upstream handler support for model names with forward slash (#298)

The upstream handler would break on model IDs that contained a forward
slash. Model IDs like "aaa/bbb" called at upstream/aaa/bbb would result
in an error. This commit adds support for model IDs with a forward slash
by iteratively searching the path for a match.

Fixes: #229

README.md

@@ -73,6 +73,30 @@ However, there are many more capabilities that llama-swap supports:
 
 See the [configuration documentation](https://github.com/mostlygeek/llama-swap/wiki/Configuration) in the wiki all options and examples.
 
+## Reverse Proxy Configuration (nginx)
+
+If you deploy llama-swap behind nginx, disable response buffering for streaming endpoints. By default, nginx buffers responses which breaks Server‑Sent Events (SSE) and streaming chat completion. ([#236](https://github.com/mostlygeek/llama-swap/issues/236))
+
+Recommended nginx configuration snippets:
+
+```nginx
+# SSE for UI events/logs
+location /api/events {
+    proxy_pass http://your-llama-swap-backend;
+    proxy_buffering off;
+    proxy_cache off;
+}
+
+# Streaming chat completions (stream=true)
+location /v1/chat/completions {
+    proxy_pass http://your-llama-swap-backend;
+    proxy_buffering off;
+    proxy_cache off;
+}
+```
+
+As a safeguard, llama-swap also sets `X-Accel-Buffering: no` on SSE responses. However, explicitly disabling `proxy_buffering` at your reverse proxy is still recommended for reliable streaming behavior.
+
 ## Web UI
 
 llama-swap includes a real time web interface for monitoring logs and models:

proxy/process.go

@@ -458,6 +458,10 @@ func (p *Process) ProxyRequest(w http.ResponseWriter, r *http.Request) {
 			w.Header().Add(k, v)
 		}
 	}
+	// prevent nginx from buffering streaming responses (e.g., SSE)
+	if strings.Contains(strings.ToLower(resp.Header.Get("Content-Type")), "text/event-stream") {
+		w.Header().Set("X-Accel-Buffering", "no")
+	}
 	w.WriteHeader(resp.StatusCode)
 
 	// faster than io.Copy when streaming

proxy/proxymanager.go

@@ -227,7 +227,7 @@ func (pm *ProxyManager) setupGinEngine() {
 	pm.ginEngine.GET("/upstream", func(c *gin.Context) {
 		c.Redirect(http.StatusFound, "/ui/models")
 	})
-	pm.ginEngine.Any("/upstream/:model_id/*upstreamPath", pm.proxyToUpstream)
+	pm.ginEngine.Any("/upstream/*upstreamPath", pm.proxyToUpstream)
 
 	pm.ginEngine.GET("/unload", pm.unloadAllModelsHandler)
 	pm.ginEngine.GET("/running", pm.listRunningProcessesHandler)
@@ -393,24 +393,52 @@ func (pm *ProxyManager) listModelsHandler(c *gin.Context) {
 }
 
 func (pm *ProxyManager) proxyToUpstream(c *gin.Context) {
-	requestedModel := c.Param("model_id")
+	upstreamPath := c.Param("upstreamPath")
 
-	if requestedModel == "" {
+	// split the upstream path by / and search for the model name
+	parts := strings.Split(strings.TrimSpace(upstreamPath), "/")
+	if len(parts) == 0 {
 		pm.sendErrorResponse(c, http.StatusBadRequest, "model id required in path")
 		return
 	}
 
-	processGroup, realModelName, err := pm.swapProcessGroup(requestedModel)
+	modelFound := false
+	searchModelName := ""
+	var modelName, remainingPath string
+	for i, part := range parts {
+		if parts[i] == "" {
+			continue
+		}
+
+		if searchModelName == "" {
+			searchModelName = part
+		} else {
+			searchModelName = searchModelName + "/" + parts[i]
+		}
+
+		if real, ok := pm.config.RealModelName(searchModelName); ok {
+			modelName = real
+			remainingPath = "/" + strings.Join(parts[i+1:], "/")
+			modelFound = true
+			break
+		}
+	}
+
+	if !modelFound {
+		pm.sendErrorResponse(c, http.StatusBadRequest, "model id required in path")
+		return
+	}
+
+	processGroup, realModelName, err := pm.swapProcessGroup(modelName)
 	if err != nil {
 		pm.sendErrorResponse(c, http.StatusInternalServerError, fmt.Sprintf("error swapping process group: %s", err.Error()))
 		return
 	}
 
