MantisBT - NetSurf |
| View Issue Details |
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| ID | Project | Category | View Status | Date Submitted | Last Update |
| 0002252 | NetSurf | [All Projects] General | public | 2015-01-10 17:46 | 2016-11-22 21:54 |
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| Reporter | Chris Young | |
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| Assigned To | Chris Young | |
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| Priority | normal | Severity | minor | Reproducibility | sometimes |
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| Status | closed | Resolution | fixed | |
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| Platform | Amiga | OS | AmigaOS | OS Version | 4.1 |
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| Product Version | 3.3 | |
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| Target Version | | Fixed in Version | 3.6 | |
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| Fixed in CI build # | 3751 |
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| Reported in CI build # | 2514 |
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| URL of problem page | http://forums.digitalspy.co.uk |
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| Summary | 0002252: Server returned nothing when posting >~550bytes |
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| Description | I get the following error when posting about more than 550 bytes in the Digital Spy forums:
Server returned nothing (no headers, no data)
This appears after an apparent timeout waiting for data to be received back. |
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| Steps To Reproduce | Visit forums.digitalspy.co.uk (you will need an account)
Start or reply to an existing thread with more than 550 characters
Click "preview post" or "go advanced" (this causes the same error as submitting, but without actually starting a thread)
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| Additional Information | This seems to happen quite consistently, although when I was trying to reproduce to get a log file with the curl debug I couldn't reproduce it (it has happened again since). If I can get a log I'll add it.
I'm unable to reproduce on the GTK or Windows versions of NetSurf at this time, or on any other website. It seems quite isolated but this was definitely working last year (November?). I've tried updating to libcurl 7.40 but it hasn't made any difference.
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| Tags | No tags attached. |
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| Relationships | |
| Attached Files |  ns.log.gz (77,311) 2015-01-13 19:18
https://bugs.netsurf-browser.org/mantis/file_download.php?file_id=233&type=bug
wireshark.7z (15,554) 2015-04-26 14:15
https://bugs.netsurf-browser.org/mantis/file_download.php?file_id=288&type=bug |
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Notes |
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Log attached - Contains a couple of successes and then a failure (as I added more and more text to produce the issue).
The key failure part is this:
* Connection died, retrying a fresh connect
* Closing connection 0
* Issue another request to this URL: 'http://forums.digitalspy.co.uk/newthread.php?do=postthread&f=108'
* Found bundle for host forums.digitalspy.co.uk: 0x570519f8
* Connection 10 seems to be dead!
* Closing connection 10
* Hostname was NOT found in DNS cache
* Trying 54.154.112.81...
* Connected to forums.digitalspy.co.uk (54.154.112.81) port 80 (#21)
> POST /newthread.php?do=postthread&f=108 HTTP/1.1
User-Agent: NetSurf/3.3 (AmigaOS)
Host: forums.digitalspy.co.uk
Accept: */*
Accept-Encoding: gzip
Referer: http://forums.digitalspy.co.uk/newthread.php?do=postthread&f=108
Cookie: bblastvisit=1417044682; bblastactivity=0; bbuserid=xxxx; bbpassword=xxxxxxxxxxxxx; DSid=7329%3A4ae4f30b0cfb624dca3aaaa097c6ddd0; hearst_id=66379000; bbsessionhash=492ca0a0361c465e1320eed1262516de
Accept-Language: en-GB, en, *;q=0.1
DNT: 1
Content-Length: 906
Content-Type: application/x-www-form-urlencoded
* upload completely sent off: 906 out of 906 bytes
* Empty reply from server
* Connection #21 to host forums.digitalspy.co.uk left intact
(204.103683) content/fetchers/curl.c fetch_curl_done 838: done http://forums.digitalspy.co.uk/newthread.php?do=postthread&f=108
(204.103876) content/fetchers/curl.c fetch_curl_done 876: Unknown cURL response code 52
(204.103926) content/fetchers/curl.c fetch_curl_stop 703: fetch 0x55a45fd0, url 'http://forums.digitalspy.co.uk/newthread.php?do=postthread&f=108'
(204.137399) amiga/misc.c ami_misc_req 54: Server returned nothing (no headers, no data)
I suspect "Unknown cURL response code 52" might be the key. |
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A quick Google reveals this (old) message: http://curl.haxx.se/mail/archive-2002-04/0042.html
In that case the server was segfaulting, so it might be the same problem here, in which case we won't be able to do much about it, unless we are sending something weird to the server. |
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well the curl error is CURLE_GOT_NOTHING (52) in general our handling of curl error codes is very poor. |
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I've had a nose around with Wireshark to try and figure out what is going on. It appears when the "nothing received" error appears, NetSurf has not even attempted to send the request. I've attached the logs for the failure [wireshark_ds.pcapng] and the log for a working request (ie. with much shorter input) [wireshark_ds_working.pcapng] |
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Looking at Curl, it appears that it handles posts >1K slightly differently, which would explain why adding extra characters suddenly stops it working. this is the relevant excerpt from curl http.c:
---8<---
/* For really small posts we don't use Expect: headers at all, and for
the somewhat bigger ones we allow the app to disable it. Just make
sure that the expect100header is always set to the preferred value
here. */
ptr = Curl_checkheaders(conn, "Expect:");
if(ptr) {
data->state.expect100header =
Curl_compareheader(ptr, "Expect:", "100-continue");
}
else if(postsize > TINY_INITIAL_POST_SIZE || postsize < 0) {
result = expect100(data, conn, req_buffer);
if(result)
return result;
}
else
data->state.expect100header = FALSE;
---8<---
As this appears to be related to Expect: 100-continue, I tried removing the line in NetSurf which disables that header. I'm now getting an HTTP 100 Continue response from the server, but of course NetSurf doesn't know what to do with it.
I'm thinking the bug might be in libcurl, where with >1K posts the non-Expect:100 behaviour isn't working correctly. |
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I have no idea what has changed or when, but this is working now. |
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this issue has been closed because it is included in the 3.6 release |
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