1. Initialize curl. (|curl_init|
      <http://us3.php.net/manual/en/function.curl-init.php>, or
      |curl_multi_init|
      <http://www.php.net/manual/en/function.curl-multi-init.php>)
   2. Do thing(s). (in multiple |curl_exec|
      <http://us2.php.net/manual/en/function.curl-exec.php> calls if
      needed, or |curl_multi_exec|
      <http://www.php.net/manual/en/function.curl-multi-exec.php>)
   3. Close curl. (|curl_close|
      <http://www.php.net/manual/en/function.curl-close.php> or
      |curl_multi_close|
      <http://www.php.net/manual/en/function.curl-multi-close.php>)

http://www.php.net/manual/en/function.curl-multi-init.php

On 3/16/2011 1:05 PM, Kuberan Marimuthu wrote:
> Can somebody throw some light on this. Is it true that php-curl binding does not scale for more than one request at a time ?? I am really curious
>
> On 16-Mar-2011, at 6:12 AM, John Lange wrote:
>
>> I have some code (written in PHP) that checks on the status of a
>> "server" but I need this code to scale up to hundreds of parallel
>> checks.
>>
>> For example, you call the script like this:
>>
>> http://mytest.com/checkserver.php?ip=10.11.12.13
>>
>> where the ip=X.X.X.X is different every time depending on which server
>> you are checking.
>>
>> And the PHP for checkserver.php looks something like this:
>>
>> <?php
>>
>> $ch = curl_init();
>> curl_setopt($ch, CURLOPT_URL, "http://".$ip."/status.html");
>> curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
>> $output = curl_exec($ch);
>> curl_close($ch);
>>
>> ?>
>>
>> To my way of thinking, this should scale easily. Lets say 200 people
>> hit the page at the same time all passing different "ip=" values, this
>> should check all 200 different IPs in parallel and return results.
>>
>> It doesn't. I wrote this little bash script to test it (yes I'm using
>> command line curl to test php-curl, please don't be confused by that):
>>
>> ---
>> #!/bin/bash
>>
>> IPS="10.18.136.20
>> 10.18.136.21
>> 10.18.136.22
>> ... ( a hundred more IPs)"
>>
>> for IP in $IPS ; do
>> curl -s http://mytest.com/checkserver.php?ip=$IP&
>> done
>> ---
>>
>> All the curl commands launch into the background as you expect and I
>> see all the apache child threads startup, but the results return only
>> one by one. It's like each php-curl somehow blocks all the others.
>>
>> I can't for the life of me figure out how this can be possible. Each
>> apache thread should run it's PHP in a separate thread and return in
>> parallel.
>>
>> The only thing I can think of is that php is tracking all the requests
>> as being part of the same session and imposing some limit on the
>> outbound curl requests? But there is no global configuration for
>> php-curl so how would you overcome this?
>>
>> Just thought someone might have had to do something similar in the
>> past and run into this.
>>
>> By the way, it's not an OS limit or anything like that because if I
>> bypass php if I go direct with command line curl like this:
>>
>> for IP in $IPS ; do
>> curl -s http://".$IP"/status.html&
>> done
>>
>> It works just exactly as you'd expect, all results return in parallel
>> so it's got to be a problem with either PHP or apache.
>>
>> --
>> John Lange
>> www.johnlange.ca
>> _______________________________________________
>> http://cool.haxx.se/cgi-bin/mailman/listinfo/curl-and-php
>
> _______________________________________________
> http://cool.haxx.se/cgi-bin/mailman/listinfo/curl-and-php

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Received on 2011-03-16