Post JSON instead of URL queries for oauth flow

Packages/Network/Sources/Network/Endpoint/Oauth.swift

@@ -14,6 +14,24 @@ public enum Oauth: Endpoint {
     }
   }
   
+  public var jsonValue: Encodable? {
+    switch self {
+    case let .token(code, clientId, clientSecret):
+      return TokenData(clientId: clientId, clientSecret: clientSecret, code: code)
+    default:
+      return nil
+    }
+  }
+  
+  public struct TokenData: Encodable {
+    public let grantType = "authorization_code"
+    public let clientId: String
+    public let clientSecret: String
+    public let redirectUri = AppInfo.scheme
+    public let code: String
+    public let scope = AppInfo.scopes
+  }
+
   public func queryItems() -> [URLQueryItem]? {
     switch self {
     case let .authorize(clientId):
@@ -23,15 +41,8 @@ public enum Oauth: Endpoint {
         .init(name: "redirect_uri", value: AppInfo.scheme),
         .init(name: "scope", value: AppInfo.scopes),
       ]
-    case let .token(code, clientId, clientSecret):
+    default:
-      return [
+      return nil
-        .init(name: "grant_type", value: "authorization_code"),
-        .init(name: "client_id", value: clientId),
-        .init(name: "client_secret", value: clientSecret),
-        .init(name: "redirect_uri", value: AppInfo.scheme),
-        .init(name: "code", value: code),
-        .init(name: "scope", value: AppInfo.scopes),
-      ]
     }
   }
 }