Merge pull request #3 from loopedresolve/main

Refactor chain specification implementation and update tests

Package.swift

@@ -13,7 +13,7 @@ let package = Package(
             targets: ["SmoldotSwift"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/finsig/json-rpc2", from: "0.1.0")
+        .package(url: "https://github.com/finsig/json-rpc2", from: "0.1.1")
     ],
     targets: [
         .target(
@@ -22,13 +22,8 @@ let package = Package(
                 "CSmoldot",
                 .product(name: "JSONRPC2", package: "json-rpc2"),
             ],
-            path: "Sources/SmoldotSwift",
-            resources: [
-                .process("Resources/polkadot.json"),
-                .process("Resources/kusama.json"),
-                .process("Resources/rococo.json"),
-                .process("Resources/westend.json")]
-            ),
+            path: "Sources/SmoldotSwift"
+        ),
         .target(
             name: "CSmoldot",
             dependencies: ["smoldot"],
@@ -46,6 +41,13 @@ let package = Package(
 
         .testTarget(
             name: "SmoldotSwiftTests",
-            dependencies: ["SmoldotSwift"]),
+            dependencies: ["SmoldotSwift"],
+            resources: [
+                .process("Resources/polkadot.json"),
+                .process("Resources/kusama.json"),
+                .process("Resources/rococo.json"),
+                .process("Resources/westend.json")]
+        ),
+
     ]
 )

README.md

@@ -13,11 +13,15 @@ Add the package declaration to your project's manifest dependencies array:
 
 ## Usage
 
-Initialize a Chain from a specification. A Chain Specification is a JSON Object that describes a Polkadot-based blockchain network. Chain Specifications for Polkadot, Kusama, Rococo, and Westend are provided.
+A Chain Specification file must be provided to initialize a chain. A Chain Specification is a JSON Object that describes a Polkadot-based blockchain network. 
 
+*Example Chain Specification JSON files for Polkadot, Kusama, Rococo, and Westend can be copied for use from [/Tests/SmoldotSwiftTests/Resources](https://github.com/loopedresolve/smoldot-swift/tree/main/Tests/SmoldotSwiftTests/Resources).*
+
+
+Initialize a chain from a specification file:
 
 ```swift
-var chain = Chain(specification: .polkadot)
+var chain = Chain(specificationFile: {Resource file URL})
 ```
 
 Add the chain to the client to connect to the network:

Sources/SmoldotSwift/Chain+Specification.swift

@@ -17,12 +17,16 @@
 import Foundation
 
 extension Chain.Specification {
-
+
+    /// Chain name as defined in the specification.
     public var name: String {
+        precondition(self["name"] != nil, "Chain Specification is missing required key `name`")
         return self["name"] as! String
     }
 
+    /// Chain identifier as defined in the specification.
     var id: String {
+        precondition(self["id"] != nil, "Chain Specification is missing required key `id`")
         return self["id"] as! String
     }
 }

Sources/SmoldotSwift/Chain.swift

@@ -36,16 +36,31 @@ public final class Chain: Hashable {
     ///  connects to, the other nodes that it initially communicates with, and the initial state that nodes
     ///  must agree on to produce blocks.
     ///
+    ///  A typelias is used rather than defining an explicit type so that Foundation `JSONSerialization` 
+    ///  can be used to convert the JSON into a `Dictionary` type representation of the object with key
+    ///  values  of type `Any`.
+    ///
+    ///  - Important:
+    ///  Niether the validity of the Chain Specification JSON nor its conformance to the ChainSpec trait
+    ///  is handled by Swift and will produce fatal error information in the Rust environment logger.
+    ///
     public typealias Specification = JSONObject
 
-    ///  Creates a Chain from the provided Chain Specification.
+    ///  Creates a Chain from the a Chain Specification JSON object.
     ///
     ///  See ``Specification`` for more information.
     ///
     public init(specification: Specification) {
         self.specification = specification
     }
 
+    ///  Creates a Chain from a Chain Specification JSON file.
+    public convenience init(specificationFile url: URL) throws {
+        let data = try Data(contentsOf: url)
+        let specification = try JSONSerialization.jsonObject(with: data) as! Specification
+        self.init(specification: specification)
+    }
+
     public func hash(into hasher: inout Hasher) {
         hasher.combine(specification.id)
     }

