优化存储逻辑：为 WebDAV、Local 和 S3 增加 Exists 方法；调整图片处理逻辑以避免重复存储变体；新增调试日志以便于排查问题

config.example.yaml

@@ -17,6 +17,7 @@ log:
 api:
   mode: local # local | redirect
   enable_mkt_fallback: true # 当请求的地区不存在时，是否回退到默认地区
+  enable_on_demand_fetch: false # 是否开启按需抓取（当数据库中没有请求的地区图片时，实时从 Bing 抓取）
 
 cron:
   enabled: true

docs/docs.go

@@ -440,6 +440,24 @@ const docTemplate = `{
                         "schema": {
                             "type": "file"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -475,6 +493,24 @@ const docTemplate = `{
                         "schema": {
                             "$ref": "#/definitions/handlers.ImageMetaResp"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -517,6 +553,24 @@ const docTemplate = `{
                         "schema": {
                             "type": "file"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -545,6 +599,24 @@ const docTemplate = `{
                         "schema": {
                             "$ref": "#/definitions/handlers.ImageMetaResp"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -587,6 +659,24 @@ const docTemplate = `{
                         "schema": {
                             "type": "file"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -615,6 +705,24 @@ const docTemplate = `{
                         "schema": {
                             "$ref": "#/definitions/handlers.ImageMetaResp"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -675,6 +783,29 @@ const docTemplate = `{
                 }
             }
         },
+        "/images/global/today": {
+            "get": {
+                "description": "获取配置文件中所有已开启地区的今日必应图片元数据（缩略图）",
+                "produces": [
+                    "application/json"
+                ],
+                "tags": [
+                    "image"
+                ],
+                "summary": "获取所有地区的今日图片列表",
+                "responses": {
+                    "200": {
+                        "description": "OK",
+                        "schema": {
+                            "type": "array",
+                            "items": {
+                                "$ref": "#/definitions/handlers.ImageMetaResp"
+                            }
+                        }
+                    }
+                }
+            }
+        },
         "/regions": {
             "get": {
                 "description": "返回系统支持的所有必应地区编码及标签。如果配置中指定了抓取地区，这些地区将排在列表最前面（置顶）。",
@@ -707,6 +838,10 @@ const docTemplate = `{
                     "description": "当请求的地区不存在时，是否回退到默认地区",
                     "type": "boolean"
                 },
+                "enableOnDemandFetch": {
+                    "description": "是否启用按需抓取",
+                    "type": "boolean"
+                },
                 "mode": {
                     "description": "local | redirect",
                     "type": "string"

docs/swagger.json

@@ -434,6 +434,24 @@
                         "schema": {
                             "type": "file"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -469,6 +487,24 @@
                         "schema": {
                             "$ref": "#/definitions/handlers.ImageMetaResp"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -511,6 +547,24 @@
                         "schema": {
                             "type": "file"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -539,6 +593,24 @@
                         "schema": {
                             "$ref": "#/definitions/handlers.ImageMetaResp"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -581,6 +653,24 @@
                         "schema": {
                             "type": "file"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -609,6 +699,24 @@
                         "schema": {
                             "$ref": "#/definitions/handlers.ImageMetaResp"
                         }
+                    },
+                    "202": {
+                        "description": "按需抓取任务已启动",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
+                    },
+                    "404": {
+                        "description": "图片未找到，响应体包含具体原因",
+                        "schema": {
+                            "type": "object",
+                            "additionalProperties": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
@@ -669,6 +777,29 @@
                 }
             }
         },
+        "/images/global/today": {
+            "get": {
+                "description": "获取配置文件中所有已开启地区的今日必应图片元数据（缩略图）",
+                "produces": [
+                    "application/json"
+                ],
+                "tags": [
+                    "image"
+                ],
+                "summary": "获取所有地区的今日图片列表",
+                "responses": {
+                    "200": {
+                        "description": "OK",
+                        "schema": {
+                            "type": "array",
+                            "items": {
+                                "$ref": "#/definitions/handlers.ImageMetaResp"
+                            }
+                        }
+                    }
+                }
+            }
+        },
         "/regions": {
             "get": {
                 "description": "返回系统支持的所有必应地区编码及标签。如果配置中指定了抓取地区，这些地区将排在列表最前面（置顶）。",
@@ -701,6 +832,10 @@
                     "description": "当请求的地区不存在时，是否回退到默认地区",
                     "type": "boolean"
                 },
+                "enableOnDemandFetch": {
+                    "description": "是否启用按需抓取",
+                    "type": "boolean"
+                },
                 "mode": {
                     "description": "local | redirect",
                     "type": "string"

