diff --git a/MatrixMediaGate/MatrixMediaGate.csproj b/MatrixMediaGate/MatrixMediaGate.csproj
new file mode 100644
index 0000000..f847a82
--- /dev/null
+++ b/MatrixMediaGate/MatrixMediaGate.csproj
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+ <PropertyGroup>
+ <TargetFramework>net8.0</TargetFramework>
+ <Nullable>enable</Nullable>
+ <ImplicitUsings>enable</ImplicitUsings>
+ <InvariantGlobalization>true</InvariantGlobalization>
+ </PropertyGroup>
+
+</Project>
diff --git a/MatrixMediaGate/Program.cs b/MatrixMediaGate/Program.cs
new file mode 100644
index 0000000..a812d78
--- /dev/null
+++ b/MatrixMediaGate/Program.cs
@@ -0,0 +1,83 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Text.Json;
+using MatrixMediaGate;
+using MatrixMediaGate.Services;
+
+var builder = WebApplication.CreateBuilder(args);
+
+builder.Services.AddSingleton<ProxyConfiguration>();
+builder.Services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
+builder.Services.AddScoped<AuthValidator>();
+
+var app = builder.Build();
+
+async Task Proxy(ProxyConfiguration cfg, AuthValidator auth, HttpContext ctx, ILogger<Program> logger) {
+ if (ctx is null) return;
+ var path = ctx.Request.Path.Value;
+ if(path is null) return;
+ if (path.StartsWith('/'))
+ path = path[1..];
+ path += ctx.Request.QueryString.Value;
+
+#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+ auth.UpdateAuth();
+#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+
+ using var handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.None };
+
+ using var hc = new HttpClient(handler) { BaseAddress = new Uri(cfg.Upstream) };
+ var method = new HttpMethod(ctx.Request.Method);
+ using var req = new HttpRequestMessage(method, path);
+ foreach (var header in ctx.Request.Headers) {
+ if (header.Key != "Accept-Encoding" && header.Key != "Content-Type" && header.Key != "Content-Length") req.Headers.Add(header.Key, header.Value.ToArray());
+ }
+
+ if (ctx.Request.ContentLength > 0) {
+ req.Content = new StreamContent(ctx.Request.Body);
+ if (ctx.Request.ContentType != null) req.Content.Headers.ContentType = new MediaTypeHeaderValue(ctx.Request.ContentType);
+ if (ctx.Request.ContentLength != null) req.Content.Headers.ContentLength = ctx.Request.ContentLength;
+ }
+
+ logger.LogInformation($"Proxying {method} {path} to {hc.BaseAddress}{path}");
+
+ using var response = await hc.SendAsync(req, HttpCompletionOption.ResponseHeadersRead);
+ ctx.Response.Headers.Clear();
+ foreach (var header in response.Headers) {
+ if (header.Key != "Transfer-Encoding") ctx.Response.Headers[header.Key] = header.Value.ToArray();
+ }
+
+ ctx.Response.StatusCode = (int)response.StatusCode;
+ ctx.Response.ContentType = response.Content.Headers.ContentType?.ToString() ?? "application/json";
+ await ctx.Response.StartAsync();
+ await using var content = await response.Content.ReadAsStreamAsync();
+ await content.CopyToAsync(ctx.Response.Body);
+ await ctx.Response.Body.FlushAsync();
+ await ctx.Response.CompleteAsync();
+}
+
+async Task ProxyMedia(string serverName, ProxyConfiguration cfg, AuthValidator auth, HttpContext ctx, ILogger<Program> logger) {
+ if (cfg.TrustedServers.Contains(serverName) || auth.ValidateAuth()) {
+ await Proxy(cfg, auth, ctx, logger);
+ }
+ else {
+ ctx.Response.StatusCode = 403;
