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yum install libevent-dev 安装libevent
yum install libevent
PHP Extention: http://pecl.php.net/package/libevent/0.0.5



再就是：自己编译 http://libevent.org/

缘起：PHP5的先进之处在于，你可以用stream_select()处理几乎所有的stream-例如你可以通过include STDIN用它接收键盘输入并保存进数组，你还可以接收通过proc_open()打开的管道中的数据。
目的：想用这个函数进行对文件句柄进行监控，其并不是想用于网络的socket句柄，为此做了如下试验：
探索：能否用PHP的stream_select的方式对CentOs下的串口进行监控呢？经过一系列的研究，发现是可以进行多串口的监控的。
研究： 发现会报错，stream_select(): cannot represent a stream of type dio as a select()
解决： 最后，见代码吧。代码下载：
如果，你想时间更短一点，E文是这样说的：
If you want to set an absolute maximum execution time for stream_select in a loop, it's important to decrement the max_time value passed to stream_select.修改了一下的情况，好像效果不明显，呵呵：

完善的第三个版本备案下载，这个实现了对多个串口的同时读写。By:jack
  其实主要是对这个超时机制的理解。见下面这段代码的超时：
//cmd为要执行的程序， timeout是超时时间        $descriptorspec = array(     0 => array("pipe", "r"),     1 => array("pipe", "w"),     2 => array("pipe", "w")     );         $process = proc_open($cmd, $descriptorspec, $pipes);     $stdout_str = $stderr_str = "";     if (is_resource($process)) {         //执行成功         stream_set_blocking($pipes[1], 0);         stream_set_blocking($pipes[2], 0);  //不阻塞         fwrite($pipes[0], $stdin_str);         fclose($pipes[0]);         //设置超时时钟         $endtime = time() + $timeout;         do {             $timeleft = $endtime - time();             $ret = stream_select(                 $read = array($pipes[1],$pipes[2]),                 $write = null,                 $except = null,                 $timeleft             );             if ($ret === false) {                 $err = true;                 break;             } else if ($ret === 0) {                 $timeleft = 0;                 break;             } else {                 foreach ($read as $sock) {                     if ($sock === $pipes[1]) {                         $stdout_str .= fread($sock, 4096);                     } else if ($sock === $pipes[2]) {                         $stderr_str .= fread($sock, 4096);                     }                 }             }         }while((feof($pipes[1]) === false || feof($pipes[2]) === false) && $timeleft > 0);         fclose($pipes[1]);         fclose($pipes[2]);         if($timeleft <= 0) {             proc_terminate($process);             $stderr_str = "操作已超时(".$timeout."秒)";         }         if (isset($err) && $err === true){  //这种情况的出现是通过信号发送中断时产生             proc_terminate($process);             $stderr_str = "操作被用户取消";         }         proc_close($process);         return true;     }     else {         return false;     }
插曲：dio.raw://[device]
for raw streams anddio.serial://[devicefor serials streams. 这两种stream有什么区别啊？用serial不行，而用raw就Ok了。但是会出现上面的报错：stream_select(): cannot represent a stream of type dio as a select()
php有个libevent扩展，我觉得这个扩展应该可以有更广泛的用途，比如：
(1)异步的服务器端开发框架.
(2)类似unix下的tail命令行.
(3)用php和ZeroMQ实现的一个事件驱动服务器端
http://blog.sina.com.cn/s/blog_60b9ee7f0100qdmh.html
搞录：
问题：
有没有办法在php中实现多线程呢？
假设你正在写一个基于多台服务器的php应用，理想的情况时同时向多台服务器发送请求，而不是一台接一台。
可以实现吗？
回答：
当有人想要实现并发功能时，他们通常会想到用fork或者spawn threads，但是当他们发现php不支持多线程的时候，大概会转换思路去用一些不够好的语言，比如perl。
其实的是大多数情况下，你大可不必使用fork或者线程，并且你会得到比用fork或thread更好的性能。
。。。

PHP5的先进之处在于，你可以用stream_select()处理几乎所有的stream-例如你可以通过include STDIN用它接收键盘输入并保存进数组，你还可以接收通过proc_open()打开的管道中的数据。

