Implemented APNs Support in the API

FirebaseAdmin/FirebaseAdmin/Messaging/AndroidNotification.cs

@@ -135,21 +135,15 @@ internal AndroidNotification CopyAndValidate()
             };
             if (copy.Color != null && !Regex.Match(copy.Color, "^#[0-9a-fA-F]{6}$").Success)
             {
-                throw new ArgumentException("Color must be in the form #RRGGBB");
+                throw new ArgumentException("Color must be in the form #RRGGBB.");
             }
-            if (copy.TitleLocArgs != null && copy.TitleLocArgs.Any())
+            if (copy.TitleLocArgs?.Any() == true && string.IsNullOrEmpty(copy.TitleLocKey))
             {
-                if (string.IsNullOrEmpty(copy.TitleLocKey))
-                {
-                    throw new ArgumentException("TitleLocKey is required when specifying TitleLocArgs");
-                }
+                throw new ArgumentException("TitleLocKey is required when specifying TitleLocArgs.");
             }
-            if (copy.BodyLocArgs != null && copy.BodyLocArgs.Any())
+            if (copy.BodyLocArgs?.Any() == true && string.IsNullOrEmpty(copy.BodyLocKey))
             {
-                if (string.IsNullOrEmpty(copy.BodyLocKey))
-                {
-                    throw new ArgumentException("BodyLocKey is required when specifying BodyLocArgs");
-                }
+                throw new ArgumentException("BodyLocKey is required when specifying BodyLocArgs.");
             }
             return copy;
         }

FirebaseAdmin/FirebaseAdmin/Messaging/ApnsConfig.cs

@@ -0,0 +1,135 @@
+// Copyright 2018, Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Google.Apis.Json;
+using Newtonsoft.Json;
+
+namespace FirebaseAdmin.Messaging
+{
+    /// <summary>
+    /// Represents the APNS-specific options that can be included in a <see cref="Message"/>. Refer
+    /// to <see href="https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/APNSOverview.html">
+    /// APNs documentation</see> for various headers and payload fields supported by APNS.
+    /// </summary>
+    public sealed class ApnsConfig
+    {
+        private ApnsPayload _payload = new ApnsPayload();
+
+        /// <summary>
+        /// A collection of APNs headers.
+        /// </summary>
+        [JsonProperty("headers")]
+        public IReadOnlyDictionary<string, string> Headers { get; set; }
+
+        /// <summary>
+        /// The <code>aps</code> dictionary to be included in the APNs payload.
+        /// </summary>
+        [JsonIgnore]
+        public Aps Aps
+        {
+            get
+            {
+                return Payload.Aps;
+            }
+            set
+            {
+                Payload.Aps = value;
+            }
+        }
+
+        /// <summary>
+        /// APNs payload as accepted by the FCM backend servers.
+        /// </summary>
+        [JsonProperty("payload")]
+        private ApnsPayload Payload
+        {
+            get
+            {
+                if (_payload.Aps != null && _payload.CustomData?.ContainsKey("aps") == true)
+                {
+                    throw new ArgumentException("Multiple specifications for ApnsConfig key: aps");
+                }
+                return _payload;
+            }
+            set
+            {
+                _payload = value;
+            }
+        }
+
+        /// <summary>
+        /// A collection of arbitrary key-value data to be included in the APNs payload.
+        /// </summary>
+        [JsonIgnore]
+        public IDictionary<string, object> CustomData
+        {
+            get
+            {
+                return Payload.CustomData;
+            }
+            set
+            {
+                Payload.CustomData = value;
+            }
+        }
+
+        /// <summary>
+        /// Copies this APNs config, and validates the content of it to ensure that it can be
+        /// serialized into the JSON format expected by the FCM service.
+        /// </summary>
+        internal ApnsConfig CopyAndValidate()
+        {
+            var copy = new ApnsConfig()
+            {
+                Headers = this.Headers?.Copy(),
+                Payload = this.Payload.CopyAndValidate(),
+            };
+            return copy;
+        }
+    }
+
+    /// <summary>
+    /// The APNs payload object as expected by the FCM backend service.
+    /// </summary>
+    internal sealed class ApnsPayload
+    {
+        [JsonProperty("aps")]
+        internal Aps Aps { get; set; }
+
+        [JsonExtensionData]
+        internal IDictionary<string, object> CustomData { get; set; }
+
+        /// <summary>
+        /// Copies this APNs payload, and validates the content of it to ensure that it can be
+        /// serialized into the JSON format expected by the FCM service.
+        /// </summary>
+        internal ApnsPayload CopyAndValidate()
+        {
+            var copy = new ApnsPayload()
+            {
+                CustomData = this.CustomData?.ToDictionary(e => e.Key, e => e.Value),
+            };
+            var aps = this.Aps;
+            if (aps == null && copy.CustomData?.ContainsKey("aps") == false)
+            {
+                throw new ArgumentException("Aps dictionary is required in ApnsConfig");
+            }
+            copy.Aps = aps?.CopyAndValidate();
+            return copy;
+        }
+    }
+}