Android Basic by Amey bapat

1. Introduction to RESTful webservice
By-
Amey Bapat

2. What is RESTtful webservice?
• REST describes a set of architectural principles by which
data can be transmitted over a standardized interface (such
as HTTP).
• The acronym REST stands for Representational State
Transfer, this basically means that each unique URL is a
representation of some object.
• REST asks developers to use HTTP methods explicitly and in
a way that’s consistent with the protocol definition.
• This basic REST design principle establishes a one-to-one
mapping between create, read, update, and delete (CRUD)
operations and HTTP methods. According to this mapping:
• To create a resource on the server, use POST.
To retrieve a resource, use GET.
To change the state of a resource or to update it, use PUT.
To remove or delete a resource, use DELETE.

3. Examples
• http://weatherinfo.org/getweather/mumbai – It
gets the weather information of Mumbai (one of
the Indian cities)
• http://employer.com/update/salary/130/3000 –
It updates Salary of Employee with Employee ID
’130′ as $3000.
• http://countries.com/add/singapore – It adds
country ‘Singapore’ to the list of Countries
• http://product.com/delete/dell/inspiron15r – It
deletes Dell Inspiron 15R from the list of products

4. Rest vs SOAP
REST SOAP
REST stands for REpresentational State
Transfer
SOAP stands for Simple Object Access
Protocol
REST is not XML protocol based SOAP is a XML based messaging protocol
REST doesn’t have any specification SOAP has specifications like WSDL etc
REST doesn’t enforce message format as
XML or JSON
SOAP enforces message format as XML
Light weight – due to the usage of JSON Heavy weight – due to the usage of XML
Easy to parse the response Bit difficult to parse the response

5. RESTFul Webservice Request and
Response
• ist step in designing RESTFul webservice is
choosing the right domain name – say
weatherinfo.org to retrieve weather information
of cities.
• Let us take the first example (weatherinfo.org)
which takes city name as input, composes
weather information of the city and respond back
to the browser. Assume the response is in XML
format, this can be in other formats like JSON as
well.
• Here is the structure of Request and Response:

6. GET
http://weatherinfo.org/getweather/mumba
i HTTP/1.1
HTTP Request
The client request from the browser will look like:

7. HTTP Response
• he server response will look like:
• HTTP/1.1 200 Ok
• Date: Mon, 14 Apr 2014 10:20:58 GMT
• Content-Type: text/xml
• Content-length: 139
•
• <City name="Mumbai" datetime="2014-04-14
10:20:58 GMT" >
• <Condition>Scattered Clouds</Condition>
• <Temp>33</Temp>
• </City>

8. Advantages of using RESTful
webservice
• RESTful Web services are designed with less dependence on
proprietary middleware (for example, an application server) than
the SOAP- and WSDL-based kind.
• As per the RESTful interface design, XML or JSON over HTTP is a
powerful interface that allows internal applications, such as
Asynchronous JavaScript + XML/JSON (Ajax)-based custom user
interfaces, to easily connect, address, and consume resources.
• The great fit between Ajax and REST has increased the amount of
attention REST is getting these days.
• Exposing a system’s resources through a RESTful API is a flexible
way to provide different kinds of applications with data formatted
in a standard way. It helps to meet integration requirements that
are critical to building systems where data can be easily combined
(mashups) and to extend or build on a set of base, RESTful services
into something much bigger.