The most simple HttpComponent example

The following example demonstrates the most simple component sending a GET request to a HTTP resource. This is accomplished by defining request options and passing them to HttpComponent.get.

var HttpComponent = require('elasticio-node').HttpComponent;

// exporting the process function to be called by elastic.io runtime
exports.process = doProcess;

function doProcess(msg, cfg) {

    // creating requestion options
    var options = {
        url: 'http://foobarbazbarney.com/api',
        json: true
    };
    
    // sending GET request with given options
    new HttpComponent(this).get(options); 
}

Please note that HttpComponent.get sends a HTTP GET request. The response is checked to have a status codes 200 OK or 201 Created. If so, the response's body will be be used as component's output. Any other status code will result in an error being thrown.

Supported HTTP verbs

The HttpComponent class exposes function for each of the supported HTTP verbs. Currently following are supported:

• HttpComponent.get: sends HTTP GET
• HttpComponent.post: sends HTTP POST
• HttpComponent.put: sends HTTP PUT

Here is an example of how to send a HTTP POST request:

var HttpComponent = require('elasticio-node').HttpComponent;

// exporting the process function to be called by elastic.io runtime
exports.process = doProcess;

function doProcess(msg, cfg) {

    // creating requestion options
    var options = {
        url: 'http://foobarbazbarney.com/api',
        body : JSON.stringify({message : "Hello, world!"})
    };
    
    // sending GET request with given options
    new HttpComponent(this).post(options); 
}

Headers

HTTP Headers for the request can be set in the options object:

// creating requestion options
var options = {
    url: 'http://foobarbazbarney.com/api',
    json : {message : "Hello, world!"},
    headers: {
        'Authorization': 'Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==',
        'Accept-Charset': 'utf-8',
        'User-Agent': 'Mozilla/5.0'
    }
};

Overriding the success handler

var elasticio = require('elasticio-node');
var HttpComponent = elasticio.HttpComponent;
var messages = elasticio.messages;

exports.process = doProcess;

function doProcess(msg, cfg) {

    var self = this;

    // creating requestion options
    var options = {
        url: 'http://foobarbazbarney.com/api',
        json: true
    };
    
    // overrides the default response handler
    function onSuccess(response, body) {
        
        if (response.statusCode === 400) {
            throw new Error(JSON.stringify(body));
        }
        
        // you may also modify the data before emitting them
        delete body.internalId;
        
        // creating a message from given response body
        var data = messages.newMessageWithBody(body);
        
        // emitting the "data" event
        self.emit('data', data);
    }
    
    // sending GET request with given options
    new HttpComponent(this).success(onSuccess).get(options); 
}