Connection Options¶

saprfclib.connect() supports five transport modes. All modes share the same conn.call() / conn.close() interface once connected.

Direct TCP (application server)¶

Connect directly to an SAP application server by hostname and system number. The gateway port is calculated as 3300 + sysnr.

conn = saprfclib.connect(
    ashost="10.0.1.5",
    sysnr=0,          # Gateway port = 3300 + sysnr
    client="100",
    user="USER",
    passwd="pass",
    timeout=30.0,     # Socket timeout in seconds (optional)
)

SAProuter hop¶

Route the connection through an SAProuter when the SAP system is not directly reachable. The saprouter parameter accepts a router string in SAP NI format.

conn = saprfclib.connect(
    ashost="internal-sap-host",
    sysnr=0,
    client="100",
    user="USER",
    passwd="pass",
    saprouter="/H/saprouter.example.com/S/3299/H/sap-host",
)

Message server (load-balanced)¶

Connect to a logon group via the SAP message server. The message server returns the least-loaded application server, and saprfclib connects to it directly.

conn = saprfclib.connect(
    ashost="dummy",           # Required positionally; ignored when mshost is set
    sysnr=0,
    client="100",
    user="USER",
    passwd="pass",
    mshost="sapms.example.com",
    sysid="A4H",
    group="PUBLIC",
)

SNC (X.509 / Kerberos)¶

Use SAP Secure Network Communications for encrypted and mutually authenticated connections. Set snc_lib to the path of your SNC library (e.g. SAP CommonCryptoLib libsapcrypto.so).

conn = saprfclib.connect(
    ashost="sap-host",
    sysnr=0,
    client="100",
    user="USER",
    passwd="",                # Empty when SNC provides auth
    snc_lib="/usr/sap/sapcryptolib/libsapcrypto.so",
    snc_partnername="p:CN=SAPserver, O=Example, C=DE",
    snc_myname="p:CN=myclient, O=Example, C=DE",  # optional
    snc_qop=3,                # 1=auth, 2=integrity, 3=privacy (default)
)

`snc_qop`	Protection level
1	Authentication only
2	Authentication + integrity
3	Authentication + integrity + privacy (encryption)

WebSocket RFC (BTP / Cloud)¶

Connect to SAP BTP ABAP Environment or other cloud systems via WebSocket RFC (RFC over WebSocket over TLS). Use wshost instead of ashost.

conn = saprfclib.connect(
    ashost="dummy",           # Not used for wRFC; required positionally
    sysnr=0,
    client="100",
    user="USER",
    passwd="pass",
    wshost="my-system.abap.eu10.hana.ondemand.com",
    wsport=443,               # default 443
    ws_path="/sap/bc/rfc?sap-apc-stateful=true",  # default
    ws_tls_verify=True,       # set False for self-signed certs (dev only)
)

To route the WebSocket connection through an HTTP CONNECT proxy:

conn = saprfclib.connect(
    ashost="dummy",
    sysnr=0,
    client="100",
    user="USER",
    passwd="pass",
    wshost="my-system.abap.eu10.hana.ondemand.com",
    ws_proxy_host="proxy.internal.example.com",
    ws_proxy_port=3128,
)

Logon language¶

The lang parameter sets the SAP logon language. It accepts either form, matching the LANG option of the SAP NetWeaver RFC SDK:

conn = saprfclib.connect(
    ashost="10.0.1.5",
    sysnr=0,
    client="100",
    user="USER",
    passwd="pass",
    lang="EN",        # two-character ISO code
)

conn = saprfclib.connect(..., lang="E")    # or the one-character SAP code

lang defaults to "E" (English). Input is case-insensitive.

The RFC logon frame itself only ever carries one character — the SAP language code from the ABAP SPRAS domain. A two-character ISO code is converted before the frame is built, exactly as the C SDK does it, so both spellings above produce identical bytes on the wire.

The ISO code is not the first letter of the SAP code

EN→E and DE→D suggest a rule that does not hold. Spanish is ES→S, Danish is DA→K, Finnish is FI→U, Greek is EL→G, and Chinese is ZH→1. Do not truncate an ISO code by hand — pass it whole and let saprfclib convert it.

Converting between the two forms¶

Two helpers are exported for callers migrating from pyrfc, which exposes the same names:

import saprfclib

saprfclib.language_iso_to_sap("EN")   # "E"
saprfclib.language_iso_to_sap("ES")   # "S"
saprfclib.language_sap_to_iso("1")    # "ZH"

An unknown code raises ValueError. This differs deliberately from the C SDK, whose forward conversion returns an undefined character for an unrecognised ISO code rather than reporting an error.

A one-character code is never looked up — it is taken at face value and sent as given. Systems can have custom languages that appear in no standard table, and the SDK does not validate one-character input either. The trade-off is that a typo in a one-character code reaches the server rather than being caught locally.

Unknown keyword arguments¶

Connection.call() matches keyword arguments against the function module's interface. strict_params decides what happens to a name the interface does not declare:

conn = saprfclib.connect(...)                       # default: drop + warn
conn = saprfclib.connect(..., strict_params=True)   # raise ValueError

The default is lenient, so code ported from pyrfc that passes a superset of kwargs across differing SAP releases keeps working:

conn.call("SXPG_STEP_XPG_START", COMMANDNAME="LIST_DB2DUMP", MXROW=100)
# MXROW is not in the interface -> dropped, warning logged, call proceeds

Each dropped argument is logged. The first occurrence of a given (function, argument-names) combination logs at WARNING; repeats fall to DEBUG, so a long-running loop leaves a record without flooding its log.

A dropped argument changes what the call does

The function then runs without it and returns a result you did not ask for, and nothing in the response indicates an argument went missing. In the example above, SXPG_STEP_XPG_START runs with no row limit. Watch the warnings, and prefer strict_params=True wherever a dropped argument would change the result.

For reference, both pyrfc and the SAP NetWeaver RFC SDK raise here — the SDK's RfcGetParameterDescByName returns RFC_INVALID_PARAMETER for a name it cannot resolve, and pyrfc propagates that. strict_params=True matches them; the lenient default is a deliberate convenience for migration.