Freeswitch Outbounds call provider settings

FreeSWITCH is a scalable open source cross-platform telephony platform designed to route and interconnect popular communication protocols using audio, video, text or any other form of media.

To setup Freeswitch Outbounds call to landline or cell phone, must go through a PSTN or SIP gateway. Didlogic provides DID and SIP gateway.

This tutorial is going to configure SIP gateway on Didlogic, and configure the necessary settings in Freeswitch, in order to make outbounds call to landline or cellphone.

The step 1. Register an account on Didlogic and navigate to SIP Tab (https://didlogic.com/sipaccounts).

Create a SIP Account you will get SIP Username, Password, and you may set a caller ID from a list of DID you registered.

DIDLogic SIP Profiles

 

The step 2. You may navigate to Didlogic ‘s provided Freeswitch Configuration page (https://didlogic.com/support/setup-guides/freeswitch-config).

What we want is Freeswitch General Config


<include>
<gateway name="didlogic">
<param name="username" value="12354"/>
<param name="realm" value="sip.didlogic.net"/>
<param name="password" value="your_SIP_password"/>
<param name="register" value="true"/>
<param name="context" value="public"/>
</gateway>
</include>

Replace it with your SIP account username, and password created in Didlogic SIP Accounts Page.

The step 3. Go to your Freeswitch installation directory, for example, installed in a Linux box the location will be: /usr/local/freeswitch/conf/sip_profiles/external

Vi didlogic.xml, and paste the contents above, and :wq! to save the file.

If your Freeswitch is open and running, go to /usr/local/freeswitch/bin/fs_cli, then type reloadxml, it will reload the xml configuration.

Now, you can make a test call.

The step 4. You may go to /usr/local/freeswitch/bin/fs_cli, type:

originate sofia/gateway/didlogic/65xxxxxxxx ''

Then your phone will get the call. You will see the caller id is the same you defined at Didlogic SIP Profiles page.

For advanced Caller ID settings in Freeswitch, I not tried, you need have a verified business custoemr in Didlogic, then you can follow this tutorial https://didlogic.com/support/setup-guides/freeswitch-own-cli, then you may be able to configure your custom CLI.

JavaScript inet_aton functions comparison

I came across this stun.js code and found one interesting implementation of inet_aton functions. I curious of its formula and equation.

function inet_aton(a) {
    var d = a.split('.');
    return ((((((+d[0])*256)+(+d[1]))*256)+(+d[2]))*256)+(+d[3]);
}

I written a simple Node.JS test script just to evaluate, calculate different implementations of inet_aton, and here is my findings:

function inet_aton(a) {
    var d = a.split('.');
    return ((((((+d[0])*256)+(+d[1]))*256)+(+d[2]))*256)+(+d[3]);
}
function inet_aton_b(ip){
    var a = new Array();
    a = ip.split('.');
    return((a[0] < < 24) >>> 0)  + ((a[1] < < 16) >>> 0) + ((a[2] < < 8) >>> 0) + (a[3] >>> 0);
}

function inet_aton_c(a) {
   var d = a.split('.');
   return d[0] * 256 * 256 * 256 + d[1] * 256 * 256 + d[2] * 256 + d[3];
}

var start;
start = new Date().getTime();
for(var i = 0; i < 1000000; i++) {
inet_aton('1.1.1.1')
}
console.log('elapsed:' + (new Date().getTime() - start));


start = new Date().getTime();
for(var i = 0; i < 1000000; i++) {
inet_aton_b('1.1.1.1')
}
console.log('elapsed:' + (new Date().getTime() - start));

start = new Date().getTime();
for(var i = 0; i < 1000000; i++) {
inet_aton_c('1.1.1.1')
}
console.log('elapsed:' + (new Date().getTime() - start));

See the first implementation run faster. The key point is lesser multiplication is performed, by factoring using simple math.

I run the same code on Java but I found different things, I can't tell which one run faster than other one. If I run the first code first, second code followed, always the second block faster than first block. If I exchange, run second code first, first code followed, always the second block faster than first block. They both run in same speed. I even use javap to view its bytecode and found second code have more instruction than first one, but might be JVM can do its optimization so that end result both code run same speed.

Built custom sharer on iOS safari

I built a custom sharer module on iOS Safari. Without using iOS8 latest Action module, I used bookmark to emulate this function.