+ ctx.Response.ContentType = "application/json";
+ await ctx.Response.StartAsync();
+ var json = JsonSerializer.Serialize(new { errcode = "M_FORBIDDEN", error = "Unauthenticated access to remote media has been disabled on this server." });
+ await ctx.Response.WriteAsync(json);
+ await ctx.Response.Body.FlushAsync();
+ await ctx.Response.CompleteAsync();
+ }
+}
+
+app.Map("{*_}", Proxy);
+
+foreach (var route in (string[]) [
+ "/_matrix/media/{version}/download/{serverName}/{mediaId}",
+ "/_matrix/media/{version}/download/{serverName}/{mediaId}/{fileName}",
+ "/_matrix/media/{version}/thumbnail/{serverName}/{mediaId}",
+ ])
+ app.Map(route, ProxyMedia);
+
+app.Run();
\ No newline at end of file
diff --git a/MatrixMediaGate/Properties/launchSettings.json b/MatrixMediaGate/Properties/launchSettings.json
new file mode 100644
index 0000000..dc26c8d
--- /dev/null
+++ b/MatrixMediaGate/Properties/launchSettings.json
@@ -0,0 +1,41 @@
+{
+ "$schema": "http://json.schemastore.org/launchsettings.json",
+ "iisSettings": {
+ "windowsAuthentication": false,
+ "anonymousAuthentication": true,
+ "iisExpress": {
+ "applicationUrl": "http://localhost:41407",
+ "sslPort": 44394
+ }
+ },
+ "profiles": {
+ "http": {
+ "commandName": "Project",
+ "dotnetRunMessages": true,
+ "launchBrowser": true,
+ "launchUrl": "swagger",
+ "applicationUrl": "http://localhost:5011",
+ "environmentVariables": {
+ "ASPNETCORE_ENVIRONMENT": "Development"
+ }
+ },
+ "https": {
+ "commandName": "Project",
+ "dotnetRunMessages": true,
+ "launchBrowser": true,
+ "launchUrl": "swagger",
+ "applicationUrl": "https://localhost:7227;http://localhost:5011",
+ "environmentVariables": {
+ "ASPNETCORE_ENVIRONMENT": "Development"
+ }
+ },
+ "IIS Express": {
+ "commandName": "IISExpress",
+ "launchBrowser": true,
+ "launchUrl": "swagger",
+ "environmentVariables": {
+ "ASPNETCORE_ENVIRONMENT": "Development"
+ }
+ }
+ }
+}
diff --git a/MatrixMediaGate/ProxyConfiguration.cs b/MatrixMediaGate/ProxyConfiguration.cs
new file mode 100644
index 0000000..0a126d4
--- /dev/null
+++ b/MatrixMediaGate/ProxyConfiguration.cs
@@ -0,0 +1,14 @@
+namespace MatrixMediaGate;
+
+public class ProxyConfiguration {
+ //bind to config
+ public ProxyConfiguration(IConfiguration configuration)
+ {
+ configuration.GetRequiredSection("ProxyConfiguration").Bind(this);
+ }
+
+ public required string Upstream { get; set; }
+ public required string Host { get; set; }
+ public required List<string> TrustedServers { get; set; }
+ public bool ForceHost { get; set; }
+}
\ No newline at end of file
diff --git a/MatrixMediaGate/Services/AuthValidator.cs b/MatrixMediaGate/Services/AuthValidator.cs
new file mode 100644
index 0000000..08ccd14
--- /dev/null
+++ b/MatrixMediaGate/Services/AuthValidator.cs
@@ -0,0 +1,71 @@
+using System.Net;
+using System.Text.Json;
+
+namespace MatrixMediaGate.Services;
+
+public class AuthValidator(ILogger<AuthValidator> logger, ProxyConfiguration cfg, IHttpContextAccessor ctx) {
+ private static Dictionary<string, DateTime> _authCache = new();
+
+ public async Task<bool> UpdateAuth() {
+ if (ctx.HttpContext is null) return false;
+ if (ctx.HttpContext.Connection.RemoteIpAddress is null) return false;
+ var remote = ctx.HttpContext.Connection.RemoteIpAddress.ToString();
+
+
