47d401d159
* Added the same, slightly modified GPL based license that is used in other parts of GnuPG.
228 lines
7.6 KiB
Org Mode
228 lines
7.6 KiB
Org Mode
#+TITLE: GNU Privacy Guard (GnuPG) Made Easy Python Bindings HOWTO (English)
|
|
|
|
#+LATEX_COMPILER: xelatex
|
|
#+LATEX_CLASS: article
|
|
#+LATEX_CLASS_OPTIONS: [12pt]
|
|
#+LATEX_HEADER: \usepackage{xltxtra}
|
|
#+LATEX_HEADER: \usepackage[margin=1in]{geometry}
|
|
#+LATEX_HEADER: \setmainfont[Ligatures={Common}]{Times New Roman}
|
|
#+LATEX_HEADER: \author{Ben McGinnes <ben@gnupg.org>}
|
|
|
|
|
|
* Introduction
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: intro
|
|
:END:
|
|
|
|
Version: 0.0.1-alpha [2018-03-07 Wed]
|
|
Author: Ben McGinnes <ben@gnupg.org>
|
|
Author GPG Key: DB4724E6FA4286C92B4E55C4321E4E2373590E5D
|
|
|
|
This document provides basic instruction in how to use the GPGME
|
|
Python bindings to programmatically leverage the GPGME library.
|
|
|
|
|
|
* GPGME Concepts
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: gpgme-concepts
|
|
:END:
|
|
|
|
** A C API
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: gpgme-c-api
|
|
:END:
|
|
|
|
Unlike many modern APIs with which programmers will be more
|
|
familiar with these days, the GPGME API is a C API. The API is
|
|
intended for use by C coders who would be able to access its
|
|
features by including the =gpgme.h= header file eith their own C
|
|
source code and then access its functions just as they would any
|
|
other C headers.
|
|
|
|
This is a very effective method of gaining complete access to the
|
|
API and in the most efficient manner possible. It does, however,
|
|
have the drawback that it cannot be directly used by other
|
|
languages without some means of providing an interface to those
|
|
languages. This is where the need for bindings in various
|
|
languages stems.
|
|
|
|
** Python bindings
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: gpgme-python-bindings
|
|
:END:
|
|
|
|
The Python bindings for GPGME provide a higher level means of
|
|
accessing the complete feature set of GPGME itself. It also
|
|
provides a more pythonic means of calling these API functions.
|
|
|
|
The bindings are generated dynamically with SWIG and the copy of =gpgme.h= generated when GPGME is compiled.
|
|
|
|
This means that a version of the Python bindings is fundamentally
|
|
tied to the exact same version of GPGME used to gemerate that copy
|
|
of =gpgme.h=.
|
|
|
|
** Difference between the Python bindings and other GnuPG Python packages
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: gpgme-python-bindings-diffs
|
|
:END:
|
|
|
|
There have been numerous attempts to add GnuPG support to Python
|
|
over the years. Some of the most well known are listed here, along
|
|
with what differentiates them.
|
|
|
|
*** The python-gnupg package maintained by Vinay Sajip
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: diffs-python-gnupg
|
|
:END:
|
|
|
|
This is arguably the most popular means of integrating GPG with
|
|
Python. The package utilises the =subprocess= module to implement
|
|
wrappers for the =gpg= and =gpg2= executables normally invoked on
|
|
the command line (=gpg.exe= and =gpg2.exe= on Windows).
|
|
|
|
The popularity of this package stemmed from its ease of use and
|
|
capability in providing the most commonly required features.
|
|
|
|
Unfortunately it has been beset by a number of security issues,
|
|
most of which stemmed from using unsafe methods of accessing the
|
|
command line via the =subprocess= calls.
|
|
|
|
The python-gnupg package is available under the MIT license.
|
|
|
|
*** The gnupg package created and maintained by Isis Lovecruft
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: diffs-isis-gnupg
|
|
:END:
|
|
|
|
In 2015 Isis Lovecruft from the Tor Project forked and then
|
|
re-implemented the python-gnupg package as just gnupg. This new
|
|
package also relied on subprocess to call the =gpg= or =gpg2=
|
|
binaries, but did so somewhat more securely.
