki></code> namespace, which is statically bound to the {{Code|http}} prefix.<br/> |
− | All errors are assigned to the | + | All errors are assigned to the <code><nowiki>http://expath.org/ns/error</nowiki></code> namespace, which is statically bound to the {{Code|experr}} prefix. |
=Functions= | =Functions= | ||
Line 13: | Line 15: | ||
|- | |- | ||
| width='120' | '''Signatures''' | | width='120' | '''Signatures''' | ||
− | |{{Func|http:send-request|$request as element(http:request) | + | |{{Func|http:send-request|$request as element(http:request)|item()+}}<br />{{Func|http:send-request|$request as element(http:request)?, $href as xs:string?|item()+}}<br />{{Func|http:send-request|$request as element(http:request)?, $href as xs:string?, $bodies as item()*|item()+}}<br/> |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Sends an HTTP request and interprets the corresponding response | + | |Sends an HTTP request and interprets the corresponding response: |
+ | * {{Code|$request}} contains the parameters of the HTTP request such as HTTP method and headers. | ||
+ | * In addition to this it can also contain the URI to which the request will be sent and the body of the HTTP method. | ||
+ | * If the URI is not given with the parameter {{Code|$href}}, its value in {{Code|$request}} is used instead. | ||
+ | * The request body can also be supplied via the {{Code|$bodies}} parameter. | ||
+ | * Certificate verification can be globally disabled via the {{Option|IGNORECERT}} option. | ||
+ | |||
+ | Notes: | ||
+ | * Both basic and digest authentication is supported. | ||
+ | * While the contents of the request can be supplied as child of the {{Code|http:body}} element, it is faster and safer to pass them on via the third argument. | ||
+ | * For further information, please check out the [http://expath.org/spec/http-client EXPath] specification. | ||
|- | |- | ||
|'''Errors''' | |'''Errors''' | ||
|{{Error|HC0001|#Errors}} an HTTP error occurred.<br/>{{Error|HC0002|#Errors}} error parsing the entity content as XML or HTML.<br/>{{Error|HC0003|#Errors}} with a multipart response, the override-media-type must be either a multipart media type or application/octet-stream.<br/>{{Error|HC0004|#Errors}} the src attribute on the body element is mutually exclusive with all other attribute (except the media-type).<br/>{{Error|HC0005|#Errors}} the request element is not valid.<br/>{{Error|HC0006|#Errors}} a timeout occurred waiting for the response. | |{{Error|HC0001|#Errors}} an HTTP error occurred.<br/>{{Error|HC0002|#Errors}} error parsing the entity content as XML or HTML.<br/>{{Error|HC0003|#Errors}} with a multipart response, the override-media-type must be either a multipart media type or application/octet-stream.<br/>{{Error|HC0004|#Errors}} the src attribute on the body element is mutually exclusive with all other attribute (except the media-type).<br/>{{Error|HC0005|#Errors}} the request element is not valid.<br/>{{Error|HC0006|#Errors}} a timeout occurred waiting for the response. | ||
− | |||
− | |||
− | |||
|} | |} | ||
− | + | =Examples= | |
− | + | ==Status Only== | |
Simple GET request. As the attribute {{Code|status-only}} is set to true, only the response element is returned. | Simple GET request. As the attribute {{Code|status-only}} is set to true, only the response element is returned. | ||
'''Query:''' | '''Query:''' | ||
− | < | + | <syntaxhighlight lang="xquery">http:send-request(<http:request method='get' status-only='true'/>, 'http://basex.org')</syntaxhighlight> |
'''Result:''' | '''Result:''' | ||
− | < | + | <syntaxhighlight lang="xml"><http:response status="200" message="OK"> |
