saprfclib - Pure Python SAP RFC Protocol Implementation

saprfclib is a pure-Python reimplementation of the SAP RFC wire protocol - zero native/C dependencies. Call any SAP function module from Python with just a pip install. Supports direct TCP, SAProuter, message server (load-balanced), SNC (X.509/Kerberos), and WebSocket RFC (SAP BTP/cloud) connections. Requires Python 3.12 or later.

No SAP NetWeaver RFC SDK. No C compiler. No LD_LIBRARY_PATH. No container image built around a proprietary .so.

Installation

pip install saprfclib

Pulls two pure-Python dependencies (wsproto and h11)

Quick Start

import saprfclib

conn = saprfclib.connect(
    ashost="your-sap-host",   # Application server hostname or IP
    sysnr=0,                  # System number (port = 3300 + sysnr)
    client="100",             # SAP client (Mandant)
    user="RFC_USER",          # SAP logon user
    passwd="secret",          # Password (never logged by saprfclib)
)

result = conn.call("STFC_CONNECTION", REQUTEXT="Hello from saprfclib!")
print(result["ECHOTEXT"])    # "Hello from saprfclib!"
print(result["RESPTEXT"])    # SAP server response text

conn.close()

conn.call() fetches function module metadata from DDIC on the first call and caches it in-process - no configuration needed.

Connection Options

Reach an on-premise system through the SAP BTP Connectivity Proxy / Cloud Connector (e.g. from a Kyma workload) with no NW RFC SDK or Transparent Proxy:

# trusted mode (no proxy authentication)
conn = saprfclib.connect(
    ashost="s4-2025-raw", sysnr="00", client="001", user="Developer", passwd="...",
    proxy_type="socks5",
    proxy_host="connectivity-proxy.kyma-system.svc.cluster.local",
    proxy_port=20004,
    gwhost="vhcala4hci",  # SAP system's internal host (ashost is the virtual tunnel host)
)

# untrusted mode — SAP JWT (method 0x80), token fetched via client_credentials
conn = saprfclib.connect(
    ashost="s4-2025", sysnr="00", client="001", user="Developer", passwd="...",
    proxy_type="socks5", proxy_host="...", proxy_port=20004,
    proxy_client_id="...", proxy_client_secret="...",
    proxy_token_url="https://<subaccount>.authentication.<region>.hana.ondemand.com/oauth/token",
    proxy_scc_location_id="MyLocation",  # optional Cloud Connector location
)

# or let saprfclib read the bound Connectivity service (VCAP_SERVICES / SERVICE_BINDING_ROOT)
cfg = saprfclib.connectivity_proxy_kwargs()           # add with_auth=False in trusted mode
conn = saprfclib.connect(ashost="s4-2025", sysnr="00", client="001",
                         user="Developer", passwd="...", **cfg)

See the Connection Options guide for the full parameter reference.

Documentation

Full documentation: https://randomstr1ng.github.io/saprfclib/

• Getting Started - install, connect, and make your first call in 10 minutes
• Cookbook - TABLE parameters, RFC server, tRFC/qRFC, connection pool, SNC, WebSocket RFC
• API Reference - auto-generated from typed docstrings via MkDocs + mkdocstrings
• Protocol Docs - NI/CPIC framing, ABAP type serialization, RFC handshake, SNC, tRFC/bgRFC wire specs

Example Scripts

The examples/ directory contains runnable scripts for common patterns:

All examples read connection parameters from SAPRFC_* environment variables.

Development

git clone https://github.com/randomstr1ng/saprfclib
cd saprfclib
pip install -e ".[dev]"

# Run offline test suite (no live SAP needed)
hatch run test -m "not integration"

# Lint and format
hatch run lint:check
hatch run lint:fmt

# Type-check
hatch run lint:type

# Build wheel + sdist
hatch build

Live integration tests require a running SAP system. Set environment variables:

export SAPRFC_ASHOST=your-sap-host
export SAPRFC_SYSNR=0
export SAPRFC_CLIENT=100
export SAPRFC_USER=RFC_USER
export SAPRFC_PASSWD=secret
pytest -m integration

See CONTRIBUTING.md for the full contributor guide, and CLAUDE.md for the protocol-fidelity rules every change must follow.

License

Licensed under the Mozilla Public License 2.0 - see LICENSE.

MPL-2.0 is deliberate: you may use saprfclib inside a closed-source, commercial product with no obligation to release your own code. If you modify saprfclib's own source files, those modified files must remain under MPL-2.0 and be made available. Improvements to the library flow back; your product stays yours.

Trademarks and Affiliation

This project is not affiliated with, endorsed by, or supported by SAP SE. SAP, ABAP, SAP NetWeaver, SAProuter, and SAP S/4HANA are trademarks or registered trademarks of SAP SE in Germany and other countries, used here for identification only. saprfclib contains no SAP code, binaries, or headers. Using it does not grant you any licence to SAP software - you remain responsible for your own SAP licensing.

See NOTICE for details.