The receiving server only receive the following headers:

GET / HTTP/1.1
Host: www.example.com
Connection: close

Checked with tcpdump

Workaround is:

$opts = array(
  'http'=>array(
    'user_agent' => 'foo'
  )
);

$context = stream_context_create($opts);
$client = new SoapClient('http://www.example.com/', array('stream_context' => 
$context));

I could not reproduce your problem, using PHP 5.3.9 (linux) was able to send a 
request with user_agent header set


I captured with WireShark.... could you please try to:
a) capture with another program (maybe)
b) make sure that on the other end , the user_agent is not being stripped

or provide more info

Forgot to mention, I tested with 5.3.9 realeased version, and also with the 
current snapshot

I've tested it on several machines.

It's not a matter of stripping the header, since stream_context works.

My test script:

<?php
if ( isset($_GET['check']) ) {
        mail('you@example.com', 'ff', print_r(apache_request_headers(), true));
} else {
        $client = new SoapClient('http://example.com/soap.php?check=1', 
array('user_agent' => 'foo'));
}
?>

Oooh sorry, my bad; yeah you were right;

 I've posted a fix, I already tested it with no problem, waiting for someone to 
comment or commit.

Regarding your patch, I believe the header is "User-Agent", not "User Agent" :)

This is what I now get after running your script with my patch

Array
(
   [DOCUMENT_ROOT] => /home/chilld/public_html
   [GATEWAY_INTERFACE] => CGI/1.1
   [HTTP_CONNECTION] => close
   [HTTP_HOST] => pfdn.local.chilldata.com
   [HTTP_USER_AGENT] => foo
   [PATH] => /bin:/usr/bin
   [QUERY_STRING] => check=1
   [REDIRECT_STATUS] => 200
   [REMOTE_ADDR] => 189.253.78.75
   [REMOTE_PORT] => 20615
   [REQUEST_METHOD] => GET
   [REQUEST_URI] => /dev/soap.php?check=1
   [SCRIPT_FILENAME] => /home/chilld/public_html/dev/soap.php
   [SCRIPT_NAME] => /dev/soap.php
   [SERVER_ADDR] => 10.34.11.56
   [SERVER_ADMIN] => webmaster@chilldata.com
   [SERVER_NAME] => www.chilldata.com
   [SERVER_PORT] => 80
   [SERVER_PROTOCOL] => HTTP/1.1
   [SERVER_SIGNATURE] =>
   [SERVER_SOFTWARE] => Apache
   [UNIQUE_ID] => TyOIZK3Hp1AAADUKGtYAAAAL
   [PHP_SELF] => /dev/soap.php
   [REQUEST_TIME] => 1327728740


   [argv] => Array
       (
           [0] => check=1
       )

   [argc] => 1
)


and if i change to see the $_SERVER['HTTP_USER_AGENT'] variable I get also foo

Checked it with "User-Agent" and the behavior is the same with and without the "-"

Better to be RFC compliant (RFC 2616) and add the '-;, I'll upload the patch 
again.

Thanks!

After yawk@irc replicated the issue, the problem is that the WSDL request is the 
one that is not being sent with the user-agent header set.

Subsequent requests are.

Pending to determine if WSDL request should have user-agent set
 
(replication with screenshots: http://chilldata.com/dev/soapbug/)

Email will be sent to internals mailing list

This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.