<http:header name="Date" value="Mon, 14 Mar 2011 20:55:53 GMT"/> | <http:header name="Date" value="Mon, 14 Mar 2011 20:55:53 GMT"/> | ||
<http:header name="Content-Length" value="12671"/> | <http:header name="Content-Length" value="12671"/> | ||
Line 44: | Line 53: | ||
<http:header name="Cache-Control" value="max-age=90"/> | <http:header name="Cache-Control" value="max-age=90"/> | ||
<http:body media-type="text/html; charset=utf-8"/> | <http:body media-type="text/html; charset=utf-8"/> | ||
− | </http:response></ | + | </http:response></syntaxhighlight> |
− | + | ==Google Homepage== | |
− | Retrieve Google search home page. [ | + | |
+ | Retrieve the Google search home page with a timeout of 10 seconds. In order to [[Parsers#HTML_Parser|parse HTML]], TagSoup must be contained in the class path. | ||
'''Query:''' | '''Query:''' | ||
− | < | + | <syntaxhighlight lang="xquery">http:send-request(<http:request method='get' href='http://www.google.com' timeout='10'/>)</syntaxhighlight> |
'''Result:''' | '''Result:''' | ||
− | < | + | <syntaxhighlight lang="xml"> |
<http:response status="200" message="OK"> | <http:response status="200" message="OK"> | ||
<http:header name="Date" value="Mon, 14 Mar 2011 22:03:25 GMT"/> | <http:header name="Date" value="Mon, 14 Mar 2011 22:03:25 GMT"/> | ||
Line 66: | Line 76: | ||
<html xmlns="http://www.w3.org/1999/xhtml"> | <html xmlns="http://www.w3.org/1999/xhtml"> | ||
<head> | <head> | ||
− | <meta http-equiv=" | + | <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> |
<title>Google</title> | <title>Google</title> | ||
− | + | ... | |
− | |||
− | |||
− | |||
</body> | </body> | ||
</html> | </html> | ||
− | </ | + | </syntaxhighlight> |
− | The response content type can also be overwritten in order to retrieve HTML pages and other textual data as plain string (using {{Code|text/plain}} or in its binary representation (using {{Code|application/octet-stream}}). | + | The response content type can also be overwritten in order to retrieve HTML pages and other textual data as plain string (using {{Code|text/plain}}) or in its binary representation (using {{Code|application/octet-stream}}). With the {{Code|http:header}} element, a custom user agent can be set. See the following example: |
'''Query:''' | '''Query:''' | ||
− | < | + | <syntaxhighlight lang="xquery"> |
let $binary := http:send-request( | let $binary := http:send-request( | ||
<http:request method='get' | <http:request method='get' | ||
− | override-media-type='application/octet-stream' | + | override-media-type='application/octet-stream' |
− | href='http://www.google.com'/> | + | href='http://www.google.com'> |
+ | <http:header name="User-Agent" value="Opera"/> | ||
+ | </http:request> | ||
)[2] | )[2] | ||
return try { | return try { | ||
Line 90: | Line 99: | ||
'Conversion to XML failed: ' || $err:description | 'Conversion to XML failed: ' || $err:description | ||
} | } | ||
− | </ | + | </syntaxhighlight> |
===SVG Data=== | ===SVG Data=== | ||
+ | |||
Content-type ending with +xml, e.g. image/svg+xml. | Content-type ending with +xml, e.g. image/svg+xml. | ||
'''Query:''' | '''Query:''' | ||
− | < | + | <syntaxhighlight lang="xquery">http:send-request(<http:request method='get'/>, 'http://upload.wikimedia.org/wikipedia/commons/6/6b/Bitmap_VS_SVG.svg')</syntaxhighlight> |
'''Result:''' | '''Result:''' | ||
− | < | + | <syntaxhighlight lang="xml"><http:response status="200" message="OK"> |
<http:header name="ETag" value="W/"11b6d-4ba15ed4""/> | <http:header name="ETag" value="W/"11b6d-4ba15ed4""/> | ||
<http:header name="Age" value="9260"/> | <http:header name="Age" value="9260"/> | ||
Line 119: | Line 129: | ||
