Remove SSE support (#37)

Remove legacy SSE support, simplify data contract

Author: llxu1

README.md

@@ -9,7 +9,7 @@
 - [Architecture](#architecture)
 - [Features](#features)
 - [Getting Started – Local Deployment](#getting-started---local-deployment)
-- [Getting Started – Deploy to Azure](#getting-started---deploy-to-azure)
+- [Getting Started – 1-Click Deploy to Azure](#getting-started---deploy-to-azure)
 
 ## Overview
 
@@ -23,7 +23,7 @@ This project provides:
 
 ## Key Concepts
 
-- **MCP Server**: A server implementing the Model Context Protocol, which typically exposes SSE or streamable HTTP endpoints.
+- **MCP Server**: A server implementing the Model Context Protocol, which typically a streamable HTTP endpoint.
 - **Adapters**: Logical resources representing MCP servers in the gateway, managed under the `/adapters` scope. Designed to coexist with other resource types (e.g., `/agents`) in a unified AI development platform.
 - **Session-Aware Stateful Routing**: Ensures that all requests with a given `session_id` are consistently routed to the same MCP server instance.
 
@@ -81,8 +81,6 @@ flowchart LR
 
 ### Data Plane – Gateway Routing for MCP Servers
 
-- `GET /adapters/{name}/sse` — Establish an initial SSE connection.
-- `POST /adapters/{name}/messages` — Send subsequent requests using `session_id`.
 - `POST /adapters/{name}/mcp` — Establish a streamable HTTP connection.
 
 ### Additional Capabilities
@@ -167,7 +165,6 @@ kubectl port-forward -n adapter svc/mcpgateway-service 8000:8000
 
 - For other servers:  
   - `http://localhost:8000/adapters/{name}/mcp` (Streamable HTTP)  
-  - `http://localhost:8000/adapters/{name}/sse` (SSE)
 
 ### 9. Clean the Environment  
    To remove all deployed resources, delete the Kubernetes namespace:

dotnet/Microsoft.McpGateway.Management/src/Contracts/AdapterData.cs

@@ -7,7 +7,7 @@
 namespace Microsoft.McpGateway.Management.Contracts
 {
     /// <summary>
-    /// This class represents the data for an adapter, including its name, image details, protocol, connection type, environment variables, and description.
+    /// This class represents the data for an adapter, including its name, image details, environment variables, and description.
     /// </summary>
     public class AdapterData
     {
@@ -30,18 +30,6 @@ public class AdapterData
         [JsonPropertyOrder(3)]
         public required string ImageVersion { get; set; }
 
-        /// <summary>
-        /// The protocol used by the adapter. Default is MCP.
-        /// </summary>
-        [JsonPropertyOrder(6)]
-        public ServerProtocol Protocol { get; set; } = ServerProtocol.MCP;
-
-        /// <summary>
-        /// The connection type used by the adapter. Default is SSE.
-        /// </summary>
-        [JsonPropertyOrder(7)]
-        public ConnectionType ConnectionType { get; set; } = ConnectionType.StreamableHttp;
-
         /// <summary>
         /// Environment key variables in M3 service for the adapter.
         /// </summary>
@@ -57,13 +45,13 @@ public class AdapterData
         /// <summary>
         /// A description of the adapter.
         /// </summary>
-        [JsonPropertyOrder(8)]
+        [JsonPropertyOrder(6)]
         public string Description { get; set; } = string.Empty;
 
         /// <summary>
         /// Indicates whether to use workload identity for the deployed adapter instance. Default is false.
         /// </summary>
-        [JsonPropertyOrder(9)]
+        [JsonPropertyOrder(7)]
         public bool UseWorkloadIdentity { get; set; } = false;
 
