support event stream

cmd/webserver.go

@@ -420,6 +420,18 @@ func bindApiWithTokenUpdate(fn core.ApiHandlerFunc, config *settings.Config) gin
 	}
 }
 
+func bindEventStreamApi(fn core.EventStreamApiHandlerFunc) gin.HandlerFunc {
+	return func(ginCtx *gin.Context) {
+		c := core.WrapWebContext(ginCtx)
+		utils.SetEventStreamHeader(c)
+		err := fn(c)
+
+		if err != nil {
+			utils.WriteEventStreamJsonErrorResult(c, err)
+		}
+	}
+}
+
 func bindCachedJs(fn core.DataHandlerFunc, store persistence.CacheStore) gin.HandlerFunc {
 	return cache.CachePage(store, time.Minute, func(ginCtx *gin.Context) {
 		c := core.WrapWebContext(ginCtx)

pkg/core/handler.go

@@ -15,6 +15,9 @@ type MiddlewareHandlerFunc func(*WebContext)
 // ApiHandlerFunc represents the api handler function
 type ApiHandlerFunc func(*WebContext) (any, *errs.Error)
 
+// EventStreamApiHandlerFunc represents the event stream api handler function
+type EventStreamApiHandlerFunc func(*WebContext) *errs.Error
+
 // DataHandlerFunc represents the handler function that returns file data byte array and file name
 type DataHandlerFunc func(*WebContext) ([]byte, string, *errs.Error)
 

pkg/utils/api.go

@@ -1,6 +1,7 @@
 package utils
 
 import (
+	"encoding/json"
 	"net/http"
 	"reflect"
 
@@ -80,6 +81,75 @@ func PrintDataErrorResult(c *core.WebContext, contentType string, err *errs.Erro
 	c.Abort()
 }
 
+// SetEventStreamHeader sets the headers for event stream response
+func SetEventStreamHeader(c *core.WebContext) {
+	c.Writer.Header().Set("Content-Type", "text/event-stream")
+	c.Writer.Header().Set("Cache-Control", "no-cache")
+	c.Writer.Header().Set("Connection", "keep-alive")
+}
+
+func WriteEventStreamJsonSuccessResult(c *core.WebContext, result any) {
+	data, err := json.Marshal(result)
+
+	if err != nil {
+		c.Abort()
+		return
+	}
+
+	_, err = c.Writer.WriteString("data: " + string(data) + "\n\n")
+
+	if err != nil {
+		c.Abort()
+		return
+	}
+
+	c.Writer.Flush()
+}
+
+func WriteEventStreamJsonErrorResult(c *core.WebContext, originalErr *errs.Error) {
+	c.SetResponseError(originalErr)
+
+	errorMessage := originalErr.Error()
+
+	if originalErr.Code() == errs.ErrIncompleteOrIncorrectSubmission.Code() && len(originalErr.BaseError) > 0 {
+		validationErrors, ok := originalErr.BaseError[0].(validator.ValidationErrors)
+
+		if ok {
+			for _, err := range validationErrors {
+				errorMessage = getValidationErrorText(err)
+				break
+			}
+		}
+	}
+
+	result := gin.H{
+		"success":      false,
+		"errorCode":    originalErr.Code(),
+		"errorMessage": errorMessage,
+		"path":         c.Request.URL.Path,
+	}
+
+	if originalErr.Context != nil {
+		result["context"] = originalErr.Context
+	}
+
+	data, err := json.Marshal(result)
+
+	if err != nil {
+		c.Abort()
+		return
+	}
+
+	_, err = c.Writer.WriteString("data: " + string(data) + "\n\n")
+
+	if err != nil {
+		c.Abort()
+		return
+	}
+
+	c.Writer.Flush()
+}
+
 func getValidationErrorText(err validator.FieldError) string {
 	fieldName := GetFirstLowerCharString(err.Field())