日常生活中：
如对多个URL进行异步访问，那个curl_multi一族函数的函数是循环，而用这个就是真正调用类似Linux下的select函数：
实践安装步骤如下：
wget http://pecl.php.net/get/libevent-0.0.4.tgz
checking for libevent support... yes, shared
checking for libevent headers in default path... not found
configure: error: Cannot find libevent headers
root@192.168.1.108:~/software/libevent-0.0.4# yum -y install libevent-devel   libevent
不安libevent-devel会在具体安php的libevent扩展时出现找不到.h文件，用指定路径也成也就是下面的：
最好还是安上吧，但要是版本低于1.4还是指定的好，可能会出现问题，这样：
在安php的libevent扩展时加上 -with-libevent=/usr/local/webserver/libevent/：
./configure  -with-libevent=/usr/local/webserver/libevent/
---
原因是如下的包没有安装
libevent-devel
把此包安装上去就好了
yum -y install libevent-devel

root@116.255.139.240:~/software# rpm -qa|grep libevent
libevent-1.4.13-1
root@116.255.139.240:~/software# rpm -ql libevent-1.4.13-1
/usr/lib/libevent-1.4.so.2
/usr/lib/libevent-1.4.so.2.1.3
/usr/lib/libevent_core-1.4.so.2
/usr/lib/libevent_core-1.4.so.2.1.3
/usr/lib/libevent_extra-1.4.so.2
/usr/lib/libevent_extra-1.4.so.2.1.3
/usr/share/doc/libevent-1.4.13
/usr/share/doc/libevent-1.4.13/README

libevent的官网：http://libevent.org/
wget https://github.com/downloads/libevent/libevent/libevent-2.0.16-stable.tar.gz

yum -y install libevent-devel  主要是防止编译PHP扩展Configure时出现找不到.h文件，有了它就不用指明：-with-libevent=/usr/local/webserver/libevent/
./configure prefix=/usr/local/webserver/libevent/

扩展安装：http://pecl.php.net/package/libevent
wget http://pecl.php.net/get/libevent-0.0.4.tgz
/usr/local/webserver/php/bin/phpize
./configure  -with-libevent=/usr/local/webserver/libevent/
自己安或者yum，注意：yum安可能会出现问题:由於 PHP libevent 需要搭配C 的 libevent 1.4 以上版本 , 所以並非每個 Linux 套件都有 , 例如我的 CentOS 的 libevent 版本就比較舊 , 因此要自行編譯 , 以下就說明 CentOS 5.4 下成功編譯 PHP libevent 的步驟,PHP Warning:  stream_select(): supplied argument is not a valid stream resource .
root@192.168.1.108:~/software/libevent-0.0.4# ./configure  -with-libevent=/usr/local/webserver/libevent/
root@192.168.1.108:~/software/libevent-0.0.4# make;make install
......
........
Build complete.
Don't forget to run 'make test'.
Installing shared extensions:     /usr/local/webserver/php/lib/php/extensions/no-debug-non-zts-20090626/

安装完毕，如下：
/usr/local/webserver/php/lib/php/extensions/no-debug-non-zts-20090626/libevent.so
DownLoad 测试源码，来自网上：


代码示例，来自网上,注释部分代码，测试读部分是ok的，如下：
<?php $url = "www.baidu.com"; if(array_key_exists('url',$_GET)){   $url = $_GET['url']; } $hosts = array("www.baidu.com", "www.google.com.hk"); #$hosts = array($url); $timeout = 5; $status = array(); $retdata = array(); $sockets = array(); $e = array(); /* Initiate connections to all the hosts simultaneously */ foreach ($hosts as $id => $host) {   $errno = 0;   $errstr = "";   $s = stream_socket_client("$host:80", $errno, $errstr, $timeout,STREAM_CLIENT_ASYNC_CONNECT|STREAM_CLIENT_CONNECT);   if ($s) {     $sockets[$id] = $s;     $status[$id] = "in progress";   } else {     $status[$id] = "failed, $errno $errstr";   }   $retdata[$id] = ''; } /* Now, wait for the results to come back in */ while (count($sockets)) {   echo "Select function Judges read or write has  status change\n";   $read = $write = $sockets;   /* This is the magic function - explained below */   $n = stream_select($read, $write, $e, $timeout);   if ($n > 0) {     /* readable sockets either have data for us, or are failed connection attempts */     foreach ($read as $r) {       $id = array_search($r, $sockets);       $data = fread($r, 8192);       if (strlen($data) == 0) {         if ($status[$id] == "in progress") {           $status[$id] = "failed to connect";         }         fclose($r);         unset($sockets[$id]);       } else {         $retdata[$id] .= $data;       }     }     /* writeable sockets can accept an HTTP request */     /*     foreach ($write as $w) {       if(!is_resource($w))continue;       $id = array_search($w, $sockets);       fwrite($w, "GET / HTTP/1.0\r\nHost: ".$hosts[$id]."\r\n\r\n");       $status[$id] = "waiting for response";     }     */   } else {     /* timed out waiting; assume that all hosts associated      * with $sockets are faulty */     foreach ($sockets as $id => $s) {       $status[$id] = "timed out " . $status[$id];     }     break;   } } /* foreach ($hosts as $id => $host) { #echo "Host: $host\n"; #echo "Status: " . $status[$id] . "\n"; #echo "Retdata: " . $retdata[$id] . "\n";   $strs = explode("\r\n\r\n",$retdata[$id],2);   echo isset($strs[1])?$strs[1]:$retdata[$id]; } function debug($i){   var_dump($i);   var_dump(gettype($i));   var_dump(is_resource($i)); } */ ?>





