feat: implement memos chat backend function (#1934)

* feat: implment backend function

* eslint

* eslint

* eslint

api/v1/openai.go

+package v1
+
+import (
+	"encoding/json"
+	"net/http"
+	"time"
+
+	echosse "github.com/CorrectRoadH/echo-sse"
+	"github.com/PullRequestInc/go-gpt3"
+	"github.com/labstack/echo/v4"
+	"github.com/usememos/memos/plugin/openai"
+	"github.com/usememos/memos/store"
+)
+
+func (s *APIV1Service) registerOpenAIRoutes(g *echo.Group) {
+	g.POST("/openai/chat-completion", func(c echo.Context) error {
+		ctx := c.Request().Context()
+		openAIConfigSetting, err := s.Store.GetSystemSetting(ctx, &store.FindSystemSetting{
+			Name: SystemSettingOpenAIConfigName.String(),
+		})
+		if err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, "Failed to find openai key").SetInternal(err)
+		}
+
+		openAIConfig := OpenAIConfig{}
+		if openAIConfigSetting != nil {
+			err = json.Unmarshal([]byte(openAIConfigSetting.Value), &openAIConfig)
+			if err != nil {
+				return echo.NewHTTPError(http.StatusInternalServerError, "Failed to unmarshal openai system setting value").SetInternal(err)
+			}
+		}
+		if openAIConfig.Key == "" {
+			return echo.NewHTTPError(http.StatusBadRequest, "OpenAI API key not set")
+		}
+
+		messages := []openai.ChatCompletionMessage{}
+		if err := json.NewDecoder(c.Request().Body).Decode(&messages); err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest, "Malformatted post chat completion request").SetInternal(err)
+		}
+		if len(messages) == 0 {
+			return echo.NewHTTPError(http.StatusBadRequest, "No messages provided")
+		}
+
+		result, err := openai.PostChatCompletion(messages, openAIConfig.Key, openAIConfig.Host)
+		if err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, "Failed to post chat completion").SetInternal(err)
+		}
+
+		return c.JSON(http.StatusOK, result)
+	})
+
+	g.POST("/openai/chat-streaming", func(c echo.Context) error {
+		messages := []gpt3.ChatCompletionRequestMessage{}
+		if err := json.NewDecoder(c.Request().Body).Decode(&messages); err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest, "Malformatted post chat completion request").SetInternal(err)
+		}
+		if len(messages) == 0 {
+			return echo.NewHTTPError(http.StatusBadRequest, "No messages provided")
+		}
+
+		ctx := c.Request().Context()
+		openAIConfigSetting, err := s.Store.GetSystemSetting(ctx, &store.FindSystemSetting{
+			Name: SystemSettingOpenAIConfigName.String(),
+		})
+		if err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, "Failed to find openai key").SetInternal(err)
+		}
+
+		openAIConfig := OpenAIConfig{}
+		if openAIConfigSetting != nil {
+			err = json.Unmarshal([]byte(openAIConfigSetting.Value), &openAIConfig)
+			if err != nil {
+				return echo.NewHTTPError(http.StatusInternalServerError, "Failed to unmarshal openai system setting value").SetInternal(err)
+			}
+		}
+		if openAIConfig.Key == "" {
+			return echo.NewHTTPError(http.StatusBadRequest, "OpenAI API key not set")
+		}
+
+		sse := echosse.NewSSEClint(c)
+
+		// to do these things in server may not elegant.
+		// But move it to openai plugin will break the simple. Because it is a streaming. We must use a channel to do it.
+		// And we can think it is a forward proxy. So it in here is not a bad idea.
+		client := gpt3.NewClient(openAIConfig.Key)
+		err = client.ChatCompletionStream(ctx, gpt3.ChatCompletionRequest{
+			Model:    gpt3.GPT3Dot5Turbo,
+			Messages: messages,
+			Stream:   true,
+		},
+			func(resp *gpt3.ChatCompletionStreamResponse) {
+				// _ is for to pass the golangci-lint check
+				_ = sse.SendEvent(resp.Choices[0].Delta.Content)
+
+				// to delay 0.5 s
+				time.Sleep(50 * time.Millisecond)
+				// the delay is a very good way to make the chatbot more comfortable
+				// otherwise the chatbot will reply too fast. Believe me it is not good.🤔
+			})
+
+		if err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, "Failed to chat with OpenAI").SetInternal(err)
+		}
+
+		return nil
+	})
+
+	g.GET("/openai/enabled", func(c echo.Context) error {
+		ctx := c.Request().Context()
+		openAIConfigSetting, err := s.Store.GetSystemSetting(ctx, &store.FindSystemSetting{
+			Name: SystemSettingOpenAIConfigName.String(),
+		})
+		if err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, "Failed to find openai key").SetInternal(err)
+		}
+
+		openAIConfig := OpenAIConfig{}
+		if openAIConfigSetting != nil {
+			err = json.Unmarshal([]byte(openAIConfigSetting.Value), &openAIConfig)
+			if err != nil {
+				return echo.NewHTTPError(http.StatusInternalServerError, "Failed to unmarshal openai system setting value").SetInternal(err)
+			}
+		}
+		if openAIConfig.Key == "" {
+			return echo.NewHTTPError(http.StatusBadRequest, "OpenAI API key not set")
+		}
+
+		return c.JSON(http.StatusOK, openAIConfig.Key != "")
+	})
+}