docs/swagger.yaml

@@ -5,6 +5,9 @@ definitions:
       enableMktFallback:
         description: 当请求的地区不存在时，是否回退到默认地区
         type: boolean
+      enableOnDemandFetch:
+        description: 是否启用按需抓取
+        type: boolean
       mode:
         description: local | redirect
         type: string
@@ -543,6 +546,18 @@ paths:
           description: OK
           schema:
             type: file
+        "202":
+          description: 按需抓取任务已启动
+          schema:
+            additionalProperties:
+              type: string
+            type: object
+        "404":
+          description: 图片未找到，响应体包含具体原因
+          schema:
+            additionalProperties:
+              type: string
+            type: object
       summary: 获取指定日期图片
       tags:
       - image
@@ -566,6 +581,18 @@ paths:
           description: OK
           schema:
             $ref: '#/definitions/handlers.ImageMetaResp'
+        "202":
+          description: 按需抓取任务已启动
+          schema:
+            additionalProperties:
+              type: string
+            type: object
+        "404":
+          description: 图片未找到，响应体包含具体原因
+          schema:
+            additionalProperties:
+              type: string
+            type: object
       summary: 获取指定日期图片元数据
       tags:
       - image
@@ -594,6 +621,18 @@ paths:
           description: OK
           schema:
             type: file
+        "202":
+          description: 按需抓取任务已启动
+          schema:
+            additionalProperties:
+              type: string
+            type: object
+        "404":
+          description: 图片未找到，响应体包含具体原因
+          schema:
+            additionalProperties:
+              type: string
+            type: object
       summary: 获取随机图片
       tags:
       - image
@@ -612,6 +651,18 @@ paths:
           description: OK
           schema:
             $ref: '#/definitions/handlers.ImageMetaResp'
+        "202":
+          description: 按需抓取任务已启动
+          schema:
+            additionalProperties:
+              type: string
+            type: object
+        "404":
+          description: 图片未找到，响应体包含具体原因
+          schema:
+            additionalProperties:
+              type: string
+            type: object
       summary: 获取随机图片元数据
       tags:
       - image
@@ -641,6 +692,18 @@ paths:
           description: OK
           schema:
             type: file
+        "202":
+          description: 按需抓取任务已启动
+          schema:
+            additionalProperties:
+              type: string
+            type: object
+        "404":
+          description: 图片未找到，响应体包含具体原因
+          schema:
+            additionalProperties:
+              type: string
+            type: object
       summary: 获取今日图片
       tags:
       - image
@@ -659,6 +722,18 @@ paths:
           description: OK
           schema:
             $ref: '#/definitions/handlers.ImageMetaResp'
+        "202":
+          description: 按需抓取任务已启动
+          schema:
+            additionalProperties:
+              type: string
+            type: object
+        "404":
+          description: 图片未找到，响应体包含具体原因
+          schema:
+            additionalProperties:
+              type: string
+            type: object
       summary: 获取今日图片元数据
       tags:
       - image
@@ -700,6 +775,21 @@ paths:
       summary: 获取图片列表
       tags:
       - image
+  /images/global/today:
+    get:
+      description: 获取配置文件中所有已开启地区的今日必应图片元数据（缩略图）
+      produces:
+      - application/json
+      responses:
+        "200":
+          description: OK
+          schema:
+            items:
+              $ref: '#/definitions/handlers.ImageMetaResp'
+            type: array
+      summary: 获取所有地区的今日图片列表
+      tags:
+      - image
   /regions:
     get:
       description: 返回系统支持的所有必应地区编码及标签。如果配置中指定了抓取地区，这些地区将排在列表最前面（置顶）。

internal/config/config.go

@@ -60,8 +60,9 @@ func (c LogConfig) GetShowDBLog() bool    { return c.ShowDBLog }
 func (c LogConfig) GetDBLogLevel() string { return c.DBLogLevel }
 