网上其他的步骤，主要是注意不有yum默认的安装方法【由於 PHP libevent 需要搭配C 的 libevent 1.4 以上版本 , 所以並非每個 Linux 套件都有 , 例如我的 CentOS 的 libevent 版本就比較舊 , 因此要自行編譯 , 以下就說明 CentOS 5.4 下成功編譯 PHP libevent 的步驟】：

1. 編譯 libevent

解開 libevent source code , 進入 source code 目錄

執行 ./configure –prefix=/usr/local

執行 make

執行 make install

2. 編譯 PHP libevent

解開 PHP libevent source code , 進入 source code 目錄

執行 phpize

執行 ./configure –with-libevent=/usr/local

執行 make

執行 make install

這樣會把 libevent.so 安裝到 /usr/lib/php/modoules 或 /usr/lib64/php/modules , 看 os 是 32bit 或 64bit

同时呢，也可以参考下这个URL：http://www.ooso.net/archives/607

附录，关于curl_multi一族函数的问题：

相信许多人对php手册中语焉不详的curl_multi一族的函数头疼不已，它们文档少，给的例子 更是简单的让你无从借鉴，我也曾经找了许多网页，都没见一个完整的应用例子。
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
一般来说，想到要用这些函数时，目的显然应该是要同时请求多个url，而不是一个一个依次请求，否则不如自己循环去调curl_exec好了。
步骤总结如下：
第一步：调用curl_multi_init
第二步：循环调用curl_multi_add_handle
这一步需要注意的是，curl_multi_add_handle的第二个参数是由curl_init而来的子handle。
第三步：持续调用curl_multi_exec
第四步：根据需要循环调用curl_multi_getcontent获取结果
第五步：调用curl_multi_remove_handle，并为每个字handle调用curl_close
第六步：调用curl_multi_close
这里有一个网上找的简单例子，其作者称为dirty的例子，（稍后我会说明为何dirty）：
/* Here’s a quick and dirty example for curl-multi from PHP, tested on PHP 5.0.0RC1 CLI / FreeBSD 5.2.1 */ <?php $connomains = array( "http://www.cnn.com/", "http://www.canada.com/", "http://www.yahoo.com/" ); 　　 ?$mh = curl_multi_init(); 　　 foreach (?$connomains as ?$i => ?$url) { 　　 ?$conn[?$i]=curl_init(?$url); 　　　curl_setopt(?$conn[?$i],CURLOPT_RETURNTRANSFER,1); 　　　curl_multi_add_handle (?$mh,?$conn[?$i]); } 　　 do { ?$n=curl_multi_exec(?$mh,?$active); } while (?$active); 　　 foreach (?$connomains as ?$i => ?$url) { 　　　?$res[?$i]=curl_multi_getcontent(?$conn[?$i]); 　　　curl_close(?$conn[?$i]); } 　　 print_r(?$res); ?>
整个使用过程差不多就是这样，但是，这个简单代码有个致命弱点，就是在do循环的那段，在整个url请求期间是个死循环，它会轻易导致CPU占用100%。
现在我们来改进它，这里要用到一个几乎没有任何文档的函数curl_multi_select了，虽然C的curl库对select有说明，但是，php里的接口和用法确与C中有不同。
把上面do的那段改成下面这样：
do { 　　　　?$mrc = curl_multi_exec(?$mh,?$active); } while (?$mrc == CURLM_CALL_MULTI_PERFORM); while (?$active and ?$mrc == CURLM_OK) {　　　if (curl_multi_select(?$mh) != -1) { 　　　　　　　　do { 　　　　　　　　　　　　?$mrc = curl_multi_exec(?$mh, ?$active); 　　　　　　　　} while (?$mrc == CURLM_CALL_MULTI_PERFORM); 　　　　} }
因为?$active要等全部url数据接受完毕才变成false，所以这里用到了
curl_multi_exec的返回值判断是否还有数据，当有数据的时候就不停调用curl_multi_exec，暂时没有数据就进入select阶段，新数据一来就可以被唤醒继续执行。这里的好处就是CPU的无谓消耗没有了。
另外：还有一些细节的地方可能有时候要遇到：
控制每一个请求的超时时间，在curl_multi_add_handle之前通过curl_setopt去做：
curl_setopt(?$ch, CURLOPT_TIMEOUT, ?$timeout);
判断是否超时了或者其他错误，在curl_multi_getcontent之前用：curl_error(?$conn[?$i]);


相关参考：
http://www.iteye.com/news/21255-swoole-php-framework
http://code.google.com/p/swoole/
http://blog.163.com/huv520@126/blog/static/2776523920119149283594/
http://matyhtf.iteye.com/blog/844311