</linearGradient> | </linearGradient> | ||
... | ... | ||
− | </svg></ | + | </svg></syntaxhighlight> |
+ | |||
+ | ==POST Request== | ||
− | |||
POST request to the BaseX REST Service, specifying a username and password. | POST request to the BaseX REST Service, specifying a username and password. | ||
'''Query:''' | '''Query:''' | ||
− | < | + | <syntaxhighlight lang="xquery"> |
− | + | http:send-request( | |
− | <http:request | + | <http:request method='post' username='admin' password='admin'> |
− | + | <http:body media-type='application/xml'/> | |
− | <http:body media-type='application/xml'> | + | </http:request>, |
− | + | 'http://localhost:8984/rest', | |
− | + | <query> | |
− | + | <text> | |
− | + | <html>{ | |
− | + | for $i in 1 to 3 | |
− | + | return <div>Section {$i }</div> | |
− | + | }</html> | |
− | + | </text> | |
− | + | </query> | |
− | + | ) | |
− | + | </syntaxhighlight> | |
− | </ | ||
'''Result:''' | '''Result:''' | ||
− | < | + | <syntaxhighlight lang="xml"> |
<http:response xmlns:http="http://expath.org/ns/http-client" status="200" message="OK"> | <http:response xmlns:http="http://expath.org/ns/http-client" status="200" message="OK"> | ||
<http:header name="Content-Length" value="135"/> | <http:header name="Content-Length" value="135"/> | ||
Line 156: | Line 166: | ||
<div>Section 3</div> | <div>Section 3</div> | ||
</html> | </html> | ||
− | </ | + | </syntaxhighlight> |
+ | |||
+ | ==File Upload== | ||
+ | |||
+ | Performs an HTML file upload. In the RESTXQ code, the uploaded file is written to the temporary directory: | ||
+ | |||
+ | '''Query:''' | ||
+ | |||
+ | <syntaxhighlight lang="xquery"> | ||
+ | let $path := 'file-to-be.uploaded' | ||
+ | return http:send-request( | ||
+ | <http:request method='POST'> | ||
+ | <http:multipart media-type='multipart/form-data'> | ||
+ | <http:header name='content-disposition' | ||
+ | value='form-data; name="files"; filename="{ file:name($path) }"'/> | ||
+ | <http:body media-type='application/octet-stream'/> | ||
+ | </http:multipart> | ||
+ | </http:request>, | ||
+ | 'http://localhost:8984/write-to-temp', | ||
+ | file:read-binary($path) | ||
+ | ) | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | '''RESTXQ service:''' | ||
+ | |||
+ | <syntaxhighlight lang="xquery"> | ||
+ | declare | ||
+ | %rest:POST | ||
+ | %rest:path('/write-to-temp') | ||
+ | %rest:form-param('files', '{$files}') | ||
+ | function dba:file-upload( | ||
+ | $files as map(xs:string, xs:base64Binary) | ||
+ | ) as empty-sequence() { | ||
+ | map:for-each($files, function($file, $content) { | ||
+ | file:write-binary(file:temp-dir() || $file, $content) | ||
+ | }); | ||
+ | }; | ||
+ | </syntaxhighlight> | ||
=Errors= | =Errors= | ||
Line 184: | Line 231: | ||
=Changelog= | =Changelog= | ||
+ | |||
+ | ;Version 9.0 | ||
+ | * Updated: support for gzipped content encoding | ||
+ | |||
+ | ;Version 8.0 | ||
+ | * Added: digest authentication | ||
;Version 7.6 | ;Version 7.6 | ||
− | * Updated: [[#http:send-request|http:send-request]]: {{ | + | * Updated: [[#http:send-request|http:send-request]]: {{Code|HC0002}} is raised if the input cannot be parsed or converted to the final data type. |
* Updated: errors are using {{Code|text/plain}} as media-type. | * Updated: errors are using {{Code|text/plain}} as media-type. | ||
− | |||
− |
Revision as of 16:30, 27 February 2020
This XQuery Module contains a single function to send HTTP requests and handle HTTP responses. The function send-request
is based on the EXPath HTTP Client Module. It gives full control over the available request and response parameters. For simple GET requests, the Fetch Module may be sufficient.