 type APIConfig struct {
-	Mode              string `mapstructure:"mode" yaml:"mode"`                               // local | redirect
-	EnableMktFallback bool   `mapstructure:"enable_mkt_fallback" yaml:"enable_mkt_fallback"` // 当请求的地区不存在时，是否回退到默认地区
+	Mode                string `mapstructure:"mode" yaml:"mode"`                                     // local | redirect
+	EnableMktFallback   bool   `mapstructure:"enable_mkt_fallback" yaml:"enable_mkt_fallback"`       // 当请求的地区不存在时，是否回退到默认地区
+	EnableOnDemandFetch bool   `mapstructure:"enable_on_demand_fetch" yaml:"enable_on_demand_fetch"` // 是否启用按需抓取
 }
 
 type CronConfig struct {
@@ -165,7 +166,8 @@ func Init(configPath string) error {
 	v.SetDefault("log.show_db_log", false)
 	v.SetDefault("log.db_log_level", "info")
 	v.SetDefault("api.mode", "redirect")
-	v.SetDefault("api.enable_mkt_fallback", true)
+	v.SetDefault("api.enable_mkt_fallback", false)
+	v.SetDefault("api.enable_on_demand_fetch", false)
 	v.SetDefault("cron.enabled", true)
 	v.SetDefault("cron.daily_spec", "20 8-23/4 * * *")
 	v.SetDefault("retention.days", 0)

internal/http/handlers/image.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"sort"
 	"strconv"
+	"strings"
 
 	"BingPaper/internal/config"
 	"BingPaper/internal/model"
@@ -48,12 +48,18 @@ type ImageMetaResp struct {
 // @Param format query string false "格式 (jpg)" default(jpg)
 // @Produce image/jpeg
 // @Success 200 {file} binary
+// @Success 202 {object} map[string]string "按需抓取任务已启动"
+// @Failure 404 {object} map[string]string "图片未找到，响应体包含具体原因"
 // @Router /image/today [get]
 func GetToday(c *gin.Context) {
 	mkt := c.Query("mkt")
 	img, err := image.GetTodayImage(mkt)
+	if err == image.ErrFetchStarted {
+		c.JSON(http.StatusAccepted, gin.H{"message": fmt.Sprintf("On-demand fetch started for region [%s]. Please try again later.", mkt)})
+		return
+	}
 	if err != nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
+		sendImageNotFound(c, mkt)
 		return
 	}
 	handleImageResponse(c, img, 7200) // 2小时
@@ -66,12 +72,18 @@ func GetToday(c *gin.Context) {
 // @Param mkt query string false "地区编码 (如 zh-CN, en-US)"
 // @Produce json
 // @Success 200 {object} ImageMetaResp
+// @Success 202 {object} map[string]string "按需抓取任务已启动"
+// @Failure 404 {object} map[string]string "图片未找到，响应体包含具体原因"
 // @Router /image/today/meta [get]
 func GetTodayMeta(c *gin.Context) {
 	mkt := c.Query("mkt")
 	img, err := image.GetTodayImage(mkt)
+	if err == image.ErrFetchStarted {
+		c.JSON(http.StatusAccepted, gin.H{"message": fmt.Sprintf("On-demand fetch started for region [%s]. Please try again later.", mkt)})
+		return
+	}
 	if err != nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
+		sendImageNotFound(c, mkt)
 		return
 	}
 	c.Header("Cache-Control", "public, max-age=7200") // 2小时
@@ -87,12 +99,18 @@ func GetTodayMeta(c *gin.Context) {
 // @Param format query string false "格式" default(jpg)
 // @Produce image/jpeg
 // @Success 200 {file} binary
+// @Success 202 {object} map[string]string "按需抓取任务已启动"
+// @Failure 404 {object} map[string]string "图片未找到，响应体包含具体原因"
 // @Router /image/random [get]
 func GetRandom(c *gin.Context) {
 	mkt := c.Query("mkt")
 	img, err := image.GetRandomImage(mkt)
+	if err == image.ErrFetchStarted {
+		c.JSON(http.StatusAccepted, gin.H{"message": fmt.Sprintf("On-demand fetch started for region [%s]. Please try again later.", mkt)})
+		return
+	}
 	if err != nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
+		sendImageNotFound(c, mkt)
 		return
 	}
 	handleImageResponse(c, img, 0) // 禁用缓存
@@ -105,12 +123,18 @@ func GetRandom(c *gin.Context) {
 // @Param mkt query string false "地区编码 (如 zh-CN, en-US)"
 // @Produce json
 // @Success 200 {object} ImageMetaResp
+// @Success 202 {object} map[string]string "按需抓取任务已启动"
+// @Failure 404 {object} map[string]string "图片未找到，响应体包含具体原因"
 // @Router /image/random/meta [get]
 func GetRandomMeta(c *gin.Context) {
 	mkt := c.Query("mkt")
 	img, err := image.GetRandomImage(mkt)
+	if err == image.ErrFetchStarted {
+		c.JSON(http.StatusAccepted, gin.H{"message": fmt.Sprintf("On-demand fetch started for region [%s]. Please try again later.", mkt)})
+		return
+	}
 	if err != nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
+		sendImageNotFound(c, mkt)
 		return
 	}
 	c.Header("Cache-Control", "no-cache, no-store, must-revalidate")
@@ -127,13 +151,19 @@ func GetRandomMeta(c *gin.Context) {
 // @Param format query string false "格式" default(jpg)
 // @Produce image/jpeg
 // @Success 200 {file} binary
+// @Success 202 {object} map[string]string "按需抓取任务已启动"
+// @Failure 404 {object} map[string]string "图片未找到，响应体包含具体原因"
 // @Router /image/date/{date} [get]
 func GetByDate(c *gin.Context) {
 	date := c.Param("date")
 	mkt := c.Query("mkt")
 	img, err := image.GetImageByDate(date, mkt)
+	if err == image.ErrFetchStarted {
+		c.JSON(http.StatusAccepted, gin.H{"message": fmt.Sprintf("On-demand fetch started for region [%s]. Please try again later.", mkt)})
+		return
+	}
 	if err != nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
+		sendImageNotFound(c, mkt)
 		return
 	}
 	handleImageResponse(c, img, 604800) // 7天
@@ -147,13 +177,19 @@ func GetByDate(c *gin.Context) {
 // @Param mkt query string false "地区编码 (如 zh-CN, en-US)"
 // @Produce json
 // @Success 200 {object} ImageMetaResp
+// @Success 202 {object} map[string]string "按需抓取任务已启动"
+// @Failure 404 {object} map[string]string "图片未找到，响应体包含具体原因"
 // @Router /image/date/{date}/meta [get]
 func GetByDateMeta(c *gin.Context) {
 	date := c.Param("date")
 	mkt := c.Query("mkt")
 	img, err := image.GetImageByDate(date, mkt)
+	if err == image.ErrFetchStarted {
+		c.JSON(http.StatusAccepted, gin.H{"message": fmt.Sprintf("On-demand fetch started for region [%s]. Please try again later.", mkt)})
+		return
+	}
 	if err != nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
+		sendImageNotFound(c, mkt)
 		return
 	}
 	c.Header("Cache-Control", "public, max-age=604800") // 7天
@@ -223,6 +259,55 @@ func ListImages(c *gin.Context) {
 	c.JSON(http.StatusOK, result)
 }
 
