Wrap request body.md

Wrapping the request body before passing it to GraphQL

Consider this GraphQL mutation and GraphQL2REST manifest entry:

type Mutation {
	createUser(userData: UserDataInput!): User
}

input UserDataInput {
	name: String
	dateOfBirth: Date
}

"endpoints": {
		"/users": {
			"post": {
				"operation": "createUser",
				"wrapRequestBodyWith": "userData",
				"successStatusCode": 201
			}
		}

"wrapRequestBodyWith" is used here to wrap the HTTP body in the request with a "userData" property (userData: { ... }) before passing the request to createUser(). This allows the user to provide a flat body that looks like this:

{
	"name": "Roy Fielding",
	"dateOfBirth": "09-01-1965"
}

Which is what we expect of REST request, rather than these fields within a "userData" object. When createUser() is finally invoked, it is called with the following arguments:

{
	"userData":
	{	
		"name": "Roy Fielding",
		"dateOfBirth": "09-01-1965"
	}
}

This way we can map a flat REST body to a specific object argument in the GraphQL operation.