If <http:header name="Accept-Encoding" value="gzip"/>
is specified and if the addressed web server provides support for the gzip
compression algorithm, the response will automatically be decompressed.
Contents
Conventions
All functions in this module are assigned to the http://expath.org/ns/http-client
namespace, which is statically bound to the http
prefix.
All errors are assigned to the http://expath.org/ns/error
namespace, which is statically bound to the experr
prefix.
Functions
http:send-request
Signatures | http:send-request($request as element(http:request)) as item()+ http:send-request($request as element(http:request)?, $href as xs:string?) as item()+ http:send-request($request as element(http:request)?, $href as xs:string?, $bodies as item()*) as item()+ |
Summary | Sends an HTTP request and interprets the corresponding response:
Notes:
|
Errors | HC0001 : an HTTP error occurred.HC0002 : error parsing the entity content as XML or HTML.HC0003 : with a multipart response, the override-media-type must be either a multipart media type or application/octet-stream.HC0004 : the src attribute on the body element is mutually exclusive with all other attribute (except the media-type).HC0005 : the request element is not valid.HC0006 : a timeout occurred waiting for the response.
|
Examples
Status Only
Simple GET request. As the attribute status-only
is set to true, only the response element is returned.
Query: <syntaxhighlight lang="xquery">http:send-request(<http:request method='get' status-only='true'/>, 'http://basex.org')</syntaxhighlight> Result: <syntaxhighlight lang="xml"><http:response status="200" message="OK">
<http:header name="Date" value="Mon, 14 Mar 2011 20:55:53 GMT"/> <http:header name="Content-Length" value="12671"/> <http:header name="Expires" value="Mon, 14 Mar 2011 20:57:23 GMT"/> <http:header name="Set-Cookie" value="fe_typo_user=d10c9552f9a784d1a73f8b6ebdf5ce63; path=/"/> <http:header name="Connection" value="close"/> <http:header name="Content-Type" value="text/html; charset=utf-8"/> <http:header name="Server" value="Apache/2.2.16"/> <http:header name="X-Powered-By" value="PHP/5.3.5"/> <http:header name="Cache-Control" value="max-age=90"/> <http:body media-type="text/html; charset=utf-8"/>
</http:response></syntaxhighlight>
Google Homepage
Retrieve the Google search home page with a timeout of 10 seconds. In order to parse HTML, TagSoup must be contained in the class path.
Query: <syntaxhighlight lang="xquery">http:send-request(<http:request method='get' href='http://www.google.com' timeout='10'/>)</syntaxhighlight> Result: <syntaxhighlight lang="xml"> <http:response status="200" message="OK">
<http:header name="Date" value="Mon, 14 Mar 2011 22:03:25 GMT"/> <http:header name="Transfer-Encoding" value="chunked"/> <http:header name="Expires" value="-1"/> <http:header name="X-XSS-Protection" value="1; mode=block"/> <http:header name="Set-Cookie" value="...; expires=Tue, 13-Sep-2011 22:03:25 GMT; path=/; domain=.google.ch; HttpOnly"/> <http:header name="Content-Type" value="text/html; charset=ISO-8859-1"/> <http:header name="Server" value="gws"/> <http:header name="Cache-Control" value="private, max-age=0"/> <http:body media-type="text/html; charset=ISO-8859-1"/>
</http:response> <html xmlns="http://www.w3.org/1999/xhtml">
<head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> <title>Google</title> ... </body>
</html> </syntaxhighlight>
The response content type can also be overwritten in order to retrieve HTML pages and other textual data as plain string (using text/plain
) or in its binary representation (using application/octet-stream
). With the http:header
element, a custom user agent can be set. See the following example:
Query: <syntaxhighlight lang="xquery"> let $binary := http:send-request(
<http:request method='get' override-media-type='application/octet-stream' href='http://www.google.com'> <http:header name="User-Agent" value="Opera"/> </http:request>
)[2] return try {
html:parse($binary)
} catch * {
'Conversion to XML failed: ' || $err:description
} </syntaxhighlight>
SVG Data
Content-type ending with +xml, e.g. image/svg+xml.
