RestClient

Overview

RestClient is a small REST client that you can use to write JavaScript programs that control a firenodejs robot remotely via REST.

Example

rest-demo.js shows how to use RestClient. In this demo, we do two things:

• Step 1. home FPD
• Step 2. move FPD to (x:50,y:50}

In the firenodejs directory, type the following bash command, substituting PI2 with the hostname or ip address of the firenodejs server:

node js/rest-demo.js -h PI2

Your FPD should move and you'll see something like the following:

START	: rest-demo.js
INFO    : Step 1. Homing...
HTTP	: POST http://localhost:8080/firestep
HTTP	: <=  [{"hom":""},{"mpo":""}]
END     : rest-demo.js
HTTP	: =>  {"s":0,"r":{"mpo":{"1":0,"2":0,"3":0,"x":0,"y":0,"z":0,"xn":0,"yn":0,"zn":0}},"t":0.001}
INFO    : FPD is at position x: 0  y: 0  z: 0
INFO    : Step 2. Move to (50,50)...
HTTP	: POST http://localhost:8080/firestep
HTTP	: <=  [{"mov":{"x":50,"y":50}},{"mpo":""}]
HTTP	: =>  {"s":0,"r":{"mpo":{"1":1654,"2":-1025,"3":957,"x":49.999,"y":49.998,"z":-0.002,"xn":50,"yn":50,"zn":0}},"t":0.001}
INFO    : FPD is at position x: 49.999  y: 49.998  z: -0.002

Walkthrough

We first include everything we need and set up defaults:

var should = require("should");
var RestClient = require("./RestClient");

console.log("START\t: rest-demo.js");
var restOptions = {
    protocol: "http://",
    host: "localhost",
    port: "8080",
};

Now we read command line arguments:

for (var i=1; i < process.argv.length; i++) {
    var arg = process.argv[i];
    if (arg === "-h") {
        (++i).should.below(process.argv.length);
        restOptions.host = process.argv[i];
    }
}

We create a RestClient with our updated options:

var rest = new RestClient(restOptions);

And declare the actions we wish to perform:

function step1() {
    console.log("Step 1. Homing...");
    rest.post("/firestep", [{hom:""},{mpo:""}], function(data) { // Step 1 http response callback
        console.log("FPD is at position x:", data.r.mpo.x, " y:", data.r.mpo.y, " z:", data.r.mpo.z);
        step2(); // do AFTER step1 is done
    });
}

function step2() {
    console.log("Step 2. Move to (50,50)...");
    rest.post("/firestep", [{mov:{x:50,y:50}},{mpo:""}], function(data) { // Step 2 http response callback
        console.log("FPD is at position x:", data.r.mpo.x, " y:", data.r.mpo.y, " z:", data.r.mpo.z);
    });
}

Now we kick off step1() and sit back till it's done. Notice that we do not call step2() directly--we have to WAIT until step1 is done:

step1();
// step2(); <= DANGER! we can't just put step2 here because it will run in PARALLEL!

console.log("END\t: rest-demo.js");

Summary

Using RestClient, you can orchestrate the behavior of one or more FPD(s), doing arbitrary calculations with the returned REST results.

Have fun!