OpenAI: /v1/embeddings compatibility (#5285)

* OpenAI v1 models

* Empty List Testing

* Add back envconfig

* v1/models docs

* Remove Docs

* OpenAI batch embed compatibility

* merge conflicts

* integrate with api/embed

* ep

* merge conflicts

* request tests

* rm resp test

* merge conflict

* merge conflict

* test fixes

* test fn renaming

* input validation for empty string

---------

Co-authored-by: jmorganca <jmorganca@gmail.com>

openai/openai_test.go

@@ -161,6 +161,78 @@ func TestMiddlewareRequests(t *testing.T) {
 				}
 			},
 		},
+		{
+			Name:    "embed handler single input",
+			Method:  http.MethodPost,
+			Path:    "/api/embed",
+			Handler: EmbeddingsMiddleware,
+			Setup: func(t *testing.T, req *http.Request) {
+				body := EmbedRequest{
+					Input: "Hello",
+					Model: "test-model",
+				}
+
+				bodyBytes, _ := json.Marshal(body)
+
+				req.Body = io.NopCloser(bytes.NewReader(bodyBytes))
+				req.Header.Set("Content-Type", "application/json")
+			},
+			Expected: func(t *testing.T, req *http.Request) {
+				var embedReq api.EmbedRequest
+				if err := json.NewDecoder(req.Body).Decode(&embedReq); err != nil {
+					t.Fatal(err)
+				}
+
+				if embedReq.Input != "Hello" {
+					t.Fatalf("expected 'Hello', got %s", embedReq.Input)
+				}
+
+				if embedReq.Model != "test-model" {
+					t.Fatalf("expected 'test-model', got %s", embedReq.Model)
+				}
+			},
+		},
+		{
+			Name:    "embed handler batch input",
+			Method:  http.MethodPost,
+			Path:    "/api/embed",
+			Handler: EmbeddingsMiddleware,
+			Setup: func(t *testing.T, req *http.Request) {
+				body := EmbedRequest{
+					Input: []string{"Hello", "World"},
+					Model: "test-model",
+				}
+
+				bodyBytes, _ := json.Marshal(body)
+
+				req.Body = io.NopCloser(bytes.NewReader(bodyBytes))
+				req.Header.Set("Content-Type", "application/json")
+			},
+			Expected: func(t *testing.T, req *http.Request) {
+				var embedReq api.EmbedRequest
+				if err := json.NewDecoder(req.Body).Decode(&embedReq); err != nil {
+					t.Fatal(err)
+				}
+
+				input, ok := embedReq.Input.([]any)
+
+				if !ok {
+					t.Fatalf("expected input to be a list")
+				}
+
+				if input[0].(string) != "Hello" {
+					t.Fatalf("expected 'Hello', got %s", input[0])
+				}
+
+				if input[1].(string) != "World" {
+					t.Fatalf("expected 'World', got %s", input[1])
+				}
+
+				if embedReq.Model != "test-model" {
+					t.Fatalf("expected 'test-model', got %s", embedReq.Model)
+				}
+			},
+		},
 	}
 
 	gin.SetMode(gin.TestMode)