Query: <syntaxhighlight lang="xquery">http:send-request(<http:request method='get'/>, 'http://upload.wikimedia.org/wikipedia/commons/6/6b/Bitmap_VS_SVG.svg')</syntaxhighlight>
Result: <syntaxhighlight lang="xml"><http:response status="200" message="OK">
<http:header name="ETag" value="W/"11b6d-4ba15ed4""/> <http:header name="Age" value="9260"/> <http:header name="Date" value="Mon, 14 Mar 2011 19:17:10 GMT"/> <http:header name="Content-Length" value="72557"/> <http:header name="Last-Modified" value="Wed, 17 Mar 2010 22:59:32 GMT"/> <http:header name="Content-Type" value="image/svg+xml"/> <http:header name="X-Cache-Lookup" value="MISS from knsq22.knams.wikimedia.org:80"/> <http:header name="Connection" value="keep-alive"/> <http:header name="Server" value="Sun-Java-System-Web-Server/7.0"/> <http:header name="X-Cache" value="MISS from knsq22.knams.wikimedia.org"/> <http:body media-type="image/svg+xml"/>
</http:response> <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="1063" height="638">
<defs> <linearGradient id="lg0"> <stop stop-color="#3333ff" offset="0"/> <stop stop-color="#3f3fff" stop-opacity="0" offset="1"/> </linearGradient> ...
</svg></syntaxhighlight>
POST Request
POST request to the BaseX REST Service, specifying a username and password.
Query: <syntaxhighlight lang="xquery"> http:send-request(
<http:request method='post' username='admin' password='admin'> <http:body media-type='application/xml'/> </http:request>, 'http://localhost:8984/rest', <query> <text> <html>{ for $i in 1 to 3
return
}</html> </text> </query>
) </syntaxhighlight>
Result: <syntaxhighlight lang="xml"> <http:response xmlns:http="http://expath.org/ns/http-client" status="200" message="OK">
<http:header name="Content-Length" value="135"/> <http:header name="Content-Type" value="application/xml"/> <http:header name="Server" value="Jetty(6.1.26)"/> <http:body media-type="application/xml"/>
</http:response> <html>
</html> </syntaxhighlight>
File Upload
Performs an HTML file upload. In the RESTXQ code, the uploaded file is written to the temporary directory:
Query:
<syntaxhighlight lang="xquery"> let $path := 'file-to-be.uploaded' return http:send-request(
<http:request method='POST'> <http:multipart media-type='multipart/form-data'> <http:header name='content-disposition' value='form-data; name="files"; filename="{ file:name($path) }"'/> <http:body media-type='application/octet-stream'/> </http:multipart> </http:request>, 'http://localhost:8984/write-to-temp', file:read-binary($path)
) </syntaxhighlight>
RESTXQ service:
<syntaxhighlight lang="xquery"> declare
%rest:POST %rest:path('/write-to-temp') %rest:form-param('files', '{$files}')
function dba:file-upload(
$files as map(xs:string, xs:base64Binary)
) as empty-sequence() {
map:for-each($files, function($file, $content) { file:write-binary(file:temp-dir() || $file, $content) });
}; </syntaxhighlight>
Errors
Code | Description |
---|---|
HC0001
|
An HTTP error occurred. |
HC0002
|
Error parsing the entity content as XML or HTML. |
HC0003
|
With a multipart response, the override-media-type must be either a multipart media type or application/octet-stream. |
HC0004
|
The src attribute on the body element is mutually exclusive with all other attribute (except the media-type). |
HC0005
|
The request element is not valid. |
HC0006
|
A timeout occurred waiting for the response. |
Changelog
- Version 9.0
- Updated: support for gzipped content encoding
- Version 8.0
- Added: digest authentication
- Version 7.6
- Updated: http:send-request:
HC0002
is raised if the input cannot be parsed or converted to the final data type. - Updated: errors are using
text/plain
as media-type.