api/v1/system_setting.go

@@ -37,6 +37,8 @@ const (
 	SystemSettingTelegramBotTokenName SystemSettingName = "telegram-bot-token"
 	// SystemSettingMemoDisplayWithUpdatedTsName is the name of memo display with updated ts.
 	SystemSettingMemoDisplayWithUpdatedTsName SystemSettingName = "memo-display-with-updated-ts"
+	// SystemSettingOpenAIConfigName is the name of OpenAI config.
+	SystemSettingOpenAIConfigName SystemSettingName = "openai-config"
 )
 
 // CustomizedProfile is the struct definition for SystemSettingCustomizedProfileName system setting item.
@@ -66,6 +68,11 @@ type SystemSetting struct {
 	Description string `json:"description"`
 }
 
+type OpenAIConfig struct {
+	Key  string `json:"key"`
+	Host string `json:"host"`
+}
+
 type UpsertSystemSettingRequest struct {
 	Name        SystemSettingName `json:"name"`
 	Value       string            `json:"value"`
@@ -127,6 +134,11 @@ func (upsert UpsertSystemSettingRequest) Validate() error {
 		if err := json.Unmarshal([]byte(upsert.Value), &value); err != nil {
 			return fmt.Errorf(systemSettingUnmarshalError, settingName)
 		}
+	case SystemSettingOpenAIConfigName:
+		value := OpenAIConfig{}
+		if err := json.Unmarshal([]byte(upsert.Value), &value); err != nil {
+			return fmt.Errorf(systemSettingUnmarshalError, settingName)
+		}
 	case SystemSettingTelegramBotTokenName:
 		if upsert.Value == "" {
 			return nil

api/v1/v1.go

@@ -43,6 +43,7 @@ func (s *APIV1Service) Register(rootGroup *echo.Group) {
 	s.registerMemoOrganizerRoutes(apiV1Group)
 	s.registerMemoResourceRoutes(apiV1Group)
 	s.registerMemoRelationRoutes(apiV1Group)
+	s.registerOpenAIRoutes(apiV1Group)
 
 	// Register public routes.
 	publicGroup := rootGroup.Group("/o")

go.mod

@@ -3,6 +3,8 @@ module github.com/usememos/memos
 go 1.19
 
 require (
+	github.com/CorrectRoadH/echo-sse v0.1.4
+	github.com/PullRequestInc/go-gpt3 v1.1.15
 	github.com/aws/aws-sdk-go-v2 v1.17.4
 	github.com/aws/aws-sdk-go-v2/config v1.18.12
 	github.com/aws/aws-sdk-go-v2/credentials v1.13.12

server/server.go

@@ -64,6 +64,11 @@ func NewServer(ctx context.Context, profile *profile.Profile, store *store.Store
 	}))
 
 	e.Use(middleware.TimeoutWithConfig(middleware.TimeoutConfig{
+		Skipper: func(c echo.Context) bool {
+			// this is a hack to skip timeout for openai chat streaming
+			// because streaming require to flush response. But the timeout middleware will break it.
+			return c.Request().URL.Path == "/api/openai/chat-streaming"
+		},
 		ErrorMessage: "Request timeout",
 		Timeout:      30 * time.Second,
 	}))