+ if (_authCache.TryGetValue(remote, out var value)) {
+ if (value > DateTime.Now.AddSeconds(30)) {
+ return true;
+ }
+
+ _authCache.Remove(remote);
+ }
+
+ string? token = getToken();
+ if (token is null) return false;
+
+ using var hc = new HttpClient();
+ using var req = new HttpRequestMessage(HttpMethod.Get, $"{cfg.Upstream}/_matrix/client/v3/account/whoami?access_token={token}");
+ req.Headers.Host = cfg.Host;
+ var response = await hc.SendAsync(req);
+
+ if (response.Content.Headers.ContentType?.MediaType != "application/json") return false;
+ var content = await response.Content.ReadAsStringAsync();
+ var json = JsonDocument.Parse(content);
+ if (json.RootElement.TryGetProperty("user_id", out var userId)) {
+ _authCache[remote] = DateTime.Now.AddMinutes(5);
+ logger.LogInformation("Authenticated {userId} on {remote}, expiring at {time}", userId, remote, _authCache[remote]);
+ return true;
+ }
+
+ return false;
+ }
+
+ public bool ValidateAuth() {
+ if (ctx.HttpContext is null) return false;
+ if (ctx.HttpContext.Connection.RemoteIpAddress is null) return false;
+ var remote = ctx.HttpContext.Connection.RemoteIpAddress.ToString();
+
+ if (_authCache.ContainsKey(remote)) {
+ if (_authCache[remote] > DateTime.Now) {
+ return true;
+ }
+
+ _authCache.Remove(remote);
+ }
+
+ return false;
+ }
+
+ private string? getToken() {
+ if (ctx is null) return null;
+ if (ctx.HttpContext.Request.Headers.ContainsKey("Authorization")) {
+ return ctx.HttpContext.Request.Headers["Authorization"].ToString().Split(' ', 2)[1];
+ }
+ else if (ctx.HttpContext.Request.Query.ContainsKey("access_token")) {
+ return ctx.HttpContext.Request.Query["access_token"]!;
+ }
+ else {
+ return null;
+ }
+ }
+}
\ No newline at end of file
diff --git a/MatrixMediaGate/appsettings.Development.json b/MatrixMediaGate/appsettings.Development.json
new file mode 100644
index 0000000..627ac37
--- /dev/null
+++ b/MatrixMediaGate/appsettings.Development.json
@@ -0,0 +1,17 @@
+{
+ "Logging": {
+ "LogLevel": {
+ "Default": "Information",
+ "Microsoft.AspNetCore": "Information",
+ "Microsoft.AspNetCore.Routing": "Warning",
+ "Microsoft.AspNetCore.Mvc": "Warning"
+ }
+ },
+ "ProxyConfiguration": {
+ "Upstream": "https://rory.gay",
+ "Host": "matrix.rory.gay",
+ "TrustedServers": [
+ "rory.gay"
+ ]
+ }
+}
diff --git a/MatrixMediaGate/appsettings.json b/MatrixMediaGate/appsettings.json
new file mode 100644
index 0000000..4d56694
--- /dev/null
+++ b/MatrixMediaGate/appsettings.json
@@ -0,0 +1,9 @@
+{
+ "Logging": {
+ "LogLevel": {
+ "Default": "Information",
+ "Microsoft.AspNetCore": "Warning"
+ }
+ },
+ "AllowedHosts": "*"
+}
diff --git a/MatrixMediaGate/deps.nix b/MatrixMediaGate/deps.nix
new file mode 100644
index 0000000..3d0b76b
--- /dev/null
+++ b/MatrixMediaGate/deps.nix
@@ -0,0 +1,5 @@
+{ fetchNuGet }: [
+ (fetchNuGet { pname = "Microsoft.DotNet.ILCompiler"; version = "8.0.1"; sha256 = "1pmh2wdw7n0906x7qc2mlgjhyndap78dm60zrz76bbmzhwc4r0mv"; })
+ (fetchNuGet { pname = "Microsoft.NET.ILLink.Tasks"; version = "8.0.1"; sha256 = "1drbgqdcvbpisjn8mqfgba1pwb6yri80qc4mfvyczqwrcsj5k2ja"; })
+ (fetchNuGet { pname = "runtime.linux-x64.Microsoft.DotNet.ILCompiler"; version = "8.0.1"; sha256 = "0mky32k6kv2iy14c89xbznyrr33ni616s85z40ny43j5w9scxh04"; })
+]
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