Python RPC Client

The [pydase.Client][pydase.Client] allows you to connect to a remote pydase service using Socket.IO, facilitating interaction with the service as though it were running locally.

Basic Usage

import pydase

# Replace <ip_addr> and <service_port> with the appropriate values for your service
client_proxy = pydase.Client(url="ws://<ip_addr>:<service_port>").proxy

# For SSL-encrypted services, use the wss protocol
# client_proxy = pydase.Client(url="wss://your-domain.ch").proxy

# Interact with the service attributes as if they were local
client_proxy.voltage = 5.0
print(client_proxy.voltage)  # Expected output: 5.0

This example shows how to set and retrieve the voltage attribute through the client proxy. The proxy acts as a local representation of the remote service, enabling intuitive interaction.

The proxy class automatically synchronizes with the server's attributes and methods, keeping itself up-to-date with any changes. This dynamic synchronization essentially mirrors the server's API, making it feel like you're working with a local object.

Direct API Access

In addition to using the proxy object, users may access the server API directly via the following methods:

client = pydase.Client(url="ws://localhost:8001")

# Get the current value of an attribute
value = client.get_value("device.voltage")

# Update an attribute
client.update_value("device.voltage", 5.0)

# Call a method on the remote service
result = client.trigger_method("device.reset")

This bypasses the proxy and is useful for lower-level access to individual service endpoints.

Accessing Services Behind Firewalls or SSH Gateways

If your service is only reachable through a private network or SSH gateway, you can route your connection through a local SOCKS5 proxy using the proxy_url parameter.

See Connecting Through a SOCKS5 Proxy for details.

Context Manager Support

You can also use the client within a context manager, which automatically handles connection management (i.e., opening and closing the connection):

import pydase


with pydase.Client(url="ws://localhost:8001") as client:
    client.proxy.my_method()

Using the context manager ensures that connections are cleanly closed once the block of code finishes executing.

Tab Completion Support

In interactive environments like Python interpreters or Jupyter notebooks, the proxy supports tab completion. This allows users to explore available methods and attributes.

Integrating the Client into Another Service

You can integrate a pydase client proxy within another service. Here's an example of how to set this up:

import pydase

class MyService(pydase.DataService):
    proxy = pydase.Client(
        url="ws://<ip_addr>:<service_port>",
        block_until_connected=False,
        client_id="my_pydase_client_id",  # optional, defaults to system hostname
    ).proxy

    # For SSL-encrypted services, use the wss protocol
    # proxy = pydase.Client(
    #     url="wss://your-domain.ch",
    #     block_until_connected=False,
    #     client_id="my_pydase_client_id",
    # ).proxy

if __name__ == "__main__":
    service = MyService()
    # Create a server that exposes this service
    server = pydase.Server(service, web_port=8002).run()

In this example:

The MyService class has a proxy attribute that connects to a pydase service at <ip_addr>:<service_port>.
By setting block_until_connected=False, the service can start without waiting for the connection to succeed.
The client_id is optional. If not specified, it defaults to the system hostname, which will be sent in the X-Client-Id HTTP header for logging or authentication on the server side.

Custom `socketio.AsyncClient` Connection Parameters

You can configure advanced connection options by passing arguments to the underlying [AsyncClient][socketio.AsyncClient] via sio_client_kwargs. For example:

client = pydase.Client(
    url="ws://localhost:8001",
    sio_client_kwargs={
        "reconnection_attempts": 3,
        "reconnection_delay": 2,
        "reconnection_delay_max": 10,
    }
).proxy

In this setup, the client will attempt to reconnect three times, with an initial delay of 2 seconds (each successive attempt doubles this delay) and a maximum delay of 10 seconds between attempts.

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