Consider the most common POST request in any application—the request sent for logins. Will it be sufficient if the request body has the user's credentials in, say, a JSON or XML format? Will the request handler be able to extract this data and process it directly? No, since the data in the request has to be understood by the application code, it must be translated into a compatible type. For example, XML sent in a request must be translated to Scala XML for a Scala application.

There are several libraries, such as Jackson, XStream, and so on, which can be used to achieve this task, but we wouldn't need them as Play supports this internally. Play provides request body parsers to transform the request body into equivalent Scala objects for some of the frequently used content types. In addition to this, we can extend existing parsers or define new ones.

Every Action has a parser. How do I know this ? Well, the Action object, which we used to define how our app should respond...