POST with string body is failing on Windows

From: Michael Ost via curl-library <curl-library_at_lists.haxx.se>
Date: Thu, 10 Feb 2022 00:35:06 +0000

Hi,

I've got a C++ library that is using libCurl to communicate with www.google-analytics.com. For the most part, it is working. But in one case it is not. When I POST a string to that site from Windows it responds with 411 - Length required. I've attached libCurl logging output below, and "Content-Length" is being set. I've debugged into the library and found/fixed some things in my library, but I'm still getting this 411 response. When I POST with the same code from the Mac, it works: GA responds with 200.

Other data points:

  * Our libCurl library is old 7.42, but the problem happens with 7.77 as well
  * The same code POSTs successfully on the Mac
  * GET commands work
  * A second site that we POST to is responding with a 400 error, and I was told by the DevOp at that site that the body being sent is empty
  * I fabricated the same command and sent it via curl.exe on the command line, successfully
Any suggestions of what could be going wrong? Or how to debug this further? I'm at a brick wall. Thanks!

/Michael Ost, Avid Technology

Appendix 1:
Here are all of the curl_easy_setopt that we make. You won't necessarily know what the values are, but I thought maybe the setup calls might provide a clue.

  * CURLOPT_ACCEPT_ENCODING, ""
  * CURLOPT_VERBOSE, 1
  * CURLOPT_DEBUGFUNCTION, debug_callback
  * CURLOPT_CONNECTTIMEOUT, cConnectTimeout
  * CURLOPT_NOSIGNAL, 1L
  * CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1
  * CURLOPT_URL, pr->mRequest->mURL.c_str()
  * CURLOPT_POST, 1
  * CURLOPT_POSTFIELDSIZE, upStream.mUploadString.size()
  * CURLOPT_COPYPOSTFIELDS, upStream.mUploadString.c_str()
  * CURLOPT_HTTPHEADER, pr->mHeaders
  * CURLOPT_WRITEFUNCTION, &RstE_Worker::WriteFunction
  * CURLOPT_WRITEDATA, pr
  * CURLOPT_HEADERFUNCTION, &RstE_Worker::HeaderFunction
  * CURLOPT_HEADERDATA, pr
  * CURLOPT_SSL_VERIFYPEER, 1L
  * CURLOPT_SSL_VERIFYHOST, 2L
Appendix 2:
And here is debug logging from the library when the call is made. I added the CURL_DEBUG_CALLBACK(type) strings:

CURL_DEBUG_CALLBACK (info):
Hostname www.google-analytics.com<http://www.google-analytics.com> was found in DNS cache
CURL_DEBUG_CALLBACK (info):
  Trying 216.58.194.206...
CURL_DEBUG_CALLBACK (info):
Connected to www.google-analytics.com<http://www.google-analytics.com> (216.58.194.206) port 443 (#8)
CURL_DEBUG_CALLBACK (info):
schannel: SSL/TLS connection with www.google-analytics.com<http://www.google-analytics.com> port 443 (step 1/3)
CURL_DEBUG_CALLBACK (info):
schannel: checking server certificate revocation
CURL_DEBUG_CALLBACK (info):
schannel: sending initial handshake data: sending 185 bytes...
CURL_DEBUG_CALLBACK (info):
schannel: sent initial handshake data: sent 185 bytes
CURL_DEBUG_CALLBACK (info):
schannel: SSL/TLS connection with www.google-analytics.com<http://www.google-analytics.com> port 443 (step 2/3)
CURL_DEBUG_CALLBACK (info):
schannel: failed to receive handshake, need more data
RstE_Worker::ThreadMethod - calling curl_multi_performCURL_DEBUG_CALLBACK (info):
schannel: SSL/TLS connection with www.google-analytics.com<http://www.google-analytics.com> port 443 (step 2/3)
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data buffer: offset 4096 length 4096
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data length: 4028
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data buffer: offset 4028 length 4096
CURL_DEBUG_CALLBACK (info):
schannel: received incomplete message, need more data
CURL_DEBUG_CALLBACK (info):
schannel: SSL/TLS connection with www.google-analytics.com<http://www.google-analytics.com> port 443 (step 2/3)
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data buffer: offset 4391 length 5052
CURL_DEBUG_CALLBACK (info):
schannel: sending next handshake data: sending 93 bytes...
CURL_DEBUG_CALLBACK (info):
schannel: SSL/TLS connection with www.google-analytics.com<http://www.google-analytics.com> port 443 (step 2/3)
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data buffer: offset 292 length 5052
CURL_DEBUG_CALLBACK (info):
schannel: SSL/TLS handshake complete
CURL_DEBUG_CALLBACK (info):
schannel: SSL/TLS connection with www.google-analytics.com<http://www.google-analytics.com> port 443 (step 3/3)
CURL_DEBUG_CALLBACK (info):
schannel: incremented credential handle refcount = 1
CURL_DEBUG_CALLBACK (info):
schannel: stored credential handle in session cache
CURL_DEBUG_CALLBACK (=> Send header):
POST /batch HTTP/1.1
Host: www.google-analytics.com<http://www.google-analytics.com>
Accept: */*
Accept-Encoding: identity
Authorization: Bearer MDA***********************

