使用PHP+FPDF生成PDF失败：HTTP ERROR 500问题求助

Hey there, that HTTP 500 error is a generic server-side issue—let’s dig into the most common fixes for your FPDF setup. Here’s how to troubleshoot step by step:

• Double-check the FPDF file path
  The require('fpdf.php'); line assumes the file is in the exact same directory as your PHP script. If it’s in a subfolder (like /fpdf/fpdf.php), update the path to use an absolute reference for reliability:

  require(__DIR__ . '/fpdf.php'); // __DIR__ gets the current script's directory
  

  If the file is missing entirely, grab the latest stable FPDF version and place it correctly in your project.

• Turn on PHP error display
  The 500 error hides the actual problem. Add these lines at the top of your script to see detailed errors (like missing files, permission issues, or syntax problems):

  error_reporting(E_ALL);
  ini_set('display_errors', 1);
  

  Once you see the specific error message, fixing it becomes way easier.

• Verify PHP-FPDF compatibility
  Make sure your PHP version is compatible with the FPDF version you’re using. For example, older FPDF versions might have issues with PHP 7.4+. Grab the latest FPDF release if you’re running a newer PHP version.

• Check server permissions (if needed)
  While your Output("myPdfFile.pdf", "D") is set to force a download (which shouldn’t need server write permissions), if you ever switch to saving the file to the server ("F" instead of "D"), ensure the target directory has write permissions for the web server user.

Here’s a revised version of your code with error checking and reliable pathing:

<?php
// Enable error display for debugging
error_reporting(E_ALL);
ini_set('display_errors', 1);

// Load FPDF with absolute path
require(__DIR__ . '/fpdf.php');

$pdf = new FPDF();
$pdf->AddPage();
$pdf->SetFont('Arial','B',16);
$pdf->Cell(40,10,'Hello World!');
$pdf->Output("myPdfFile.pdf", "D");
?>

Start with enabling error display—that’ll tell you exactly what’s going wrong, which is the fastest way to fix the 500 error.

内容的提问来源于stack exchange，提问作者ajay kumar