Add per-request header support to Rest requests (#2261)

* add support for per-request headers

* remove unnecessary usings

src/Discord.Net.Core/Net/Rest/IRestClient.cs

@@ -30,9 +30,13 @@ namespace Discord.Net.Rest
         /// <param name="cancelToken">The cancellation token used to cancel the task.</param>
         /// <param name="headerOnly">Indicates whether to send the header only.</param>
         /// <param name="reason">The audit log reason.</param>
+        /// <param name="requestHeaders">Additional headers to be sent with the request.</param>
         /// <returns></returns>
-        Task<RestResponse> SendAsync(string method, string endpoint, CancellationToken cancelToken, bool headerOnly = false, string reason = null);
-        Task<RestResponse> SendAsync(string method, string endpoint, string json, CancellationToken cancelToken, bool headerOnly = false, string reason = null);
-        Task<RestResponse> SendAsync(string method, string endpoint, IReadOnlyDictionary<string, object> multipartParams, CancellationToken cancelToken, bool headerOnly = false, string reason = null);
+        Task<RestResponse> SendAsync(string method, string endpoint, CancellationToken cancelToken, bool headerOnly = false, string reason = null,
+            IEnumerable<KeyValuePair<string, IEnumerable<string>>> requestHeaders = null);
+        Task<RestResponse> SendAsync(string method, string endpoint, string json, CancellationToken cancelToken, bool headerOnly = false, string reason = null,
+            IEnumerable<KeyValuePair<string, IEnumerable<string>>> requestHeaders = null);
+        Task<RestResponse> SendAsync(string method, string endpoint, IReadOnlyDictionary<string, object> multipartParams, CancellationToken cancelToken, bool headerOnly = false, string reason = null,
+            IEnumerable<KeyValuePair<string, IEnumerable<string>>> requestHeaders = null);
     }
 }

src/Discord.Net.Core/RequestOptions.cs

@@ -1,5 +1,6 @@
 using Discord.Net;
 using System;
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -19,7 +20,7 @@ namespace Discord
         ///     Gets or sets the maximum time to wait for this request to complete.
         /// </summary>
         /// <remarks>
-        ///     Gets or set the max time, in milliseconds, to wait for this request to complete. If 
+        ///     Gets or set the max time, in milliseconds, to wait for this request to complete. If
         ///     <c>null</c>, a request will not time out. If a rate limit has been triggered for this request's bucket
         ///     and will not be unpaused in time, this request will fail immediately.
         /// </remarks>
@@ -53,7 +54,7 @@ namespace Discord
 		/// </summary>
 		/// <remarks>
 		///		This property can also be set in <see cref="DiscordConfig"/>.
-		///		On a per-request basis, the system clock should only be disabled 
+		///		On a per-request basis, the system clock should only be disabled
 		///		when millisecond precision is especially important, and the
 		///		hosting system is known to have a desynced clock.
 		/// </remarks>
@@ -69,9 +70,10 @@ namespace Discord
         internal bool IsClientBucket { get; set; }
         internal bool IsReactionBucket { get; set; }
         internal bool IsGatewayBucket { get; set; }
+        internal IDictionary<string, IEnumerable<string?>> RequestHeaders { get; }
 
         internal static RequestOptions CreateOrClone(RequestOptions options)
-        {            
+        {
             if (options == null)
                 return new RequestOptions();
             else
@@ -96,8 +98,9 @@ namespace Discord
         public RequestOptions()
         {
             Timeout = DiscordConfig.DefaultRequestTimeout;
+            RequestHeaders = new Dictionary<string, IEnumerable<string?>>();
         }
-        
+
         public RequestOptions Clone() => MemberwiseClone() as RequestOptions;
     }
 }

src/Discord.Net.Rest/Net/DefaultRestClient.cs

@@ -66,33 +66,45 @@ namespace Discord.Net.Rest
             _cancelToken = cancelToken;
         }
 
