1 files changed, 79 insertions, 0 deletions
diff --git a/ModAS.Server/Services/AuthenticationService.cs b/ModAS.Server/Services/AuthenticationService.cs
new file mode 100644
index 0000000..27e12ad
--- /dev/null
+++ b/ModAS.Server/Services/AuthenticationService.cs
@@ -0,0 +1,79 @@
+using LibMatrix;
+using LibMatrix.Services;
+using MxApiExtensions.Services;
+
+namespace ModAS.Server.Services;
+
+public class AuthenticationService(ILogger<AuthenticationService> logger, ModASConfiguration config, IHttpContextAccessor request, HomeserverProviderService homeserverProviderService) {
+    private readonly HttpRequest _request = request.HttpContext!.Request;
+
+    private static Dictionary<string, string> _tokenMap = new();
+
+    internal string? GetToken(bool fail = true) {
+        string? token;
+        if (_request.Headers.TryGetValue("Authorization", out var tokens)) {
+            token = tokens.FirstOrDefault()?[7..];
+        }
+        else {
+            token = _request.Query["access_token"];
+        }
+
+        if (string.IsNullOrWhiteSpace(token) && fail) {
+            throw new MatrixException() {
+                ErrorCode = "M_MISSING_TOKEN",
+                Error = "Missing access token"
+            };
+        }
+
+        return token;
+    }
+
+    public async Task<string> GetMxidFromToken(string? token = null, bool fail = true) {
+        token ??= GetToken(fail);
+        if (string.IsNullOrWhiteSpace(token)) {
+            if (fail) {
+                throw new MatrixException() {
+                    ErrorCode = "M_MISSING_TOKEN",
+                    Error = "Missing access token"
+                };
+            }
+
+            return "@anonymous:*";
+        }
+
+        if (_tokenMap is not { Count: > 0 } && File.Exists("token_map")) {
+            _tokenMap = (await File.ReadAllLinesAsync("token_map"))
+                .Select(l => l.Split('\t'))
+                .ToDictionary(l => l[0], l => l[1]);
+        }
+
+
+        if (_tokenMap.TryGetValue(token, out var mxid)) return mxid;
+
+        var lookupTasks = new Dictionary<string, Task<string?>>();
+        
+        
+        logger.LogInformation("Looking up mxid for token {}", token);
+        var hs = await homeserverProviderService.GetAuthenticatedWithToken(config.ServerName, token, config.HomeserverUrl);
+        try {
+            var res = hs.WhoAmI.UserId;
+            logger.LogInformation("Got mxid {} for token {}", res, token);
+            await SaveMxidForToken(token, mxid);
+
+            return res;
+        }
+        catch (MatrixException e) {
+            if (e.ErrorCode == "M_UNKNOWN_TOKEN") {
+                return null;
+            }
+
+            throw;
+        }
+    }
+
+
+    public async Task SaveMxidForToken(string token, string mxid) {
+        _tokenMap.Add(token, mxid);
+        await File.AppendAllLinesAsync("token_map", new[] { $"{token}\t{mxid}" });
+    }
+}