如何用Node.js将多份PDF文件打包为.RAR文件并提供下载

Great question! To bundle all your project PDFs into a single RAR and download it, we'll need to modify both your Express backend and AngularJS frontend. Here's how to do it step by step:

Backend (Express) Modifications #

First, since Node.js doesn't have native support for creating RAR files (RAR is a proprietary format), we'll use 7-Zip—a free tool that can handle RAR compression. Make sure it's installed on your server:

• On Linux: Run sudo apt install p7zip-full
• On Windows: Download from the official site and add it to your system PATH, or use the full path to 7z.exe in your command.

Update routes.js #

Add a new route that fetches all project PDF filenames, creates a RAR archive, and sends it for download. We'll also clean up the temporary RAR file after the download completes:

const fs = require('fs');
const path = require('path');
const { exec } = require('child_process');
// Import your Project model here (adjust the path as needed)
const Project = require('./models/Project');

app.get('/api/download/all-archive', async function(req, res) {
  try {
    // Fetch all project documentation filenames from your database
    const projects = await Project.find({}, 'Documentation');
    const pdfFilenames = projects
      .map(project => project.Documentation)
      .filter(filename => filename); // Remove any null/empty entries

    if (pdfFilenames.length === 0) {
      return res.status(404).send('No PDF files available to archive');
    }

    // Define paths
    const uploadsDir = path.join(__dirname, 'public', 'uploads');
    const tempRarPath = path.join(__dirname, 'temp_project_docs.rar');

    // Build the list of PDF paths (escape spaces for filenames with spaces)
    const pdfPaths = pdfFilenames.map(filename => `"${path.join(uploadsDir, filename)}"`);
    const filesToArchive = pdfPaths.join(' ');

    // 7-Zip command to create a RAR archive
    // Adjust the 7z path if it's not in your system PATH (e.g., "C:\\Program Files\\7-Zip\\7z.exe" on Windows)
    const rarCommand = `7z a -tRAR "${tempRarPath}" ${filesToArchive}`;

    // Execute the 7-Zip command
    exec(rarCommand, (error, stdout, stderr) => {
      if (error) {
        console.error(`Error creating RAR archive: ${error.message}`);
        return res.status(500).send('Failed to generate the archive');
      }
      if (stderr) {
        console.error(`7-Zip warnings: ${stderr}`);
      }

      // Send the RAR file as a download
      res.download(tempRarPath, 'all_project_docs.rar', (downloadErr) => {
        // Clean up the temporary RAR file after download
        fs.unlink(tempRarPath, (unlinkErr) => {
          if (unlinkErr) {
            console.error(`Failed to delete temporary RAR: ${unlinkErr.message}`);
          }
        });
      });
    });
  } catch (dbError) {
    console.error(`Database error: ${dbError.message}`);
    res.status(500).send('Failed to fetch project files');
  }
});

// Keep your existing single file download route
app.get('/api/download/archive/:filename', function(req,res){ 
  res.download("public/uploads/"+req.params.filename, req.params.filename); 
});

Frontend (AngularJS) Modifications #

Add a new function to your archive.js to trigger the bulk download route, and add a button in your UI to call it.

Update archive.js #

// Keep your existing single file download function
$scope.downloadPdf = function(obj){ 
  $http.get('api/download/archive/'+obj.Documentation) 
    .success(function(data){ 
      window.open('api/download/archive/'+obj.Documentation); 
    }); 
};

// Add this new function for bulk download
$scope.downloadAllPdfsAsRar = function() {
  // Open the bulk archive route to trigger the download
  window.open('/api/download/all-archive');
};

Add a Download Button in Your HTML #

Add a button to your project table or page to let users trigger the bulk download:

<button ng-click="downloadAllPdfsAsRar()" class="btn btn-primary">
  Download All PDFs as RAR
</button>

Key Considerations #

• Permissions: Ensure your server has write access to the directory where you're creating the temporary RAR file, and read access to the public/uploads folder.
• Temporary File Cleanup: The code deletes the temporary RAR after download, but if a user cancels the download, the file might remain. Consider adding a periodic cleanup task (e.g., using node-schedule) to remove old temp files.
• Filename Spaces: The code escapes filenames with spaces using quotes, which works with 7-Zip.
• 7-Zip Path: If 7-Zip isn't in your system PATH, replace 7z in the command with the full path to the executable (e.g., "C:\\Program Files\\7-Zip\\7z.exe" on Windows).

内容的提问来源于stack exchange，提问作者Vitali