handling HTTP redirects

[Laurent Bourgès]

Hi all,

I just want to inform you about technical details.

A reference implementation of HTTP 1.1 is available for the java  
environment thanks to apache.org (so, open source) :
	Apache commons Http Client 3.1
	
	http://hc.apache.org/httpclient-3.x/

	(in near future : Http Client 4.0 will be released as a release  
candidate ...)

This library is able to handle properly (tested in several projects) :
	- cookies for session management (authentication)
	- HTTP follow redirect (302) ...
	- supports all HTTP methods (GET, POST, DELETE, HEAD...)
	- Http headers are easy parsed and built


 From apache docs :

Features

     * Standards based, pure Java, implementation of HTTP versions  
1.0 and 1.1
     * Full implementation of all HTTP methods (GET, POST, PUT,  
DELETE, HEAD, OPTIONS, and TRACE) in an extensible OO framework.
     * Supports encryption with HTTPS (HTTP over SSL) protocol.
     * Granular non-standards configuration and tracking.
     * Transparent connections through HTTP proxies.
     * Tunneled HTTPS connections through HTTP proxies, via the  
CONNECT method.
     * Transparent connections through SOCKS proxies (version 4 & 5)  
using native Java socket support.
     * Authentication using Basic, Digest and the encrypting NTLM (NT  
Lan Manager) methods.
     * Plug-in mechanism for custom authentication methods.
     * Multi-Part form POST for uploading large files.
     * Pluggable secure sockets implementations, making it easier to  
use third party solutions
     * Connection management support for use in multi-threaded  
applications. Supports setting the maximum total connections as well  
as the maximum connections per host. Detects and closes stale  
connections.
     * Automatic Cookie handling for reading Set-Cookie: headers from  
the server and sending them back out in a Cookie: header when  
appropriate.
     * Plug-in mechanism for custom cookie policies.
     * Request output streams to avoid buffering any content body by  
streaming directly to the socket to the server.
     * Response input streams to efficiently read the response body  
by streaming directly from the socket to the server.
     * Persistent connections using KeepAlive in HTTP/1.0 and  
persistance in HTTP/1.1
     * Direct access to the response code and headers sent by the  
server.
     * The ability to set connection timeouts.
     * HttpMethods implement the Command Pattern to allow for  
parallel requests and efficient re-use of connections.
     * Source code is freely available under the Apache Software  
License.

Standards Compliance

HttpClient implements the following specifications endorsed by the  
Internet Engineering Task Force (IETF) and the internet at large:

     * RFC1945 Hypertext Transfer Protocol -- HTTP/1.0
     * RFC2616 Hypertext Transfer Protocol -- HTTP/1.1
     * RFC2617 HTTP Authentication: Basic and Digest Access  
Authentication
     * RFC2109 HTTP State Management Mechanism (Cookies)
     * RFC2396 Uniform Resource Identifiers (URI): Generic Syntax
     * RFC1867 Form-based File Upload in HTML

Enjoy,
Good morning or afternoon,

Laurent

Le 4 juin 08 à 19:49, Roy Williams a écrit :

> Sebastien
>
> Of course the Vizier people can use redirects if they want, it is  
> quite legal. It is also legal to make a cone search which never  
> returns more than three sources, or one that returns an error for  
> every possible request.
>
> I have done a rough timing test of Vizier cone searches, and I find  
> that the redirect costs about 0.5 seconds per cone search. In other  
> words, a Vizier service will be quite a bit faster if you simply  
> replace up front the string "vizier" with "webviz" in all the  
> accessURLs that you get from the registry. Since Vim runs hundreds  
> of cone searches at a time, this is what I have chosen to do, to  
> save a few minutes of my customer's valuable time.
>
> Roy
>
> -- 
>
> California Institute of Technology
> 626 395 3670
>

------------------------------------------------------------------------ 
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  Laurent Bourgès, engineer
  EURO-VO-DCA Project
  LUTh, Observatoire de Paris-Meudon
  5 place Jules Janssen
  F-92 195 Meudon Cedex
Tel     : 01 45 07 74 25
  Email: Laurent.Bourges at obspm.fr
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