-        public async Task<RestResponse> SendAsync(string method, string endpoint, CancellationToken cancelToken, bool headerOnly, string reason = null)
+        public async Task<RestResponse> SendAsync(string method, string endpoint, CancellationToken cancelToken, bool headerOnly, string reason = null,
+            IEnumerable<KeyValuePair<string, IEnumerable<string>>> requestHeaders = null)
         {
             string uri = Path.Combine(_baseUrl, endpoint);
             using (var restRequest = new HttpRequestMessage(GetMethod(method), uri))
             {
                 if (reason != null) restRequest.Headers.Add("X-Audit-Log-Reason", Uri.EscapeDataString(reason));
+                if (requestHeaders != null)
+                    foreach (var header in requestHeaders)
+                        restRequest.Headers.Add(header.Key, header.Value);
                 return await SendInternalAsync(restRequest, cancelToken, headerOnly).ConfigureAwait(false);
             }
         }
-        public async Task<RestResponse> SendAsync(string method, string endpoint, string json, CancellationToken cancelToken, bool headerOnly, string reason = null)
+        public async Task<RestResponse> SendAsync(string method, string endpoint, string json, CancellationToken cancelToken, bool headerOnly, string reason = null,
+            IEnumerable<KeyValuePair<string, IEnumerable<string>>> requestHeaders = null)
         {
             string uri = Path.Combine(_baseUrl, endpoint);
             using (var restRequest = new HttpRequestMessage(GetMethod(method), uri))
             {
                 if (reason != null) restRequest.Headers.Add("X-Audit-Log-Reason", Uri.EscapeDataString(reason));
+                if (requestHeaders != null)
+                    foreach (var header in requestHeaders)
+                        restRequest.Headers.Add(header.Key, header.Value);
                 restRequest.Content = new StringContent(json, Encoding.UTF8, "application/json");
                 return await SendInternalAsync(restRequest, cancelToken, headerOnly).ConfigureAwait(false);
             }
         }
 
         /// <exception cref="InvalidOperationException">Unsupported param type.</exception>
-        public async Task<RestResponse> SendAsync(string method, string endpoint, IReadOnlyDictionary<string, object> multipartParams, CancellationToken cancelToken, bool headerOnly, string reason = null)
+        public async Task<RestResponse> SendAsync(string method, string endpoint, IReadOnlyDictionary<string, object> multipartParams, CancellationToken cancelToken, bool headerOnly, string reason = null,
+            IEnumerable<KeyValuePair<string, IEnumerable<string>>> requestHeaders = null)
         {
             string uri = Path.Combine(_baseUrl, endpoint);
             using (var restRequest = new HttpRequestMessage(GetMethod(method), uri))
             {
                 if (reason != null) restRequest.Headers.Add("X-Audit-Log-Reason", Uri.EscapeDataString(reason));
+                if (requestHeaders != null)
+                    foreach (var header in requestHeaders)
+                        restRequest.Headers.Add(header.Key, header.Value);
                 var content = new MultipartFormDataContent("Upload----" + DateTime.Now.ToString(CultureInfo.InvariantCulture));
                 MemoryStream memoryStream = null;
                 if (multipartParams != null)
@@ -126,7 +138,7 @@ namespace Discord.Net.Rest
 
                                 content.Add(streamContent, p.Key, fileValue.Filename);
 #pragma warning restore IDISP004
-                                    
+
                                 continue;
                             }
                             default:

src/Discord.Net.Rest/Net/Queue/Requests/RestRequest.cs

@@ -28,7 +28,7 @@ namespace Discord.Net.Queue
 
         public virtual async Task<RestResponse> SendAsync()
         {
-            return await Client.SendAsync(Method, Endpoint, Options.CancelToken, Options.HeaderOnly, Options.AuditLogReason).ConfigureAwait(false);
+            return await Client.SendAsync(Method, Endpoint, Options.CancelToken, Options.HeaderOnly, Options.AuditLogReason, Options.RequestHeaders).ConfigureAwait(false);
         }
     }
 }