实践代码如下，运行成功：
<?php echo "Program starts at ". date('h:i:s') . ".\n"; $timeout=10; $streams=array(); $handles=array(); /* First launch a program with a delay of three seconds, then one which returns after only one second. */ $delay=3; for ($id=0; $id <= 1; $id++) { $error_log="/tmp/error" . $id . ".txt"; $descriptorspec=array( 0 => array("pipe", "r"), 1 => array("pipe", "w"), 2 => array("file", $error_log, "w") ); $cmd='sleep ' . $delay . '; echo "Finished with delay of ' . $delay . '".'; $handles[$id]=proc_open($cmd, $descriptorspec, $pipes); $streams[$id]=$pipes[1]; $all_pipes[$id]=$pipes; $delay -= 2; } while (count($streams)) { $read=$streams; stream_select($read, $w=null, $e=null, $timeout); foreach ($read as $r) { $id=array_search($r, $streams); echo stream_get_contents($all_pipes[$id][1]); if (feof($r)) { fclose($all_pipes[$id][0]); fclose($all_pipes[$id][1]); $return_value=proc_close($handles[$id]); unset($streams[$id]); } } } ?>
执行如下：
root@116.255.139.240:/home/admin/php/stream_select# php stream_select.php
Program starts at 02:30:27.
Finished with delay of 1.
Finished with delay of 3.
这里的关键在于 PHP 启动了两个独立子进程，取回待完成的第一个进程的输出，然后取回第二个进程的输出，即使后者启动得较早。如果主机是多处理器计算机，并且操作系统已正确配置，则操作系统本身负责将各个子程序分配给不同的处理器。这是在多处理器主机中良好应用 PHP 的一种方法。


时间如下，特别注意是这样的如果是PHp串口实现fd的话，因为只有这个常规的fd才能用stream_select监控，而PHP的串口扩展是不行的，我实践了好几次才发现这个问题，
dio.raw://[device]
for raw streams and
dio.serial://[device
for serials streams.
这两种stream有什么区别啊？这点我不太明白，反正用raw就能读取到，而用serial就不行，
用serial不行，而用raw就Ok了，也就满足了偶的需求，呵呵。
参考的扩展和实践Ok的代码都来自：http://www.cyberspice.org.uk/blog/2010/02/15/serial-io-in-php-using-the-dio-extension/

Ok的读取代码如下：
<?php
  Error_reporting(E_ALL);
  // Create a stream context that configures the serial port
  // And enables canonical input.
  $c = stream_context_create(array('dio' =>
    array('data_rate' => 9600,
          'data_bits' => 8,
          'stop_bits' => 1,
          'parity' => 0,
          'is_canonical' => 1)));

  // Are we POSIX or Windows?  POSIX platforms do not have a
  // Standard port naming scheme so it could be /dev/ttyUSB0
  // or some long /dev/tty.serial_port_name_thingy on OSX.
  $filename = "dio.raw:///dev/ttyUSB0";

  // Open the stream for read only and use it.
  $f = fopen($filename, "r+", false, $c);
  stream_set_blocking($f, 0);
  if ($f) {
    echo "Reading from port...\n";
    while(1)
    {
      //$data = fgets($f);
      $data =  fread($f,10);
      if ($data)
      {
        echo $data."\n";
      }
    }
  }
?>

参考其他网上的实例代码如下，代码来自，http://plugins.svn.wordpress.org/wp-tsina/trunk/wp-tsina.curl.cls.php：