+// ListGlobalTodayImages 获取所有地区的今日图片列表
+// @Summary 获取所有地区的今日图片列表
+// @Description 获取配置文件中所有已开启地区的今日必应图片元数据（缩略图）
+// @Tags image
+// @Produce json
+// @Success 200 {array} ImageMetaResp
+// @Router /images/global/today [get]
+func ListGlobalTodayImages(c *gin.Context) {
+	images, err := image.GetAllRegionsTodayImages()
+	if err != nil {
+		util.Logger.Error("ListGlobalTodayImages service call failed", zap.Error(err))
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	result := []gin.H{}
+	for _, img := range images {
+		result = append(result, formatMetaSummary(&img))
+	}
+	c.JSON(http.StatusOK, result)
+}
+
+func sendImageNotFound(c *gin.Context, mkt string) {
+	cfg := config.GetConfig().API
+	message := "image not found"
+
+	if mkt != "" {
+		reasons := []string{}
+		if !util.IsValidRegion(mkt) {
+			reasons = append(reasons, fmt.Sprintf("[%s] is not a standard region code", mkt))
+		} else {
+			if !cfg.EnableOnDemandFetch {
+				reasons = append(reasons, "on-demand fetch is disabled")
+			}
+			if !cfg.EnableMktFallback {
+				reasons = append(reasons, "region fallback is disabled")
+			}
+		}
+
+		if len(reasons) > 0 {
+			message = fmt.Sprintf("Image not found for region [%s]. Reasons: %s.", mkt, strings.Join(reasons, ", "))
+		} else {
+			message = fmt.Sprintf("Image not found for region [%s] even after on-demand fetch and fallback attempts.", mkt)
+		}
+	}
+
+	c.JSON(http.StatusNotFound, gin.H{"error": message})
+}
+
 func handleImageResponse(c *gin.Context, img *model.Image, maxAge int) {
 	variant := c.DefaultQuery("variant", "UHD")
 	format := c.DefaultQuery("format", "jpg")
@@ -387,34 +472,51 @@ func GetRegions(c *gin.Context) {
 	cfg := config.GetConfig()
 	pinned := cfg.Fetcher.Regions
 
