establish NostrEvent subclassing pattern with basic event kinds (#56)

* establish NostrEvent subclassing pattern with basic event kinds

Closes #48
Closes #49
Closes #50
Closes #51

* lint

* validate relay URLs

* add external interface for creating set metadata and recommend server events, plus tests

Sources/NostrSDK/EventCreating.swift

@@ -7,15 +7,51 @@
 
 import Foundation
 
+enum EventCreatingError: Error {
+    case invalidInput
+}
+
 public protocol EventCreating {}
 public extension EventCreating {
 
-    /// Creates a text note event (kind 1) and signs it with the provided ``Keypair``
+    /// Creates a set metadata event (kind 0) and signs it with the provided ``Keypair``.
+    /// - Parameters:
+    ///   - userMetadata: The metadata to set.
+    ///   - keypair: The Keypair to sign with.
+    /// - Returns: The signed set metadata event.
+    ///
+    /// See [NIP-01 - Basic Event Kinds](https://github.com/nostr-protocol/nips/blob/master/01.md#basic-event-kinds)
+    func setMetadataEvent(withUserMetadata userMetadata: UserMetadata, signedBy keypair: Keypair) throws -> SetMetadataEvent {
+        let metadataAsData = try JSONEncoder().encode(userMetadata)
+        guard let metadataAsString = String(data: metadataAsData, encoding: .utf8) else {
+            throw EventCreatingError.invalidInput
+        }
+        return try SetMetadataEvent(kind: .setMetadata, content: metadataAsString, signedBy: keypair)
+    }
+
+    /// Creates a text note event (kind 1) and signs it with the provided ``Keypair``.
+    /// - Parameters:
+    ///   - content: The content of the text note.
+    ///   - keypair: The Keypair to sign with.
+    /// - Returns: The signed text note event.
+    ///
+    /// See [NIP-01 - Basic Event Kinds](https://github.com/nostr-protocol/nips/blob/master/01.md#basic-event-kinds)
+    func textNote(withContent content: String, signedBy keypair: Keypair) throws -> TextNoteEvent {
+        try TextNoteEvent(kind: .textNote, content: content, signedBy: keypair)
+    }
+
+    /// Creates a recommend server event (kind 2) and signs it with the provided `Keypair``.`
     /// - Parameters:
-    ///   - content: The content of the text note
-    ///   - keypair: The Keypair to sign with
-    /// - Returns: The signed text note event
-    func textNote(withContent content: String, signedBy keypair: Keypair) throws -> NostrEvent {
-        try NostrEvent(kind: .textNote, content: content, signedBy: keypair)
+    ///   - relayURL: The URL of the relay, which must be a websocket URL.
+    ///   - keypair: The Keypair to sign with.
+    /// - Returns: The signed recommend server event.
+    ///
+    /// See [NIP-01 - Basic Event Kinds](https://github.com/nostr-protocol/nips/blob/master/01.md#basic-event-kinds)
+    func recommendServerEvent(withRelayURL relayURL: URL, signedBy keypair: Keypair) throws -> RecommendServerEvent {
+        let components = URLComponents(url: relayURL, resolvingAgainstBaseURL: false)
+        guard components?.scheme == "wss" || components?.scheme == "ws" else {
+            throw EventCreatingError.invalidInput
+        }
+        return try RecommendServerEvent(kind: .recommendServer, content: relayURL.absoluteString, signedBy: keypair)
     }
 }

Sources/NostrSDK/NostrEvent.swift → Sources/NostrSDK/Events/NostrEvent.swift

@@ -10,7 +10,7 @@ import Foundation
 /// A structure that describes a Nostr event.
 ///
 /// > Note: [NIP-01 Specification](https://github.com/nostr-protocol/nips/blob/master/01.md#events-and-signatures)
-public struct NostrEvent: Codable {
+public class NostrEvent: Codable {
 
     /// 32-byte, lowercase, hex-encoded sha256 of the serialized event data
     public let id: String

Sources/NostrSDK/Events/RecommendServerEvent.swift

@@ -0,0 +1,21 @@
+//
+//  RecommendServerEvent.swift
+//  
+//
+//  Created by Bryan Montz on 7/23/23.
+//
+
+import Foundation
+
+/// An event that contains a relay the event creator wants to recommend to its followers.
+///
+/// > Note: [NIP-01 Specification](https://github.com/nostr-protocol/nips/blob/b503f8a92b22be3037b8115fe3e644865a4fa155/01.md#basic-event-kinds)
+public final class RecommendServerEvent: NostrEvent {
+    public var relayURL: URL? {
+        let components = URLComponents(string: content)
+        guard components?.scheme == "wss" || components?.scheme == "ws" else {
+            return nil
+        }
+        return components?.url
+    }
+}