<?php /** * curl发送请求 */ define('CURLW_ERR_OK',0); define('CURLW_ERR_NORMAL',-1); define('CURLW_ERR_TIMEOUT',-2); define('CURLW_ERR_TIMEOUT_RW',-3); define('CURLW_ERR_CONNECT_REFUSED',-4); class CurlWrapper {   //连接超时   var $_tm_con = 5;   //读写超时   var $_tm_rw = 5;   //stream_select超时(ms)   var $_tm_select = 2000000;   //多进程   var $_multiple = 0;   //请求数组   var $_req_arr = array();   //回应数组   var $_res_arr = array();   //是否输出调试信息   var $_if_debug = 0;   //调试信息   var $_debug = array();   //错误信息   var $_error = '';   //是否安装了curl包   var $_curl_package = 1;      function CurlWrapper()   {     $this->checkCurlPackage();   }      /**    * 调试函数    */   function debug($info,$newline="\n")   {     echo $info.$newline;     $this->_debug[] = $info;   }      /**    * 监测是否安装了curl包    */   function checkCurlPackage()   {     if( !function_exists('curl_init') )     {       $this->_curl_package = 0;     }   }      /**    * 设置是否采用并发形式    */   function setMultiple($status=0)   {     $this->_multiple = $status;   }      /**    * 设置是否输出调试信息    */   function setDebug($status=0)   {     $this->_if_debug = $status;   }      /**    * 设置stream_select超时(ms)    */   function setSelectTimeout($time)   {     $this->_tm_select = $time;   }      /**    * 打印debug信息    */   function &getDebug()   {     return $this->_debug;   }      /**    * 获取返回结果    */   function &getResult()   {     return $this->_res_arr;   }      /**    * 获取指定key的结果    */   function &getResultByKey($key)   {     return $this->_res_arr[$key];   }      /**    * 获取结果状态    */   function getResultStatus(&$params)   {     if( $params['errno'] != CURLW_ERR_OK )     {       $params['error'] = 'curl_error='.$params['error'].',curl_errno='.$params['errno'].',curl_code='.$params['code'];       return false;     }     else if( $params['errno'] == CURLW_ERR_OK && $params['code'] != '200' )     {       $params['error'] = 'curl_error='.$params['error'].',curl_errno='.$params['errno'].',curl_code='.$params['code'];       return false;     }     return true;   }      /**    * 添加一个请求    */   function addRequest($params=null)   {     //url形式默认为get方式请求     if( $params['url'] )     {       $url_arr = parse_url($params['url']);       $params['method'] = $params['method'] ? $params['method'] : 'get';       $params['host'] = $url_arr['host'];       $params['uri'] = $url_arr['path'].'?'.$url_arr['query'];       $params['port'] = $url_arr['port'];     }          //host     if( !$params['host'] )     {       $this->debug('['.__FUNCTION__.':'.__LINE__.']host为空');       return false;     }          //uri     if( !$params['uri'] )     {       $this->debug('['.__FUNCTION__.':'.__LINE__.']uri为空');       return false;     }          //port     if( !$params['port'] )     {       $params['port'] = 80;     }          //proxy host     if( $params['proxy_host'] )     {       $params['uri'] = 'http://'.$params['host'].':'.$params['port'].'/'.$params['uri'];     }          //proxy port     if( !$params['proxy_port'] )     {       $params['proxy_port'] = 80;     }          //method     $method = strtolower($params['method']);     if( $method != 'get' && $method != 'post' && $method != 'purge' && $method != 'header' )     {       $params['method'] = 'get';     }          //请求内容     $content = trim($params['content']);     if( $method == 'post' && $content == '' )     {       $this->debug('['.__FUNCTION__.':'.__LINE__.']请求内容为空');       return false;     }          //connection timeout     if( !$params['timeout'] )     {       $params['timeout'] = $this->_tm_con;     }          //read,write timeout     if( !$params['timeout_rw'] )     {       $params['timeout_rw'] = $this->_tm_rw;     }          if( $params['key'] ) $this->_req_arr[$params['key']] = $params;     else $this->_req_arr[] = $params;     if( $this->_if_debug ) print_r($this->_req_arr);     return true;   }      function send()   {     if( $this->_multiple == 0 )//非并发请求     {       if( !$this->_curl_package )  $this->_sendRequest();       else $this->_sendRequestByCURL();     }     else if( $this->_multiple == 1 )//并发请求     {       $this->_sendMultiRequest();     }   }      /**    * 发送请求 -> 连接超时判断 -> 读写超时判断    */   function _sendRequest()   {     foreach( $this->_req_arr as $req_key=>$req )     {       //初始化数据       $errno = CURLW_ERR_OK;       $error = "";       $ret_arr = array('errno'=>0,'error'=>'','data'=>'','code'=>'');              //调试       if( $this->_if_debug )       {         $this->debug($fp);                  $debug_msg = '';         foreach( $req as $req_key_debug=>$req_val_debug ) $debug_msg.= $req_key_debug.'='.$req_val_debug.",\n";         $this->debug($debug_msg);       }            //创建句柄       //if( $req['proxy_host'] ) $fp = @fsockopen($req['proxy_host'],$req['proxy_port'],$errno,$error,$req['timeout']);       //else $fp = @fsockopen($req['host'],$req['port'],$errno,$error,$req['timeout']);       if( $req['proxy_host'] )       {         $req['host'] = $req['proxy_host'];         $req['port'] = $req['proxy_port'];       }       $fp = @fsockopen($req['host'],$req['port'],$errno,$error,$req['timeout']);       if( !$fp )       {         if( $this->_if_debug ) $this->debug('['.__FUNCTION__.':'.__LINE__.']host='.$req['host'].',error='.$error);         if( $errno == 60 ) $ret_arr['errno'] = CURLW_ERR_TIMEOUT;         else if( $errno == 61 ) $ret_arr['errno'] = CURLW_ERR_CONNECT_REFUSED;         else $ret_arr['errno'] = CURLW_ERR_NORMAL;         $ret_arr['error'] = '['.$errno.']'.$error;         $ret_arr['data'] = '';         $ret_arr['code'] = '';         $this->_res_arr[$req_key] = $ret_arr;         continue;       }              //发送请求       $reqstr = &$this->_getRequestStr($req);       if( $this->_if_debug ) $this->debug('request='.$reqstr);       @fwrite($fp,$reqstr,strlen($reqstr));              //设置读取超时时间       $tm_rw = isset($req['timeout_rw'])?$req['timeout_rw']:$this->_tm_rw;       stream_set_timeout($fp,$tm_rw);              //获取返回内容       if( $retval=$this->_getResponseStr( array('fp'=>$fp,'header'=>1) ) )       {         $ret_arr['errno'] = CURLW_ERR_OK;         $ret_arr['error'] = '';         $ret_arr['data'] = trim(strstr($retval,"\r\n\r\n"));         $ret_arr['code'] = $this->_getHTTPCode($retval);         $this->_res_arr[$req_key] = $ret_arr;       }       else       {         $ret_arr['errno'] = CURLW_ERR_TIMEOUT_RW;         $ret_arr['error'] = $this->_error;         $ret_arr['data'] = '';         $ret_arr['code'] = '';         $this->_res_arr[$req_key] = $ret_arr;       }       fclose($fp);     }   }      /**    * 使用curl发送请求    */   function _sendRequestByCURL()   {     foreach( $this->_req_arr as $req_key=>$req )     {       //初始化数据       $ret_arr = array('errno'=>CURLW_ERR_OK,'error'=>'','data'=>'','code'=>'');       if( !