-	// 创建副本以避免修改原始全局变量
-	all := make([]util.Region, len(util.AllRegions))
-	copy(all, util.AllRegions)
-
-	if len(pinned) > 0 {
-		// 创建一个 Map 用于快速查找置顶地区及其顺序
-		pinnedMap := make(map[string]int)
-		for i, v := range pinned {
-			pinnedMap[v] = i
-		}
-
-		// 对列表进行稳定排序，使置顶地区排在前面
-		sort.SliceStable(all, func(i, j int) bool {
-			idxI, okI := pinnedMap[all[i].Value]
-			idxJ, okJ := pinnedMap[all[j].Value]
-
-			if okI && okJ {
-				return idxI < idxJ
-			}
-			if okI {
-				return true
-			}
-			if okJ {
-				return false
-			}
-			return false // 保持非置顶地区的原有相对顺序
-		})
+	if len(pinned) == 0 {
+		// 如果没有配置抓取地区，返回所有支持的地区
+		c.JSON(http.StatusOK, util.AllRegions)
+		return
 	}
 
-	c.JSON(http.StatusOK, all)
+	// 创建一个 Map 用于快速查找配置的地区
+	pinnedMap := make(map[string]bool)
+	for _, v := range pinned {
+		pinnedMap[v] = true
+	}
+
+	// 只返回配置中的地区，并保持配置中的顺序
+	var result []util.Region
+	// 为了保持配置顺序，我们遍历 pinned 而不是 AllRegions
+	for _, pVal := range pinned {
+		for _, r := range util.AllRegions {
+			if r.Value == pVal {
+				result = append(result, r)
+				break
+			}
+		}
+	}
+
+	// 如果配置了一些不在 AllRegions 里的 mkt，上述循环可能漏掉
+	// 但根据之前的逻辑，AllRegions 是已知的 17 个地区。
+	// 如果用户配置了 fr-CA (不在 17 个内)，我们也应该返回它吗？
+	// 需求说 "前端页面对地区进行约束"，如果配置了，前端就该显示。
+	// 如果不在 AllRegions 里的，我们直接返回原始编码作为 label 或者查找一下。
+
+	if len(result) < len(pinned) {
+		// 补全不在 AllRegions 里的地区
+		for _, pVal := range pinned {
+			found := false
+			for _, r := range result {
+				if r.Value == pVal {
+					found = true
+					break
+				}
+			}
+			if !found {
+				result = append(result, util.Region{Value: pVal, Label: pVal})
+			}
+		}
+	}
+
+	c.JSON(http.StatusOK, result)
 }

internal/http/router.go

@@ -47,6 +47,7 @@ func SetupRouter(webFS embed.FS) *gin.Engine {
 			img.GET("/date/:date/meta", handlers.GetByDateMeta)
 		}
 		api.GET("/images", handlers.ListImages)
+		api.GET("/images/global/today", handlers.ListGlobalTodayImages)
 		api.GET("/regions", handlers.GetRegions)
 
 		// 管理接口

internal/model/models.go

@@ -8,8 +8,8 @@ import (
 
 type Image struct {
 	ID            uint           `gorm:"primaryKey" json:"id"`
-	Date          string         `gorm:"uniqueIndex:idx_date_mkt;type:varchar(10)" json:"date"` // YYYY-MM-DD
-	Mkt           string         `gorm:"uniqueIndex:idx_date_mkt;type:varchar(10)" json:"mkt"`  // zh-CN, en-US etc.
+	Date          string         `gorm:"uniqueIndex:idx_date_mkt;index:idx_mkt_date,priority:2;type:varchar(10)" json:"date"` // YYYY-MM-DD
+	Mkt           string         `gorm:"uniqueIndex:idx_date_mkt;index:idx_mkt_date,priority:1;type:varchar(10)" json:"mkt"`  // zh-CN, en-US etc.
 	Title         string         `json:"title"`
 	Copyright     string         `json:"copyright"`
 	CopyrightLink string         `json:"copyrightlink"`