I had already sharer module in my Apps, that shows a window, enter text, embed link, and share to many social sites, such as Facebook and Twitter. I had another module so called GooGLShortenURL that can request shorten URL from goo.gl, embed in my text, share to Twitter which had character limit (140 characters).

To add the bookmark into iOS Safari, I found an intuitive way, but need Mac Apple Safari, built in iCloud works along with iOS Safari, I can then add book mark through Mac Apple Safari, edit the address bar, put in some JavaScript, and then save, and then iOS Safari will get auto synced book mark.

Screen Shot 2014-08-31 at 12.10.00 pm

The JavaScript will open my apps, using iOS Custom URL Scheme set on iPhone/build/pList file.

Screen Shot 2014-08-31 at 12.11.35 pm

I then have my code to handle incoming URL scheme request.

Screen Shot 2014-08-31 at 12.12.22 pm

In my handler, interpret the incoming URL scheme request, based on parameters, fire up Sharer module, then start sharing. I can share to many social sites just in one click.

Photo 31-8-14 12 13 35 pm

Java/JavaScript Tips on Append to File

This is Java/JavaScript Tips on Append content to file. I will introduce append file via command line, Java, and Node.JS (JavaScript).

To append file via command line, in Windows or Unix, you can do:

echo "test" >> a.txt

The file a.txt will be created if not exist at the first time. And the subsequence calls of >> will append the content to next line of the end of file.

To append file via Java, you can do:

PrintWriter pw = new PrintWriter(new FileWriter(new File("a.txt"), true)); 
pw.println("test");
pw.close();

The file a.txt will be created if not exist at the first time. And the subsequence calls of PrintWriter.println will append the content to next line of the end of file.

The interesting thing is I like to use PrintWriter, to call println, which I not need to append \n myself.

Notice the true variable at new FileWriter, this let Java know you want to append file, if you not provide this variable, Java will always overwrite the file but not appending.

To append file via JavaScript, you can do:

in asynchronous calls:

var fs = require('fs');
fs.appendFile('a.txt', 'content\n', function(err) {
 // some callback after append file
});

OR

in synchronize calls:

var fs = require('fs');
fs.appendFileSync('a.txt', 'content\n');

The file a.txt will be created if not exist at the first time. And the subsequence calls of appendFile or appendFileSync will append the content to next line of the end of file.

Node.JS provides asynchronous and synchronize versions for each File IO Calls. Refer the link here. Other than appendFile, for example, readFile/readFileSync, writeFile/writeFileSync.

Node.JS itself is a single threaded and asynchronous. It is always recommended to use asynchronous version of method instead of synchronize version, as synchronize version is a blocking calls. If the content need append to file is very very big, the calls will just hang there, Node.JS cannot handle other requests anymore. To learn how Node.JS back end works, refer here.

Java tips String concatenations using StringBuffer

Java provides StringBuffer and String. Always use StringBuffer when you want concatenate string. StringBuffer has better performance over String when doing simple string concatenation.

String is immutable, that something cannot be changed. When you concatenate using String, JVM actually create new Object for each concatenation. Create new Object is expensive. See below example.

When using String, you may doing something like:

String message = ""; // new object
message = message + "I am "; // another new
message = message + "25"; // another new
message = message + " years old"; // another new

When using StringBuffer, you will doing something like

StringBuffer sb = new StringBuffer(); // new object here
sb.append("I am ");
sb.append("25");
sb.append(" years old");
String message = sb.toString(); // another new

As you can see, by using String, you create a bunch of new objects. When you have more things to concatenate, more and more objects created, and again, creating new object is very expensive, and make application performance worse.

It is strongly recommended by using StringBuffer to append string, and at the last, call toString() to export the string content into String object, then you can use it for any purpose.

So for the example on Java tips on joining string with separator, the code can be changed to below:

private static String join_1(String[] array, String separator) {
	StringBuffer sb = new StringBuffer();
	String comma = "";
	for(int i = 0; i < array.length; i++) {
		sb.append(comma + array[i]);
		comma = separator;
	}
	return sb.toString();
}

private static String join_2(String[] array, String separator) {
        StringBuffer sb = new StringBuffer();
	for(int i = 0; i < array.length; i++) {
		sb.append(array[i] + separator);
	}
        String s = sb.toString();
	return s.substring(0, s.length() - separator.length());
}

Another note, when use String for concatenation, internally it will create StringBuffer to do actual concatenation. Refer this link for more information.

