The word “web services” mean different things to people with different fields. For general users, it is like using online services, like surfing the internet, but for developers it has different meanings. Overall it is a broad term that tells us how the communication between two different set of devices or applications held over the World Wide Web (WWW).
This communication can be categorized into two types:-
- SOAP (Simple Object Access Protocol)
- REST (Representational State Transfer)
Simple Object Access Protocol is a standards-based web services access protocol that has been around for a long time. originally developed by Microsoft.
SOAP relies heavily on XML and together with schema it defines a very strongly typed messaging framework.
Every operation the service provides is explicitly defined, along with the XML structure of the request and response for that operation.
Each input parameter is similarly defined and bound to a type: for example an integer, a string, or some other complex object.
All of this is coded in the WSDL – Web Service Description Language. The WSDL is often explained as a contract between the provider and the consumer of the service. In programming terms the WSDL can be thought of as a method signature for the web service.
REST is quickly becoming the preferred design model for public APIs. REST stands for REpresentational State Transfer.
It is a software architecture style that relies on a stateless communications protocol, most commonly, HTTP. some of the basicREST HTTP requests that are widely used are: POST, GET, PUT, and DELETE.
Instead of using XML to make a request, REST relies on a simple URL. In some situations you must provide additional information, but most web services using REST rely on using the URL approach.
REST structures data in XML, YAML, or any other format that is machine readable, but usually JSON is most widely used.
REST is a data-driven, compared to SOAP, which is strongly function-driven. Sometimes people refer to REST as RESTful APIs or RESTful web services.
Difference Between SOAP and REST
- SOAP is a protocol whereas REST is an architectural pattern.
- SOAP uses service interfaces to expose its functionality to client applications while REST uses Uniform Service locators to access to the components on the hardware device.
- SOAP needs more bandwidth for its usage whereas REST doesn’t need much bandwidth.
- SOAP only works with XML formats whereas REST work with plain text, XML, HTML and JSON.
- SOAP cannot make use of REST whereas REST can make use of SOAP.
Advantage of SOAP
- Language, platform, and transport independent (REST requires use of HTTP).
- Works well in distributed enterprise environments (REST assumes direct point-to-point communication).
- Built-in error handling.
Advantage of REST
- Efficient (SOAP uses XML for all messages, REST mostly uses smaller message formats like JSON).
- Fast (no extensive processing required).
- Closer to other Web technologies in design philosophy.
When to Use SOAP
SOAP should be used in the following instances:-
- If there is a requirement that the client needs a guaranteed level of reliability and security then SOAP provides a lot of special feature related to security.
- If both the client and server have an agreement on the exchange format then SOAP gives the rigid specifications for this type of interaction.
- If the application has a requirement that state needs to be maintained from one request to another, then the SOAP standard provides the structure to support such requirements.
When to use REST
REST should be used in the following instances:-
- REST should be used in instances where we have limited resource and network bandwidth.
- If there is no need to maintain a state of information from one request to another then REST should be used.
- If there is a need to cache a lot of requests then REST is the perfect solution.
- Coding REST Services and subsequent implementation is far easier than SOAP. So if a quick win solution is required for web services, then REST is the way to go.
I hope this will help you to understand better about the web services.
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