PDF decryption

src/main/resources/static/js/multitool/DecryptFiles.js

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+export class DecryptFile {
+  async decryptFile(file) {
+    try {
+      const password = prompt('This file is password-protected. Please enter the password:');
+
+      if (password === null) {
+        // User cancelled
+        console.error(`Password prompt cancelled for PDF: ${file.name}`);
+        this.showErrorBanner(`Operation cancelled for PDF: ${file.name}`, 'You cancelled the decryption process.');
+        return null; // No file to return
+      }
+
+      if (!password) {
+        // No password provided
+        console.error(`No password provided for encrypted PDF: ${file.name}`);
+        this.showErrorBanner(`No password provided for encrypted PDF: ${file.name}`, 'Please enter a valid password.');
+        return null; // No file to return
+      }
+
+      const formData = new FormData();
+      formData.append('fileInput', file);
+      formData.append('password', password);
+
+      // Send decryption request
+      const response = await fetch('/api/v1/security/remove-password', {
+        method: 'POST',
+        body: formData,
+      });
+
+      if (response.ok) {
+        const decryptedBlob = await response.blob();
+        this.removeErrorBanner();
+        return new File([decryptedBlob], file.name, {type: 'application/pdf'});
+      } else {
+        const errorText = await response.text();
+        console.error(`Server error while decrypting: ${errorText}`);
+        this.showErrorBanner(
+          'Please try again with the correct password.',
+          errorText,
+          `Incorrect password for PDF: ${file.name}`
+        );
+        return null; // No file to return
+      }
+    } catch (error) {
+      // Handle network or unexpected errors
+      console.error(`Failed to decrypt PDF: ${file.name}`, error);
+      this.showErrorBanner(
+        `Decryption error for PDF: ${file.name}`,
+        error.message || 'Unexpected error occurred.',
+        'There was an error processing the file. Please try again.'
+      );
+      return null; // No file to return
+    }
+  }
+
+  async checkFileEncrypted(file) {
+    try {
+      pdfjsLib.GlobalWorkerOptions.workerSrc = './pdfjs-legacy/pdf.worker.mjs';
+      const arrayBuffer = await file.arrayBuffer(); // Convert file to ArrayBuffer
+      await pdfjsLib.getDocument({
+        data: arrayBuffer,
+        password: '',
+      }).promise;
+
+      return false; // File is not encrypted
+    } catch (error) {
+      if (error.name === 'PasswordException') {
+        return true; // File is encrypted
+      }
+      console.error('Error checking encryption:', error);
+      throw new Error('Failed to determine if the file is encrypted.');
+    }
+  }
+
+  showErrorBanner(message, stackTrace, error) {
+    const errorContainer = document.getElementById('errorContainer');
+    errorContainer.style.display = 'block'; // Display the banner
+    errorContainer.querySelector('.alert-heading').textContent = error;
+    errorContainer.querySelector('p').textContent = message;
+    document.querySelector('#traceContent').textContent = stackTrace;
+  }
+
+  removeErrorBanner() {
+    const errorContainer = document.getElementById('errorContainer');
+    errorContainer.style.display = 'none'; // Hide the banner
+    errorContainer.querySelector('.alert-heading').textContent = '';
+    errorContainer.querySelector('p').textContent = '';
+    document.querySelector('#traceContent').textContent = '';
+  }
+}