curl_init
(PHP 4 >= 4.0.2, PHP 5)
curl_init — Initialize a cURL session
Description
resource curl_init
([ string
$url = NULL
] )Initializes a new session and return a cURL handle for use with the curl_setopt(), curl_exec(), and curl_close() functions.
Parameters
-
url -
If provided, the
CURLOPT_URLoption will be set to its value. You can manually set this using the curl_setopt() function.Note:
The file protocol is disabled by cURL if open_basedir is set.
Return Values
Returns a cURL handle on success, FALSE on errors.
Examples
Example #1 Initializing a new cURL session and fetching a web page
<?php
// create a new cURL resource
$ch = curl_init();
// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, "http://www.example.com/");
curl_setopt($ch, CURLOPT_HEADER, 0);
// grab URL and pass it to the browser
curl_exec($ch);
// close cURL resource, and free up system resources
curl_close($ch);
?>
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Другие службы
- Клиентская библиотека работы с URL
- curl_close
- curl_copy_handle
- curl_errno
- curl_error
- curl_escape
- curl_exec
- curl_file_create
- curl_getinfo
- curl_init
- curl_multi_add_handle
- curl_multi_close
- curl_multi_exec
- curl_multi_getcontent
- curl_multi_info_read
- curl_multi_init
- curl_multi_remove_handle
- curl_multi_select
- curl_multi_setopt
- curl_multi_strerror
- curl_pause
- curl_reset
- curl_setopt_array
- curl_setopt
- curl_share_close
- curl_share_init
- curl_share_setopt
- curl_strerror
- curl_unescape
- curl_version
Коментарии
This may be obvious, but:
Note that is MUCH faster to use use a single instance to make a series of curl requests rather than creating a new instance for each request.
NextgenThemes' note is applicable for very very limited situations. For completeness's sake, let's consider the following code snippet:
<?php
/*
Your localhost has a default Apache which simply returns "It works!"
*/
$repeatCount = 1000;
// begin section
// this section is slow
// call localhost, create new handle each time
$time = microtime(true);
foreach (range(1, $repeatCount) as $ignored) {
$ch = curl_init("http://localhost");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
// do something with the response
unset($response);
curl_close($ch);
}
unset($ch);
$elapsed = microtime(true) - $time;
echo "Recreate curl handle, time taken: " . $elapsed . "\n";
// end section
// begin section
// this section is much faster
// call localhost, but reuse the handle
$time = microtime(true);
$ch = curl_init("http://localhost");
foreach (range(1, $repeatCount) as $ignored) {
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
// do something with the response
unset($response);
}
curl_close($ch);
$elapsed = microtime(true) - $time;
echo "Reuse curl handle, time taken: " . $elapsed . "\n";
// end section
/*
Example output:
Recreate curl handle, time taken: 11.289301872253
Reuse curl handle, time taken: 0.53790807723999
*/
?>
The above code supports the claim by NextgenThemes, however the "send curl requests in sequence" method in general is unnecessarily slow because:
- network transfer time (e.g. 100ms)
- remote processing time (e.g. 50ms)
- usually, no need to send requests in specific sequence
So, in practice, when you need to send multiple curl requests at the same time, just use the curl_multi_init method. Don't consider the "send curl requests in sequence" method unless you have very very specific/special needs.