wsrpc

Module github.com/jrick/wsrpc/v2 provides a partial implementation of a JSON-RPC 2.0 websocket client. Inspired by net/rpc, clients call methods by their name with arguments and return values marshaled by encoding/json. The client may be used to create convenience calls with types specific to an application.

Receiving notifications is supported but it is up to the caller to unmarshal the JSON-RPC parameters into meaningful data.

This module currently does not implement JSON-RPC 2.0 request batching or keyed request parameters when performing calls.

CLI

A command line tool is provided to perform individual websocket JSON-RPCs against a server.

A JSON array must be used to pass parameters in a method call.

$ wsrpc -h
usage: wsrpc address [flags] method [arg]
  -c string
        Root certificate PEM file
  -p string
        Password
  -u string
        User
$ wsrpc wss://dcrd0.i.zettaport.com:9109/ws -c dcrd0.pem -u jrick -p sekrit getinfo
{
  "version": 1050000,
  "protocolversion": 6,
  "blocks": 324795,
  "timeoffset": 0,
  "connections": 65,
  "proxy": "",
  "difficulty": 19920803496.64989,
  "testnet": false,
  "relayfee": 0.0001,
  "errors": ""
}
$ wsrpc wss://dcrd0.i.zettaport.com:9109/ws -c dcrd0.pem -u jrick -p sekrit getblockhash '[324795]'
"0000000000000000235b1210221d412c428237175dbb0aef202277d1706b9312"

The wsrpc-agent tool can be optionally used to manage persistent connections. Usage of the agent is similar to ssh-agent. The agent can exec a command, running only so long as the command continues to run, or by daemonizing and using eval to set the environment of the Bourne shell:

$ wsrpc-agent -h
usage (exec):   wsrpc-agent cmd [args...]
usage (daemon): eval $(wsrpc-agent)

Once running, wsrpc will use the WSRPCAGENT_SOCK and WSRPCAGENT_AUTH environment variables to perform IPC with the agent. TLS and RPC authentication flags only apply to the initial connection.

$ eval `wsrpc-agent`
Agent listening on /tmp/wsrpc732266934/agent.19981
$ wsrpc wss://dcrd0.i.zettaport.com:9109/ws -c dcrd0.pem -u jrick -p sekrit getblockhash '[324795]'
"0000000000000000235b1210221d412c428237175dbb0aef202277d1706b9312"
$ wsrpc wss://dcrd0.i.zettaport.com:9109/ws getblockhash '[324795]'
"0000000000000000235b1210221d412c428237175dbb0aef202277d1706b9312"

It is sometimes desirable for wsrpc-agent to run at login and stay running for the duration of the user's X session. This can be accomplished with the following in a .xsession script:

if [ -z "$WSRPCAGENT_PID" -a "$(whence wsrpc-agent)" ]; then
	eval $(wsrpc-agent)
fi

do_exit() {
	if [ "$WSRPCAGENT_PID" ]; then
		kill "$WSRPCAGENT_PID"
		export WSRPCAGENT_SOCK=
		export WSRPCAGENT_AUTH=
		export WSRPCAGENT_PID=
	fi
	exit
}

your_window_manager
do_exit

License

wsrpc is licensed under the permissive Blue Oak Model License 1.0.0.