PHP - Create Vertical Text Image

Create vertical text image in PHP

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PHP MVC Part - I

MVC:

Model
View
Controller

What is MVC?
MVC is a way of coding. how do we distribute functions/classes/files. 

What MVC is not ?
MVC is not any programming language, rather it is a framework/architecture/design schema.
MVC architecture, we can implement in PHP, JAVA, C# and also JavaScript

Analogy:
1. How do you keep things in your kitchen. ?
2. We can keep all tools and utilities scattered on one table - ( No Pattern )
3. We can keep tools categorized by use. i.e. knife,spoon in one box, Plates near sink   - ( some pattern )

Real world example:
1. We have to build Book Store
2. We need to add/remove books
3. Show users list of books
4. Registered user can see preview

Here, we have some logic, lets call them, business logic:
i.e. add/remove books:

Also, we have some-thing to show user
i.e. List of books

Also, we have one rule
i.e. Registered user can see preview


All classes/functions of business logic, we can call: MODEL
All classes/files which helps to render product list, we can call:VIEW
All classes/files/functions which helps to decide/implement rule, we can call: CONTROLLER


Technically:
Model: Encompasses business logic ( Mostly base classes )
View: Helps to present/render data ( Mostly template files + classes which helps to render )
Controller: Helps to decide some rule. like, which page to render, which page not to render

Prime Example of MVC architecture:
Zend
Magento - way to complex to understand

End of part one.

Cheers!!

PHP MVC Singleton pattern

What is Singleton pattern ?
- A simple design schema, in which, we instantiate object only once in a page life cycle.

Explanation with analogy.
- Lets say, you went to restaurant and ordered 3 types of Soup.
- Each Soup comes up with Bowl + Spoon
- Now, you have 3 spoons.
- Normal pattern : you use 3 spoons for each bowl
- problem in that: wastage of 3 spoons
-Singleton pattern: each time, you use: same spoon to drink soup.
- Thats it.

Real-time example:
- DB Object.
- We invoke DB object in page life cycle only once.
- Each time, we need to run query, we use same object.

Example with code:

class db{



publis static $_instance; 



public static _getInstance(){

       // Lets check, do we have object already instantiated ? 

        if(self::$_instance){

             // return already instantiated object 

             return self::$_instance 

        }

        else{

             // else instantiate and return object 

             return self::$instance = new db(); 

        } 

} 

}


Seems so easy :)

cheers!!!

Javascript Closure

Good way in javascript to have dynamic content using closure

Lets say, we have to use the string:

" content has been posted 1 times"
" content has been posted 2 times"

we can use below code

var message = function(count){
return " content has been posted " + count + times ";
}
console.log(message(1));
console.log(message(2));

Cheers!!

jQuery $.ajax IE and Cross Domain

jQuery $.ajax fails in IE for cross-domain request, even-though we have allowed origin on server configuration.

Basically AJAX is an transport mechanism, with few rules. we can have our own transport too. Here is how we can override $.ajax transport and allow cross-domain AJAX request in IE.

Add below code at the end of page.

$.ajaxTransport("+*", function( options, originalOptions, jqXHR ) {
    if(jQuery.browser.msie && window.XDomainRequest) {
        var xdr;
        return {
            send: function( headers, completeCallback ) {
                // Use Microsoft XDR
                xdr = new XDomainRequest();
                xdr.open("get", options.url);
                xdr.onload = function() {
                    if(this.contentType.match(/\/xml/)){
                        var dom = new ActiveXObject("Microsoft.XMLDOM");
                        dom.async = false;
                        dom.loadXML(this.responseText);
                        completeCallback(200, "success", [dom]);
                    }else{
                        completeCallback(200, "success", [this.responseText]);
                    }
                };
                xdr.ontimeout = function(){
                    completeCallback(408, "error", ["The request timed out."]);
                };
                xdr.onerror = function(){
                    completeCallback(404, "error", ["The requested resource could not be found."]);
                };
                xdr.send();
          },
          abort: function() {
              if(xdr)xdr.abort();
          }
        };
      }
    });

Cheers!!