fputcsv創建文件，但將其下載爲空

Question

我有這段PHP代碼旨在從mySQL數據庫檢索數據，並將其導出到CSV文件，該文件必須在創建後自動下載。

$connection = mysqli_connect($host, $username, $password, $dbname) or die("Connection Error " . mysqli_error($connection)); 

// fetch mysql table rows 
$sql = "select * from users"; 
$result = mysqli_query($connection, $sql) or die("Selection Error " . mysqli_error($connection)); 

$fp = fopen('users.csv', 'w'); 

while($row = mysqli_fetch_assoc($result)) { 
    fputcsv($fp, $row); 
} 

fclose($fp); 

header('Content-Type: text/csv'); 

header('Content-Disposition: attachment; filename="users.csv"'); 

mysqli_close($connection); 

這裏的問題是，它：

• 檢索數據。
• 檢索服務器上的export.php文件的同一目錄中的CSV文件及其上的數據。
• 下載要與同名文件，但它是空的

感謝。

Answer 1

您正在將其寫入名爲users.csv的文件，但是您強制用戶下載的文件是頁面的輸出。

只要您的查詢是正確的，一旦PHP腳本運行，應該有一個名爲users.csv的文件與包含正確數據的PHP文件位於同一目錄中。

您需要將數據輸出到瀏覽器，以便將其歸因於您下載的文件。

試試這個：

//Connect to database 
$connection = mysqli_connect($host, $username, $password, $dbname) or die("Connection Error " . mysqli_error($connection)); 

//Fetch mysql table rows 
$sql = "select * from users"; 
$result = mysqli_query($connection, $sql) or die("Selection Error " . mysqli_error($connection)); 

//Close connection 
mysqli_close($connection); 

//Set $output 
$output = ""; 

//Set header values 
$headers = array("Header 1", "Header 2", "Header 3"); 

//Insert header values to $output 
foreach($headers as $h){ 
    $output .= fieldCheck($h) . ","; 
} 
$output = rtrim($output, ","). "\n"; 

//Iterate through results 
while($row = mysqli_fetch_assoc($result)) { 
    foreach($row as $cell){ 
     //Comma-separate each value 
     $output .= fieldCheck($cell).","; 
    } 
    //Remove last comma of each line and add newline 
    $output = rtrim($output, ",") . "\n"; 
} 

//Set headers 
header('Content-Type: text/csv'); 
header('Content-Disposition: attachment; filename="users.csv"'); 

//Output 
echo $output; 

exit; 

//Function in case of comma in field 
function fieldCheck($string){ 
    if(strpos($string, ",") !== false){ 
     $string = '"'.$string.'"'; 
    } 
    return $string; 
}