DeltaChat Python bindings

This package provides Python bindings to the deltachat-core library which implements IMAP/SMTP/MIME/OpenPGP e-mail standards and offers a low-level Chat/Contact/Message API to user interfaces and bots.

Installing pre-built packages (Linux-only)

If you have a Linux system you may install the deltachat binary “wheel” packages without any “build-from-source” steps. Otherwise you need to compile the Delta Chat bindings yourself.

We recommend to first create a fresh Python virtual environment and activate it in your shell:

python -m venv env
source env/bin/activate

Afterwards, invoking python or pip install only modifies files in your env directory and leaves your system installation alone.

For Linux we build wheels for all releases and push them to a python package index. To install the latest release:

pip install deltachat

To verify it worked:

python -c "import deltachat"

Running tests

Recommended way to run tests is using scripts/run-python-test.sh script provided in the core repository.

This script compiles the library in debug mode and runs the tests using tox. By default it will run all “offline” tests and skip all functional end-to-end tests that require accounts on real e-mail servers.

Running “live” tests with temporary accounts

If you want to run live functional tests you can set DCC_NEW_TMP_EMAIL to a URL that creates e-mail accounts. Most developers use https://testrun.org URLs created and managed by mailadm.

Please feel free to contact us through a github issue or by e-mail and we’ll send you a URL that you can then use for functional tests like this:

export DCC_NEW_TMP_EMAIL=<URL you got from us>

With this account-creation setting, pytest runs create ephemeral e-mail accounts on the http://testrun.org server. These accounts are removed automatically as they expire. After setting the variable, either rerun scripts/run-python-test.sh or run offline and online tests with tox directly:

tox -e py

Each test run creates new accounts.

Developing the bindings

If you want to develop or debug the bindings, you can create a testing development environment using tox:

export DCC_RS_DEV="$PWD"
export DCC_RS_TARGET=debug
tox -c python --devenv env -e py
. env/bin/activate

Inside this environment the bindings are installed in editable mode (as if installed with python -m pip install -e) together with the testing dependencies like pytest and its plugins.

You can then edit the source code in the development tree and quickly run pytest manually without waiting for tox to recreating the virtual environment each time.

Installing bindings from source

Install Rust and Cargo first. The easiest is probably to use rustup.

Bootstrap Rust and Cargo by using rustup:

curl https://sh.rustup.rs -sSf | sh

Then clone the deltachat-core-rust repo:

git clone https://github.com/deltachat/deltachat-core-rust
cd deltachat-core-rust

To install the Delta Chat Python bindings make sure you have Python3 installed. E.g. on Debian-based systems apt install python3 python3-pip python3-venv should give you a usable python installation.

First, build the core library:

cargo build --release -p deltachat_ffi --features jsonrpc

jsonrpc feature is required even if not used by the bindings because deltachat.h includes JSON-RPC functions unconditionally.

Create the virtual environment and activate it:

python -m venv env source env/bin/activate

Build and install the bindings:

export DCC_RS_DEV=”$PWD” export DCC_RS_TARGET=release python -m pip install ./python

DCC_RS_DEV environment variable specifies the location of the core development tree. If this variable is not set, libdeltachat library and deltachat.h header are expected to be installed system-wide.

When DCC_RS_DEV is set, DCC_RS_TARGET specifies the build profile name to look up the artifacts in the target directory. In this case setting it can be skipped because DCC_RS_TARGET=release is the default.

Building manylinux based wheels

Building portable manylinux wheels which come with libdeltachat.so can be done with Docker or Podman.

If you want to build your own wheels, build container image first:

$ cd deltachat-core-rust # cd to deltachat-core-rust working tree
$ docker build -t deltachat/coredeps scripts/coredeps

This will use the scripts/coredeps/Dockerfile to build container image called deltachat/coredeps. You can afterwards find it with:

$ docker images

This docker image can be used to run tests and build Python wheels for all interpreters:

$ docker run -e DCC_NEW_TMP_EMAIL \
   --rm -it -v $(pwd):/mnt -w /mnt \
   deltachat/coredeps scripts/run_all.sh