Sources/NostrSDK/Events/SetMetadataEvent.swift

@@ -0,0 +1,71 @@
+//
+//  SetMetadataEvent.swift
+//  
+//
+//  Created by Bryan Montz on 7/22/23.
+//
+
+import Foundation
+
+/// An object that describes a user.
+public struct UserMetadata: Codable {
+
+    /// The user's name.
+    public let name: String?
+
+    /// The user's description of themself.
+    public let about: String?
+
+    /// The user's website address.
+    public let website: URL?
+
+    /// The user's Nostr address.
+    ///
+    /// > Note: [NIP-05 Specification](https://github.com/nostr-protocol/nips/blob/master/05.md#nip-05).
+    public let nostrAddress: String?
+
+    /// A URL to retrieve the user's picture.
+    public let pictureURL: URL?
+
+    /// A URL to retrieve the user's banner image.
+    public let bannerPictureURL: URL?
+
+    enum CodingKeys: String, CodingKey {
+        case name, about, website
+        case nostrAddress = "nip05"
+        case pictureURL = "picture"
+        case bannerPictureURL = "banner"
+    }
+
+    public init(name: String?, about: String?, website: URL?, nostrAddress: String?, pictureURL: URL?, bannerPictureURL: URL?) {
+        self.name = name
+        self.about = about
+        self.website = website
+        self.nostrAddress = nostrAddress
+        self.pictureURL = pictureURL
+        self.bannerPictureURL = bannerPictureURL
+    }
+}
+
+/// An event that contains a user profile.
+/// 
+/// > Note: [NIP-01 Specification](https://github.com/nostr-protocol/nips/blob/b503f8a92b22be3037b8115fe3e644865a4fa155/01.md#basic-event-kinds)
+public final class SetMetadataEvent: NostrEvent {
+
+    /// A dictionary containing all of the properties in the `content` field of the ``NostrEvent``.
+    public var rawUserMetadata: [String: Any] {
+        guard let data = content.data(using: .utf8) else {
+            return [:]
+        }
+        let dict = try? JSONSerialization.jsonObject(with: data)
+        return dict as? [String: Any] ?? [:]
+    }
+
+    /// An object that contains decoded user properties from the `content` field of the ``NostrEvent``.
+    public var userMetadata: UserMetadata? {
+        guard let data = content.data(using: .utf8) else {
+            return nil
+        }
+        return try? JSONDecoder().decode(UserMetadata.self, from: data)
+    }
+}

Sources/NostrSDK/Events/TextNoteEvent.swift

@@ -0,0 +1,26 @@
+//
+//  TextNoteEvent.swift
+//  
+//
+//  Created by Bryan Montz on 7/23/23.
+//
+
+import Foundation
+
+/// An event that contains plaintext content.
+///
+/// > Note: [NIP-01 Specification](https://github.com/nostr-protocol/nips/blob/b503f8a92b22be3037b8115fe3e644865a4fa155/01.md#basic-event-kinds)
+public final class TextNoteEvent: NostrEvent {
+
+    /// Pubkeys mentioned in the note content.
+    public var mentionedPubkeys: [String] {
+        let pubkeyTags = tags.filter { $0.identifier == .pubkey }
+        return pubkeyTags.map { $0.contentIdentifier }
+    }
+
+    /// Events mentioned in the note content.
+    public var mentionedEventIds: [String] {
+        let eventTags = tags.filter { $0.identifier == .event }
+        return eventTags.map { $0.contentIdentifier }
+    }
+}

Sources/NostrSDK/RelayResponse.swift

@@ -7,6 +7,25 @@
 
 import Foundation
 
+/// A type used for decoding and mapping a kind number to a ``NostrEvent`` subclass.
+fileprivate struct EventKindMapper: Decodable {     // swiftlint:disable:this private_over_fileprivate
+    let kind: EventKind
+
+    enum CodingKeys: CodingKey {
+        case kind
+    }
+
+    /// The ``NostrEvent`` subclass associated with the kind.
+    var classForKind: NostrEvent.Type {
+        switch kind {
+        case .setMetadata:      return SetMetadataEvent.self
+        case .textNote:         return TextNoteEvent.self
+        case .recommendServer:  return RecommendServerEvent.self
+        default:                return NostrEvent.self
+        }
+    }
+}
+
 enum RelayResponse: Decodable {
 
     struct CountResponse: Codable {
@@ -35,7 +54,15 @@ enum RelayResponse: Decodable {
         switch responseType {
         case .event:
             let subscriptionId = try container.decode(String.self)
-            let event = try container.decode(NostrEvent.self)
+            let kindMapper = try container.decode(EventKindMapper.self)
+
+            // Since the decoding index in the container cannot be decremented, create a
+            // new container so we can use the class from the mapper.
+            var container2 = try decoder.unkeyedContainer()
+            _ = try? container2.decode(MessageType.self)
+            _ = try? container2.decode(String.self)
+            let event = try container2.decode(kindMapper.classForKind.self)
+
             self = .event(subscriptionId: subscriptionId, event: event)
         case .notice:
             let message = try container.decode(String.self)