Sources/SmoldotSwift/Client.swift

@@ -52,11 +52,9 @@ public final class Client {
     ///
     public func add(chain: inout Chain) throws {
         guard !chain.isValid else {
-            throw ClientError(message: "Chain has already been added.")
-        }
-        guard let data = try? JSONSerialization.data(withJSONObject: chain.specification) else {
-            throw ClientError(message: "Invalid JSON object.") /// note: checks for validity only, does not check Chain Specification JSON object correctness. intentional.
+            throw ClientError.chainHasAlreadyBeenAdded
         }
+        let data = try JSONSerialization.data(withJSONObject: chain.specification)
         let string = String(data: data, encoding: .utf8)
         chain.id = Chain.Id( smoldot_add_chain(string) )
     }
@@ -65,7 +63,7 @@ public final class Client {
     ///
     public func remove(chain: inout Chain) throws {
         guard let id = chain.id else {
-            throw ClientError(message: "Chain not found in client.")
+            throw ClientError.chainNotFound
         }
         smoldot_remove_chain(id)
     }
@@ -79,12 +77,12 @@ public final class Client {
     ///
     public func send(request: JSONRPC2Request, to chain: Chain) throws {
         guard let id = chain.id else {
-            throw ClientError(message: "Chain not found in client.")
+            throw ClientError.chainNotFound
         }
         let encoder = JSONEncoder()
         let data = try encoder.encode(request)
         guard let string = String(data: data, encoding: .utf8) else {
-            throw ClientError(message: "Error encoding request.")
+            throw ClientError.errorEncodingRequest
         }
         smoldot_json_rpc_request(id, string)
     }
@@ -104,7 +102,7 @@ public final class Client {
             Task.detached {
                 while (true) {
                     guard let id = chain.id else {
-                        throw ClientError(message: "Chain not found in client.")
+                        throw ClientError.chainNotFound
                     }
                     guard let cString = smoldot_wait_next_json_rpc_response(id) else {
                         break
@@ -128,7 +126,7 @@ public final class Client {
     ///
     public func response(from chain: Chain) async throws -> String? {
         guard let id = chain.id else {
-            throw ClientError(message: "Chain not found in client.")
+            throw ClientError.chainNotFound
         }
         guard let cString = smoldot_wait_next_json_rpc_response(id) else {
            return nil

Sources/SmoldotSwift/ClientError.swift

@@ -16,10 +16,8 @@
 
 import Foundation
 
-public struct ClientError: Error, CustomStringConvertible {
-    let message: String
-
-    public var description: String {
-        return "[error: \(message)]"
-    }
+public enum ClientError: Error {
+    case chainHasAlreadyBeenAdded
+    case chainNotFound
+    case errorEncodingRequest
 }

Tests/SmoldotSwiftTests/SmoldotSwiftTests.swift

@@ -8,114 +8,76 @@ final class SmoldotSwiftTests: XCTestCase {
     var chain: Chain!
 
     override func setUp() async throws {
-        chain = Chain(specification: .polkadot)
+        ///
+        /// Chain specification file to use for testing. If adding a file, also explicitly declare the resource for
+        /// the test target in the package manifest.
+        ///
+        let url = Bundle.module.url(forResource: "polkadot", withExtension: "json")!
+        //let url = Bundle.module.url(forResource: "kusama", withExtension: "json")!
+        //let url = Bundle.module.url(forResource: "rococo", withExtension: "json")!
+        //let url = Bundle.module.url(forResource: "westend", withExtension: "json")!
+
+        chain = try Chain(specificationFile: url)
+
+        XCTAssertFalse( chain.isValid )
     }
 
     func testAddChain() throws {
-        try Client.shared.add(chain: &chain)
+        /// Add the chain to the client
+        XCTAssertNoThrow( try Client.shared.add(chain: &chain) )
 
         XCTAssertTrue( chain.isValid )
     }
 
     func testAddChainAlreadyAdded() throws {
-        try Client.shared.add(chain: &chain)
-
-        XCTAssertThrowsError( try Client.shared.add(chain: &chain) )
-    }
-
-    /*
-    func testAddChainRemoveChainMemoryPerformance() async throws {
-        self.measure(metrics: [XCTMemoryMetric()]) {
-            let exp = expectation(description: "Finished")
-            Task {
-                try Client.shared.add(chain: &chain)
-                //try await Task.sleep(nanoseconds: 1_000_000_000 * 30) // sleep
-                try Client.shared.remove(chain: &chain)
-                //try await Task.sleep(nanoseconds: 1_000_000_000 * 30) // sleep
-                exp.fulfill()
-            }
-            wait(for: [exp], timeout: 1_000_000_000 * 30)
+        /// Add the chain to the client
+        XCTAssertNoThrow( try Client.shared.add(chain: &chain) )
+
+        /// Add the chain to the client again
+        XCTAssertThrowsError( try Client.shared.add(chain: &chain) ) { error in
+            XCTAssertTrue( error as! ClientError == ClientError.chainHasAlreadyBeenAdded )
         }
     }
-    */
 
     func testRemoveChain() throws {
-        try Client.shared.add(chain: &chain)
-        try Client.shared.remove(chain: &chain)
+        /// Add the chain to the client
+        XCTAssertNoThrow( try Client.shared.add(chain: &chain) )
+        XCTAssertTrue( chain.isValid )
 
