inject-javascript 0.0.8

Inject JavaScript within PDF document body

Inject JavaScript

Inject JavaScript within PDF document body

---

• :arrow_up: Top of Document

• :building_construction: Requirements

• :zap: Quick Start

• 🗒 Notes

• :card_index: Attribution

• :balance_scale: Licensing

---

Requirements

Note, the following steps are not required if installing this project via Pip.

Python version 3 based dependencies may be installed via one of the following methods...

• Scoped within current user...

pip3 install --user -r requirements.txt

• Scoped with a Virtual Environment local to the directory of this project...

pip3 install --user pipenv

pipenv install -r requirements.txt

Note, review Python Guide -- virtualenvs for more information on Python Virtual Environments.

• Or scopped for the entire system...

sudo pip3 install -r requirements.txt

Note, generally installing dependencies system-wide is not recommended.

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Quick Start

Install this project via Pip

pip3 install --user --upgrade inject-javascript

---

Examples of running as command-line utility

• Print available options and exit

inject-pdf-javascript --help

• Inject .js into .pdf and save to .pdf

inject-pdf-javascript --js index.js\
 --pdf document.pdf\
 --save-path enhanced.pdf\
 --escape

• Inject .js into .pdf and overwrite .pdf

inject-pdf-javascript --js index.js\
 --pdf document.pdf\
 --escape\
 --clobber

---

Example of inheriting and modifying the Inject_JavaScript class...

#!/usr/bin/env python3


from argparse import ArgumentParser


from inject_javascript import Inject_JavaScript
from inject_javascript.lib import error


class Customized_Inject_JavaScript(Inject_JavaScript):
    """
    Customizes Inject_JavaScript class
    """

    def return_js_data(self, js_path = None):
        """
        Customizes how JavaScript data is processed prior to returning
        """
        js_data = super(Customized_Inject_JavaScript, self).return_js_data(js_path = js_path)

        return js_data


if __main__ == '__name__':
    """
    Code that is run if this file is executed as a script instead of imported
    """
    ## Command line argument parsing only if being called as a script

      arg_parser = ArgumentParser(
          prog = basename(argv[0]),
          usage = '%(prog)s --pdf "/tmp/boring.pdf" --js "/dir/script.js"',
          epilog = 'For more projects see: https://github.com/S0AndS0')

      arg_parser.add_argument('--pdf-path', '--pdf',
                              help = 'Out path to save PDF',
                              required = True)

      arg_parser.add_argument('--js-path', '--js',
                              help = 'JavaScript to inject into downloaded PDF',
                              required = True)

      arg_parser.add_argument('--save-path',
                              help = 'Path to save enhanced PDF to, ignored if clobber is True')

      arg_parser.add_argument('--escape',
                              help = 'Prevent replacing/escaping of specific character combos',
                              action = 'store_true',
                              default = False)

      arg_parser.add_argument('--clobber',
                              help = 'Overwrite preexisting/input PDF',
                              action = 'store_true',
                              default = False)

      arg_parser.add_argument('--verbose', '-v',
                              help = 'Loudness of this script',
                              action = 'count')

      verbose = arg_parser.parse_known_args()[0].verbose
      args = vars(arg_parser.parse_args())

      ## Use provided command line options
      injector = Customized_inject_javascript(clobber = args.get('clobber'),
                                              escape = args.get('escape'),
                                              verbose = verbose)

      injected_path = injector.inject_pdf_with_javascript(pdf_path = args.get('pdf_path'),
                                                          js_path = args.get('js_path'),
                                                          save_path = args.get('save_path'))

      if verbose > 0:
          print('Enhanced file maybe found at: {0}'.format(injected_path))

---

Notes

The inject_javascript.py script currently is limited to injecting JavaScript into the document body of PDF file(s), which means certain APIs are not available such as request. Please submit a Pull Request for injecting folder level script features if additional API functionality is desired.

---

The --escape command-line option will double-down on backslashes (\), for example...

if (typeof app !== 'undefined') {
  var script_context = 'pdf';
} else {
  var script_context = 'browser';
};

if (script_context === 'pdf') {
  window.alert('Script context is -> PDF\nExpect features to be limited.');
} else {
  window.alert('Script context is -> Browser\nExpect features to _mostly_ be available.')
}

... the above code if injected with the --escape option would result in the following changes...

var script_context = typeof app !== 'undefined' ? 'pdf' : 'browser';

if (script_context === 'pdf') {
  window.alert('Script context is -> PDF\\nExpect features to be limited.');
} else {
  window.alert('Script context is -> Browser\\nExpect features to _mostly_ be available.')
}

... while the default behavior of inject_javascript.py is to not add additional backslashes, generally such modifications are required for JavaScript to run properly within PDF(s).

---

Adobe Acrobat PDF readers as of last documentation checks run JavaScript based on version 1.5 of ISO-16262 (ECMA-262 Edition 3 from December 1999), meaning that some newer ECMA Script features may not be available, thus it may be a good idea to utilize a JavaScript transpiler such as TypeScript.

tsconfig.json

{
  "compilerOptions": {
    "target": "es3",
    "module": "none",
    "lib": ["dom","es5"],
    "locale": "en-US",
    "noImplicitAny": false,
    "sourceMap": true,
    "outDir": "js"
  },
  "exclude": [
    "node_modules"
  ],
  "files": [
    "ts/index.ts"
  ]
}

Note, above example configurations may transpile JavaScript of a version that is higher than supported by PDF readers of your target audience.

ts/index.ts

let hello = (arg: string) => {
  window.alert(`Hello ${arg}!`);
};

hello('world');

js/index.js

var hello = function (arg) {
    window.alert("Hello " + arg + "!");
};
hello('world');
//# sourceMappingURL=index.js.map

---

Attribution

• Adobe -- JavaScript for Acrobat

• GitHub -- github-utilities/make-readme

• Mozilla Developer -- New in JavaScript 1.5

• TypeScript -- Compiler Options

• YouTube -- Omar Rizwan (@rsnous)

---

License

Documentation for injecting JavaScript within PDF document body
Copyright (C) 2020 S0AndS0

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, version 3 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.

For further details review full length version of AGPL-3.0 License.