Open Radar

 
Summary: 

NSURLConnection does not support the "Expect: 100-continue" header.  Without this header, uploading a file using POST to server that uses HTTP authentication results in uploads taking twice as long as necessary.

  <http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.20>

  <http://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html#sec8.2.3>

Without 100-continue, the HTTP client uploads the whole file, only to get a 401 response from the server.  The client then needs to upload the file *again*, this time with the proper credentials.  With 100-continue, the HTTP client pauses before sending the body.  This allows the server to respond with a 401 before 

Steps to Reproduce: 

Upload a file using NSURLConnection and POST against a server with HTTP authentication.  I've attached a small PHP app that contains a form and PHP script to accept the upload.  The script, `private/uploader.php` is protected with the username "foo", password "bar".  A small Cocoa app that POSTs to "private/uploader.php" using NSURLConnection is required.

Expected Results: 

While running a network trace, such as tcpdump or Wireshark, the upload should only occur once, with the first upload interrupted with a 401 response, instead of a 100 Continue.

Actual Results: 

The network trace shows the file uploaded twice.  The first one is discarded and wastedful since the server responds with a 401.

Regression: 

N/A

Notes: 

Other HTTP client libraries like libcurl and .Net support 100-continue.  However, they usually allow a way to disable this behavior in case a program needs to work around a buggy server that does not implement HTTP 1.1 correctly.

  <http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTPOST>

  <http://msdn2.microsoft.com/en-us/library/system.net.servicepoint.expect100continue.aspx>


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