• How to setup Facebook Application
• How to call Facebook PHP SDK in your pages
• How to get Facebook Signed Request
• How to utilize Signed Request data
• How to deal with unnecessary scroll bar

Source Code & Demo

Videos

Last Words

Facebook API changes very rapidly. If you want a tutorial on some specific issue that is happening due to change in API please let me know.

Your questions and comments are welcome. If you like this article, please share it on your favorite website. It may help someone somewhere!

In this article, I’ll be using for each loop to demonstrate the concept of break and continue. They work in same way in almost every programming language. break will be your friend to save your loop from more iteration and continue will be really helpful to boost your logic.

Breaking out of a loop

Sometimes in our loop there is no further need to continue the loop, when a certain condition is met. For example, you might want to iterate through an array to select a particular value. And when you have taken away the desired value, you do not need to continue the loop. There break comes to play the job.

Let’s begin the learning with code example. First we create an array to be used in our example.

Code

$vitamins = array(
 'Vitamin A' => 'Milk, Eggs',
 'Vitamin C' => 'Tomatoes, Spinach',
 'Vitamin D' => 'Sunlight',
 'Vitamin E' => 'Vegetable Oils'
);

Now we want to check the sources of Vitamin C. Once we get the sources of Vitamin C, it is useless to continue the loop and we will be interested in stopping the process. We will accomplish this by using break and an if statement in our code.

Code

foreach ($vitamins as $key=>$value){

 $sources = $value;

 if($key == 'Vitamin C'){
   break;
 }
}

//Print: Vitamin C sources: Tomatoes, Spinach
echo 'Vitamin C sources: ' . $sources;

Explanation

Above code iterates through all the values in our $vitamins array and put the $value of current index into $sources. It also checks, if current index is Vitamin C then break the loop. Hence above code does not iterate to Vitamin D and Vitamin E indexes.

This is really helpful when you have an array with hundreds of values in it and you want to perform some logic on it and get a value out of it. More on break can be found in PHP official manual here.

Directing loop traffic with continue

There might be time when you want to skip the execution of nested statements for a particular condition. In such case continue will be used. For example, now we want all the sources from our $vitamin array except Vitamin C sources. We will again use an if statement for this purpose.

Code

$sources = '';
foreach ($vitamins as $key=>$value) {

 if($key == 'Vitamin C'){
 continue;
 }

 $sources .= ', ' . $value;
}

//Print: All Sources except vitamin C: , Milk, Eggs, Sunlight, Vegetable Oils
echo 'All Sources except vitamin C: ' . $sources;

Explanation

In the above code inside foreach statement, first we check if current index is Vitamin C or not. If it is Vitamin C, we use continue. This continue stops the current counter of loop and move to the next counter. It really helps to write code logic in more efficient and effective way.

For more information about continue please read the official document here.

Final Words

If used wisely both break and continue php code can bring the real power in your code. There is more to do with both of them, we may also use a number after break or continue. To get the fullest of both I recommend you to take a look at official documentation.

Your comments are always welcome. If you like this article, please share it on your favorite website. It may help someone somewhere!

• include VS require
• include_once VS include
• require_once VS require
• echo VS print
• Single quote VS Double quote

Apparently all functions in each above point work in similar fashion. However, they are slightly different from other. Continue reading to explore the differences.

include VS require

Both are frequently used to include other files into our PHP code. Following are the differences between ‘include’ and ‘require’:

• ‘include’ throws a warning, if your specified file is not found. Rest of the code will be rendered.
• ‘require’ throws a fatal error, if your specified file is not found. Rest of the code will not be rendered.

Testing with Code Example

I’m using some code to make it more clear. To check it yourself you may follow the steps with me. Create a new file  ‘inc.file.php’, put below code in it:

<?php
function printMe()
{
 return "I have some code <br>";
}

echo printMe();
?>

Save the file in any directory of server. Now create a new file ‘index.php’ and put the below code in it:

<?php
include 'inc.nofile.php'; //File does not exist
include 'inc.file.php'; //This line will be rendered
?>

Save the file in same directory. To see how ‘include’ works, run the ‘index.php’ file from your browser. You will see an error something similar to:

Warning: include(inc.nofile.php) [function.include]: failed to open stream: No such file or directory in…

But still you can see that the text – “I have some code” is printed to the screen.

However, same test for ‘require’, shows that second line will not be rendered. Here is the code for testing ‘require’. Just copy and paste below code to your ‘index.php’ file (Remove any existing code)

<?php
require 'inc.nofile.php'; //File does not exist
include 'inc.file.php'; //This line will not be rendered
?>

This time we again get an error, but note that nothing is rendered after an error occurred.

