amfinav/amfi.js

AMFI NAV Data for Mutual Funds in India.

var http = require('http');
var events = require('events');

var amfiHost = "portal.amfiindia.com"; //changed on 19 Oct 2013
var amfiPath = "/spages/NAVAll.txt";

var lineBuffer = "";

var headers = [];
var types = [];
var managers = [];
var funds = [];
var managerHash = {};
var typesHash = {};
var currTyp, currMgr;
var callback, refreshInterval;

var AMFINavs = function (options) {
    events.EventEmitter.call(this);
	var self = this;
    if (options) {
        if (options.callback)
        	callback = options.callback;
        if (options.refreshInterval)
        	refreshInterval = options.refreshInterval * 1000;
    }
    acquireData.call(self);
    if (refreshInterval) {
    	var int = setInterval(function () {
    		acquireData.call(self);
    	}, refreshInterval);    
    }
}

//inherit events.EventEmitter
AMFINavs.super_ = events.EventEmitter;
AMFINavs.prototype = Object.create(events.EventEmitter.prototype, {
    constructor: {
        value: AMFINavs,
        enumerable: false
    }
});

function acquireData () {
	funds = [];
	types = [];
	managers = [];
	var self = this;
	self.status = 'Acquiring Data';
	console.log(self.status);
	http.request({host: amfiHost, path: amfiPath}, function(response) {
		  var str = '';

		  response.on('error', function (chunk) {
				var str;
			    str += chunk;
			    console.log(str);
			  });

		  response.on('data', function (chunk) {
			var str;
		    str += chunk;
		    processData(chunk.toString());
		  });

		  response.on('end', function () {
			  	//sort the lists
				managers.sort();
				types.sort();
				//set the data
				self.funds = funds;
				self.fundManagers = managers;
				self.fundTypes = types;
				self.updateDate = new Date();
				self.status = 'Data Ready';
				console.log(self.status);
				//data for callback
				self.data = {funds: self.funds, 
						fundTypes: self.fundTypes, 
						fundManagers: self.fundManagers, 
						updateDate : self.updateDate}
				//emit event
				self.emit('dataready', self.data);
				//if there is a callback, then do callback
				if (callback)
					callback(self.data);
		  });
		}).end();
}

function processData(stringChunk) {
	lineBuffer = lineBuffer + stringChunk;  //add chunk to previous incomplete line
	if (stringChunk.lastIndexOf('\r\n') > 0) {  //there are multiple lines
		lines = splitTextIntoLines(lineBuffer);
		if (lines) {
			if (lines[lines.length-1])
				lineBuffer = lines[lines.length-1];  //assign last line to buffer
			else 
				lineBuffer = "";
			lines.forEach(processLine);
		}
	}
}

function processLine(line, idx, lines) {
	if (!line)  //if line is null
		return;
	if (idx+1 == lines.length)  //if last line
		return;
	//console.log(line);
	if (headers.length==0) {  //if there are no headers yet, then treat the line as a header
		headers = [];
		processHeader(line);
	}
	else if (line.indexOf(';') > 0)  //if the line has a semi-colon, then this line has func info 
		processFund(line);
	else if (line.indexOf('Ended') > 0)  //if the line has a fund type, then it will have 'Ended' text
		processFundType(line);
	else if (line.length> 2)   //if line is not any of above but has text, then it is a Fund manager name
		processMgr(line);
}

//process line with column headers
function processHeader(line) {
	headers = line.split(';');
}

//process line with fund type
function processFundType(line) {
	currTyp = line;  //next few funds will be of this fund type, so set it as current value
	if (!typesHash[currTyp]) {   //making sure types are not duplicated
		types.push(currTyp);
		typesHash[currTyp] = currTyp;		
	}
}

//process line with fund manager name
function processMgr(line) {
	currMgr = line;   //next few funds will be of this fund manager, so set it as current value
	if (!managerHash[currMgr]) {   //making sure fund managers are not duplicated
		managers.push(currMgr);
		managerHash[currMgr] = currMgr;
	}	
}

//process line with fund information
function processFund(line) {
	fundVals = line.split(';');
	var fund = {};
	for (i=0; i < fundVals.length; i++)
		fund[headers[i]] = fundVals[i];
	fund.Type = currTyp;  //add type to fund information
	fund.Manager = currMgr;  //add manager to fund information
	funds.push(fund);
}

function splitTextIntoLines(txt) {
	if (txt && txt.length > 0)
		lineArr = txt.split('\r\n');
	return lineArr;
}

module.exports = AMFINavs;