Support image input for OpenAI chat compatibility (#5208)

* OpenAI v1 models

* Refactor Writers

* Add Test

Co-Authored-By: Attila Kerekes

* Credit Co-Author

Co-Authored-By: Attila Kerekes <439392+keriati@users.noreply.github.com>

* Empty List Testing

* Use Namespace for Ownedby

* Update Test

* Add back envconfig

* v1/models docs

* Use ModelName Parser

* Test Names

* Remove Docs

* Clean Up

* Test name

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

* Add Middleware for Chat and List

* Testing Cleanup

* Test with Fatal

* Add functionality to chat test

* Support image input for OpenAI chat

* Decoding

* Fix message processing logic

* openai vision test

* type errors

* clean up

* redundant check

* merge conflicts

* merge conflicts

* merge conflicts

* flattening and smaller image

* add test

* support python and js SDKs and mandate prefixing

* clean up

---------

Co-authored-by: Attila Kerekes <439392+keriati@users.noreply.github.com>
Co-authored-by: Jeffrey Morgan <jmorganca@gmail.com>

openai/openai_test.go

@@ -2,6 +2,7 @@ package openai
 
 import (
 	"bytes"
+	"encoding/base64"
 	"encoding/json"
 	"io"
 	"net/http"
@@ -15,6 +16,10 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+const prefix = `data:image/jpeg;base64,`
+const image = `iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=`
+const imageURL = prefix + image
+
 func TestMiddlewareRequests(t *testing.T) {
 	type testCase struct {
 		Name     string
@@ -112,6 +117,50 @@ func TestMiddlewareRequests(t *testing.T) {
 				}
 			},
 		},
+		{
+			Name:    "chat handler with image content",
+			Method:  http.MethodPost,
+			Path:    "/api/chat",
+			Handler: ChatMiddleware,
+			Setup: func(t *testing.T, req *http.Request) {
+				body := ChatCompletionRequest{
+					Model: "test-model",
+					Messages: []Message{
+						{
+							Role: "user", Content: []map[string]any{
+								{"type": "text", "text": "Hello"},
+								{"type": "image_url", "image_url": map[string]string{"url": imageURL}},
+							},
+						},
+					},
+				}
+
+				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 chatReq api.ChatRequest
+				if err := json.NewDecoder(req.Body).Decode(&chatReq); err != nil {
+					t.Fatal(err)
+				}
+
+				if chatReq.Messages[0].Role != "user" {
+					t.Fatalf("expected 'user', got %s", chatReq.Messages[0].Role)
+				}
+
+				if chatReq.Messages[0].Content != "Hello" {
+					t.Fatalf("expected 'Hello', got %s", chatReq.Messages[0].Content)
+				}
+
+				img, _ := base64.StdEncoding.DecodeString(imageURL[len(prefix):])
+
+				if !bytes.Equal(chatReq.Messages[0].Images[0], img) {
+					t.Fatalf("expected image encoding, got %s", chatReq.Messages[0].Images[0])
+				}
+			},
+		},
 	}
 
 	gin.SetMode(gin.TestMode)