Procedures

Procedures are Python functions decorated with @rpc. They receive params from the client and return a result (or raise an error).

Basic Definition

from prpc import rpc

@rpc
def add(a: int, b: int) -> int:
    return a + b

@rpc
def greet(name: str = "World") -> str:
    return f"Hello, {name}!"

The client sends {"jsonrpc": "2.0", "method": "add", "params": {"a": 1, "b": 2}, "id": 1}. pRPC deserializes params, calls add(a=1, b=2), and returns the result in the JSON-RPC response.

Types and Validation

Params are validated from the JSON payload using the request model. Type hints on your function parameters define the expected structure. Use standard Python types (int, str, list, dict, etc.) and Pydantic models where helpful.

Sync vs Async

Procedures can be sync or async. pRPC detects awaitables and awaits them:

@rpc
def sync_proc(x: int) -> int:
    return x * 2

@rpc
async def async_proc(x: int) -> int:
    await asyncio.sleep(0.1)
    return x * 2

Naming

Procedure names default to the function name. Use name to expose a different name:

@rpc(name="getUser")
def get_user(user_id: int) -> dict:
    ...

Errors

Exceptions in a procedure are caught and returned as JSON-RPC errors. See Error Handling for the protocol details.

Next Steps

• Context — Accessing request context
• Adapters — Mounting your procedures