When you use a web API to check in to a website using your Facebook account or drag a drop-off point across a Google map in a ride-hailing app, the app talks with Google or Facebook. An API, or application programming interface, is a contract between online services that specifies how they will communicate data, such as a map or your account credentials. Data is organized in messages that systems communicate to one another. When you launch an app like Uber, your phone sends a message to Google Maps, which responded with the map itself.
What is SOAP?
Simple Objects Access Protocol (SOAP) is a web communication protocol that was created in 1998 by Microsoft. It’s primarily used nowadays to expose web services and send data over HTTP/HTTPS. However, they aren’t the only ones. SOAP, unlike the REST paradigm, only accepts the XML data format and adheres to pre-determined standards such as message structure, encoding requirements, and a procedural request and response procedure. SOAP can manage communications and produce answers that are language and platform-agnostic.
SOAP uses XML
Data sent via the internet is generally organized. XML and JSON are the most widely used data formats. Extensible Markup Language (XML) is a text format that defines a set of rules for structuring communications as both human and machine-readable records. XML, on the other hand, is verbose since it is designed to create a formal online document. JSON has a more amorphous form that emphasizes the data.
Message structure of SOAP
SOAP is regarded as lengthy and hefty in comparison to REST not just because of XML. It’s also the structure of SOAP messages. Standard SOAP API queries and answers take the form of an enclosed message made up of four components, each with its own set of functionalities.
1. The envelope: is a fundamental and vital aspect of every communication that begins and ends with tags, encircling it, thus the name.
2. The header (optional): specifies the message’s details and additional needs, such as authentication.
3. The body: the request or response is included in the body.
4. Fault (optional): displays all information about any errors that may occur during the API request and response.
When to use SOAP?
- When you need high security for your app
If your application requires a high level of dependability and security, SOAP 1.2 provides extra guidelines. WSRM (WS-Reliable Messaging) is an example of this.
- Formal contracts
SOAP 1.2 provides rigorous rules for this sort of interaction if both parties (provider and consumer) must agree on the exchange format.
For stateful operations
If the application requires contextual data or conversational state management, SOAP 1.2 includes an extra specification in the WS* structure to fulfill these requirements (Security, Transactions, Coordination, etc). The REST method, on the other hand, would need the developers to provide this proprietary infrastructure.
Each technology method has its own set of advantages and disadvantages, as indicated above. They both have underlying security, transport layer, and other concerns, but they can both get the job done, and they each offer something to the web in many situations. So, in this case, the ideal rule is the rule of flexibility, since no matter what the problem is, web developers can solve it using either of these protocols, at least in today’s web development environment.