Introduction to file_get_contents and curl_get_contents in php_PHP tutorial

Introduction to file_get_contents and curl_get_contents in php. Friends in need can refer to it.

Share an actually used function:

The file_get_contents() function is the preferred method for reading the contents of a file into a string. If supported by the operating system, memory mapping technology is also used to enhance performance.

/*Much more stable than file_get_contents! $timeout is the timeout time, the unit is seconds, and the default is 1s. */

代码如下	复制代码
function curl_get_contents($url,$timeout=1) {   $curlHandle = curl_init();   curl_setopt( $curlHandle , CURLOPT_URL, $url );   curl_setopt( $curlHandle , CURLOPT_RETURNTRANSFER, 1 );   curl_setopt( $curlHandle , CURLOPT_TIMEOUT, $timeout );   $result = curl_exec( $curlHandle );   curl_close( $curlHandle );   return $result; } $hx = curl_get_contents('http://www.bKjia.c0m/');

I believe friends who have used the file_get_contents function know that when the obtained $url cannot be accessed, it will cause the page to wait for a long time, and even cause the PHP process to occupy 100% of the CPU, so this function was born.

Through the default_socket_timeout setting in php.ini, the default timeout is default_socket_timeout = 60

The code is as follows

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max_execution_time = 30

代码如下	复制代码
max_execution_time = 30 default_socket_timeout = 60

default_socket_timeout = 60

Suppose you use file_get_contents which takes 45 and max_execution_time is 30, will it time out?
The answer is NO, because max_execution_time does not affect operating system calls or stream operations Another point to point out is that default_socket_timeout is calculated before the socket responds. As long as a response is received, it will continue to be executed

Can be set in the following three ways

代码如下	复制代码
1 直接在php.ini中修改  default_socket_timeout =120 2 ini_set('default_socket_timeout',    120);   3 $strm = stream_context_create(array(     'http' => array(         'timeout' => 120         )     ) );

The code is as follows	Copy code
1 Modify directly in php.ini default_socket_timeout =120 2 ini_set('default_socket_timeout', 120); 3 $strm = stream_context_create(array( 'http' => array(          'timeout' => 120 ) ) );

Some common sense introduction to curl

The reason for retaining the original file_get_contents function is that when reading local files, it is obviously more appropriate to use the native file_get_contents.

Another optimization of file_get_contnets from Zhang Yan, please see:

First, use the top command to view the php-cgi process with high CPU usage.

The code is as follows

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top - 10:34:18 up 724 days, 21:01, 3 users, load average: 17.86, 11.16, 7.69 Tasks: 561 total, 15 running, 546 sleeping, 0 stopped, 0 zombie Cpu(s): 5.9%us, 4.2%sy, 0.0%ni, 89.4%id, 0.2%wa, 0.0%hi, 0.2%si, 0.0%st Mem: 8100996k total, 4320108k used, 3780888k free, 772572k buffers Swap: 8193108k total, 50776k used, 8142332k free, 412088k cached   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                                               10747 www       18   0  360m  22m  12m R 100.6 0.3    0:02.60 php-cgi                                                                                                              10709 www       16   0  359m  28m  17m R 96.8  0.4    0:11.34 php-cgi                                                                                                               10745 www       18   0  360m  24m  14m R 94.8  0.3    0:39.51 php-cgi                                                                                                               10707 www       18   0  360m  25m  14m S 77.4  0.3    0:33.48 php-cgi                                                                                                               10782 www       20   0  360m  26m  15m R 75.5  0.3    0:10.93 php-cgi                                                                                                               10708 www       25   0  360m  22m  12m R 69.7  0.3    0:45.16 php-cgi                                                                                                               10683 www       25   0  362m  28m  15m R 54.2  0.4    0:32.65 php-cgi                                                                                                               10711 www       25   0  360m  25m  15m R 52.2  0.3    0:44.25 php-cgi                                                                                                               10688 www       25   0  359m  25m  15m R 38.7  0.3    0:10.44 php-cgi                                                                                                               10719 www       25   0  360m  26m  16m R  7.7  0.3    0:40.59 php-cgi 　　找其中一个 CPU 100% 的 php-cgi 进程的 PID，用以下命令跟踪一下： strace -p 10747

　　如果屏幕显示：

 代码如下

代码如下

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select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout) select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0}) poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)

复制代码

select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)
select(7, [6], [6], [], {15, 0})        = 1 (out [6], left {15, 0})
poll([{fd=6, events=POLLIN}], 1, 0)     = 0 (Timeout)

代码如下	复制代码
$ctx = stream_context_create(array(      'http' => array(          'timeout' => 1 //设置一个超时时间，单位为秒          )      )   );   file_get_contents("http://www.hzhuti.com/", 0, $ctx);

那么，就可以确定是 file_get_contents() 导致的问题了。

同样是设置超时时间来解决这个问题。如果没装curl，就必须得用这个方式了。

代码如下	复制代码
$ctx = stream_context_create(array(      'http' => array(          'timeout' => 1 //设置一个超时时间，单位为秒          )      )   );   file_get_contents("http://www.hzhuti.com/", 0, $ctx); http://www.bkjia.com/PHPjc/631590.html www.bkjia.comtruehttp://www.bkjia.com/PHPjc/631590.htmlTechArticlephp中file_get_contents和curl_get_contents介绍 有需要的朋友可参考一下。 分享一个实际在用的函数： file_get_contents() 函数是用于将文件的内容读入...