feat: add Mastodon instance api

MastodonSDK.xctestplan

@@ -32,6 +32,7 @@
     {
       "skippedTests" : [
         "MastodonSDKTests\/testCreateAnAnpplication()",
+        "MastodonSDKTests\/testHomeTimeline()",
         "MastodonSDKTests\/testVerifyAppCredentials()"
       ],
       "target" : {

MastodonSDK/Sources/MastodonSDK/API/Mastodon+API+Instance.swift

@@ -0,0 +1,46 @@
+//
+//  Mastodon+API+Instance.swift
+//  
+//
+//  Created by MainasuK Cirno on 2021-2-5.
+//
+
+import Foundation
+import Combine
+
+extension Mastodon.API.Instance {
+
+    static func instanceEndpointURL(domain: String) -> URL {
+        return Mastodon.API.endpointURL(domain: domain).appendingPathComponent("instance")
+    }
+    
+    /// Information about the server
+    ///
+    /// - Since: 1.0.0
+    /// - Version: 3.3.0
+    /// # Last Update
+    ///   2021/2/5
+    /// # Reference
+    ///   [Document](https://docs.joinmastodon.org/methods/instance/)
+    /// - Parameters:
+    ///   - session: `URLSession`
+    ///   - domain: Mastodon instance domain. e.g. "example.com"
+    /// - Returns: `AnyPublisher` contains `Instance` nested in the response
+    public static func instance(
+        session: URLSession,
+        domain: String
+    ) -> AnyPublisher<Mastodon.Response.Content<Mastodon.Entity.Instance>, Error>  {
+        let request = Mastodon.API.get(
+            url: instanceEndpointURL(domain: domain),
+            query: nil,
+            authorization: nil
+        )
+        return session.dataTaskPublisher(for: request)
+            .tryMap { data, response in
+                let value = try Mastodon.API.decode(type: Mastodon.Entity.Instance.self, from: data, response: response)
+                return Mastodon.Response.Content(value: value, response: response)
+            }
+            .eraseToAnyPublisher()
+    }
+    
+}

MastodonSDK/Sources/MastodonSDK/API/Mastodon+API.swift

@@ -84,6 +84,7 @@ extension Mastodon.API {
 extension Mastodon.API {
     public enum Account { }
     public enum App { }
+    public enum Instance { }
     public enum OAuth { }
     public enum Timeline { }
 }

MastodonSDK/Sources/MastodonSDK/Entity/Mastodon+Entity+Instance.swift

@@ -13,7 +13,7 @@ extension Mastodon.Entity {
     /// - Since: 1.1.0
     /// - Version: 3.3.0
     /// # Last Update
-    ///   2021/1/28
+    ///   2021/2/5
     /// # Reference
     ///  [Document](https://docs.joinmastodon.org/entities/instance/)
     public struct Instance: Codable {
@@ -28,7 +28,7 @@ extension Mastodon.Entity {
         public let registrations: Bool?
         public let approvalRequired: Bool?
         public let invitesEnabled: Bool?
-        public let urls: [InstanceURL]?
+        public let urls: InstanceURL?
         public let statistics: Statistics?
         
         public let thumbnail: String?

MastodonSDK/Tests/MastodonSDKTests/API/MastodonSDK+API+Instance.swift

@@ -0,0 +1,41 @@
+//
+//  MastodonSDK+API+Instance.swift
+//  
+//
+//  Created by MainasuK Cirno on 2021-2-5.
+//
+
+import os.log
+import XCTest
+import Combine
+@testable import MastodonSDK
+
+extension MastodonSDKTests {
+    
+    func testInstance() throws {
+        try _testInstance(domain: domain)
+    }
+    
+    func _testInstance(domain: String) throws {
+        let theExpectation = expectation(description: "Fetch Instance Infomation")
+        
+        Mastodon.API.Instance.instance(session: session, domain: domain)
+            .receive(on: DispatchQueue.main)
+            .sink { completion in
+                switch completion {
+                case .failure(let error):
+                    XCTFail(error.localizedDescription)
+                case .finished:
+                    break
+                }
+            } receiveValue: { response in
+                XCTAssertEqual(response.value.uri, domain)
+                print(response.value)
+                theExpectation.fulfill()
+            }
+            .store(in: &disposeBag)
+
+        wait(for: [theExpectation], timeout: 10.0)
+    }
+
+}