gvap.js

Start and stop gvap from Node.js.

Usage

$ npm install gvap

To use gvap.js, simply require it:

var gvap = require("gvap");

Starting and stopping gvap

gvap's start method accepts a configuration object, which uses the same flags as the gvap command line client. (Here, the flags are organized into an object.) Flags that are not accompanied by a value on the command line (for example, --mine) should be passed in as { flag: null }.

var options = {
    networkid: "10101",
    port: 30303,
    rpcport: 8545,
    mine: null
};

gvap.start(options, function (err, proc) {
    if (err) return console.error(err);
    // get your gvap on!
});

The callback's parameter proc is the child process, which is also attached to the gvap object (gvap.proc) for your convenience.

When you and gvap have had enough lively times, stop kills the underlying gvap process:

gvap.stop(function () {
    // no more lively times :( 
});

Listeners

The callback for start fires after gvap has successfully started. Specifically, it looks for "IPC service started" in gvap's stderr. If you want to change the start callback trigger to something else, this can be done by replacing gvap's default listeners. gvap.start accepts an optional second parameter which should specify the listeners to overwrite, for example:

{
    stdout: function (data) {
        process.stdout.write("I got a message!! " + data.toString());
    },
    stderr: function (data) {
        if (data.toString().indexOf("Protocol Versions") > -1) {
            gvap.trigger(null, gvap.proc);
        }
    },
    close: function (code) {
        console.log("It's game over, man!  Game over!");
    }
}

In the above code, gvap.trigger is the callback passed to gvap.start. (This callback is stored so that the startup trigger can be changed if needed.) These three listeners (stdout, stderr, and close) are the only listeners which can be specified in this parameter, since only these three are set by default in gvap.start.

If you want to swap out or add other listeners (after the initial startup), you can use the gvap.listen convenience method:

gvap.listen("stdout", "data", function (data) { process.stdout.write(data); });

This example (re-)sets the "data" listener on stdout by setting gvap.proc.stdout._events.data = function (data) { process.stdout.write(data); }.

Tests

gvap.js's tests use vaprpc to send some basic requests to gvap.

$ npm test