Dart Requires Chilkat v11.7.0+

Extract Text from a Password-Protected PDF

See more PDF Text Extraction Examples

Demonstrates extracting text from a PDF that requires a password to open. The PDF loads without the password (its structure can be read), but the "text" operation fails because the content cannot be decrypted; "assess" reports that a password is required. With the UserPassword property set before loading, extraction works normally. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // The PDF used in this example (user password: secret) is available at encrypted_user_password.pdf

  final pdf = CkPdf();
  final json = CkJsonObject();
  final jsonOut = CkJsonObject();

  // The PDF loads without its password: the file's structure is readable, so properties such as
  // NumPages and the security settings are available...
  try {
    pdf.loadFile('qa_data/pdf/encrypted_user_password.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // ...but the content cannot be decrypted, so extracting text fails.
  try {
    pdf.extractText('text', json, jsonOut);
  } on ChilkatException catch (e) {
    print('Cannot extract: ${e.lastErrorText}');
  }

  // "assess" still works: it reports that a password is required and nothing else.
  try {
    pdf.extractText('assess', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('passwordRequired: ${jsonOut.boolOf('quality.passwordRequired')}');
  print('rating: ${jsonOut.stringOf('quality.rating')}');

  // Set the password and load again.
  pdf.userPassword = 'secret';
  try {
    pdf.loadFile('qa_data/pdf/encrypted_user_password.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  try {
    pdf.extractText('text', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(jsonOut.stringOf('text'));

  // Sample output:

  // Cannot extract: ChilkatLog:
  //   ExtractText:
  //     ...
  //       The PDF is encrypted and could not be opened (wrong or missing password); its text cannot be read.
  //     ...
  // passwordRequired: true
  // rating: none
  // Board Minutes (Confidential)
  // 
  // The board met on 3 November 2026. Present: the chair, the treasurer and four members. The treasurer reported that spending for the season came in under budget.
  // 
  // The meeting closed at 8.45 p.m.
}