User-Agent: avid-ptc-google-analytics
Content-type: text/plain
Content-Length: 522

CURL_DEBUG_CALLBACK (=> Send data):
v=1&ds=app&tid=UA-85021764-2&an=protools_unit_test&av=x.y.z&ua=AvidProTools%2f12.X%20(Windows%20NT%201.2%3b%20Win64%3b%20x64)&ul=zh-CN&cid=b5543933-084c-a54b-8b90-a515dd86a4c4&t=event&ec=jawhol&ea=sargeantSchultz&el=deutsch&ev=999&cd=protools_unit_test&z=984363590
v=1&ds=app&tid=UA-85021764-2&an=protools_unit_test&av=x.y.z&ua=AvidProTools%2f12.X%20(Windows%20NT%201.2%3b%20Win64%3b%20x64)&ul=zh-CN&cid=b5543933-084c-a54b-8b90-a515dd86a4c4&t=event&ec=jawhol&ea=colonelHogan&el=gi&ev=777&cd=protools_unit_test&z=311506490
CURL_DEBUG_CALLBACK (info):
upload completely sent off: 522 out of 522 bytes
CURL_DEBUG_CALLBACK (info):
schannel: client wants to read 16384 bytes
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data buffer: offset 0 length 16384
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data got 1783
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data buffer: offset 1783 length 16384
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data length: 1401
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data added: 1401
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data cached: offset 1401 length 16384
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data length: 353
CURL_DEBUG_CALLBACK (info):
schannel: encrypted data cached: offset 353 length 16384
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data length: 324
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data added: 324
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data cached: offset 1725 length 16384
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data buffer: offset 1725 length 16384
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data returned 1725
CURL_DEBUG_CALLBACK (info):
schannel: decrypted data buffer: offset 0 length 16384
CURL_DEBUG_CALLBACK (info):
HTTP 1.0, assume close after body
CURL_DEBUG_CALLBACK (<= Recv header):
HTTP/1.0 411 Length Required
CURL_DEBUG_CALLBACK (<= Recv header):
Content-Type: text/html; charset=UTF-8
CURL_DEBUG_CALLBACK (<= Recv header):
Referrer-Policy: no-referrer
CURL_DEBUG_CALLBACK (<= Recv header):
Content-Length: 1564
CURL_DEBUG_CALLBACK (<= Recv header):
Date: Wed, 09 Feb 2022 23:41:30 GMT
CURL_DEBUG_CALLBACK (<= Recv header):

CURL_DEBUG_CALLBACK (<= Recv data):
<!DOCTYPE html>
<html lang=en>
  <meta charset=utf-8>
  <meta name=viewport content="initial-scale=1, minimum-scale=1, width=device-width">
  <title>Error 411 (Length Required)!!1</title>
  <style>
    *{margin:0;padding:0}html,code{font:15px/22px arial,sans-serif}html{background:#fff;color:#222;padding:15px}body{margin:7% auto 0;max-width:390px;min-height:180px;padding:30px 0 15px}* > body{background:url(//www.google.com/images/errors/robot.png<http://www.google.com/images/errors/robot.png>) 100% 5px no-repeat;padding-right:205px}p{margin:11px 0 22px;overflow:hidden}ins{color:#777;text-decoration:none}a img{border:0}_at_media screen and (max-width:772px){body{background:none;margin-top:0;max-width:none;padding-right:0}}#logo{background:url(//www.google.com/images/branding/googlelogo/1x/googlelogo_color_150x54dp.png<http://www.google.com/images/branding/googlelogo/1x/googlelogo_color_150x54dp.png>) no-repeat;margin-left:-5px}_at_media only screen and (min-resolution:192dpi){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png<http://www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png>) no-repeat 0% 0%/100% 100%;-moz-border-image:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png<http://www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png>) 0}}_at_media only screen and (-webkit-min-device-pixel-ratio:2){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png<http://www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png>) no-repeat;-webkit-background-size:100% 100%}}#logo{display:inline-block;height:54px;width:150px}
  </style>
  <a href=//www.google.com/<http://www.google.com/>><span id=logo aria-label=Google></span></a>
  <p><b>411.</b> <ins>ThatΓÇÖs an error.</ins>
  <p>POST requests require a <code>Content-length</code> header. <ins>ThatΓÇÖs all we know.</ins>
CURL_DEBUG_CALLBACK (info):
Closing connection 8
CURL_DEBUG_CALLBACK (info):
schannel: shutting down SSL/TLS connection with www.google-analytics.com<http://www.google-analytics.com> port 443
CURL_DEBUG_CALLBACK (info):
schannel: clear security context handle
CURL_DEBUG_CALLBACK (info):
schannel: decremented credential handle refcount = 0

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Received on 2022-02-10