JSONRPCKit

JSONRPCKit is a type-safe JSON-RPC 2.0 library purely written in Swift.

// Generating request JSON
let batchFactory = BatchFactory(version: "2.0", idGenerator: NumberIdGenerator())
let request = Subtract(minuend: 42, subtrahend: 23)
let batch = batchFactory.create(request)
batch.requestObject // ["jsonrpc": "2.0", "method": "subtract", "params": [42, 23], "id": 1]

// Parsing response JSON
let responseObject: Any = ["jsonrpc": "2.0", "result": 19, "id": 1]
let response = try! batch.responses(from: responseObject)
response // 19 (type of response is inferred from SubtractRequest.Response)

Requirements

Swift 4.0 / Xcode 9.0 or later
- If you use Swift 3.1 (Xcode 8.3), you can use 2.0.3 instead.
iOS 8.0 or later
macOS 10.9 or later
watchOS 2.0 or later
tvOS 9.0 or later
Linux is also supported

Basic usage

Define request type
Generate request JSON
Parse response JSON

Defining request type

First of all, define a request type that conforms to Request.

struct Subtract: JSONRPCKit.Request {
    typealias Response = Int

    let minuend: Int
    let subtrahend: Int

    var method: String {
        return "subtract"
    }

    var parameters: Any? {
        return [minuend, subtrahend]
    }

    func response(from resultObject: Any) throws -> Response {
        if let response = resultObject as? Response {
            return response
        } else {
            throw CastError(actualValue: resultObject, expectedType: Response.self)
        }
    }
}

Generating request JSON

To generate request JSON, pass Request instances to BatchFactory instance, which has common JSON-RPC version and identifier generator. When BatchFactory instance receives request(s), it generates identifier(s) for the request(s) and request JSON by combining id, version, method and parameters.

let batchFactory = BatchFactory(version: "2.0", idGenerator: NumberIdGenerator())
let request1 = Subtract(minuend: 42, subtrahend: 23)
let request2 = Subtract(minuend: 23, subtrahend: 42)
let batch = batchFactory.create(request1, request2)

The request JSON is available in batch.requestObject. It looks like below:

[
  {
    "method" : "subtract",
    "jsonrpc" : "2.0",
    "id" : 1,
    "params" : [
      42,
      23
    ]
  },
  {
    "method" : "subtract",
    "jsonrpc" : "2.0",
    "id" : 2,
    "params" : [
      23,
      42
    ]
  }
]

Parsing response JSON

Suppose that following JSON is returned from server:

[
  {
    "result" : 19,
    "jsonrpc" : "2.0",
    "id" : 1,
    "status" : 0
  },
  {
    "result" : -19,
    "jsonrpc" : "2.0",
    "id" : 2,
    "status" : 0
  }
]

To parse response object, execute responses(from:) of Batch instance. When responses(from:) is called, Batch finds corresponding response object by comparing request id and response id. After it find the response object, it executes responses(from:) of Response to get Request.Response from the response object.

let responseObject = ...
let (response1, response2) = try! batch.responses(from: responseObject)
print(response1) // 19
print(response2) // -19

JSON-RPC over HTTP by APIKit

APIKit is a type-safe networking abstraction layer.

Defining HTTP request type

APIKit also has RequestType that represents HTTP request.

import APIKit

struct MyServiceRequest<Batch: JSONRPCKit.Batch>: APIKit.Request {
    let batch: Batch

    typealias Response = Batch.Responses

    var baseURL: URL {
        return URL(string: "https://api.example.com/")!
    }

    var method: HTTPMethod {
        return .post
    }

    var path: String {
        return "/"
    }

    var parameters: Any? {
        return batch.requestObject
    }

    func response(from object: Any, urlResponse: HTTPURLResponse) throws -> Response {
        return try batch.responses(from: object)
    }
}

Sending HTTP/HTTPS request

let batchFactory = BatchFactory(version: "2.0", idGenerator: NumberIdGenerator())
let request1 = Subtract(minuend: 42, subtrahend: 23)
let request2 = Subtract(minuend: 23, subtrahend: 42)
let batch = batchFactory.create(request1, request2)
let httpRequest = MyServiceRequest(batch: batch)

Session.sendRequest(httpRequest) { result in
    switch result {
    case .Success(let response1, let response2):
        print(response1.count) // CountCharactersResponse
        print(response2.count) // CountCharactersResponse

    case .Failure(let error):
        print(error)
    }
}

License

JSONRPCKit is released under the MIT License.

bricklife/JSONRPCKit

bricklife

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