Conclusion

Use ‘include’ when you want to render the code even if an error occurs. And use ‘require’ when you do not want to render the remaining code after an error occurs.

include_once VS include AND require_once VS require

‘include_once’ and ‘require_once’ are same in nature. Here we will see the difference of ‘include_once’ against ‘include’. Following are the differences between ‘include’ and ‘include_once’:

• All includes for same file will be rendered, if you are using ‘include’.
• While all includes for same file will be rendered only once, if you are using ‘include_once’. This helps you to prevent an error, if same file included again.

Testing with Code Example

To start off with experimenting, replace below code in ‘index.php’

<?php
include 'inc.file.php';
include 'inc.file.php'; //It will generate a fatal error
?>

Above code will be ended with following error,

Fatal error: Cannot redeclare printMe() (previously declared

Because, we are using same file in our includes. And our file – inc.file.php – has a function of printMe(). Since, we cannot re-declare a function in PHP, it throws an error.

But if we test below code by replacing it in our ‘index.php’ file, it will not throw any error.

<?php
include_once 'inc.file.php';
include_once 'inc.file.php'; //This will be ignored
?>

Since ‘inc.file.php’ is included using ‘include_once’, it will ignore the second line because it includes same file only once.

Conclusion

Use ‘include_once’, where you are in doubt of including the same file again somewhere in your code.

print VS echo

‘print’ and ‘echo’ are almost similar. Both are used to write text to screen. But there is a single difference between them:

• ‘print’ does not accept multiple parameters.
• While ‘echo’ accepts multiple parameters.

Above difference may be confusing to many people. I try to clear the confusion by explaining the difference by code.

Testing with Code Example

Let’s begin with ‘echo’ example. We pass two parameters to ‘echo’:

<?php
echo ("Tech "), ("Mug");
?>

Above code will be rendered without any error. But if we try same thing with ‘print’, it will be ended with a parse error. Let’s try it:

<?php
print ("Tech "), ("Mug"); //This will generate an error
?>

Above code will give you an error something similar to,

Parse error: parse error in…

Conclusion

We may pass multiple parameters to ‘echo’ but not to ‘print’.

Single quote VS Double quote

This might be very confusing for many developers to choose between single and double quote for writing string. There is a couple of difference between using single and double quote:

• Any variable or special character like \n \r etc under the single quote will not be rendered. It will be displayed as an string.
• Any variable or special character like \n \r etc under the double quote will be rendered properly.

Test with Code Example

Test the below code in ‘index.php’ file and run the file.

<?php
$var = 'I am a string!';

echo 'I write - $var'; //It will not render $var variable
echo "I write - $var"; //It will render $var successfully

// Special formatting characters (\n \r etc) also do not
// work with single quote
echo 'My first line \n my new line'; // \n sequence will not be rendered and displayed as a string
echo "My first line \n my new line"; // \n sequence will be rendered
?>

Explanation of above code should be understandable by reading the comments, the code has.

Conclusion

It does not make any difference to use single or double quote until you want to render a variable and/or any special character in it.

Hopefully, now you have a better understanding of above discussion and it helps for php beginner developers . Please feel free to share your thoughts or ask any question. Your comments are always welcome. If you like this article, please share it on your favorite website. It may help someone somewhere!

• Creating an instance of a PHP Class
• Getting session information of Facebook logged-in user
• Getting User ID of Facebook User
• Getting login URL for authentication purpose
• Using FBML redirect tag

What you need?

In order to develop Facebook Application, we need a client library. Client library is a PHP class which offers us to talk to Facebook APIs in an easy manner. Download Facebook client library from:

http://github.com/facebook/php-sdk/blob/master/src/facebook.php

Start the process!

Create a folder named ‘fb’ in your application folder and move this facebook.php file into the ‘fb’ folder. Create a file fb.inc.php in your ‘fb’ folder and insert below code in it:

<?php

require 'facebook.php';

define('APP_ID','xxxxxxxxxx');
define('SECRET_KEY', 'xxxxxxxxxx');
define('CANVAS_PAGE', 'http://apps.facebook.com/shareacake/');
define('CANVAS_URL', 'http://www.techmug.com/demo/FBFromScratchSeries/');

// Create our Application instance.
$facebook = new Facebook(array(
 'appId'  => APP_ID,
 'secret' => SECRET_KEY,
 'cookie' => true,
));

//Get current user's Facebook session
$session = $facebook->getSession();

// Session based API call.
if ($session) {
 try {
 $uid = $facebook->getUser();
 } catch (FacebookApiException $e) {
 error_log($e);
 }
}

// login or logout url will be needed depending on current user state.
if ($uid) {
 //Do nothing
} else {
 $params = array(
 'next'          =>    CANVAS_PAGE,
 'cancel_url'    =>    CANVAS_PAGE,
 'fbconnect'     =>    0,
 'canvas'        =>    1,
 'req_perms'     =>    ''
 );

 $loginUrl = $facebook->getLoginUrl($params);

 echo '<fb:redirect url="' . $loginUrl . '"/>';
}

?>

Change Application ID and Secret Key of your own. We got these keys in our first episode of this series. Above code is enough for Facebook Application authentication.