         public AdapterData(
@@ -73,8 +61,6 @@ public AdapterData(
             Dictionary<string, string>? environmentVariables = null,
             int? replicaCount = 1,
             string description = "",
-            ServerProtocol protocol = ServerProtocol.MCP,
-            ConnectionType connectionType = ConnectionType.StreamableHttp,
             bool useWorkloadIdentity = false)
         {
             ArgumentException.ThrowIfNullOrEmpty(name);
@@ -84,8 +70,6 @@ public AdapterData(
             Name = name;
             ImageName = imageName;
             ImageVersion = imageVersion;
-            Protocol = protocol;
-            ConnectionType = connectionType;
             EnvironmentVariables = environmentVariables ?? [];
             ReplicaCount = replicaCount ?? 1;
             Description = description;
@@ -94,17 +78,4 @@ public AdapterData(
 
         public AdapterData() { }
     }
-
-    [JsonConverter(typeof(JsonStringEnumConverter))]
-    public enum ConnectionType
-    {
-        SSE,
-        StreamableHttp,
-    }
-
-    [JsonConverter(typeof(JsonStringEnumConverter))]
-    public enum ServerProtocol
-    {
-        MCP
-    }
 }

dotnet/Microsoft.McpGateway.Management/src/Contracts/AdapterResource.cs

@@ -30,7 +30,7 @@ public class AdapterResource : AdapterData
         public DateTimeOffset LastUpdatedAt { get; set; }
 
         public AdapterResource(AdapterData adapterData, string createdBy, DateTimeOffset createdAt, DateTimeOffset lastUpdatedAt)
-            : base(adapterData.Name, adapterData.ImageName, adapterData.ImageVersion, adapterData.EnvironmentVariables, adapterData.ReplicaCount, adapterData.Description, adapterData.Protocol, adapterData.ConnectionType, adapterData.UseWorkloadIdentity)
+            : base(adapterData.Name, adapterData.ImageName, adapterData.ImageVersion, adapterData.EnvironmentVariables, adapterData.ReplicaCount, adapterData.Description, adapterData.UseWorkloadIdentity)
         {
             CreatedBy = createdBy;
             CreatedAt = createdAt;
@@ -47,8 +47,6 @@ public static AdapterResource Create(AdapterData data, string createdBy, DateTim
                 EnvironmentVariables = data.EnvironmentVariables,
                 ReplicaCount = data.ReplicaCount,
                 Description = data.Description,
-                Protocol = data.Protocol,
-                ConnectionType = data.ConnectionType,
                 CreatedBy = createdBy,
                 CreatedAt = createdAt,
                 LastUpdatedAt = DateTime.UtcNow,

dotnet/Microsoft.McpGateway.Service/src/Controllers/AdapterReverseProxyController.cs

@@ -13,7 +13,6 @@ namespace Microsoft.McpGateway.Service.Controllers
     [Authorize]
     public class AdapterReverseProxyController(IHttpClientFactory httpClientFactory, IAdapterSessionStore sessionStore, ISessionRoutingHandler sessionRoutingHandler) : ControllerBase
     {
-        private const string MCPSSEMarker = "/messages/?session_id=";
         private readonly IHttpClientFactory httpClientFactory = httpClientFactory ?? throw new ArgumentNullException(nameof(httpClientFactory));
         private readonly IAdapterSessionStore sessionStore = sessionStore ?? throw new ArgumentNullException(nameof(sessionStore));
         private readonly ISessionRoutingHandler sessionRoutingHandler = sessionRoutingHandler ?? throw new ArgumentNullException(nameof(sessionRoutingHandler));
@@ -52,100 +51,6 @@ public async Task ForwardStreamableHttpRequest(string name, CancellationToken ca
             await HttpProxy.CopyProxiedHttpResponseAsync(HttpContext, response, cancellationToken).ConfigureAwait(false);
         }
 
