PHP 檔案操作

如何對檔案進行 唯一 的資料讀寫

fopen  開檔
flock LOCK_EX 鎖檔
fread filesize  讀入檔案
rewind  移動檔案 point
ftruncate 0 清空檔案
fwrite   寫入檔案
flock LOCK_UN  解鎖
fclose  關檔

程式範例

$handle = fopen("file.txt","r+");

//Lock File, error if unable to lock
if(flock($handle, LOCK_EX)) {
    $count = fread($handle, filesize("file.txt"));    //Get Current Hit Count
    $count = $count + 1;    //Increment Hit Count by 1
    rewind($handle);    //Move file point
    ftruncate($handle, 0);    //Truncate the file to 0
    fwrite($handle, $count);    //Write the new Hit Count
    flock($handle, LOCK_UN);    //Unlock File
} else {
    echo "Could not Lock File!";
}

//Close Stream
fclose($handle);