Add a function to allow a raw post instead of a form post to allow fo…

…r e.g. JSON

src/BizHawk.Client.Common/Api/HttpCommunication.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Net.Http;
+using System.Text;
 using System.Threading.Tasks;
 
 using BizHawk.Common;
@@ -37,6 +38,11 @@ public string ExecPost(string url = null, string payload = "") => Post(
 			new FormUrlEncodedContent(new Dictionary<string, string> { ["payload"] = payload })
 		).Result;
 
+		public string ExecPostRaw(string url = null, string payload = "", string contentType = "text/plain") => Post(
+			url ?? PostUrl,
+			new StringContent(payload, Encoding.UTF8, contentType)
+		).Result;
+
 		public async Task<string> Get(string url)
 		{
 			_client.DefaultRequestHeaders.ConnectionClose = false;
@@ -48,7 +54,7 @@ public async Task<string> Get(string url)
 			return null;
 		}
 
-		public async Task<string> Post(string url, FormUrlEncodedContent content)
+		public async Task<string> Post(string url, HttpContent content)
 		{
 			_client.DefaultRequestHeaders.ConnectionClose = true;
 			_client.DefaultRequestHeaders.ExpectContinue = ExpectContinue;

src/BizHawk.Client.Common/lua/CommonLibs/CommLuaLibrary.cs

@@ -196,13 +196,20 @@ public string HttpGet(string url)
 			return APIs.Comm.HTTP?.ExecGet(url);
 		}
 
-		[LuaMethod("httpPost", "makes a HTTP POST request")]
+		[LuaMethod("httpPost", "makes a HTTP POST request with the payload form encoded as the 'payload' field")]
 		public string HttpPost(string url, string payload)
 		{
 			CheckHttp();
 			return APIs.Comm.HTTP?.ExecPost(url, payload);
 		}
 
+		[LuaMethod("httpPostRaw", "makes a HTTP POST request with the supplied payload sent directly as the body")]
+		public string HttpPostRaw(string url, string payload, string contentType)
+		{
+			CheckHttp();
+			return APIs.Comm.HTTP?.ExecPostRaw(url, payload, contentType);
+		}
+
 		[LuaMethod("httpPostScreenshot", "HTTP POST screenshot")]
 		public string HttpPostScreenshot()
 		{