|
|
|
|
However the naming and version numbering selected for this package
|
|
resulted in conflicts with the original python-gnupg and since its
|
|
functions were called in a different manner, the release of this
|
|
package also resulted in a great deal of consternation when people
|
|
installed what they thought was an upgrade that subsequently broke
|
|
the code relying on it.
|
|
|
|
The gnupg package is available under the GNU General Public
|
|
License version 3.0 (or later).
|
|
|
|
*** The PyME package maintained by Martin Albrecht
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: diffs-pyme
|
|
:END:
|
|
|
|
This package is the origin of these bindings, though they are
|
|
somewhat different now. For details of when and how the PyME
|
|
package was folded back into GPGME itself see the [[Short_History.org][Short History]]
|
|
document in this Python bindings =docs= directory.
|
|
|
|
The PyME package was first released in 2002 and was also the first
|
|
attempt to implement a low level binding to GPGME. In doing so it
|
|
provided access to considerably more functionality than either the =python-gnupg= or =gnupg= packages.
|
|
|
|
The PyME package is only available for Python 2.6 and 2.7.
|
|
|
|
Porting the PyME package to Python 3.4 in 2015 is what resulted in
|
|
it being folded into the GPGME project and the current bindings
|
|
are the end result of that effort.
|
|
|
|
The PyME package is available under the same dual licensing as
|
|
GPGME itself: the GNU General Public License version 2.0 (or any
|
|
later version) and the GNU Lesser Public License version 2.1 (or
|
|
any later version).
|
|
|
|
|
|
* GPGME Python bindings installation
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: gpgme-python-install
|
|
:END:
|
|
|
|
** No PyPI
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: do-not-use-pypi
|
|
:END:
|
|
|
|
Most third-party Python packages and modules are available and
|
|
distributed through the Python Package Installer, known as PyPI.
|
|
|
|
Due to the nature of what these bindings are and how they work, it
|
|
is infeasible to install the GPGME Python bindings in the same way.
|
|
|
|
** Requirements
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: gpgme-python-requirements
|
|
:END:
|
|
|
|
The GPGME Python bindings only have three requirements:
|
|
|
|
1. A suitable version of Python 2 or Python 3. With Python 2 that
|
|
means Python 2.7 and with Python 3 that means Python 3.4 or
|
|
higher.
|
|
2. SWIG.
|
|
3. GPGME itself. Which also means that all of GPGME's dependencies
|
|
must be installed too.
|
|
|
|
** Installation
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: installation
|
|
:END:
|
|
|
|
Installing the Python bindings is effectively achieved by compiling
|
|
and installing GPGME itself.
|
|
|
|
Once SWIG is installed with Python and all the dependencies for
|
|
GPGME are installed you only need to confirm that the version(s) of
|
|
Python you want the bindings installed for are in your =$PATH=.
|
|
|
|
By default GPGME will attempt to install the bindings for the most
|
|
recent or highest version number of Python 2 and Python 3 it
|
|
detects in =$PATH=. It specifically checks for the =python= and =python3= executabled first and then checks for specific version
|
|
numbers.
|
|
|
|
For Python 2 it checks for these executables in this order: =python=, =python2= and =python2.7=.
|
|
|
|
For Python 3 it checks for these executables in this order: =python3=, =python3.6=, =python3.5= and =python3.4=.
|
|
|
|
*** Installing GPGME
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: install-gpgme
|
|
:END:
|
|
|
|
See the [[../../../README][GPGME README file]] for details of how to install GPGME from
|
|
source.
|
|
|
|
|
|
* Copyright and Licensing
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: copyright-and-license
|
|
:END:
|
|
|
|
** Copyright (C) The GnuPG Project, 2018
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: copyright
|
|
:END:
|
|
|
|
Copyright © The GnuPG Project, 2018.
|
|
|
|
** License GPL compatible
|
|
:PROPERTIES:
|
|
:CUSTOM_ID: license
|
|
:END:
|
|
|
|
This file is free software; as a special exception the author gives
|
|
unlimited permission to copy and/or distribute it, with or without
|
|
modifications, as long as this notice is preserved.
|
|
|
|
This file is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY, to the extent permitted by law; without even
|
|
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
|
|
PURPOSE.
|