Create a file outside the ‘fb’ folder and name it index.php. Include the above file (fb.inc.php) in this newly created index.php file using below code.

<?php
require 'fb/fb.inc.php';
?>

Finally upload all the files to your server to test the application (At CANVAS_URL).

Code Explanation

In the beginning we include Facebook client library class. After this we define 4 Constants to be used in our application.  Then we create an instance of Facebook Class with $facebook object.

After creating an instance, we use our newly created object to get current user’s session by using getSession() method of Facebook Class. If our code finds a session, we try to get current logged-in  user’s Facebook ID. We use getUser() method to acquire currently logged-in user’s ID.

At the moment we will not be able to get information about user, because he has not authenticated our application yet. In the result $uid will not be created.

Now, we move forward to authentication process. We check if we have $uid variable available or not. If this variable is not set yet, we try to get the login URL of our application. We start with creating an array named $params. keys inside this array are the hub of our authentication process. Below is the explanation of used keys:

For all available additional or extended permissions, please visit – http://developers.facebook.com/docs/authentication/permissions

Now its time to put our $params array in to getLoginUrl() method. At this point we have the login url, where user can actually authenticate our application. We use redirect tag of FBML(Facebook Markup Language) to send the user to authentication page.

At the authentication page, user has two options – Allow and Don’t Allow. Once user clicks on Allow button, our application will be authenticated by user. That was all about getting authentication for your Facebook Application.

Since, our application has been authenticated, we can use different API methods to get needful data. To read more about Facebook API and available methods, please visit – http://developers.facebook.com/docs/api

To see a demo of above code, visit our application at:

http://apps.facebook.com/shareacake/

Once you authenticate the application, you will see some information about you. That’s the thing we will learn in next episode…Cheers!

What’s next?

In the next episode, we will get user data using Facebook API. We will also display some cakes to be shared and we will also talk about that what can be achieved by using Facebook API. So stay tune for your Facebook hunger.

Please feel free to ask, your comments are always welcome. If you like this article, please share it on your favorite website. It may help someone somewhere!

We will build a currency converter from scratch, it pulls data from Google and display the results using jQuery AJAX function. For you better understanding, you may visit demo or download source code below:

Basically our whole code consist of three components – HTML for displaying interface, Javascript for AJAX functionality and PHP for fetching and manipulating conversion results from Google.

HTML Structure

HTML structure for this application is simple enough. There are two drop downs, one input field, one button and a div for displaying results. Drop downs are used for selecting From Currency and To Currency while input field is used for entering the desired amount to be converted in your selected currency. Conversion result displays in results div once you click on convert button. When you click on the button, it fires a Javascript function which is described below.

Javascript

Following is the code for our AJAX enabled javascript. Below code is executed upon clicking on convert button.

$(document).ready(function() {

 $('#convert').click(function(){

 //Get all the values
 var amount = $('#amount').val();
 var from = $('#fromCurrency').val();
 var to = $('#toCurrency').val();

 //Make data string
 var dataString = "amount=" + amount + "&from=" + from + "&to=" + to;

 $.ajax({
 type: "POST",
 url: "ajax_converter.php",
 data: dataString,

 success: function(data){
 //Show results div
 $('#results').show();

 //Put received response into result div
 $('#results').html(data);
 }

 });
 });
});

Above code is very simple and should be self explanatory, if you are familiar with jQuery AJAX function. For those who does not know, what’s going on here I tr to explain them.

$(‘#convert’).click(function… this is the starting point of our code, it means that execute the underneath code of this function when an element with id of  ‘convert’ is clicked. In our case this id is used for ‘convert’ button.

After that we grab values from our HTML elements by using .val() function of jQuery and assign these values into Javascript variables. These variables are then used in dataString variable.

In our AJAX function we are using POST method and in ‘url’, we provide the url of our PHP file which will provide conversion results back to this AJAX function. We are sending ‘dataString’ as data to our PHP script.

After successful iterating to our PHP script, this AJAX function first shows our results div and out the received data into our results div as HTML.

