5.7.4 Go (RPC)

This frontend library relies on the Reach RPC Server.

Once installed, add the following import line to your Go file which will connect to the Reach RPC Server:

import reachrpc "github.com/reach-sh/reach-lang/rpc-client/go"

The library provides the following bindings:

—

rpc, rpcCallbacks := reachrpc.Mk(opts)

reachrpc.Mk accepts the Reach RPC Client Standard Options as a map and returns two functions, traditionally called rpc and rpcCallbacks.

rpc is a function that invokes a synchronous value RPC method. It takes a string, naming the RPC method, and some JSON values to provide as arguments. It returns a single JSON value as the result.

For example,

rpc("/stdlib/formatCurrency", i, 4).(string)

calls formatCurrency with some value i and 4 and returns the result as a string.

rpcCallbacks is a function that invokes an interactive RPC method, such as for a backend. It takes a string, naming the RPC method, a JSON value as an argument, and map from strings to JSON values or functions. The functions will be provided as interactive RPC callbacks to the RPC method and should expect JSON values as arguments and return a JSON value as a result. It returns void.

For example,

showX := func(xo interface{}) {
  x := int(rpc("/stdlib/bigNumberToNumber", xo).(float64))
  fmt.Printf("Alice saw that X is %f\n", x)
}
ms := map[string]interface{} {
  "price": 10,
  "showX": showX,
}
rpcCallbacks("/backend/Alice", ctc, ms)

calls a backend named Alice with the contract ctc and a value named price and a method named showX that prints out a result from the Reach backend.