Add /v1/audio/transcriptions support (#41)

* add support for /v1/audio/transcriptions

README.md

@@ -18,6 +18,7 @@ Written in golang, it is very easy to install (single binary with no dependancie
   - `v1/embeddings`
   - `v1/rerank`
   - `v1/audio/speech` ([#36](https://github.com/mostlygeek/llama-swap/issues/36))
+  - `v1/audio/transcriptions` ([docs](https://github.com/mostlygeek/llama-swap/issues/41#issuecomment-2722637867))
 - ✅ Run multiple models at once with `profiles` ([docs](https://github.com/mostlygeek/llama-swap/issues/53#issuecomment-2660761741))
 - ✅ Remote log monitoring at `/log`
 - ✅ Direct access to upstream HTTP server via `/upstream/:model_id` ([demo](https://github.com/mostlygeek/llama-swap/pull/31))

misc/simple-responder/simple-responder.go

@@ -67,6 +67,46 @@ func main() {
 		c.String(200, *responseMessage)
 	})
 
+	// issue #41
+	r.POST("/v1/audio/transcriptions", func(c *gin.Context) {
+		// Parse the multipart form
+		if err := c.Request.ParseMultipartForm(10 << 20); err != nil { // 10 MB max memory
+			c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("Error parsing multipart form: %s", err)})
+			return
+		}
+
+		// Get the model from the form values
+		model := c.Request.FormValue("model")
+
+		if model == "" {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "Missing model parameter"})
+			return
+		}
+
+		// Get the file from the form
+		file, _, err := c.Request.FormFile("file")
+		if err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("Error getting file: %s", err)})
+			return
+		}
+		defer file.Close()
+
+		// Read the file content to get its size
+		fileBytes, err := io.ReadAll(file)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("Error reading file: %s", err)})
+			return
+		}
+
+		fileSize := len(fileBytes)
+
+		// Return a JSON response with the model and transcription text including file size
+		c.JSON(http.StatusOK, gin.H{
+			"text":  fmt.Sprintf("The length of the file is %d bytes", fileSize),
+			"model": model,
+		})
+	})
+
 	r.GET("/slow-respond", func(c *gin.Context) {
 		echo := c.Query("echo")
 		delay := c.Query("delay")

proxy/proxymanager.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"mime/multipart"
 	"net/http"
 	"sort"
 	"strconv"
@@ -95,6 +96,7 @@ func New(config *Config) *ProxyManager {
 
 	// Support audio/speech endpoint
 	pm.ginEngine.POST("/v1/audio/speech", pm.proxyOAIHandler)
+	pm.ginEngine.POST("/v1/audio/transcriptions", pm.proxyOAIAudioTranscriptionHandler)
 
 	pm.ginEngine.GET("/v1/models", pm.listModelsHandler)
 
@@ -374,6 +376,105 @@ func (pm *ProxyManager) proxyOAIHandler(c *gin.Context) {
 	}
 }
 
