PHP Curl API Response Time Differs from different Server

Question

I have a set up where I have two servers running a thin-client (Apache, PHP). On Server A, it's consider a client machine and connects to Server B to obtain data via a Restful API. Both servers are on the same network. On Server B, the response of the request is shown below:

{
   "code": 200,
   "response_time": {
      "time": 0.43,
      "measure": "seconds"
   }
}

Server B calculates the time completed for each task by using microseconds to flag the start and end of a request block. But when I use curl on Server A to make the call to the Server B, I get very strange results in terms on execution time:

   $url = "https://example.com/api"; 
   /*server B address. I've tried IP address as well without any change in results. 
     This must go over a SSL connection. */

    $start_time = microtime(true);

    $curl2 = curl_init();

    curl_setopt($curl2, CURLOPT_URL, $url);
    curl_setopt($curl2, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($curl2, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($curl2, CURLOPT_USERAGENT, "Server A User Agent");

    $result = curl_exec($curl2);

    $HttpCode = curl_getinfo($curl2, CURLINFO_HTTP_CODE);
    $total_time = curl_getinfo($curl2, CURLINFO_TOTAL_TIME);
    $connect_time = curl_getinfo($curl2, CURLINFO_CONNECT_TIME);
    $namelookup_time = curl_getinfo($curl2, CURLINFO_NAMELOOKUP_TIME);

    $end_time = microtime(true);

    $timeDiff = round(((float)$end_time - (float)$start_time), 3);

I get the following for each Time Check:

 $timeDiff = 18.7381 (Using Microseconds)
 $total_time = 18.7381 (Transfer Time)
 $connect_time = 0.020679
 $namelookup_time = 0.004144

So I'm not sure why this is happening. Is there a better way to source data from another server in your network that holds your API? It would be like if Twitter's Site was consuming their API from another server that isn't the API server. I would think that the time for the curl to the API would be pretty similar to the time reported by the API. I understand there the API doesn't take into account network traffic and speed to open the connection - but 18 seconds versus 0.43 seems strange to me.

Any ideas here?

Answer 1

This is not the issue with curl anymore. Rather its the problem with your network setup. You can check this out by doing few things.

1) Use ping command to check the response time.

From Server-A: ping Server-B-IP
From Server-B: ping Server-A-IP

2) Similarly you can use the traceroute(for windows tracert) command to check the response time as well. You should get the response instantly.

From Server-A: traceroute Server-B-IP
From Server-B: traceroute Server-A-IP

3) Use wget or curl commandline to download a large file(let say 100 MB) From one server to another, and then check how long does they take. For example using wget:

From Server-B: wget http://server-A-IP/test/test-file.flv
From Server-A: wget http://server-B-IP/test/test-file.flv

4) Apart from these basic routine check, you can also use some advance tools to sort this network problem out. For example the commands/examples from the following two links:

Test network connection performance between two Linux servers
Command line tool to test bandwidth between 2 servers

Answer 2

I had the same problem about 3 days ago. I've wasted an entire afternoon to find the problem. At the end I contacted my server provider and told him the problem. He said, that this is not a problem of my script, but of the carrier (network).

Maybe it is the same problem I had, so contact your server provider and ask him. Did you tried it with file_get_contents? It would be interesting if the response time is the same with it.