PHP Code

The brain of our application is below PHP code.

<?php
//Get Posted data
$amount = $_POST['amount'];
$from = $_POST['from'];
$to = $_POST['to'];

//make string to be put in API
$string = "1".$from."=?".$to;

//Call Google API
$google_url = "http://www.google.com/ig/calculator?hl=en&q=".$string;

//Get and Store API results into a variable
$result = file_get_contents($google_url);

//Explode result to convert into an array
$result = explode('"', $result);

################################
# Right Hand Side
################################
$converted_amount = explode(' ', $result[3]);
$conversion = $converted_amount[0];
$conversion = preg_replace('/[\x00-\x08\x0B-\x1F]/', '', $conversion);
$conversion = $conversion * $amount;
$conversion = round($conversion, 2);

//Get text for converted currency
$rhs_text = ucwords(str_replace($converted_amount[0],"",$result[3]));

//Make right hand side string
$rhs = $conversion.$rhs_text;

################################
# Left Hand Side
################################
$google_lhs = explode(' ', $result[1]);
$from_amount = $google_lhs[0];

//Get text for converted from currency
$from_text = ucwords(str_replace($from_amount,"",$result[1]));

//Make left hand side string
$lhs = $amount." ".$from_text;

################################
# Make the result
################################

echo $lhs." = ".$rhs;
?>

Above code is well commented to make you understand better. In this code we are using some built-in PHP functions – file_get_contents, explode, round and ucwords.

• In start we grab the values posted to this script by our AJAX function. We store these values into variables.
• We make a string variable using above explained variables.
• We concatenate this string variable to Google Currency Calculator API url and store the url in a new variable named $google_url.
• We fetch the data of $google_url to $result variable using PHP’s file_get_contents function.
• We receive data from Google something similar to
  {lhs: “1 Euro”,rhs: “1.2692 U.S. dollars”,error: “”,icc: true}
• Using PHP’s explode function, we separate lhs and rhs from the received response.
• From rhs we get the converted value and multiply it by our dsired amount to get total conversion.
• Using PHP’s round function, converted amount is round off to two digits.
• After this we use PHP’s ucwords function to Capitalize our text’s first letter.
• We almost do the same for lhs.
• At last we make results by joining lhs and rhs and echo it to give the results back to our AJAX function.

Last words

In the source code I have applied some CSS to make the user interface better. So don’t be puzzled with the code in source file.

Finally, you have a working Live Currency Converter. You may use this script in your website to attract more visitors. Just play around the code and let me know if you can enhance it further. Please feel free to ask, your comments are always welcome.

If you like this article, please share it on your favorite website. It may help someone somewhere!

• Setup a Facebook Application
• Use Facebook Authentication for aplications
• Learn FBJS
• Learn Facebook Graph API
• Learn how to post data on users wall using Facebook Application
• Learn how to post data on users’ friends wall using Facebook Application
• Create a custom tab for your application

Let’s kick the app!

To develop Facebook applications you need to have a developer account on facebook.com. Click here and follow simple steps to create your developer account. Once you have created your developer account, go to:

http://www.facebook.com/developers/

At this stage you should have something similar to below screen. Click on the “Set Up New Application” button:

Tip: Click on any of below snapshots to view bigger image.

Create Application

Give your application a name and choose “Agree” for terms and click “Create Application”. Congratulations! your new facebook application has been created. Now we will look at some of configurations.

Basic Configuration

When you hit the “Create Application” button, you will be redirected to a page similar to below screen. Here you can configure your application according to your needs. For the sack of simplicity we will go for basic configuration. Later in this series of tutorials we will come back here to do more stuff.

For now you should see the same application name, you provided in last step  (Share a Cake in our case). Give your application some description. And click on ‘Facebook Integration‘ at the left side of the screen.

Canvas Settings

The area where people interact with your facebook application usually is called Canvas. The URL to access your applcation is called Canvas Page and the location where you host your files for facebook application is called Canvas URL.

Canvas Page is unique for every facebook application and subject to the availability. While Canvas URL is your server URL. Facebook does not host your files, you will need a server to store your application files.

Enter your values for Canvas Page and Canvas URL.

In last, choose FBML for Canvas Type in Canvas Settings. Difference between IFrame and FBML application is a topic – we are leaving for some later time in future.

Finally click on Save Changes button at bottom.

Final Step

Three elements Application ID, API Key and Application Secret are very important in order to run our application in the Facebook. You should notice hidden values for API Key and Application Secret in below screen shot. In your case you must be having some alpha numeric characters for them.

