hc-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "M.S. Dousti (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HTTPCORE-475) Occasional issues in handling "204 No Content"
Date Mon, 03 Jul 2017 12:02:00 GMT

    [ https://issues.apache.org/jira/browse/HTTPCORE-475?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16072313#comment-16072313
] 

M.S. Dousti commented on HTTPCORE-475:
--------------------------------------

Thanks again, Oleg.

I suspect 204 is the culprit because if it's not present, the error does not occur. Simply
comment the line {{header("HTTP/1.1 204 NO CONTENT");}} in [form.php|https://gist.github.com/msdousti/b98f225512bd21ba23caebc5548f4678],
and retry the experiment. You won't see the exception anymore.

Also, in Bing example, here's a screenshot {color:red}without{color} the proxy:
!without-proxy.png!


----

and the corresponding screenshot {color:#14892c}with{color} the proxy:

!with-proxy.png!

It comes to me as a surprise too, but +only POST requests whose response is a 204+ suffer
from the issue. I tried this a lot of times with Bing, and the result is always the same.

I also wrote the simple PHP script to show this. You may say the server is overwhelmed, but
I tried with as low as 10 requests, and made them synchronous so as not to put much pressure
on the proxy server. On the other hand, when no 204 is involved, you may go as high as 100s
of requests, and no issue occurs.

I first thought that for some reason, {{ElementalReverseProxy}} tries to read the body of
the the message, while for 204s, no body exists. Therefore, it returns an error. But as this
is not always the case, my theory fails there.

> Occasional issues in handling "204 No Content"
> ----------------------------------------------
>
>                 Key: HTTPCORE-475
>                 URL: https://issues.apache.org/jira/browse/HTTPCORE-475
>             Project: HttpComponents HttpCore
>          Issue Type: Bug
>          Components: Examples, HttpCore
>    Affects Versions: 4.4.6
>         Environment: Windows, Java 8
>            Reporter: M.S. Dousti
>            Priority: Minor
>         Attachments: without-proxy.png, with-proxy.png
>
>
> While testing {{ElementalReverseProxy}}, I noted that occasionally, some requests fail.
Digging further, it seems that the code has some difficulty in handling POST requests whose
responses have "204 No Content" status. The bug is intermittent, so it is a bit tricky to
reproduce. One way is to run the proxy against [http://www.bing.com]. (Notice it's HTTP and
not HTTPS). Here are the steps:
> 1) Change line 274 of {{ElementalReverseProxy}} to further assist in debugging, from:
> {code:java}
> System.err.println("I/O error: " + ex.getMessage());
> {code}
> to:
> {code:java}
> ex.printStackTrace(); System.exit(-1);
> {code}
> 2) Add the following lines to your {{hosts}} file ({{/etc/hosts}} in Linux, and {{%SystemRoot%\System32\drivers\etc\hosts}}
in Windows):
> {code:none}
> 127.0.0.1 bing.com
> 127.0.0.1 www.bing.com
> {code}
> 3) Run {{ElementalReverseProxy}} against one of Bing's IP addresses. I used {{204.79.197.200}}.
> 4) Navigate your browser to {{http://www.bing.com:8888}}, and watch the output of 
> {{ElementalReverseProxy}}. Here's a sample run:
> {noformat}
> Listening on port 8888
> Incoming connection from /127.0.0.1
> Outgoing connection to /204.79.197.200
> New connection thread
> >> Request URI: /
> << Response: HTTP/1.1 200 OK
> Incoming connection from /127.0.0.1
> Outgoing connection to /204.79.197.200
> Incoming connection from /127.0.0.1
> New connection thread
> >> Request URI: /fd/ls/l?IG=3C1FD9BC348B419DAF07D5D09D135555&CID=3ED5D1926AB96D71082FDB206BCB6CA6&Type=Event.CPT&DATA={%22pp%22:{%22S%22:%22L%22,%22FC%22:-1,%22BC%22:-1,%22SE%22:-1,%22TC%22:-1,%22H%22:116,%22BP%22:134,%22CT%22:169,%22IL%22:1},%22ad%22:[-1,-1,1600,770,1600,770,0]}&P=SERP&DA=Bn2
> Outgoing connection to /204.79.197.200
> New connection thread
> >> Request URI: /fd/ls/lsp.aspx?
> Incoming connection from /127.0.0.1
> Outgoing connection to /204.79.197.200
> New connection thread
> Incoming connection from /127.0.0.1
> >> Request URI: /notifications/render?bnptrigger=%7B%22PartnerId%22%3A%22HomePage%22%2C%22IID%22%3A%22SERP.2000%22%2C%22Attributes%22%3A%7B%22RawRequestURL%22%3A%22%2F%22%7D%7D&IG=3C1FD9BC348B419DAF07D5D09D135555&IID=SERP.2000
> Outgoing connection to /204.79.197.200
> New connection thread
> Incoming connection from /127.0.0.1
> >> Request URI: /sa/8_01_0_000000/HpbHeaderPopup.js
> << Response: HTTP/1.1 204 OK
> Outgoing connection to /204.79.197.200
> New connection thread
> >> Request URI: /sa/8_01_0_000000/homepageImgViewer_c.js
> << Response: HTTP/1.1 200 OK
> << Response: HTTP/1.1 200 OK
> << Response: HTTP/1.1 200 OK
> >> Request URI: /HPImageArchive.aspx?format=js&idx=0&n=1&nc=1498898493932&pid=hp
> org.apache.http.NoHttpResponseException: The target server failed to respondIncoming
connection from /127.0.0.1
>         at org.apache.http.impl.io.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:131)
>         at org.apache.http.impl.io.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:53)
>         at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:259)
>         at org.apache.http.impl.DefaultBHttpClientConnection.receiveResponseHeader(DefaultBHttpClientConnection.java:163)
>         at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:273)
>         at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125)
>         at ElementalReverseProxy$ProxyHandler.handle(ElementalReverseProxy.java:134)
>         at org.apache.http.protocol.HttpService.doService(HttpService.java:437)
>         at org.apache.http.protocol.HttpService.handleRequest(HttpService.java:342)
>         at ElementalReverseProxy$ProxyThread.run(ElementalReverseProxy.java:262)
> {noformat}
> I don't know whether the problem lies within {{ElementalReverseProxy}}, or the way HC
handles the requests/responses.
> I also wrote a simple PHP/HTML/JavaScript to reproduce the error without relying on Bing,
which I can provide if needed.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@hc.apache.org
For additional commands, e-mail: dev-help@hc.apache.org


Mime
View raw message