$req['url'] ) $req['url'] = 'http://'.$req['host'].':'.$req['port'].$req['uri'];       if( $this->_if_debug ) $this->debug('['.__FUNCTION__.':'.__LINE__.']url='.$req['url']);              //创建句柄       $curl_handle = curl_init($req['url']);              //设置选项       if( $this->_if_debug ) curl_setopt($curl_handle,CURLOPT_VERBOSE,1);       curl_setopt($curl_handle,CURLOPT_TIMEOUT,$req['timeout_rw']);       curl_setopt($curl_handle,CURLOPT_RETURNTRANSFER,1);       curl_setopt($curl_handle,CURLOPT_HEADER,1);       if( $req['method'] == 'post' )       {         curl_setopt($curl_handle,CURLOPT_POST,1);         curl_setopt($curl_handle,CURLOPT_POSTFIELDS,$req['content']);       }else if( $req['method'] == 'header' )       {         curl_setopt($curl_handle, CURLOPT_NOBODY, 1);         curl_setopt($curl_handle, CURLOPT_HEADER, 1);       }       if( $req['proxy_host'] ) curl_setopt($curl_handle,CURLOPT_PROXY,$req['proxy_host'].':'.$req['proxy_port']);              //发送请求,获取返回内容       $curl_rst = curl_exec($curl_handle);       if( $this->_if_debug ) $this->debug('[_sendRequestByCURL]'.$curl_rst);       if( !$curl_rst )       {         if( curl_errno($curl_handle) == CURLE_OPERATION_TIMEOUTED )         {           $ret_arr['errno'] = CURLW_ERR_TIMEOUT_RW;           $ret_arr['error'] = curl_error($curl_handle);           $ret_arr['data'] = '';           $ret_arr['code'] = '';           $this->_res_arr[$req_key] = $ret_arr;         }       }       else       {         $ret_arr['errno'] = CURLW_ERR_OK;         $ret_arr['error'] = '';         if ( $req['method'] == 'header' ){           $ret_arr['data'] = curl_getinfo( $curl_handle );         }else {           $ret_arr['data'] = trim(strstr($curl_rst,"\r\n\r\n"));         }         $ret_arr['code'] = $this->_getHTTPCode($curl_rst);         $this->_res_arr[$req_key] = $ret_arr;       }              //关闭       curl_close($curl_handle);     }   }      /**    * 发送并发请求    * 连接超时有效    * 读写超时无效    * stream_select超时用来控制程序执行时间    */   function _sendMultiRequest()   {     $fp_r = array();     foreach( $this->_req_arr as $req_key=>$req )     {       $errno = 0;       $error = "";            //创建句柄       if( $req['proxy_host'] ) $fp = @fsockopen($req['proxy_host'],$req['proxy_port'],$errno,$error,$req['timeout']);       else $fp = @fsockopen($req['host'],$req['port'],$errno,$error,$req['timeout']);       if( !$fp )       {         if( $this->_if_debug ) $this->debug('['.__FUNCTION__.':'.__LINE__.']host='.$req['host'].',error='.$error);         continue;       }       $fp_r[] = $fp;              if( $this->_if_debug )       {         $debug_msg = $fp.',host='.$req['host'].',uri='.$req['uri'].',port='.$req['port'].',timeout='.$req['timeout'];         echo $debug_msg."\n";         $this->_debug[] = $debug_msg;       }              //设置为非阻塞模式       stream_set_blocking($fp,0);              //发送请求       $reqstr = &$this->_getRequestStr($req);       @fwrite($fp,$reqstr,strlen($reqstr));     }          $stime = microtime(true);     while( 1 )     {       //利用select原理,获取有效fp       $fp_r_select = $fp_r;       $ret_select = stream_select($fp_r_select,$fp_w_select=null,$fp_e_select=null,0,$this->_selectTimeout($this->_tm_select,$stime));       if( $ret_select === false || $ret_select == 0 )       {         if( $ret_select === false ) $this->_debug[] = 'stream_select错误';         else if( $ret_select == 0 ) $this->_debug[] = 'stream_select超时';         break;       }              //if( $this->_if_debug ) echo '***fp_r_select:'.implode(',',$fp_r_select)."\n";       foreach( $fp_r_select as $fp )       {         if( !is_resource($fp) )         {           if( $this->_if_debug ) echo $fp.',error!';           continue;         }                  $tmp = $this->_getResponseStr( array('fp'=>$fp,'header'=>0) );                  //清除不用的fp对象         foreach( $fp_r as $fp_r_key=>$fp_r_val )         {           if( $fp_r_val == $fp )           {             $this->_res_arr[$fp_r_key] = $tmp;             //if( $this->_if_debug ) echo $fp_r[$fp_r_key].",被关闭\n";             if( feof($fp_r_val) ) fclose($fp_r[$fp_r_key]);             unset($fp_r[$fp_r_key]);           }         }       }              //退出       if( count($fp_r)==0 )       {         break;       }     }   }      /**    * 使用curl发送并发请求    */   function _sendMultiRequestByCurl()   {     //在子类中实现   }      /**    * 获取返回字符串    */   function _getResponseStr($params=null)   {     if( !$params['fp'] )     {       if( $this->_if_debug ) $this->debug('['.__FUNCTION__.':'.__LINE__.']fp无效');       return false;     }     $fp = $params['fp'];          $tmp = "";     while( !feof($fp) )     {       $tmp.= @fread($fp,1024);       $info = stream_get_meta_data($fp);       if( $info['timed_out'] )//超时       {         if( $this->_if_debug ) $this->debug('['.__FUNCTION__.':'.__LINE__.']'.$fp.',获取数据超时');         $this->_error = '获取数据超时';         return false;       }     }     //if( $this->_if_debug ) $this->debug('[_getResponseStr]服务器返回结果='.$tmp);          //是否保留头信息     $header = isset($params['header'])?$params['header']:0;     if( !$header )       $tmp = strstr($tmp,"\r\n\r\n");     $str = trim($tmp);     return $str;   }      /**    * 返回发送请求字符串    */   function &_getRequestStr($params=null)   {     switch($params['method'])     {       case 'post':         $reqstr = "POST ".$params['uri']." HTTP/1.0\r\n";         $reqstr.= "Host: ".$params['host']."\r\n";         $reqstr.= "Content-type: application/x-www-form-urlencoded\r\n";         $reqstr.= "Content-length: ".strlen($params['content'])."\r\n";         $reqstr.= "Connection: Close\r\n\r\n";         $reqstr.= $params['content'];         break;       case 'purge':         $reqstr = "PURGE ".$params['uri']." HTTP/1.1\n";         $reqstr.= "Host: ".$params['host']."\n";         $reqstr.= "Connection: Close\n\n";         break;       case 'get':       case 'header':       default:         $reqstr = "GET ".$params['uri']." HTTP/1.0\r\n";         $reqstr.= "Host: ".$params['host']."\r\n";         $reqstr.= "Connection: Close\r\n\r\n";         break;     }     return $reqstr;   }      /**    * 计算stream_select需要超时的时间    */   function _selectTimeout($mtime,$stime)   {     $time = $mtime - ((microtime(true) - $stime) * 1000000);     if( $time < 0 ) $time = 0;     $time = ceil($time);     //if( $this->_if_debug ) echo 'time='.$time."\n";     return $time;   }      /**    * 获取http code    */   function _getHTTPCode(&$str)   {     $header_line1 = substr($str,0,strpos($str,"\n"));     $header_line1 = trim($header_line1);     $arr = explode(' ',$header_line1);     return $arr[1];   } } ?>



