Eric

Rust bindings and SDK for the ELSTER Rich Client (ERiC)

• What is ELSTER?
• What is ERiC?
• Requirements
• Rust bindings
  • Select bindings
  • Generate bindings
  • Test bindings
• Eric SDK
  • Usage
  • Supported Eric versions
  • Test SDK
• Changelog

What is ELSTER?

Elster (short for Elektronische Steuererklärung) is a project by the German tax administration to process tax returns and declarations.

What is ERiC?

ERiC (short for Elster Rich Client) is a shared C library that is integrated into a tax application. ERiC checks the data provided by the tax application for plausibility, and transmits the validated data in encrypted form to the computing center of the respective tax administration.

Requirements

You need to have the shared library libericapi.so and the header file ericapi.h available on your system which can be downloaded from ELSTER for developers after access has been requested here.

Rust bindings

Specify the path to the Eric library via environment variable ERIC_PATH. For example:

ERIC_PATH="ERiC-43.3.2.0-Linux-x86_64/ERiC-43.3.2.0/Linux-x86_64"

Relevant environment variables then default to

LIBRARY_NAME=ericapi
LIBRARY_PATH="$ERIC_PATH/lib"
HEADER_FILE="$ERIC_PATH/include/ericapi.h"
PLUGIN_PATH="$ERIC_PATH/lib/plugins"

Select bindings

Select bindings from the pre-generated bindings:

cargo build -p eric-bindings

Generate bindings

You can also generate bindings on-the-fly for your specific platform and architecture by using feature flag generate-bindings:

cargo build -p eric-bindings --features generate-bindings

The bindings are generated in target/debug/build/eric-bindings-<random-id>/out/bindings.rs.

To generate the bindings on your platform and architecture, you need libclang as well. For example, on Debian/Ubuntu install:

apt install llvm-dev libclang-dev clang

Test bindings

The bindings are included in src/lib.rs via include! macro and tested by:

cargo test -p eric-bindings --lib

Logs are written to eric.log in the current directory.

Eric SDK

eric-sdk supports single-threaded Eric instances.

Usage

To use eric-sdk, add the shared C library to your path (e.g. to LD_LIBRARY_PATH on Linux):

export LD_LIBRARY_PATH="$ERIC_PATH/lib:$LD_LIBRARY_PATH"

To send the xml file, the path and password of the Elster certificate have to be provided via environment variables CERTIFICATE_PATH and CERTIFICATE_PASSWORD. External tests also require a VENDOR_ID.

Supported Eric versions

Currently, only the latest version of the Eric library is supported.

Test SDK

# Run unit tests
cargo test -p eric-sdk --lib

# Run integration tests (requires ERiC library)
cargo test -p eric-sdk --test '*' -- --test-threads=1

To run those tests that interact with the ELSTER servers, you need to provide the following environment variables:

• CERTIFICATE_PATH: Path to your ELSTER certificate (.pfx)
• CERTIFICATE_PASSWORD: Password for your certificate
• VENDOR_ID: Your official ELSTER Vendor ID (Hersteller-ID)

cargo test -p eric-sdk --test '*' --features external-test -- --test-threads=1

Changelog

The eric-rs repository contains multiple crates with separate changelogs:

• eric-bindings: view changelog
• eric-sdk: view changelog