cURL 'Content-length required' error... 3 days of searching, no luck

Question

Before you ask: I have already checked every similar question that already had an answer, and none of the proposed solutions work. So I'm hoping someone may be able to notice a mistake in my code.

When submitting a cURL post to Google, I am returned with a 411 error, "POST requests require a Content-length header"

//Info required to authenticate
$URL = "https://www.google.com/accounts/ClientLogin";
$POST = http_build_query(array(
 'Email' => '[email protected]',
 'Passwd' => 'XXXXXXXXXXXXXXX',
 'source' => 'primary',
 'service' => 'cl'
));

$ch = curl_init( $URL );
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $POST);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_HEADER, 1); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
$response = curl_exec($ch); //returns SID=<sid code>nLSID=<lsid code>nAuth=<auth code> or ERROR=<message>
if ( curl_errno($ch) )
 die( 'Error contacting server' );

//Successful auth results in http code 200
if ( curl_getinfo($ch, CURLINFO_HTTP_CODE) != 200 )
 die( 'Failed to authenticate' );

//Extract auth code - Authorization: GoogleLogin auth=yourAuthToken
$auth_code = substr($response, strpos($response, 'Auth=')+5);

//We're done here
curl_close($ch);


$url = "https://www.googleapis.com/calendar/v3/calendars/".urlencode('[email protected]')."/events?sendNotifications=true&pp=1&key=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx";  

$post_data = http_build_query(array(
    "end" => array("dateTime" => "2013-14-11T10:40:00.000-07:00"),  
    "start" => array("dateTime" => "2013-14-11T10:00:00.000-07:00"),  
    "summary" => "my_summary",
    "description" => "my_description"
));

$headers = array(
    'Authorization: GoogleLogin auth='.$auth_code.'',
    'Content-Type: application/json'
);

$ch2 = curl_init();  
curl_setopt($ch2, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch2, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch2, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch2, CURLOPT_POSTFIELDS, $post_data);  

$output = curl_exec($ch2);  

curl_close($ch2);

echo '<pre>'.print_r($output).'</pre>';

Things I have tried:

-Adding the 'Content-length: '.strlen($post_data)

-Content-type of 'x-www-form-urlencoded'

-using a very simply json string for post_data so that I didn't use http_build_query

-Trying to make it send as a PUT instead of POST

-And a few other things over the course of the last few days that I can't quite recall right now

Intent: To add an event to only MY calendar using only PHP with no authentication steps required by the user. This must be able to run all within a php function, asynchronously (called via AJAX)

NOTE: Not using Wordpress or any other CMS

-Kyle

Answer 1

I was struggling for a while with a similar problem. In my case it was because one of the values I was setting in my headers ended with a newline character. This meant that the server receiving the post would see the double-newline and prematurely think the headers were finished (which stopped the Content-Length header from being read). Solution was to trim the newline char.

Answer 2

I think you need to set CURLOPT_HTTPHEADER. You can try to pass data as a json string as stated below.

$post_data = array(
    "end" => array("dateTime" => "2013-14-11T10:40:00.000-07:00"),  
    "start" => array("dateTime" => "2013-14-11T10:00:00.000-07:00"),  
    "summary" => "my_summary",
    "description" => "my_description"
);

$post_data = json_encode($post_data);
curl_setopt($ch2, CURLOPT_HTTPHEADER, array(  
   'Content-Type: application/json',  
   'Content-Length: ' . strlen($post_data),)  
 );  

Answer 3

I was receiving the same content error as you and found that I had an erroneous line break in my header, caused by a variable I was including.

I tracked this down using curl_setopt($ch, CURLINFO_HEADER_OUT, true); which makes curl_getinfo() include the request's headers in its output.

Using trim() on the variable fixed it.