+        /// Remove the chain from the client
+        XCTAssertNoThrow( try Client.shared.remove(chain: &chain) )
         XCTAssertFalse( chain.isValid )
     }
 
     func testRemoveChainNotAdded() throws {
-        XCTAssertThrowsError( try Client.shared.remove(chain: &chain) )
-    }
-
-    func testJSONRPCRequestResponse() async throws {
-        try Client.shared.add(chain: &chain)
-
-        let request = try JSONRPC2Request(string: "{\"id\":1,\"jsonrpc\":\"2.0\",\"method\":\"system_chain\",\"params\":[]}")
-
-        XCTAssertNoThrow( try Client.shared.send(request: request, to: chain) )
-
-        let responseData = try await Client.shared.response(from: chain)?.data(using: .utf8)
-
-        XCTAssertNotNil(responseData)
-
-        let response = try JSONDecoder().decode(Response.self, from: responseData!)
-
-        XCTAssertNotNil(request.identifier)
-
-        XCTAssertEqual(response.identifier, request.identifier!)
-
-        switch response.result {
-        case .success(let json):
-            XCTAssertEqual(json.description, "Polkadot")
-        case .failure(_):
-            XCTFail()
+        /// Try to remove the chain when it has not been added to the client.
+        XCTAssertThrowsError( try Client.shared.remove(chain: &chain) ) { error in
+            XCTAssertTrue( error as! ClientError == ClientError.chainNotFound )
         }
     }
 
     func testJSONRPC2RequestInvalidJSON() async throws {
-
-        XCTAssertThrowsError(try JSONRPC2Request(string: "invalid json") )
+        /// Try to build a JSON-RPC2 request from a non-JSON value.
+        XCTAssertThrowsError( try JSONRPC2Request(string: "invalid json") ) { error in
+            XCTAssertTrue( (error as! JSONRPC2Error).code == JSONRPC2Error.Code.invalidRequest )
+        }
     }
 
     func testJSONRPC2RequestInvalidJSONRPCVersion() async throws {
-
-        XCTAssertThrowsError(try JSONRPC2Request(string: "{\"id\":1,\"jsonrpc\":\"1.0\",\"method\":\"system_chain\",\"params\":[]}") )
+        /// Try to build a JSON-RPC 1.0 request.
+        XCTAssertThrowsError( try JSONRPC2Request(string: "{\"id\":1,\"jsonrpc\":\"1.0\",\"method\":\"system_chain\",\"params\":[]}") ) { error in
+            XCTAssertTrue( (error as! JSONRPC2Error).code == JSONRPC2Error.Code.invalidRequest )
+        }
     }
 
     func testJSONRPC2RequestChainNotAdded() async throws {
-        let chain = Chain(specification: .kusama)
-
-        let request = try JSONRPC2Request(string: "{\"id\":1,\"jsonrpc\":\"2.0\",\"method\":\"system_chain\",\"params\":[]}")
+        /// Try to send a request to a chain without first adding it to the client.
+        let request = try? JSONRPC2Request(string: "{\"id\":1,\"jsonrpc\":\"2.0\",\"method\":\"system_chain\",\"params\":[]}")
+        XCTAssertNotNil(request)
 
-        XCTAssertThrowsError( try Client.shared.send(request: request, to: chain) )
-    }
-
-}
-
-
-fileprivate extension Chain.Specification {
-
-    static var polkadot: JSONObject {
-        return jsonObject(resourceName: "polkadot")
-    }
-
-    static var kusama: JSONObject {
-        return jsonObject(resourceName: "kusama")
-    }
-
-    private static func jsonObject(resourceName name: String) -> JSONObject {
-        guard let url = Bundle.module.url(forResource: name, withExtension: "json") else {
-            fatalError()
-        }
-        guard let data = try? Data(contentsOf: url) else {
-            fatalError()
+        XCTAssertThrowsError( try Client.shared.send(request: request!, to: chain) ) { error in
+            XCTAssertTrue( error as! ClientError == ClientError.chainNotFound )
         }
-        guard let jsonObject = try? JSONSerialization.jsonObject(with: data) as? JSONObject else {
-            fatalError()
-        }
-        return jsonObject
     }
+
 }