 	// rewrite the path
-	c.Request.URL.Path = c.Param("upstreamPath")
+	c.Request.URL.Path = remainingPath
 	processGroup.ProxyRequest(realModelName, c.Writer, c.Request)
 }
-
 func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 	bodyBytes, err := io.ReadAll(c.Request.Body)
 	if err != nil {

proxy/proxymanager_api.go

@@ -100,6 +100,8 @@ func (pm *ProxyManager) apiSendEvents(c *gin.Context) {
 	c.Header("Cache-Control", "no-cache")
 	c.Header("Connection", "keep-alive")
 	c.Header("X-Content-Type-Options", "nosniff")
+	// prevent nginx from buffering SSE
+	c.Header("X-Accel-Buffering", "no")
 
 	sendBuffer := make(chan messageEnvelope, 25)
 	ctx, cancel := context.WithCancel(c.Request.Context())

proxy/proxymanager_loghandlers.go

@@ -28,6 +28,8 @@ func (pm *ProxyManager) streamLogsHandler(c *gin.Context) {
 	c.Header("Content-Type", "text/plain")
 	c.Header("Transfer-Encoding", "chunked")
 	c.Header("X-Content-Type-Options", "nosniff")
+	// prevent nginx from buffering streamed logs
+	c.Header("X-Accel-Buffering", "no")
 
 	logMonitorId := c.Param("logMonitorID")
 	logger, err := pm.getLogger(logMonitorId)

proxy/proxymanager_test.go

@@ -2,6 +2,7 @@ package proxy
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"math/rand"
@@ -913,3 +914,67 @@ models:
 	assert.Equal(t, StateReady, proxy.processGroups["preloadTestGroup"].processes["model1"].CurrentState())
 	assert.Equal(t, StateReady, proxy.processGroups["preloadTestGroup"].processes["model2"].CurrentState())
 }
+
+func TestProxyManager_StreamingEndpointsReturnNoBufferingHeader(t *testing.T) {
+	config := AddDefaultGroupToConfig(Config{
+		HealthCheckTimeout: 15,
+		Models: map[string]ModelConfig{
+			"model1": getTestSimpleResponderConfig("model1"),
+		},
+		LogLevel: "error",
+	})
+
+	proxy := New(config)
+	defer proxy.StopProcesses(StopWaitForInflightRequest)
+
+	endpoints := []string{
+		"/api/events",
+		"/logs/stream",
+		"/logs/stream/proxy",
+		"/logs/stream/upstream",
+	}
+
+	for _, endpoint := range endpoints {
+		t.Run(endpoint, func(t *testing.T) {
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+
+			req := httptest.NewRequest("GET", endpoint, nil)
+			req = req.WithContext(ctx)
+			rec := httptest.NewRecorder()
+
+			// We don't need the handler to fully complete, just to set the headers
+			// so run it in a goroutine and check the headers after a short delay
+			go proxy.ServeHTTP(rec, req)
+			time.Sleep(10 * time.Millisecond) // give it time to start and write headers
+
+			assert.Equal(t, http.StatusOK, rec.Code)
+			assert.Equal(t, "no", rec.Header().Get("X-Accel-Buffering"))
+		})
+	}
+}
+
+func TestProxyManager_ProxiedStreamingEndpointReturnsNoBufferingHeader(t *testing.T) {
+	config := AddDefaultGroupToConfig(Config{
+		HealthCheckTimeout: 15,
+		Models: map[string]ModelConfig{
+			"streaming-model": getTestSimpleResponderConfig("streaming-model"),
+		},
+		LogLevel: "error",
+	})
+
+	proxy := New(config)
+	defer proxy.StopProcesses(StopWaitForInflightRequest)
+
+	// Make a streaming request
+	reqBody := `{"model":"streaming-model"}`
+	// simple-responder will return text/event-stream when stream=true is in the query
+	req := httptest.NewRequest("POST", "/v1/chat/completions?stream=true", bytes.NewBufferString(reqBody))
+	rec := httptest.NewRecorder()
+
+	proxy.ServeHTTP(rec, req)
+
+	assert.Equal(t, http.StatusOK, rec.Code)
+	assert.Equal(t, "no", rec.Header().Get("X-Accel-Buffering"))
+	assert.Contains(t, rec.Header().Get("Content-Type"), "text/event-stream")
+}

