为什么我不能用PHP写文件？

问题描述：

Hi i have a client connecting to a socket server in php.

I want to empty a particular file after connecting to the server, however, the codes is not giving me any error but it is not writing to the file?

<?php 
set_time_limit(0);

//parameters to connect to server
$ip = "127.0.0.1";
$port = "1245";
$data = "";

$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
$result = socket_connect($socket, $ip, $port);

$myFile = "test.txt";
$fh = fopen($myFile, 'w') or die("can't open file");
fwrite($fh, ""); 

while (true)
{
        $data = "some value here"

        socket_write($socket, $data, strlen($data));

        $line =@socket_read($socket,2048, PHP_NORMAL_READ);
        if($line != "")
        {
                echo $line."
";
        }   

}
socket_close($socket);
?>

您好我有一个客户端连接到php中的套接字服务器。 p>

我想在连接到服务器后清空一个特定的文件，但是，代码没有给我任何错误，但它没有写入文件？ p> \ n

 ＆lt;？php 
set_time_limit（0）; 
 
 //连接服务器的参数
 $ ip =“127.0.0.1”; 
 $ port =“1245”; 
  $ data =“”; 
 
 $ socket = socket_create（AF_INET，SOCK_STREAM，SOL_TCP）; 
 $ result = socket_connect（$ socket，$ ip，$ port）; 
 
 $ myFile =“test.txt  “; 
 $ fh = fopen（$ myFile，'w'）或死（”无法打开文件“）; 
fwrite（$ fh，”“）;  
 
而（true）
 {
 $ data =“这里有些值”
 
 socket_write（$ socket，$ data，strlen（$ data））; 
 
 $ line = @socket_read（$  socket，2048，PHP_NORMAL_READ）; 
 if（$ line！=“”）
 {
 echo $ line。“
”; 
} 
 
} 
socket_close（$ socket）; 
？  ＆gt; 
  code>  pre> 
  div>

答

I'd use an absolute path $myFile = "/tmp/test.txt"; to make sure I knew where the file was to be written. Right now with just text.txt it could be written in a variety of places but most likely where the web servers binary is located.

If you'd rather not use an absolute path you can use http://php.net/manual/en/function.getcwd.php and http://www.php.net/manual/en/function.chdir.php to control the current working directory.

答

I would check the file is writable before trying to open it:

if(is_writable($myFile)) {
  $fh = fopen($myFile, 'w');
} else {
  die('unable to write to '.$myFile);
}

为什么我不能用PHP写文件？

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