Titanium Mobile tips to get weather forecast message

This is Titanium Mobile tips to get weather forecast message, which you can use to implement in your native iOS apps.

This tutorial required Imgshow Library for Titanium Mobile hosted on Github.

We require Titanium.Geolocation method to get our current latitude and longitude, and then pass this info to API, to get weather forecast message.

The sample code to get weather forecast message:

var fetchWeather = function(cb) {
	
	Titanium.Geolocation.purpose = "Get Weather";
	Titanium.Geolocation.getCurrentPosition(function(evt) {
		
		var lat = evt.coords.latitude;
		var lng = evt.coords.longitude;
		imgshow().name('weather').p('lat', lat).p('lng', lng).p('display', 'label').load(function(data) {
			cb(data);
		});
		
	});
};
fetchWeather(function(message) {
  alert("Weather now is: " + message);
});

The sample response would be: Weather now is 28 C Mostly Cloudy at Jurong Town, Singapore.

JavaScript Tips on Objects and Array and their For loop

This is JavaScript Tips on Objects and Array and their For loop.

In JavaScript, there is an Object and represented as:


var someObj = {name:"YongHao", age:25}

There is an Array and represented as:


var someArr = [1,2,3,4]

Use normal for loop only for Array, and use for…in only for Object.

For example, for Object

var someObj = {name:"YongHao", age:25}
for(var i in someObj) {
  console.log(i + ' - ' + someObj[i]);
}

We get:
name – YongHao
age – 25

For Array

var someArr = [1,2,3,4]
for(var i = 0; i < someArr.length; i++) {
  console.log(i + ' - ' + someArr[i]);
}

We get:
0 - 1
1 - 2
2 - 3
3 - 4

Do not use for...in to Array, if you do:

var someArr = [1,2,3,4]
for(var i in someArr) {
  console.log(i + ' - ' + someArr[i]);
}

It may return good result, but not recommended, as i now is a string but not an integer.

Java/JavaScript tips for removing list elements when iterating list

This is Java and JavaScript tips for same topic, removing list elements when iterating list.

In Java, we will use List as an example, as it is uncommon to remove element from an Array. In Javascript we will use Array as an example, as only Array is supported in JavaScript.

Introduction

To remove an element from a Java List, you will do

List someList = new ArrayList();
someList.add("two");
someList.add("one");
someList.add("three");
someList.remove(1); // to remove by index
someList.remove("one); // to remove by element value
System.out.println(someList);

To remove an element from a JavaScript Array, you will do

var someArray = ["two", "one", "three"];
someArray.splice(1, 1); // to remove by index
console.log(someArray);

What if you want to remove an element from a List or Array when you iterating the List, you want to remove it based on some conditions?

In Java, you may do

List someList = new ArrayList();
someList.add("two");
someList.add("one");
someList.add("three");

for(String item : someList) {
  if(item.equals("one")) {
    someList.remove(item); // #1
  }
  else if(item.equals("three")) {
    someList.remove(item); // #2
  }
}

Unfortunately, by doing this, you will get exception thrown.

By executing line #1, “one” is removed from someList, and next if you still continue the for loop, you will get exception as someList is modified, affecting the for loop execution.

The best way to remove item from a Java list is to use Iterator

List someList = new ArrayList();
someList.add("two");
someList.add("one");
someList.add("three");

Iterator it = someList.iterator();
while(it.hasNext()) {
  String item = it.next();
  if(item.equals("one")) {
    it.remove();
  }
  else if(item.equals("three")) {
    it.remove();
  }
}

System.out.println("Latest someList: " + someList);

This is the safe way to remove items from List when you will still continue iterating over the someList.

In JavaScript, you may do

var someArray = ["two", "one", "three"];
for(var i = 0; i < someArray.length; i++) {
  if(someArray[i] == "one") {
    someArray.splice(i, 1); // #1
  }
  else if(someArray[i] == "three") {
    someArray.splice(i, 1); // #2
  }
}

Unfortunately, by doing this, you will get exception thrown.

By executing line #1, "one" is removed from someArray, and next if you still continue the for loop, you will get exception as someArray is modified, affecting the for loop execution.

The best way to remove item from a JavaScript array is to iterate the Array from last.

var someArray = ["two", "one", "three"];
for(var i = someArray.length - 1; i >= 0; i--) {
  if(someArray[i] == "one") {
    someArray.splice(i, 1); // #1
  }
  else if(someArray[i] == "three") {
    someArray.splice(i, 1); // #2
  }
}

This is the safe way to remove items from JavaScript Array.