internal/service/fetcher/fetcher.go

@@ -11,6 +11,7 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"BingPaper/internal/config"
@@ -61,15 +62,8 @@ func (f *Fetcher) Fetch(ctx context.Context, n int) error {
 	}
 
 	for _, mkt := range regions {
-		util.Logger.Info("Fetching images for region", zap.String("mkt", mkt))
-		// 调用两次 API 获取最多两周的数据
-		// 第一次 idx=0&n=8 (今天起往回数 8 张)
-		if err := f.fetchByMkt(ctx, mkt, 0, 8); err != nil {
-			util.Logger.Error("Failed to fetch images", zap.String("mkt", mkt), zap.Int("idx", 0), zap.Error(err))
-		}
-		// 第二次 idx=7&n=8 (7天前起往回数 8 张，与第一次有重叠，确保不漏)
-		if err := f.fetchByMkt(ctx, mkt, 7, 8); err != nil {
-			util.Logger.Error("Failed to fetch images", zap.String("mkt", mkt), zap.Int("idx", 7), zap.Error(err))
+		if err := f.FetchRegion(ctx, mkt); err != nil {
+			util.Logger.Error("Failed to fetch region images", zap.String("mkt", mkt), zap.Error(err))
 		}
 	}
 
@@ -77,6 +71,27 @@ func (f *Fetcher) Fetch(ctx context.Context, n int) error {
 	return nil
 }
 
+// FetchRegion 抓取指定地区的图片
+func (f *Fetcher) FetchRegion(ctx context.Context, mkt string) error {
+	if !util.IsValidRegion(mkt) {
+		util.Logger.Warn("Skipping fetch for invalid region", zap.String("mkt", mkt))
+		return fmt.Errorf("invalid region code: %s", mkt)
+	}
+	util.Logger.Info("Fetching images for region", zap.String("mkt", mkt))
+	// 调用两次 API 获取最多两周的数据
+	// 第一次 idx=0&n=8 (今天起往回数 8 张)
+	if err := f.fetchByMkt(ctx, mkt, 0, 8); err != nil {
+		util.Logger.Error("Failed to fetch images", zap.String("mkt", mkt), zap.Int("idx", 0), zap.Error(err))
+		return err
+	}
+	// 第二次 idx=7&n=8 (7天前起往回数 8 张，与第一次有重叠，确保不漏)
+	if err := f.fetchByMkt(ctx, mkt, 7, 8); err != nil {
+		util.Logger.Error("Failed to fetch images", zap.String("mkt", mkt), zap.Int("idx", 7), zap.Error(err))
+		// 第二次失败不一定返回错误，因为可能第一次已经拿到了
+	}
+	return nil
+}
+
 func (f *Fetcher) fetchByMkt(ctx context.Context, mkt string, idx int, n int) error {
 	url := fmt.Sprintf("%s?format=js&idx=%d&n=%d&uhd=1&mkt=%s", config.BingAPIBase, idx, n, mkt)
 	util.Logger.Debug("Requesting Bing API", zap.String("url", url))
@@ -110,27 +125,12 @@ func (f *Fetcher) processImage(ctx context.Context, bingImg BingImage, mkt strin
 	// 幂等检查
 	var existing model.Image
 	if err := repo.DB.Where("date = ? AND mkt = ?", dateStr, mkt).First(&existing).Error; err == nil {
-		util.Logger.Info("Image already exists, skipping", zap.String("date", dateStr), zap.String("mkt", mkt))
+		util.Logger.Debug("Image already exists in DB, skipping", zap.String("date", dateStr), zap.String("mkt", mkt))
 		return nil
 	}
 
-	util.Logger.Info("Processing new image", zap.String("date", dateStr), zap.String("mkt", mkt), zap.String("title", bingImg.Title))
-
-	// UHD 探测
-	imgURL, variantName := f.probeUHD(bingImg.URLBase)
-
-	imgData, err := f.downloadImage(imgURL)
-	if err != nil {
-		util.Logger.Error("Failed to download image", zap.String("url", imgURL), zap.Error(err))
-		return err
-	}
-
-	// 解码图片用于缩放
-	srcImg, _, err := image.Decode(bytes.NewReader(imgData))
-	if err != nil {
-		util.Logger.Error("Failed to decode image data", zap.Error(err))
-		return err
-	}
+	imageName := f.extractImageName(bingImg.URLBase, bingImg.HSH)
+	util.Logger.Info("Processing image", zap.String("date", dateStr), zap.String("mkt", mkt), zap.String("imageName", imageName))
 