-        /// <summary>
-        /// Support for the legacy MCP SSE connection.
-        /// </summary>
-        [HttpPost("{name}/messages")]
-        public async Task ForwardRequest(CancellationToken cancellationToken)
-        {
-            var targetAddress = await sessionRoutingHandler.GetExistingSessionTargetAsync(HttpContext, cancellationToken).ConfigureAwait(false);
-
-            if (targetAddress == null)
-            {
-                HttpContext.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
-                return;
-            }
-
-            using var client = httpClientFactory.CreateClient(Constants.HttpClientNames.AdapterProxyClient);
-            var proxiedRequest = HttpProxy.CreateProxiedHttpRequest(HttpContext, (uri) => ReplaceUriAddress(uri, targetAddress));
-
-            var response = await client.SendAsync(proxiedRequest, cancellationToken).ConfigureAwait(false);
-
-            await HttpProxy.CopyProxiedHttpResponseAsync(HttpContext, response, cancellationToken).ConfigureAwait(false);
-        }
-
-        /// <summary>
-        /// Support for the legacy MCP SSE connection.
-        /// </summary>
-        [HttpGet("{name}/sse")]
-        public async Task ForwardSseRequest(string name, CancellationToken cancellationToken)
-        {
-            var targetAddress = await sessionRoutingHandler.GetNewSessionTargetAsync(name, HttpContext, cancellationToken).ConfigureAwait(false);
-
-            if (targetAddress == null)
-            {
-                HttpContext.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
-                return;
-            }
-
-            var proxiedRequest = HttpProxy.CreateProxiedHttpRequest(HttpContext, (uri) => ReplaceUriAddress(uri, targetAddress));
-
-            using var client = httpClientFactory.CreateClient(Constants.HttpClientNames.AdapterProxyClient);
-            var response = await client.SendAsync(proxiedRequest, HttpCompletionOption.ResponseHeadersRead, cancellationToken).ConfigureAwait(false);
-
-            await StreamProxiedSseHttpResponseAsync(HttpContext, name, response, targetAddress, cancellationToken).ConfigureAwait(false);
-        }
-
-        private async Task StreamProxiedSseHttpResponseAsync(HttpContext context, string name, HttpResponseMessage response, string targetAddress, CancellationToken cancellationToken)
-        {
-            context.Response.StatusCode = (int)response.StatusCode;
-
-            foreach (var header in response.Headers)
-                context.Response.Headers[header.Key] = header.Value.ToArray();
-            foreach (var header in response.Content.Headers)
-                context.Response.Headers[header.Key] = header.Value.ToArray();
-
-            context.Response.Headers.Remove("transfer-encoding");
-            context.Features.Get<AspNetCore.Http.Features.IHttpResponseBodyFeature>()?.DisableBuffering();
-
-            using var stream = await response.Content.ReadAsStreamAsync(cancellationToken).ConfigureAwait(false);
-
-            var buffer = new byte[8192];
-            string? sessionId = null;
-            while (!cancellationToken.IsCancellationRequested)
-            {
-                var chunkLength = await stream.ReadAsync(buffer.AsMemory(0, buffer.Length), cancellationToken).ConfigureAwait(false);
-                if (chunkLength > 0)
-                {
-                    // There's an issue that the server response from the initialization call does not respect the base url.
-                    // Before awaiting fix from MCP, having gateway to rewrite the response from the MCP server during the initialization phrase to append the prefix routing.
-                    if (sessionId == null)
-                    {
-                        var chunkValue = Encoding.UTF8.GetString(buffer, 0, chunkLength);
-                        var index = chunkValue.IndexOf(MCPSSEMarker, StringComparison.OrdinalIgnoreCase);
-                        if (index >= 0)
-                        {
-                            var modified = chunkValue.Replace(MCPSSEMarker, $"/adapters/{name}{MCPSSEMarker}");
-                            sessionId = chunkValue[(index + MCPSSEMarker.Length)..].Trim();
-
-                            if (!string.IsNullOrEmpty(sessionId))
-                            {
-                                await sessionStore.SetAsync(sessionId, targetAddress, cancellationToken).ConfigureAwait(false);
-                            }
-
-                            await context.Response.Body.WriteAsync(Encoding.UTF8.GetBytes(modified), cancellationToken).ConfigureAwait(false);
-                        }
-                    }
-                    else
-                    {
-                        await context.Response.Body.WriteAsync(buffer, cancellationToken).ConfigureAwait(false);
-                    }
-
-                    await context.Response.Body.FlushAsync(cancellationToken).ConfigureAwait(false);
-                }
-            }
-        }
-
         private static Uri ReplaceUriAddress(Uri originalUri, string newAddress)
         {
             ArgumentNullException.ThrowIfNull(originalUri);