ui/src/contexts/APIProvider.tsx

@@ -1,4 +1,4 @@
-import { useRef, createContext, useState, useContext, useEffect, useCallback, useMemo, type ReactNode } from "react";
+import { createContext, useState, useContext, useEffect, useCallback, useMemo, type ReactNode } from "react";
 import type { ConnectionState } from "../lib/types";
 
 type ModelStatus = "ready" | "starting" | "stopping" | "stopped" | "shutdown" | "unknown";
@@ -51,12 +51,14 @@ type APIProviderProps = {
   autoStartAPIEvents?: boolean;
 };
 
+let apiEventSource: EventSource | null = null;
+
 export function APIProvider({ children, autoStartAPIEvents = true }: APIProviderProps) {
   const [proxyLogs, setProxyLogs] = useState("");
   const [upstreamLogs, setUpstreamLogs] = useState("");
   const [metrics, setMetrics] = useState<Metrics[]>([]);
   const [connectionStatus, setConnectionState] = useState<ConnectionState>("disconnected");
-  const apiEventSource = useRef<EventSource | null>(null);
+  //const apiEventSource = useRef<EventSource | null>(null);
 
   const [models, setModels] = useState<Model[]>([]);
 
@@ -69,8 +71,8 @@ export function APIProvider({ children, autoStartAPIEvents = true }: APIProvider
 
   const enableAPIEvents = useCallback((enabled: boolean) => {
     if (!enabled) {
-      apiEventSource.current?.close();
+      apiEventSource?.close();
-      apiEventSource.current = null;
+      apiEventSource = null;
       setMetrics([]);
       return;
     }
@@ -79,22 +81,22 @@ export function APIProvider({ children, autoStartAPIEvents = true }: APIProvider
     const initialDelay = 1000; // 1 second
 
     const connect = () => {
-      apiEventSource.current = null;
+      apiEventSource?.close();
-      const eventSource = new EventSource("/api/events");
+      apiEventSource = new EventSource("/api/events");
+
       setConnectionState("connecting");
 
-      eventSource.onopen = () => {
+      apiEventSource.onopen = () => {
         // clear everything out on connect to keep things in sync
         setProxyLogs("");
         setUpstreamLogs("");
         setMetrics([]); // clear metrics on reconnect
         setModels([]); // clear models on reconnect
-        apiEventSource.current = eventSource;
         retryCount = 0;
         setConnectionState("connected");
       };
 
-      eventSource.onmessage = (e: MessageEvent) => {
+      apiEventSource.onmessage = (e: MessageEvent) => {
         try {
           const message = JSON.parse(e.data) as APIEventEnvelope;
           switch (message.type) {
@@ -137,8 +139,8 @@ export function APIProvider({ children, autoStartAPIEvents = true }: APIProvider
         }
       };
 
-      eventSource.onerror = () => {
+      apiEventSource.onerror = () => {
-        eventSource.close();
+        apiEventSource?.close();
         retryCount++;
         const delay = Math.min(initialDelay * Math.pow(2, retryCount - 1), 5000);
         setConnectionState("disconnected");