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using System.Net.Http.Headers;
using System.Text.Json;
using MatrixMediaGate;
using MatrixMediaGate.Services;
using Microsoft.AspNetCore.Http.Extensions;
var builder = WebApplication.CreateBuilder(args);
builder.Host.UseSystemd();
builder.Services.AddSingleton<ProxyConfiguration>();
builder.Services.AddSingleton<AuthValidator>();
builder.Services.AddSingleton<HttpClient>(services => {
var cfg = services.GetRequiredService<ProxyConfiguration>();
return new HttpClient() {
BaseAddress = new Uri(cfg.Upstream),
MaxResponseContentBufferSize = 1 * 1024 * 1024 // 1MB
};
});
var app = builder.Build();
app.Map("{*_}", ProxyMaybeAuth);
app.Map("/_matrix/federation/{*_}", Proxy); // Don't bother with auth for federation
foreach (var route in (string[]) [ // Require recent auth for these routes
"/_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();
// Proxy a request
async Task Proxy(HttpClient hc, ProxyConfiguration cfg, HttpContext ctx, ILogger<Program> logger) {
HttpRequestMessage? upstreamRequest = null;
HttpResponseMessage? upstreamResponse = null;
Exception? exception = null;
try {
var path = ctx.Request.GetEncodedPathAndQuery();
if (path.StartsWith('/'))
path = path[1..];
var method = new HttpMethod(ctx.Request.Method);
upstreamRequest = new HttpRequestMessage(method, path);
hc.DefaultRequestHeaders.Clear();
upstreamRequest.Headers.Clear();
foreach (var header in ctx.Request.Headers) {
if (header.Key != "Accept-Encoding" && header.Key != "Content-Type" && header.Key != "Content-Length") {
// req.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray());
upstreamRequest.Headers.Remove(header.Key);
upstreamRequest.Headers.TryAddWithoutValidation(header.Key, header.Value.ToArray());
}
}
upstreamRequest.Headers.Host = cfg.Host;
if (ctx.Request.ContentLength > 0) {
upstreamRequest.Content = new StreamContent(ctx.Request.Body);
if (ctx.Request.ContentType != null) upstreamRequest.Content.Headers.ContentType = MediaTypeHeaderValue.Parse(ctx.Request.ContentType);
if (ctx.Request.ContentLength != null) upstreamRequest.Content.Headers.ContentLength = ctx.Request.ContentLength;
}
logger.LogInformation("Proxying {method} {path} to {target}", method, path, hc.BaseAddress + path);
upstreamResponse = await hc.SendAsync(upstreamRequest, HttpCompletionOption.ResponseHeadersRead);
ctx.Response.Headers.Clear();
foreach (var header in upstreamResponse.Headers) {
if (header.Key != "Transfer-Encoding")
ctx.Response.Headers[header.Key] = header.Value.ToArray();
}
ctx.Response.StatusCode = (int)upstreamResponse.StatusCode;
ctx.Response.ContentType = upstreamResponse.Content.Headers.ContentType?.ToString() ?? "application/json";
if (upstreamResponse.Content.Headers.ContentLength != null) ctx.Response.ContentLength = upstreamResponse.Content.Headers.ContentLength;
await ctx.Response.StartAsync();
await using var content = await upstreamResponse.Content.ReadAsStreamAsync();
await content.CopyToAsync(ctx.Response.Body);
}
catch (HttpRequestException e) {
exception = e;
logger.LogError(e, "Failed to proxy request");
ctx.Response.StatusCode = 502;
ctx.Response.ContentType = "application/json";
await ctx.Response.StartAsync();
await JsonSerializer.SerializeAsync(ctx.Response.Body, new { errcode = "M_UNAVAILABLE", error = "Failed to proxy request" });
}
finally {
await ctx.Response.Body.FlushAsync();
await ctx.Response.CompleteAsync();
if (ctx.Response.StatusCode >= 400) {
await ProxyDump(cfg, ctx, upstreamRequest, upstreamResponse, exception);
}
upstreamRequest?.Dispose();
upstreamResponse?.Dispose();
}
}
// We attempt to update auth, but we don't require it
async Task ProxyMaybeAuth(HttpClient hc, ProxyConfiguration cfg, AuthValidator auth, HttpContext ctx, ILogger<Program> logger) {
await auth.UpdateAuth(ctx);
await Proxy(hc, cfg, ctx, logger);
}
// We know this is a media path, we require recent auth here to prevent abuse
async Task ProxyMedia(string serverName, ProxyConfiguration cfg, HttpClient hc, AuthValidator auth, HttpContext ctx, ILogger<Program> logger) {
// Some clients may send Authorization header, so we handle this last...
if (cfg.TrustedServers.Contains(serverName) || auth.ValidateAuth(ctx) || await auth.UpdateAuth(ctx)) {
await Proxy(hc, cfg, ctx, logger);
}
else {
ctx.Response.StatusCode = 403;
ctx.Response.ContentType = "application/json";
await ctx.Response.StartAsync();
await JsonSerializer.SerializeAsync(ctx.Response.Body, new { errcode = "M_FORBIDDEN", error = "Unauthenticated access to remote media has been disabled on this server." });
await ctx.Response.Body.FlushAsync();
await ctx.Response.CompleteAsync();
}
}
var jsonOptions = new JsonSerializerOptions {
WriteIndented = true
};
// We dump failed requests to disk
async Task ProxyDump(ProxyConfiguration cfg, HttpContext ctx, HttpRequestMessage? req, HttpResponseMessage? resp, Exception? e) {
if (ctx.Response.StatusCode >= 400 && cfg.DumpFailedRequests) {
var path = Path.Combine(cfg.DumpPath, "failed_requests", $"{resp.StatusCode}-{DateTimeOffset.UtcNow.ToUnixTimeSeconds()}-{ctx.Request.Path}.json");
await using var file = File.Create(path);
await JsonSerializer.SerializeAsync(file, new {
Self = new {
Request = new {
ctx.Request.Method,
Url = ctx.Request.GetEncodedUrl(),
ctx.Request.Headers
},
Response = new {
ctx.Response.StatusCode,
ctx.Response.Headers,
ctx.Response.ContentType,
ctx.Response.ContentLength
}
},
Upstream = new {
Request = new {
req?.Method,
Url = req?.RequestUri,
req?.Headers
},
Response = new {
resp.StatusCode,
resp.Headers,
resp.Content.Headers.ContentType,
resp.Content.Headers.ContentLength
}
},
Exception = new {
Type = e?.GetType().ToString(),
Message = e?.Message.ReplaceLineEndings().Split(Environment.NewLine),
StackTrace = e?.StackTrace?.ReplaceLineEndings().Split(Environment.NewLine)
}
});
}
}
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