因blog搬家，最后的代码作为附件没有存下来，于是在此补充上：
<?php Error_reporting(E_ALL); $hosts = array("/dev/ttyUSB0" ,"/dev/ttyUSB1" ,"/dev/ttyUSB2" ,"/dev/ttyUSB3" ,"/dev/ttyUSB4" ,"/dev/ttyUSB5" ,"/dev/ttyUSB6" ,"/dev/ttyUSB7"); $timeout = 1; $status = array (); $sockets = array (); $c = stream_context_create(array('dio' =>   array('data_rate' => 9600,         'data_bits' => 8,         'stop_bits' => 1,         'parity' => 0,         'is_canonical' => 1))); foreach($hosts as $id =>$host) {   if( file_exists($host) )   {     $s = fopen($host, "r+", false, $c);     stream_set_blocking($s, true);     $data = fread($s,10);       $sockets[$id] = $s;     //$sockets[1] = $s;     $status[$id] = "in progress";   } } while (count($sockets)) {   $read = $sockets;   $write = null;   $n =  stream_select($read,$write,$e=null,$timeout);   if ($n === false)   {     break;   } else if ($n === 0) {     /* timed out */     $data = "\nERROR:"." Com-N "."timed out";   } else if ($n > 0) {     foreach ($read as $r)     {       $id = array_search($r, $sockets);       //$data= (binary)fread($r, 10);       $data= fread($r, 10);       if (strlen($data) == 0)       {         break;       }     }   }   echo $data."\n"; } ?>


