refactor: Introduce standardized API error

This commit refactors the application's error handling mechanism by introducing a new standardized error type, `types.NewAPIError`. It also renames common JSON utility functions for better clarity.

Previously, internal error handling was tightly coupled to the `dto.OpenAIError` format. This change decouples the internal logic from the external API representation.

Key changes:
- A new `types.NewAPIError` struct is introduced to serve as a canonical internal representation for all API errors.
- All relay adapters (OpenAI, Claude, Gemini, etc.) are updated to return `*types.NewAPIError`.
- Controllers now convert the internal `NewAPIError` to the client-facing `OpenAIError` format at the API boundary, ensuring backward compatibility.
- Channel auto-disable/enable logic is updated to use the new standardized error type.
- JSON utility functions are renamed to align with Go's standard library conventions (e.g., `UnmarshalJson` -> `Unmarshal`, `EncodeJson` -> `Marshal`).

relay/channel/gemini/relay-gemini.go

@@ -2,6 +2,7 @@ package gemini
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -12,6 +13,7 @@ import (
 	"one-api/relay/helper"
 	"one-api/service"
 	"one-api/setting/model_setting"
+	"one-api/types"
 	"strconv"
 	"strings"
 	"unicode/utf8"
@@ -792,7 +794,7 @@ func streamResponseGeminiChat2OpenAI(geminiResponse *GeminiChatResponse) (*dto.C
 	return &response, isStop, hasImage
 }
 
-func GeminiChatStreamHandler(c *gin.Context, resp *http.Response, info *relaycommon.RelayInfo) (*dto.OpenAIErrorWithStatusCode, *dto.Usage) {
+func GeminiChatStreamHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.Response) (*dto.Usage, *types.NewAPIError) {
 	// responseText := ""
 	id := helper.GetResponseID(c)
 	createAt := common.GetTimestamp()
@@ -858,33 +860,25 @@ func GeminiChatStreamHandler(c *gin.Context, resp *http.Response, info *relaycom
 	}
 	helper.Done(c)
 	//resp.Body.Close()
-	return nil, usage
+	return usage, nil
 }
 
-func GeminiChatHandler(c *gin.Context, resp *http.Response, info *relaycommon.RelayInfo) (*dto.OpenAIErrorWithStatusCode, *dto.Usage) {
+func GeminiChatHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.Response) (*dto.Usage, *types.NewAPIError) {
 	responseBody, err := io.ReadAll(resp.Body)
 	if err != nil {
-		return service.OpenAIErrorWrapper(err, "read_response_body_failed", http.StatusInternalServerError), nil
+		return nil, types.NewError(err, types.ErrorCodeBadResponseBody)
 	}
 	common.CloseResponseBodyGracefully(resp)
 	if common.DebugEnabled {
 		println(string(responseBody))
 	}
 	var geminiResponse GeminiChatResponse
-	err = common.UnmarshalJson(responseBody, &geminiResponse)
+	err = common.Unmarshal(responseBody, &geminiResponse)
 	if err != nil {
-		return service.OpenAIErrorWrapper(err, "unmarshal_response_body_failed", http.StatusInternalServerError), nil
+		return nil, types.NewError(err, types.ErrorCodeBadResponseBody)
 	}
 	if len(geminiResponse.Candidates) == 0 {
-		return &dto.OpenAIErrorWithStatusCode{
-			Error: dto.OpenAIError{
-				Message: "No candidates returned",
-				Type:    "server_error",
-				Param:   "",
-				Code:    500,
-			},
-			StatusCode: resp.StatusCode,
-		}, nil
+		return nil, types.NewError(errors.New("no candidates returned"), types.ErrorCodeBadResponseBody)
 	}
 	fullTextResponse := responseGeminiChat2OpenAI(c, &geminiResponse)
 	fullTextResponse.Model = info.UpstreamModelName
@@ -908,25 +902,25 @@ func GeminiChatHandler(c *gin.Context, resp *http.Response, info *relaycommon.Re
 	fullTextResponse.Usage = usage
 	jsonResponse, err := json.Marshal(fullTextResponse)
 	if err != nil {
-		return service.OpenAIErrorWrapper(err, "marshal_response_body_failed", http.StatusInternalServerError), nil
+		return nil, types.NewError(err, types.ErrorCodeBadResponseBody)
 	}
 	c.Writer.Header().Set("Content-Type", "application/json")
 	c.Writer.WriteHeader(resp.StatusCode)
-	_, err = c.Writer.Write(jsonResponse)
-	return nil, &usage
+	c.Writer.Write(jsonResponse)
+	return &usage, nil
 }
 
-func GeminiEmbeddingHandler(c *gin.Context, resp *http.Response, info *relaycommon.RelayInfo) (usage any, err *dto.OpenAIErrorWithStatusCode) {
+func GeminiEmbeddingHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http.Response) (*dto.Usage, *types.NewAPIError) {
 	defer common.CloseResponseBodyGracefully(resp)
 
 	responseBody, readErr := io.ReadAll(resp.Body)
 	if readErr != nil {
-		return nil, service.OpenAIErrorWrapper(readErr, "read_response_body_failed", http.StatusInternalServerError)
+		return nil, types.NewError(readErr, types.ErrorCodeBadResponseBody)
 	}
 
 	var geminiResponse GeminiEmbeddingResponse
-	if jsonErr := json.Unmarshal(responseBody, &geminiResponse); jsonErr != nil {
-		return nil, service.OpenAIErrorWrapper(jsonErr, "unmarshal_response_body_failed", http.StatusInternalServerError)
+	if jsonErr := common.Unmarshal(responseBody, &geminiResponse); jsonErr != nil {
+		return nil, types.NewError(jsonErr, types.ErrorCodeBadResponseBody)
 	}
 
 	// convert to openai format response
@@ -947,16 +941,16 @@ func GeminiEmbeddingHandler(c *gin.Context, resp *http.Response, info *relaycomm
 	// Google has not yet clarified how embedding models will be billed
 	// refer to openai billing method to use input tokens billing
 	// https://platform.openai.com/docs/guides/embeddings#what-are-embeddings
-	usage = &dto.Usage{
+	usage := &dto.Usage{
 		PromptTokens:     info.PromptTokens,
 		CompletionTokens: 0,
 		TotalTokens:      info.PromptTokens,
 	}
-	openAIResponse.Usage = *usage.(*dto.Usage)
+	openAIResponse.Usage = *usage
 
-	jsonResponse, jsonErr := common.EncodeJson(openAIResponse)
+	jsonResponse, jsonErr := common.Marshal(openAIResponse)
 	if jsonErr != nil {
-		return nil, service.OpenAIErrorWrapper(jsonErr, "marshal_response_failed", http.StatusInternalServerError)
+		return nil, types.NewError(jsonErr, types.ErrorCodeBadResponseBody)
 	}
 
 	common.IOCopyBytesGracefully(c, resp, jsonResponse)