Difference between revisions of "HTTP Client Module"
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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. | 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= | ||
Line 15: | 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|$bodies}} parameter. | ||
+ | |||
+ | Notes: | ||
+ | * Both basic and digest authentication is supported. | ||
+ | * While the contents of the request can be supplied as child of the {{Code|http:body}} element, it is faster and safer to pass them on via the third argument. | ||
+ | * For further information, please check out the [http://expath.org/spec/http-client EXPath] specification. | ||
|- | |- | ||
|'''Errors''' | |'''Errors''' | ||
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<html xmlns="http://www.w3.org/1999/xhtml"> | <html xmlns="http://www.w3.org/1999/xhtml"> | ||
<head> | <head> | ||
− | <meta http-equiv=" | + | <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> |
<title>Google</title> | <title>Google</title> | ||
− | + | ... | |
− | |||
− | |||
− | |||
</body> | </body> | ||
</html> | </html> |
Revision as of 19:56, 25 July 2018
This XQuery Module contains a single function to send HTTP requests and handle HTTP responses. The function send-request
is based on the EXPath HTTP Client Module. It gives full control over the available request and response parameters. For simple GET requests, the Fetch Module may be sufficient.
If <http:header name="Accept-Encoding" value="gzip"/>
is specified and if the addressed web server provides support for the gzip
compression algorithm, the response will automatically be decompressed.
Contents
Conventions
All functions in this module are assigned to the http://expath.org/ns/http-client
namespace, which is statically bound to the http
prefix.
All errors are assigned to the http://expath.org/ns/error
namespace, which is statically bound to the exerr
prefix.
Functions
http:send-request
Signatures | http:send-request($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:
http:send-request(<http:request method='get' status-only='true'/>, 'http://basex.org')
Result:
<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>
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:
http:send-request(<http:request method='get' href='http://www.google.com' timeout='10'/>)
Result:
<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>
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:
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 }
SVG Data
Content-type ending with +xml, e.g. image/svg+xml.
Query:
http:send-request(<http:request method='get'/>, 'http://upload.wikimedia.org/wikipedia/commons/6/6b/Bitmap_VS_SVG.svg')
Result:
<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>
POST Request
POST request to the BaseX REST Service, specifying a username and password.
Query:
let $request := <http:request href='http://localhost:8984/rest' method='post' username='admin' password='admin' send-authorization='true'> <http:body media-type='application/xml'> <query xmlns="http://basex.org/rest"> <text><![CDATA[ <html>{ for $i in 1 to 3 return <div>Section {$i }</div> }</html> ]]></text> </query> </http:body> </http:request> return http:send-request($request)
Result:
<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> <div>Section 1</div> <div>Section 2</div> <div>Section 3</div> </html>
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.