Why this works? You may think same thing also applies to Java right? Yes you are right. How this works? Leave it for your back home reading.

JavaScript universal http request method – frequest

I wrote some universal JavaScript method for my apps, across Node.JS and Titanium Mobile, Freeswitch, jQuery. Here introduces a very simple but useful method, http request.

We all doing HTTP request on our apps. Make a request via HTTP and get back the response. I designed an API that I can use the same method signature when I am developing apps for Node.JS and Titanium Mobile. Node.JS is a server side program, and Titanium Mobile is a framework compile to Native iOS code. Freeswitch is an open source SIP Media Server, supports JavaScripts to create IVR apps. jQuery is a web based client framework. These platforms had different underlying native libraries to do HTTP request. I just want to design a very simple API that can wrap up these platforms, then I can share code easily across these platform.

The client code I can do:

frequest({
    url : 'http://somewebsite.com',
    callback : function(data) {
        console.log(data);
    }
});

The code for Node.JS:

frequest : function(args) {
		var http = require('http');
		
		try {
			var options = {};
		
			if(args.options) {
				
				options = args.options;
				
			}
			 
			if(args.url) {
				if(args.url.indexOf('http') == -1) return;
				var b = require('url').parse(args.url);
				
				// resolve host name
				if(b.hostname) {
					options.host = b.hostname;
				}
				
				// resolve port
				if(!b.port) {
					b.port = 80;
				}
				
				if(b.port) {
					options.port = b.port;
				}
				
				// resolve web path
				if(b.pathname) {
					options.path = b.pathname;
					
					if(b.search) {
						options.path += b.search;
					}
				}
					
			}
			
			if(args.headers) {
				options.headers = args.headers;
			}
		    
		    var request = http.get(options);
		
			if(args.callback || args.callbackJSON) {
				request.addListener('response', function(response){
				    var data = '';
				
				    response.addListener('data', function(chunk){ 
				        data += chunk; 
				    });
				    response.addListener('end', function(){
				        
				        // prepare data for callback
				        
				        if(data != '') {
				        	if(args.callback) {
					        	args.callback(data);
					        }
					        
					        if(args.callbackJSON) {
					        	try {
					        		var json = JSON.parse(data);
					        		args.callbackJSON(json);	
					        	
					        	} catch (e) {
					        		console.log(e);
					        	}
					        }
				        }
				        
				    });
				});
			}
		} catch (e) {
			console.log(e);
		}
		
		
	
	}

The code for Titanium Mobile:

var frequest = function(args) {
	
	
	var xhr = Ti.Network.createHTTPClient();
	xhr.onload = function() {
		var res = this.responseText;
		
		if(args.callback) {
			args.callback(res);
		}
		
		if(args.callbackJSON) {
			args.callbackJSON(JSON.parse(res));
		}
	};
	
	xhr.onerror = function(e) {
		// detect message
		var errortitle = 'Connection Failure Error';
		var errormsg = ''; // define some suggested network failure message
		if(e.error && e.error.indexOf('A connection failure occurred')) {
			errormsg = 'A connection failure occurred';
		}
		if(args.errorCallback) {
			args.errorCallback({
				e : e,
				errormsg : errormsg
			});
		} else {
			Ti.UI.createAlertDialog({
				title : errortitle,
				message : errormsg
			}).show();
		}
	}
	if(args.timeout) {
		xhr.timeout = args.timeout;
	}
	if(args.progressCallback) {
		xhr.onsendstream = function(e) {
			args.progressCallback(e.progress);
		}
	}
	
	var method = args.method || 'GET';
	xhr.open(method, args.url);
	if(args.headers) {
		for(var k in args.headers) {
			var v = args.headers[k];
			xhr.setRequestHeader(k,v);
		}
	}
	var params = args.params || null;
	if(params != null) 
		xhr.send(params);
	else
		xhr.send();
};

The code for Freeswitch:

frequest : function(args) {
		var result = fetchUrl(args.url);
		if(args.callback) {
			args.callback(result);
		}
	}

The code for jQuery:

var frequest = function(args) {
    $.ajax({
      url : args.url,
      success : args.callback
    });
};

Feel free to share your code for related frequest implementation.