What is REST API ? || INTERVIEW STUFF

In my words, getting data from Other System or Same System using HTTP request is known as REST API.

If you know, how website works, you know REST API. Before REST API, there was SOAP request, which needed lots of configuration and very tightly coupled. If you make any modification, you had to modify client side also by generating stubs / proxy classes again. There were many more disadvantages, which got address by REST API. However, it does not mean we do not need SOAP.

Back to REST API, It is very simple to setup and almost any programming language can make HTTP request so very easy to get data from other source. Return type of REST API can be XML, Simple HTTP, JSON or any media like image. However, JSON is very popular response type amongst all.

In Past, I have already written one article demonstrating REST API usage.

How to use Salesforce REST API using JQuery in Visualforce?

REST API Playground: I have created Simple Visualforce page, which demonstrates how to use REST API of Salesforce. It is written in Visualforce with the help of JQuery. You can study this code and play with it in your organization, you just need to copy and paste it.

You also need to add URL “http://cdnjs.cloudflare.com” in Remote Site Settings, so that salesforce will allow Visualforce page to get JQuery library from CDN.

Complete Visualforce page :

<apex:page showHeader="false" sidebar="false" standardStylesheets="false">

<style>

body

{

font-family: "Open Sans", Helvetica, Arial, sans-serif;

font-size : 0.8em;

}

lable

{

font-weight : bold;

}

.trace

{

background-color:

padding : 10px;

border: 1px solid #E0E0E0;

background-color: #F8F8F8;

}

pre

{

font-size : 1em;

white-space: pre-wrap; /* css-3 */

white-space: -moz-pre-wrap !important; /* Mozilla, since 1999 */

white-space: -pre-wrap; /* Opera 4-6 */

white-space: -o-pre-wrap; /* Opera 7 */

word-wrap: break-word; /* Internet Explorer 5.5+ */

line-height: 1.1em !important;

font-family: 'Monaco', courier, monospace;

}

.leftDiv

{

width: 70%;

float:left;

}

.rightDiv

{

width: 28%;

float:right;

background-color: #EEE;

border: 1px solid #aaa;

padding:5px;

}

.hlp

{

width: auto;

color: #000000;

background-color: #e5eecc;

margin: 0px;

padding: 5px;

border: 1px solid #d4d4d4;

background-image: linear-gradient( #ffffff , #e5eecc 100px);

font-weight:bold;

margin-top:20px;

}

outline: none;

color: #21759b;

}

a:hover {

color: #0f3647;

}

.heading {

font-size : 2em;

text-align : center;

padding:10px;

background-color: #EEE;

font-weight : bold;

border: 1px solid #aaa;

margin-bottom : 10px;

color : #21759b;

}

</style>

Salesforce REST API Playground

</div>

HTTP Request Type :

<label for="rad-PATCH"><input type="radio" id="rad-PATCH" name="requestType" value="PATCH" />PATCH</label>

<label for="rad-Del"><input type="radio" id="rad-Del" name="requestType" value="DELETE" />DELETE</label>

<br />

REST URL : <input type="text" id="RESTURL" size="70" value="/services/data/v29.0/sobjects/Account/" />

<br />

Request Data :

<br />

Replace "Account" in REST URL by any other SObject.

</div>

<br />

</div>

<h3> Salesforce Documentation Reference </h3>

<ul>

<li> <a href="https://www.salesforce.com/us/developer/docs/api_rest/"> REST API Developers Guide </a> </li>

</ul>

<h3> Metadata Related APIs</h3>

<ul>

<li> <a href="javascript:setVal(0);"> Get SObject Information </a> </li>

<li> <a href="javascript:setVal(1);"> List Available REST API Versions </a> </li>

<li> <a href="javascript:setVal(2);"> List Organization Limits</a> </li>

<li> <a href="javascript:setVal(3);"> List Available REST Resources </a> </li>

<li> <a href="javascript:setVal(4);"> Get a List of Objects </a> </li>

<li> <a href="javascript:setVal(5);"> Get Object's Metadata Info </a> </li>

</ul>

<h3> Working with Records </h3>

<ul>

<li> <a href="javascript:setVal(6);"> Create Record </a> </li>

<li> <a href="javascript:setVal(7);"> Update Record </a> </li>

<li> <a href="javascript:setVal(8);"> Delete Record </a> </li>

<li> <a href="javascript:setVal(9);"> Get Field Values from Records </a> </li>

</ul>

</div>

var $errMsg = $("#errMsg");

var $getOpt = $("#rad-Get");

var $postOpt = $("#rad-POST");

var $restUrl = $("#RESTURL")

var $RestResponse = $("#RestResponse");

var $reqData = $("#RestRequestData");

var $helpDiv = $("#helpDiv");

var $patch = $("#rad-PATCH");

var $radDel = $("#rad-Del");

var arrayOfRest = new Array();

function exec()

{

var postUrl = $restUrl.val();

var postData = $reqData.val();

var reqType = $('input:radio[name=requestType]:checked').val();

var heading = '<h3> Response : </h3> <br />';

resetResult();

$.ajax({

type: reqType,

beforeSend: function (xhr)

{

xhr.setRequestHeader("Authorization", 'Bearer {!$API.Session_ID}');

headers : {'Content-Type' : 'application/json; charset=utf-8'},

url: postUrl,

data: postData,

dataType: 'text'

})

.done(function( data ) {

var res = JSON.stringify ($.parseJSON(data),null,'\t');

printResult(heading+"<pre>"+res+"</pre>");

})

.fail(function(xhr,textstatus,error){

var output = '<br /> <b> Status : </b>'+textstatus ;

output = output + '<br /> <b> Error : </b>'+error ;

printResult(output);

});

}

function printResult(htmlVal)

{

$errMsg.html(htmlVal);

$errMsg.show();

}

function resetResult()

{

$errMsg.hide();

$errMsg.html("");

}

function setVal(ind)

{

//console.log('I am called');

var ret = arrayOfRest[ind];

if(ret != null)

{

if(ret.type == 'GET')

$getOpt.attr('checked', 'checked');

else if(ret.type == 'PATCH')

$patch.attr('checked', 'checked');

else if(ret.type == 'DELETE')

$radDel.attr('checked', 'checked');

else

$postOpt.attr('checked', 'checked');

$restUrl.val(ret.URL);

$reqData.val(ret.Body);

setHelpVal(ret.Help);

resetResult();

}

function setHelpVal(val)

{

if(val != null && val != '')

{

$helpDiv.show();

$helpDiv.html(val);

}

else

$helpDiv.hide();

}

function createJSONData(reqType,resURL,reqBody,hlp)

{

return {"type":reqType,"URL":resURL,"Body":reqBody,"Help":hlp} ;

}

function createData()

{

//Dont Change Sequence