In this blog post, we will discuss the details about SOAP.
What is SOAP Protocol?
SOAP stands for Simple Object Access Protocol. SOAP protocol is a messaging protocol used to exchange structured information in the implementation of web services in computer networks. In simpler terms, we can define it as a protocol for transferring messages on the Internet.
It is XML based and can work on various protocols such as HTTP, SMTP. It offers platform-independent communication via web services. For example, a banking application can retrieve exchange rates from another financial service using SOAP. SOAP’s XML-based structure ensures that data is transmitted in a secure and structured manner, making it a frequently preferred method in enterprise integration projects.
What is the purpose of SOAP protocol?
SOAP allows developers to call processes running on different operating systems, such as macOS and Windows, to authenticate, authorize and communicate using XML. Since web protocols, especially the http protocol, are installed on almost all operating systems, SOAP allows clients to access web services and receive platform- and language-independent responses.
Thanks to these features, it is preferred in corporate projects to minimize data errors and reduce communication regarding service usage. It is also frequently used in scenarios that require integration with different programming languages such as .Net and Java.
What are the main features of SOAP?
The key features of SOAP are extensibility, neutrality and independence.
Extensibility makes it easy to add new functions and modules.
Neutrality ensures smooth operation over different protocols such as HTTP, SMTP, SOAP, UDP, TCP
Independence does not depend on a particular programming model. It can work in any programming models.
For example, SOAP can run on both Windows and Linux and integrate with different languages such as Java or .NET.
What are the Components of SOAP Protocol?
SOAP provides the messaging protocol layer within a protocol stack for web services. This XML-based protocol consists of three main components:
- an envelope indicating the message structure and how it should be processed,
- a set of coding rules for expressions of application-defined data types
- A method for representing procedure calls and responses.
Envelop, Header, Body and Fault Sections of SOAP
A SOAP message contains the following four elements:
- Envelope
The Envelope is one of the basic components of the SOAP message and acts as the root element of the entire message. This component determines the structure of the message and defines how it will be processed. It is located at the top of the SOAP message and must be used in every SOAP message.
- Header
The header is an optional component of the SOAP message. It is similar to the head tag in HTML. It contains header information. It is not mandatory to use this field in the SOAP message. The developer may or may not use it according to his needs.
- Body
Body is the most important part of the SOAP protocol. Call and response information is contained in this field.
- Fault
It provides information about errors that occur during message processing and facilitates debugging.
When to Use SOAP APIs?
SOAP is a communication protocol that enables the exchange of structured information in different environments using XML. This technology allows applications running on various operating systems and programming languages to communicate seamlessly with each other. Any business that needs to communicate between different applications can use SOAP APIs.
SOAP API Use Cases
The most common SOAP protocol use cases are as follows:
- Money Transfers:
During money transfers, it is necessary to establish a communication between different banks or different bank branches. For this, it means sending multiple calls to different web services. SOAP APIs ensure that these transactions are performed securely.
- Flight Ticket Booking
SOAP API provides access to web services of airlines and travel agencies to get flight information and prices. Thus, it can list the necessary information.
What is the Difference Between SOAP and REST?
The differences between SOAP and REST APIs, which is one of the frequently wondered topics, are as follows:
- SOAP is a protocol used to communicate between applications. REST is an architecture for designing communication interfaces.
- SOAP API exposes transactions. REST API allows data to be exposed.
- SOAP is an independent protocol and works with any transport protocol. REST can only work with the HTTPS protocol.
- SOAP exchanges data only in XML. REST supports JSON, XML, HTML and plain text formats.
- SOAP is more useful in private APIs and legacy applications. REST is more useful in public APIs and modern applications.