Tests/NostrSDKTests/EventCreatingTests.swift

@@ -11,6 +11,26 @@ import XCTest
 
 final class EventCreatingTests: XCTestCase, EventCreating, EventVerifying {
 
+    func testCreateSetMetadataEvent() throws {
+        let meta = UserMetadata(name: "Nostr SDK Test",
+                                about: "I'm a test account. I'm used to test the Nostr SDK for Apple platforms.",
+                                website: URL(string: "https://github.com/nostr-sdk/nostr-sdk-ios")!,
+                                nostrAddress: "[email protected]",
+                                pictureURL: URL(string: "[email protected]"),
+                                bannerPictureURL: URL(string: "[email protected]")!)
+
+        let event = try setMetadataEvent(withUserMetadata: meta, signedBy: Keypair.test)
+
+        XCTAssertEqual(event.userMetadata?.name, "Nostr SDK Test")
+        XCTAssertEqual(event.userMetadata?.about, "I'm a test account. I'm used to test the Nostr SDK for Apple platforms.")
+        XCTAssertEqual(event.userMetadata?.website, URL(string: "https://github.com/nostr-sdk/nostr-sdk-ios"))
+        XCTAssertEqual(event.userMetadata?.nostrAddress, "[email protected]")
+        XCTAssertEqual(event.userMetadata?.pictureURL, URL(string: "[email protected]"))
+        XCTAssertEqual(event.userMetadata?.bannerPictureURL, URL(string: "[email protected]"))
+
+        try verifyEvent(event)
+    }
+
     func testCreateSignedTextNote() throws {
         let note = try textNote(withContent: "Hello world!",
                                 signedBy: Keypair.test)
@@ -22,4 +42,23 @@ final class EventCreatingTests: XCTestCase, EventCreating, EventVerifying {
 
         try verifyEvent(note)
     }
+
+    func testCreateRecommendServerEvent() throws {
+        let inputURL = URL(string: "wss://relay.test")!
+        let event = try recommendServerEvent(withRelayURL: inputURL,
+                                             signedBy: Keypair.test)
+
+        XCTAssertEqual(event.kind, .recommendServer)
+        XCTAssertEqual(event.relayURL, inputURL)
+        XCTAssertEqual(event.pubkey, Keypair.test.publicKey.hex)
+        XCTAssertEqual(event.tags, [])
+
+        try verifyEvent(event)
+    }
+
+    func testRecommendServerEventFailsWithNonWebsocketURL() throws {
+        let inputURL = URL(string: "https://not-a-socket.com")!
+        XCTAssertThrowsError(try recommendServerEvent(withRelayURL: inputURL,
+                                                      signedBy: Keypair.test))
+    }
 }

Tests/NostrSDKTests/EventDecodingTests.swift

@@ -12,7 +12,7 @@ final class EventDecodingTests: XCTestCase, FixtureLoading {
 
     func testDecodeSetMetadata() throws {
 
-        let event: NostrEvent = try decodeFixture(filename: "set_metadata")
+        let event: SetMetadataEvent = try decodeFixture(filename: "set_metadata")
 