For now, just make a note for the values of Application ID, API Key and Application Secret. We will use this information later in this series.

We are done!

That’s all for setting up your Facebook Application. In upcoming days we are bringing more delicious CAKES for your Facebook Application development hunger. So stay tune with us.

If you like this article, please share it on your favorite website. It may help someone somewhere!

In this tutorial we will be sending HTML emails using PHP. This tutorial will teach you to keep your HTML presentation separate from your PHP code.

How it works?

Basically there are only three steps to send your branded HTML emails.

1. Read HTML template file from your specified location.
2. Replace variables with your data, if any.
3. Finally send email.

What we need?

Before we move to define the above steps, its worth to mention the requirements of this tutorial. The first thing we need to send emails is PHPMailer class. To learn more about PHPMailer class please visit the official website here. And the last other thing is your HTML template file.

Step by step learning

Here are the steps you need to take in order to develop your own email sending program.

First of all you need to include the PHPMailer class in your code. To do so you use below code:

<?php
#####################################
# Include PHP Mailer Class
#####################################
require("class.phpmailer.php");
?>

Before moving further I would like to introduce two PHP functions we will use in our code. First one is for sending emails and second is for reading your HTML template file. First function (sendEmail) accepts five parameters and return false if email is not sent and returns true if email is sent. Parameters are self explanatory in below code:

<?php
#####################################
# Function to send email
#####################################
function sendEmail ($fromName, $fromEmail, $toEmail, $subject, $emailBody) {
$mail = new PHPMailer();
$mail->FromName = $fromName;
$mail->From = $fromEmail;
$mail->AddAddress("$toEmail");

$mail->Subject = $subject;
$mail->Body = $emailBody;
$mail->isHTML(true);
$mail->WordWrap = 150;

if(!$mail->Send()) {
return false;
} else {
return true;
}
}
?>

The other function (readTemplateFile) reads your HTML template file and returns all the stuff found in that file. This function accepts only one parameter which is the location of your HTML file. Below is function:

<?php
#####################################
# Function to Read a file
# and store all data into a variable
#####################################
function readTemplateFile($FileName) {
$fp = fopen($FileName,"r") or exit("Unable to open File ".$FileName);
$str = "";
while(!feof($fp)) {
$str .= fread($fp,1024);
}
return $str;
}
?>

Finally you need to call and pass parameters to above function to complete the task of sending HTML email. Yeah! really we almost done it. Ok we are using a template which send username and password of a user. Please see HTML template file in downloaded file. We break our last and final step in three pieces:

<?php
//Data to be sent (Ideally fetched from Database)
$NameOfUser = "XYZ";
$Username = "abcdef";
$password = "123456";
$UserEmail = "receiver.email@somedomain.com";
?>

First of all we put data into some variables. These variables will be used later in our code. Ideally this data will be fetched from database in real world.

Now we put our HTML template data into other variable:

<?php
//Send email to user containing username and password
//Read Template File
$emailBody = readTemplateFile("template.html");
?>

So we have all our file data in a variable ($emailBody). And we may change anything in this variable. We will use PHP’s str_replace function to replace the data:

<?php
//Replace all the variables in template file
$emailBody = str_replace("#name#",$NameOfUser,$emailBody);
$emailBody = str_replace("#username#",$Username,$emailBody);
$emailBody = str_replace("#password#",$password,$emailBody);
?>

To understand the above code we take first line of code. It simply replace #name# with the value of $NameOfuser variable in $emailBody variable. And now our new replaced content is stored in $emailBody variable, so now we can use this content to be passed in our email sending function below:

<?php
//Send email
$emailStatus = sendEmail ("Sender Name", "some.email@yourdomain.com", $UserEmail, "Email Subject", $emailBody);
?>

If email is not sent successfully, we will display error message else we will show success message:

<?php
//If email function return false
if ($emailStatus != 1) {
echo "An error occured while sending email. Please try again later.";
} else {
echo "Email with account details were sent successfully.";
}
?>

That’s all! Now you have fully functional code to send your branded emails. If in future you want to change the design of your email, you just have to replace HTML template file. There is no need of changing your PHP code. Ideally you can use this code to send:

• Newsletters
• Registration Details
• Forgot Password email
• And for anything you want

Besides the benefits of using above code there is one shortcoming too of this code. If your user’s email client does not support HTML email, he/she will not be able to see your fancy deigned email. But there are ways to prevent this shortcoming.

Hope so you enjoyed this tutorial. Please feel free to ask or comment for this tutorial. And Don’t forget to share the post on your favorite website. It may also help someone somewhere

Send your newsletters using HTML templates and PHP