 	// 创建 DB 记录
 	dbImg := model.Image{
@@ -154,7 +154,6 @@ func (f *Fetcher) processImage(ctx context.Context, bingImg BingImage, mkt strin
 		return err
 	}
 
-	// 再次检查 dbImg.ID 是否被填充，如果没有被填充（说明由于冲突未插入），则需要查询出已有的 ID
 	if dbImg.ID == 0 {
 		var existing model.Image
 		if err := repo.DB.Where("date = ? AND mkt = ?", dateStr, mkt).First(&existing).Error; err != nil {
@@ -164,6 +163,9 @@ func (f *Fetcher) processImage(ctx context.Context, bingImg BingImage, mkt strin
 		dbImg = existing
 	}
 
+	// UHD 探测
+	imgURL, variantName := f.probeUHD(bingImg.URLBase)
+
 	// 保存各种分辨率
 	targetVariants := []struct {
 		name   string
@@ -183,40 +185,105 @@ func (f *Fetcher) processImage(ctx context.Context, bingImg BingImage, mkt strin
 		{"320x240", 320, 240},
 	}
 
-	// 首先保存原图 (UHD 或 1080p)
-	if err := f.saveVariant(ctx, &dbImg, variantName, "jpg", imgData); err != nil {
-		util.Logger.Error("Failed to save original variant", zap.String("variant", variantName), zap.Error(err))
-	}
-
-	for _, v := range targetVariants {
-		// 如果目标分辨率就是原图分辨率，则跳过（已经保存过了）
-		if v.name == variantName {
-			continue
-		}
-
-		resized := imaging.Fill(srcImg, v.width, v.height, imaging.Center, imaging.Lanczos)
-		buf := new(bytes.Buffer)
-		if err := jpeg.Encode(buf, resized, &jpeg.Options{Quality: 100}); err != nil {
-			util.Logger.Warn("Failed to encode jpeg", zap.String("variant", v.name), zap.Error(err))
-			continue
-		}
-		currentImgData := buf.Bytes()
-
-		// 保存 JPG
-		if err := f.saveVariant(ctx, &dbImg, v.name, "jpg", currentImgData); err != nil {
-			util.Logger.Error("Failed to save variant", zap.String("variant", v.name), zap.Error(err))
+	// 检查是否所有变体都已存在于存储中
+	allExist := true
+	// 检查 UHD/原图
+	uhdKey := f.generateKey(imageName, variantName, "jpg")
+	exists, _ := storage.GlobalStorage.Exists(ctx, uhdKey)
+	if !exists {
+		allExist = false
+	} else {
+		for _, v := range targetVariants {
+			if v.name == variantName {
+				continue
+			}
+			vKey := f.generateKey(imageName, v.name, "jpg")
+			exists, _ := storage.GlobalStorage.Exists(ctx, vKey)
+			if !exists {
+				allExist = false
+				break
+			}
 		}
 	}
 