+func (pm *ProxyManager) proxyOAIAudioTranscriptionHandler(c *gin.Context) {
+	// We need to reconstruct the multipart form in any case since the body is consumed
+	// Create a new buffer for the reconstructed request
+	var requestBuffer bytes.Buffer
+	multipartWriter := multipart.NewWriter(&requestBuffer)
+
+	// Parse multipart form
+	if err := c.Request.ParseMultipartForm(32 << 20); err != nil { // 32MB max memory, larger files go to tmp disk
+		pm.sendErrorResponse(c, http.StatusBadRequest, fmt.Sprintf("error parsing multipart form: %s", err.Error()))
+		return
+	}
+
+	// Get model parameter from the form
+	requestedModel := c.Request.FormValue("model")
+	if requestedModel == "" {
+		pm.sendErrorResponse(c, http.StatusBadRequest, "missing or invalid 'model' parameter in form data")
+		return
+	}
+
+	// Swap to the requested model
+	process, err := pm.swapModel(requestedModel)
+	if err != nil {
+		pm.sendErrorResponse(c, http.StatusNotFound, fmt.Sprintf("unable to swap to model, %s", err.Error()))
+		return
+	}
+
+	// Get profile name and model name from the requested model
+	profileName, modelName := splitRequestedModel(requestedModel)
+
+	// Copy all form values
+	for key, values := range c.Request.MultipartForm.Value {
+		for _, value := range values {
+			fieldValue := value
+			// If this is the model field and we have a profile, use just the model name
+			if key == "model" && profileName != "" {
+				fieldValue = modelName
+			}
+			field, err := multipartWriter.CreateFormField(key)
+			if err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error recreating form field")
+				return
+			}
+			if _, err = field.Write([]byte(fieldValue)); err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error writing form field")
+				return
+			}
+		}
+	}
+
+	// Copy all files from the original request
+	for key, fileHeaders := range c.Request.MultipartForm.File {
+		for _, fileHeader := range fileHeaders {
+			formFile, err := multipartWriter.CreateFormFile(key, fileHeader.Filename)
+			if err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error recreating form file")
+				return
+			}
+
+			file, err := fileHeader.Open()
+			if err != nil {
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error opening uploaded file")
+				return
+			}
+
+			if _, err = io.Copy(formFile, file); err != nil {
+				file.Close()
+				pm.sendErrorResponse(c, http.StatusInternalServerError, "error copying file data")
+				return
+			}
+			file.Close()
+		}
+	}
+
+	// Close the multipart writer to finalize the form
+	if err := multipartWriter.Close(); err != nil {
+		pm.sendErrorResponse(c, http.StatusInternalServerError, "error finalizing multipart form")
+		return
+	}
+
+	// Create a new request with the reconstructed form data
+	modifiedReq, err := http.NewRequestWithContext(
+		c.Request.Context(),
+		c.Request.Method,
+		c.Request.URL.String(),
+		&requestBuffer,
+	)
+	if err != nil {
+		pm.sendErrorResponse(c, http.StatusInternalServerError, "error creating modified request")
+		return
+	}
+
+	// Copy the headers from the original request
+	modifiedReq.Header = c.Request.Header.Clone()
+	modifiedReq.Header.Set("Content-Type", multipartWriter.FormDataContentType())
+
+	// Use the modified request for proxying
+	process.ProxyRequest(c.Writer, modifiedReq)
+}
+
 func (pm *ProxyManager) sendErrorResponse(c *gin.Context, statusCode int, message string) {
 	acceptHeader := c.GetHeader("Accept")
 

proxy/proxymanager_test.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"math/rand"
+	"mime/multipart"
 	"net/http"
 	"net/http/httptest"
 	"sync"
@@ -460,3 +462,73 @@ func TestProxyManager_RunningEndpoint(t *testing.T) {
 		assert.Empty(t, expectedModels, "unexpected additional models in response")
 	})
 }
+
+func TestProxyManager_AudioTranscriptionHandler(t *testing.T) {
+	config := &Config{
+		HealthCheckTimeout: 15,
+		Profiles: map[string][]string{
+			"test": {"TheExpectedModel"},
+		},
+		Models: map[string]ModelConfig{
+			"TheExpectedModel": getTestSimpleResponderConfig("TheExpectedModel"),
+		},
+	}
+
+	proxy := New(config)
+	defer proxy.StopProcesses()
+
+	testCases := []struct {
+		name        string
+		modelInput  string
+		expectModel string
+	}{
+		{
+			name:        "With Profile Prefix",
+			modelInput:  "test:TheExpectedModel",
+			expectModel: "TheExpectedModel", // Profile prefix should be stripped
+		},
+		{
+			name:        "Without Profile Prefix",
+			modelInput:  "TheExpectedModel",
+			expectModel: "TheExpectedModel", // Should remain the same
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Create a buffer with multipart form data
+			var b bytes.Buffer
+			w := multipart.NewWriter(&b)
+
+			// Add the model field
+			fw, err := w.CreateFormField("model")
+			assert.NoError(t, err)
+			_, err = fw.Write([]byte(tc.modelInput))
+			assert.NoError(t, err)
+
+			// Add a file field
+			fw, err = w.CreateFormFile("file", "test.mp3")
+			assert.NoError(t, err)
+			// Generate random content length between 10 and 20
+			contentLength := rand.Intn(11) + 10 // 10 to 20
+			content := make([]byte, contentLength)
+			_, err = fw.Write(content)
+			assert.NoError(t, err)
+			w.Close()
+
+			// Create the request with the multipart form data
+			req := httptest.NewRequest("POST", "/v1/audio/transcriptions", &b)
+			req.Header.Set("Content-Type", w.FormDataContentType())
+			rec := httptest.NewRecorder()
+			proxy.HandlerFunc(rec, req)
+
+			// Verify the response
+			assert.Equal(t, http.StatusOK, rec.Code)
+			var response map[string]string
+			err = json.Unmarshal(rec.Body.Bytes(), &response)
+			assert.NoError(t, err)
+			assert.Equal(t, tc.expectModel, response["model"])
+			assert.Equal(t, response["text"], fmt.Sprintf("The length of the file is %d bytes", contentLength)) // matches simple-responder
+		})
+	}
+}