Home » Php » php – cURL 'Content-length required' error… 3 days of searching, no luck

php – cURL 'Content-length required' error… 3 days of searching, no luck

Posted by: admin July 12, 2020 Leave a comment


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]',
 '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

$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);  


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


How to&Answers:

I think you need to set CURLOPT_HTTPHEADER. You can tried with pass data as a json string.

$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),)  


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.


So I just quickly used a curl_getinfo call to see what was being sent (not quite your recommendation, but it was faster to try this first)… and sure enough… there’s no content-length anywhere. I tried it both with the Content-length header being declared by me, and NOT being declared by me. Both options resulted in what you see:

It’s also worth noting that is says content_type = text/html… even though I had it declared as application/json

being used:

curl_setopt($ch2, CURLOPT_HTTPHEADER, array(
   'Authorization: GoogleLogin auth='.$auth_code,
   'Content-Type: application/json',  
   'Content-length:' . strlen($post_data))

Here’s the output of curl_getinfo:

Array (
    [url] => https://www.googleapis.com/calendar/v3/calendars/XXXXXXXXXX%40developer.gserviceaccount.com/events?sendNotifications=true&pp=1&key=XXXXXXXX-XXXXXXXXXXXXXXXXXXXXXX
    [content_type] => text/html; charset=UTF-8
    [http_code] => 411
    [header_size] => 147
    [request_size] => 737
    [filetime] => -1
    [ssl_verify_result] => 0
    [redirect_count] => 0
    [total_time] => 0.104391
    [namelookup_time] => 0.000687
    [connect_time] => 0.025284
    [pretransfer_time] => 0.079614
    [size_upload] => 159
    [size_download] => 934
    [speed_download] => 8947
    [speed_upload] => 1523
    [download_content_length] => 934
    [upload_content_length] => 159
    [starttransfer_time] => 0.104356
    [redirect_time] => 0
    [certinfo] => Array

    [primary_ip] => 2607:f8b0:400e:c04::5f
    [primary_port] => 443
    [local_ip] => 2600:3c01::f03c:91ff:fe69:4a05
    [local_port] => 57581
    [redirect_url] =>  )


Updated answer…

In the second curl call you seem to have used the wrong handle for one line…

curl_setopt($ch, CURLOPT_POST, true);

is supposed to be

curl_setopt($ch2, CURLOPT_POST, true);

Original answer…
You’re not passing a header. Did you try passing the content-length as a header in this format?

curl_setopt($ch,CURLOPT_HTTPHEADER,array('HeaderName: HeaderValue'));

Your header is currently just the number 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.