DEV Community: Dinakar

Let's Learn - Week 1 - REST vs SOAP

Dinakar — Mon, 27 Jul 2020 07:06:15 +0000

The final post for this week 1 , we are going to wrap up with the difference between REST vs SOAP.

Although this is not an Apple-Apple comparison because SOAP is format of XML whereas REST is actually an architectural style , I would like to highlight just the differences that gives a recap of what we have seen so far

Now we have quite some idea about the basic terminologies and key concepts , next week will meet you all with

Let's Learn - Week 1 - REST

Dinakar — Mon, 27 Jul 2020 07:06:06 +0000

    * Introduction

    * Resource

    * Data Exchange

    * Service Definition

Introduction

REST stands for REpresentational State Transfer coined by Roy Thomas Fielding who is credited for developing HTTP.

REST makes best use of HTTP (Hyper Text Transfer Protocol).
Thus, RESTful webservices try to define services using the different concepts that are already present in HTTP.

HTTP methods are used to indicate what action we are using.

Example:

GET -> to get details of a resource
POST -> during creation of a resource
PUT -> update resource
DELETE -> delete resource

What is a resource

The most important abstraction in REST is called resource.

A resource is anything that you would want to expose to the outside world through your application
A resource can have different representations
- XML
- HTML
- JSON

A resource has an URI (Uniform Resource Identifier)

Create employee -> POST /Employee
Delete an employee -> DELETE/Employee/1
Get all employees -> GET /Employees
Get Particular employee -> GET /Employee/2

The important thing about REST is the fact that
- We have to think in terms of resources
- Make proper use of HTTP methods

How does data exchange between applications take place

In REST we don’t have any restriction on Data exchange format.However,JSON is very popular and widely used.

Also note that , transport protocol is always HTTP.
REST is built on top of HTTP.

What is the service definition

There is no standard service definition attached with REST.
However the service details can be provided by WADL (Web application definition language) / Swagger

To Summarise the above

Next,we will wrap up the basics by seeing the difference between REST and SOAP

Let's Learn - Week 1 - SOAP

Dinakar — Mon, 27 Jul 2020 07:05:44 +0000

Introduction to SOAP Web Services

SOAP is an acronym for Simple Object Access Protocol.
SOAP defines specific way of building web services.
We use XML as request and response exchange format.

Any request that contains XML as request and response is not SOAP.
SOAP defines specific XML request and response structure.

We need to create SOAP envelope that contains header and body.
The header contains meta information like authentication , authorization etc.
SOAP body is where we put real content of request and response.

The service definition is managed by WSDL – Web Service Description Language

Examples of SOAP Request , Response & WSDL

SOAP Request

<?xml version="1.0"?>

<soap:Envelope
xmlns:soap="http://www.w3.org/2003/05/soap-envelope/"
soap:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
<soap:Header/>
<soap:Body xmlns:m="http://www.example.org/stock">
  <m:GetStockPrice>
    <m:StockName>IBM</m:StockName>
  </m:GetStockPrice>
</soap:Body>
</soap:Envelope>

SOAP Response

<?xml version="1.0"?>

<soap:Envelope
xmlns:soap="http://www.w3.org/2003/05/soap-envelope/"
soap:encodingStyle="http://www.w3.org/2003/05/soap-encoding">

<soap:Body xmlns:m="http://www.example.org/stock">
  <m:GetStockPriceResponse>
    <m:Price>34.5</m:Price>
  </m:GetStockPriceResponse>
</soap:Body>

</soap:Envelope>

WSDL

<message name="getTermRequest">
  <part name="term" type="xs:string"/>
</message>

<message name="getTermResponse">
  <part name="value" type="xs:string"/>
</message>

<portType name="glossaryTerms">
  <operation name="getTerm">
    <input message="getTermRequest"/>
    <output message="getTermResponse"/>
  </operation>
</portType>

Now that we have an idea about SOAP based web services , let's move to Restful Web Services

Let's Learn - Week 1 - WebServices

Dinakar — Sat, 18 Jul 2020 19:50:31 +0000

Introduction:

Spring has really evolved a lot. It has been around for over a decade and has found a place as the de facto standard framework for developing java applications.

There are many exciting things in world of spring ecosystem such as Annotation, Spring MVC, REST, spring boot, spring cloud and micro services.

We are going to deep dive into world of restful web services, spring boot and micro services.

We will start with basics of restful web services, http request methods, how do you do exception handling, and validation and so on

Introduction to Web Services:

What is a web service?

W3C definition :

"Software system designed to support interoperable machine to machine (application – application )interaction over a network"

Now we know what a web service is, let’s see the following:

How does data exchange between applications take place
- Consider a quiz application wants to communicate with security application to know whether an user is authorised to be admin or not
- So quiz application needs to send a request and security application will send a response
- Data exchange happens in form of request and response
How can we make web services platform independent?
- 2 popular formats – XML and JSON

<Learning>
    <Name>SpringBoot</SpringBoot>
    <Name>MicroService</SpringBoot>
</Learning>

[
{"Name":"SpringBoot"},
{"Name":"MicroService"}
]

How does application know the format of Request and Response ?
- Every web service offers service definition
- It provides whether request-response format is XML , JSON or any other format
- How to call the service , where is the service available
- What is the contract between service and consumer

To summarise the above

Now we have seen a quick overview about web services, next let’s see about the different ways of implementing web services