PHP檔案上傳錯誤程式碼，狀態測試，除錯

本文主題，處理檔案上傳時遇到的各種問題

思想：利用超全域性變數$_FILES所帶的['error']狀態碼確定問題

關於本文的一些關鍵字的定義，一定要注意了！！！

• $_FILES['userfile']['error']
  userfiel:上傳檔案時input表單name
  error：這個是$_FILES自帶的。不用管；下面的程式會給你說明這是個什麼東西
• move_uploaded_file()：
  此函式僅用於通過 HTTP POST 上傳的檔案。
  如果目標檔案已經存在，將會被覆蓋。

$code = $_FILES['userfile']['error'];
if( $code > 0) { //判斷檔案是否成功上傳到伺服器，0表示上傳成功
    echo 'Error: '.$code;

    switch ( $code  ) {
        case UPLOAD_ERR_OK:
            //0:沒有錯誤，上傳成功的檔案。
            $response = 'There is no error, the file uploaded with success.';
            break;
        case UPLOAD_ERR_INI_SIZE:
            //1:上傳檔案在php.ini中超過upload_max_filesize指令
            $response = 'The uploaded file exceeds the upload_max_filesize directive in php.ini.';
            break;
        case UPLOAD_ERR_FORM_SIZE:
            //2:上傳的檔案超過了在HTML表單中指定的max_file_size指令。
            $response = 'The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.';
            break;
        case UPLOAD_ERR_PARTIAL:
            //3:上傳的檔案只是部分上傳。
            $response = 'The uploaded file was only partially uploaded.';
            break;
        case UPLOAD_ERR_NO_FILE:
            //4:沒有上傳檔案。
            $response = 'No file was uploaded.';
            break;
        case UPLOAD_ERR_NO_TMP_DIR:
            //6:缺少一個臨時資料夾中。在PHP 4.3.10和PHP 5.0.3中引入。
            $response = 'Missing a temporary folder. Introduced in PHP 4.3.10 and PHP 5.0.3.';
            break;
        case UPLOAD_ERR_CANT_WRITE:
            //7:未能將檔案寫入磁碟。
            $response = 'Failed to write file to disk. Introduced in PHP 5.1.0.';
            break;
        case UPLOAD_ERR_EXTENSION:
            //8:PHP擴充套件停止了檔案上傳。PHP沒有提供一種方法來確定是哪個擴充套件導致了檔案上載停止
            $response = 'A PHP extension stopped the file upload. PHP does not provide a way to ascertain which extension caused the file upload to stop;';
            break;
        default:
            //未知的錯誤
            $response = 'Unknown error';
            break;
    }
    echo $response;

    exit; //如果$_FILES['userfile']['error']大於0都是有錯誤，輸出錯誤資訊並退出程式
}else{
    echo "success".$code;
    $file = $_FILES['userfile'];
    var_dump($file);
    die;
}

• 另外附上我的一個上傳檔案函式；自我BB一下：簡直是好用的不要不要的。

/*圖片上傳,可改動檔名加密演算法*/
    public function uploadFile($file, $path, $allow_type){
        $file = $_FILES[$file];
        if($file['error'] == 0){
            $name = $file['name'];
            /*得到上傳檔案的型別，並且都轉化成小寫*/
            $file_type = strtolower(substr($name,strrpos($name,'.')+1));
            if(!in_array($file_type, $allow_type)){
                return "請上傳允許的格式檔案";
            }
            /*上傳檔案的存放路徑*/
            $upload_path = $path.date('Y-m-d').'/';
            if( !file_exists($upload_path) ){
                mkdir($upload_path,0, true);
            }
            $sql_url = $upload_path.md5($name.time().rand(4,100) ).'.'.$file_type;
            if( move_uploaded_file($file['tmp_name'], $sql_url) ){
                /*將狀態碼返回即可，解偶。將需要進行的操作放外面*/
                return json_encode(['code'=>$file['error'],'data'=>$sql_url],JSON_UNESCAPED_UNICODE|JSON_PRETTY_PRINT );
            }else{
                return json_encode(['code'=>$file['error'],'data'=>"上傳失敗，未知錯誤！"],JSON_UNESCAPED_UNICODE|JSON_PRETTY_PRINT );
            }
        }else{
            return json_encode(['code'=>$file['error'],'data'=>"上傳失敗，錯誤程式碼:"],JSON_UNESCAPED_UNICODE|JSON_PRETTY_PRINT );
        }
    }