GraphQLRequestParser

The GraphQLRequestParser interface is required to parse the library-specific HTTP request object into the common GraphQLServerRequest class.

interface GraphQLRequestParser<Request> {
    suspend fun parseRequest(request: Request): GraphQLServerRequest?
}

While not officially part of the spec, there is a standard format used by most GraphQL clients and servers for serving GraphQL over HTTP. Following the above convention, GraphQL clients should generally use HTTP POST requests with the following body structure

{
  "query": "...",
  "operationName": "...",
  "variables": { "myVariable": "someValue" }
}

where

• query is a required field and contains the operation (query, mutation, or subscription) to be executed
• operationName is an optional string, only required if multiple operations are specified in the query string.
• variables is an optional map of JSON objects that are referenced as input arguments in the query string

GraphQL Kotlin server supports both single and batch GraphQL requests. Batch requests are represented as a list of individual GraphQL requests. When processing batch requests, the same context will be used for processing all requests and the server will respond with a list of GraphQL responses.

If the request is not a valid GraphQL format, the interface should return null and let the server specific code return a bad request status to the client. This is not the same as a GraphQL error or an exception thrown by the schema. Those types of errors should still parse the request and return a valid response with errors set via the GraphQLRequestHandler.

This interface should only be concerned with parsing the request, not about forwarding info to the context or execution. That is handled by the GraphQLContextFactory.