单个程序读取Ok在raspberry硬件上：
<?php $c = stream_context_create(array('dio' =>       array('data_rate' => 9600,         'data_bits' => 8,         'stop_bits' => 1,         'parity' => 0,         'flow_control' => 0,         'is_canonical' => 1))); // Are we POSIX or Windows?  POSIX platforms do not have a // Standard port naming scheme so it could be /dev/ttyUSB0 // or some long /dev/tty.serial_port_name_thingy on OSX. if (PATH_SEPARATOR != ";") {   $filename = "dio.serial:///dev/ttyUSB0"; } else {   $filename = "dio.serial://dev/ttyUSB0"; } // Open the stream for read and write and use it. $f = fopen($filename, "r+", false, $c); if ($f) {   $start = time();   while(true)   {     $data = fgets($f);     if ($data && $data!="\n")     {       echo "SERIAL RX:".$data;     }   } } fclose($f); ?>

测试结果：
root@raspberrypi:~/phpComSelect# php fopenFromRaspberry.php
SERIAL RX:TTest UART : Uart will ouput the ASCII 123456 if it is right!
SERIAL RX:123456

PHP的select性能测试：
http://blog.163.com/james_huangjian/blog/static/17804934520123126264385/
上文的下载的：simplehttpd.tar.gz 在台湾没有下载到，没有想到在Gaston兄弟的网上找到了，神奇了，如下：
http://gastonwu.com/tmp/simplehttpd.tar.gz


2013年再次做多串口的select实现如下，该功能在raspberry pi里调试通过：
<?php   //Error_reporting(E_ALL);   error_reporting(E_ERROR | E_WARNING | E_PARSE); //Error_reporting(0);   $hosts = array("/dev/ttyUSB0" ,"/dev/ttyUSB1" ,"/dev/ttyUSB2" ,"/dev/ttyUSB3" ,"/dev/ttyUSB4" ,"/dev/ttyUSB5" ,"/dev/ttyUSB6" ,"/dev/ttyUSB7");      $timeout = 1;   $status = array ();   $sockets = array ();   $c = stream_context_create(array('dio' =>       array('data_rate' => 115200,         'data_bits' => 8,         'stop_bits' => 1,         'parity' => 0,         'flow_control' => 0,         'is_canonical' => 1)));   foreach($hosts as $id =>$host)   {     if(file_exists($host) )     {   if (PATH_SEPARATOR != ";") {     $filename = $host;   } else {     $filename = $host;   }   $s = fopen($filename, "r+", false, $c);     //stream_set_blocking( $s, true );   stream_set_blocking( $s, false);   if ($s)   {     $data = fgets($s);     $sockets[$id] = $s;     if ($data && $data!="\n")     {       echo "SERIAL RX:".$data;     }   }     }   } while (count($sockets))   {     $read = $sockets;     $write = null;     echo "\r\n<span>";   var_dump($read);   echo "</span>\r\n";   $n =  stream_select($read,$write,$e=null,$timeout);     if ($n === false)     {       break;     } else if ($n === 0) {       /* timed out */       $data = "\nERROR:"." Com-N "."timed out";     } else if ($n > 0) {       foreach ($read as $r)       {         $id = array_search($r, $sockets);     echo "\r\nread from ttyUSB:".$hosts[$id]."\r\n";       $data = fgets($r);       if ($data && $data!="\n")       {    //print_r($read);    echo "Select:".$data;    //fclose($r);         //unset($sockets[$id]);       }       }     } }   ?>  

作者：jackxiang@向东博客 专注WEB应用 构架之美 --- 构架之美，在于尽态极妍 | 应用之美，在于药到病除
地址：http://jackxiang.com/post/4803/
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