         XCTAssertEqual(event.id, "d214c914b0ab49ec919fa5f60fabf746f421e432d96f941bd2573e4d22e36b51")
         XCTAssertEqual(event.pubkey, "00000000827ffaa94bfea288c3dfce4422c794fbb96625b6b31e9049f729d700")
@@ -21,11 +21,28 @@ final class EventDecodingTests: XCTestCase, FixtureLoading {
         XCTAssertEqual(event.tags, [])
         XCTAssertTrue(event.content.hasPrefix("{\"banner\":\"https://nostr.build/i/nostr.build"))
         XCTAssertEqual(event.signature, "7bb7f031fbf41f49eeb44fdfb061bc8d143197d33fae8d29b017709adf2b17c76e78ccb2ee128ee93d0661cad4c626a747d48a178745c94944a693ff31ea7619")
+
+        // access metadata properties from raw dictionary
+        XCTAssertEqual(event.rawUserMetadata["name"] as? String, "cameri")
+        XCTAssertEqual(event.rawUserMetadata["about"] as? String, "@HodlWithLedn. All opinions are my own.\nBitcoiner class of 2021. Core Nostr Developer. Author of Nostream. Professional Relay Operator.")
+        XCTAssertEqual(event.rawUserMetadata["website"] as? String, "https://primal.net/cameri")
+        XCTAssertEqual(event.rawUserMetadata["nip05"] as? String, "[email protected]")
+        XCTAssertEqual(event.rawUserMetadata["picture"] as? String, "https://nostr.build/i/9396d5cd901304726883aea7363543f121e1d53964dd3149cadecd802608aebe.jpg")
+        XCTAssertEqual(event.rawUserMetadata["banner"] as? String, "https://nostr.build/i/nostr.build_90a51a2e50c9f42288260d01b3a2a4a1c7a9df085423abad7809e76429da7cdc.gif")
+
+        // access metadata properties from decoded object
+        let userMetadata = try XCTUnwrap(event.userMetadata)
+        XCTAssertEqual(userMetadata.name, "cameri")
+        XCTAssertEqual(userMetadata.about, "@HodlWithLedn. All opinions are my own.\nBitcoiner class of 2021. Core Nostr Developer. Author of Nostream. Professional Relay Operator.")
+        XCTAssertEqual(userMetadata.website, URL(string: "https://primal.net/cameri"))
+        XCTAssertEqual(userMetadata.nostrAddress, "[email protected]")
+        XCTAssertEqual(userMetadata.pictureURL, URL(string: "https://nostr.build/i/9396d5cd901304726883aea7363543f121e1d53964dd3149cadecd802608aebe.jpg"))
+        XCTAssertEqual(userMetadata.bannerPictureURL, URL(string: "https://nostr.build/i/nostr.build_90a51a2e50c9f42288260d01b3a2a4a1c7a9df085423abad7809e76429da7cdc.gif"))
     }
 
     func testDecodeTextNote() throws {
 
-        let event: NostrEvent = try decodeFixture(filename: "text_note")
+        let event: TextNoteEvent = try decodeFixture(filename: "text_note")
 
         XCTAssertEqual(event.id, "fa5ed84fc8eeb959fd39ad8e48388cfc33075991ef8e50064cfcecfd918bb91b")
         XCTAssertEqual(event.pubkey, "82341f882b6eabcd2ba7f1ef90aad961cf074af15b9ef44a09f9d2a8fbfbe6a2")
@@ -39,6 +56,24 @@ final class EventDecodingTests: XCTestCase, FixtureLoading {
         XCTAssertEqual(event.tags, expectedTags)
         XCTAssertEqual(event.content, "I think it stays persistent on your profile, but interface setting doesn’t persist. Bug.  ")
         XCTAssertEqual(event.signature, "96e6667348b2b1fc5f6e73e68fb1605f571ad044077dda62a35c15eb8290f2c4559935db461f8466df3dcf39bc2e11984c5344f65aabee4520dd6653d74cdc09")
+
+        XCTAssertEqual(event.mentionedPubkeys, ["f8e6c64342f1e052480630e27e1016dce35fc3a614e60434fef4aa2503328ca9"])
+        XCTAssertEqual(event.mentionedEventIds, ["93930d65435d49db723499335473920795e7f13c45600dcfad922135cf44bd63"])
+    }
+
+    func testDecodeRecommendServer() throws {
+
+        let event: RecommendServerEvent = try decodeFixture(filename: "recommend_server")
+
+        XCTAssertEqual(event.id, "test-id")
+        XCTAssertEqual(event.pubkey, "test-pubkey")
+        XCTAssertEqual(event.createdAt, 1683799330)
+        XCTAssertEqual(event.kind, .recommendServer)
+        XCTAssertEqual(event.tags, [])
+        XCTAssertEqual(event.content, "wss://nostr.relay")
+        XCTAssertEqual(event.signature, "test-signature")
+
+        XCTAssertEqual(event.relayURL, URL(string: "wss://nostr.relay"))
     }
 
     func testDecodeContactList() throws {

Tests/NostrSDKTests/Fixtures/recommend_server.json

@@ -0,0 +1,9 @@
+{
+  "content": "wss://nostr.relay",
+  "created_at": 1683799330,
+  "id": "test-id",
+  "kind": 2,
+  "pubkey": "test-pubkey",
+  "sig": "test-signature",
+  "tags": []
+}