[
https://issues.apache.org/jira/browse/HTTPCORE-473?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16062052#comment-16062052
]
ASF subversion and git services commented on HTTPCORE-473:
----------------------------------------------------------
Commit 3a4fe27afd894ac69514f51e57b6f6652fea4cab in httpcomponents-core's branch
refs/heads/4.4.x from [~olegk]
[ https://git-wip-us.apache.org/repos/asf?p=httpcomponents-core.git;h=3a4fe27 ]
HTTPCORE-473: fixed classic i/o reverse proxy example
> ElementalReverseProxy does not properly handle POST requests
> ------------------------------------------------------------
>
> Key: HTTPCORE-473
> URL: https://issues.apache.org/jira/browse/HTTPCORE-473
> Project: HttpComponents HttpCore
> Issue Type: Bug
> Components: Examples
> Affects Versions: 4.4.6
> Environment: Windows 7, Java 8
> Reporter: M.S. Dousti
> Priority: Minor
>
> Dear Oleg et al.,
> I understand that {{ElementalReverseProxy}} is provided just as an example,
> but it will be great if this example works properly, as it shows how the
> underlying API must be used.
> Here's a simple setup that shows why {{ElementalReverseProxy}} fails to work
> with POST request (and in fact, any requests including {{Content-Length}} or
> {{Transfer-Content}} headers):
> # Let {{http://127.0.0.1:80}} denote the back-end server which we want to
> proxy against, and assume the server hosts the file {{/index.html}}.
> # Run {{ElementalReverseProxy}} with default config against the back-end
> server.
> Test the back-end server using {{wget}}:
> {code:none}
> wget http://127.0.0.1:80 --post-data="some data"
> --2017-06-24 11:52:30-- http://127.0.0.1/
> Connecting to 127.0.0.1:80... connected.
> HTTP request sent, awaiting response... 200 OK
> Length: 343 [text/html]
> Saving to: 'index.html'
> index.html
> 100%[====================================================>] 343 --.-KB/s
> in 0s
> 2017-06-24 11:52:30 (9.78 MB/s) - 'index.html' saved [343/343]
> {code}
> As you can see, it works just fine. Now try it with {{ElementalReverseProxy}}:
> {code:none}
> wget http://127.0.0.1:8888 --post-data="some data"
> --2017-06-24 11:53:31-- http://127.0.0.1:8888/
> Connecting to 127.0.0.1:8888... connected.
> HTTP request sent, awaiting response... 400 Bad Request
> 2017-06-24 11:53:31 ERROR 400: Bad Request.
> {code}
> h3. Resolution
> {{ProxyThread}} executes {{httpservice.handleRequest}}, which in turn calls
> {{processor.process(request, context)}}. This causes
> {{RequestContent.process()}} to be executed, which throws an exception as it
> finds that the request already contains the {{Content-Length}} header.
> One way to rectify this is to initialize {{inhttpproc}} with
> {{RequestContent(true)}}, which overwrites the {{Content-Length}} header even
> if it is present, without throwing an exception.
> Running {{wget}} again will now result in no error, but with one catch:
> Notice the response misses the {{Content-Length}} header (this is evident
> from {{Length: unspecified}} below):
> {code:none}
> wget http://127.0.0.1:8888 --post-data="some data"
> --2017-06-24 12:09:25-- http://127.0.0.1:8888/
> Connecting to 127.0.0.1:8888... connected.
> HTTP request sent, awaiting response... 200 OK
> Length: unspecified [text/html]
> Saving to: 'index.html'
> index.html [ <=>
> ] 343 --.-KB/s in 0s
> 2017-06-24 12:09:25 (8.82 MB/s) - 'index.html' saved [343]
> {code}
> This is due to the line {{targetResponse.removeHeaders(HTTP.CONTENT_LEN)}} in
> {{ProxyHandler#handle()}} method. Commenting this line will resolve the issue.
> In general, I don't get the {{ProxyHandler#handle()}} method: It is called by
> {{HttpService#doService()}}, which in turn gets called just after the
> following line:
> {code:java}
> this.processor.process(request, context);
> {code}
> So, it means that just after the above line applied mandatory HTTP headers,
> {{ProxyHandler#handle()}} removes them all! Next, it tries to re-apply them:
> {code:java}
> this.httpexecutor.preProcess(request, this.httpproc, context);
> {code}
> But here, {{this.httpproc}} refers to {{outhttpproc}}, for which the
> {{requestInterceptors}} instance is {{null}} effectively doing nothing.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@hc.apache.org
For additional commands, e-mail: dev-h...@hc.apache.org