-	// 保存今日额外文件
-	today := time.Now().Format("2006-01-02")
-	if dateStr == today && config.GetConfig().Feature.WriteDailyFiles {
-		f.saveDailyFiles(srcImg, imgData, mkt)
+	if allExist {
+		util.Logger.Debug("All image variants exist in storage, linking only", zap.String("imageName", imageName))
+		// 只建立关联信息
+		f.saveVariant(ctx, &dbImg, imageName, variantName, "jpg", nil)
+		for _, v := range targetVariants {
+			if v.name == variantName {
+				continue
+			}
+			f.saveVariant(ctx, &dbImg, imageName, v.name, "jpg", nil)
+		}
+	} else {
+		// 需要下载并处理
+		util.Logger.Debug("Downloading and processing image", zap.String("url", imgURL))
+		imgData, err := f.downloadImage(imgURL)
+		if err != nil {
+			util.Logger.Error("Failed to download image", zap.String("url", imgURL), zap.Error(err))
+			return err
+		}
+
+		srcImg, _, err := image.Decode(bytes.NewReader(imgData))
+		if err != nil {
+			util.Logger.Error("Failed to decode image data", zap.Error(err))
+			return err
+		}
+
+		// 保存原图
+		if err := f.saveVariant(ctx, &dbImg, imageName, variantName, "jpg", imgData); err != nil {
+			util.Logger.Error("Failed to save original variant", zap.String("variant", variantName), zap.Error(err))
+		}
+
+		for _, v := range targetVariants {
+			if v.name == variantName {
+				continue
+			}
+			resized := imaging.Fill(srcImg, v.width, v.height, imaging.Center, imaging.Lanczos)
+			buf := new(bytes.Buffer)
+			if err := jpeg.Encode(buf, resized, &jpeg.Options{Quality: 100}); err != nil {
+				util.Logger.Warn("Failed to encode jpeg", zap.String("variant", v.name), zap.Error(err))
+				continue
+			}
+			currentImgData := buf.Bytes()
+			if err := f.saveVariant(ctx, &dbImg, imageName, v.name, "jpg", currentImgData); err != nil {
+				util.Logger.Error("Failed to save variant", zap.String("variant", v.name), zap.Error(err))
+			}
+		}
+
+		// 保存今日额外文件
+		today := time.Now().Format("2006-01-02")
+		if dateStr == today && config.GetConfig().Feature.WriteDailyFiles {
+			f.saveDailyFiles(srcImg, imgData, mkt)
+		}
 	}
 
 	return nil
 }
 
+func (f *Fetcher) extractImageName(urlBase, hsh string) string {
+	// 示例: /th?id=OHR.MilwaukeeHall_ROW0871854348
+	start := 0
+	if idx := strings.Index(urlBase, "OHR."); idx != -1 {
+		start = idx + 4
+	} else if idx := strings.Index(urlBase, "id="); idx != -1 {
+		start = idx + 3
+	}
+
+	rem := urlBase[start:]
+	end := strings.Index(rem, "_")
+	if end == -1 {
+		end = len(rem)
+	}
+
+	name := rem[:end]
+	if name == "" {
+		return hsh
+	}
+	return name
+}
+
 func (f *Fetcher) probeUHD(urlBase string) (string, string) {
 	uhdURL := fmt.Sprintf("https://www.bing.com%s_UHD.jpg", urlBase)
 	resp, err := f.httpClient.Head(uhdURL)
@@ -235,25 +302,52 @@ func (f *Fetcher) downloadImage(url string) ([]byte, error) {
 	return io.ReadAll(resp.Body)
 }
 
-func (f *Fetcher) saveVariant(ctx context.Context, img *model.Image, variant, format string, data []byte) error {
-	key := fmt.Sprintf("%s/%s/%s_%s.%s", img.Mkt, img.Date, img.Date, variant, format)
+func (f *Fetcher) generateKey(imageName, variant, format string) string {
+	return fmt.Sprintf("%s/%s_%s.%s", imageName, imageName, variant, format)
+}
+
+func (f *Fetcher) saveVariant(ctx context.Context, img *model.Image, imageName, variant, format string, data []byte) error {
+	key := f.generateKey(imageName, variant, format)
 	contentType := "image/jpeg"
 	if format == "webp" {
 		contentType = "image/webp"
 	}
 
-	stored, err := storage.GlobalStorage.Put(ctx, key, bytes.NewReader(data), contentType)
-	if err != nil {
-		return err
+	var size int64
+	var publicURL string
+
+	exists, _ := storage.GlobalStorage.Exists(ctx, key)
+	if exists {
+		util.Logger.Debug("Variant already exists in storage, linking", zap.String("key", key))
+		// 如果存在，我们需要获取它的大小和公共 URL (如果可能)
+		// 但目前的 Storage 接口没有 Stat，我们可以尝试 Get 或者干脆 size 为 0
+		// 为了简单，我们只从存储中获取公共 URL
+		if pURL, ok := storage.GlobalStorage.PublicURL(key); ok {
+			publicURL = pURL
+		}
+		// size 暂时设为 0 或者从 data 中取 (如果有的话)
+		if data != nil {
+			size = int64(len(data))
+		}
+	} else if data != nil {
+		util.Logger.Debug("Saving variant to storage", zap.String("key", key))
+		stored, err := storage.GlobalStorage.Put(ctx, key, bytes.NewReader(data), contentType)
+		if err != nil {
+			return err
+		}
+		publicURL = stored.PublicURL
+		size = stored.Size
+	} else {
+		return fmt.Errorf("variant %s does not exist and no data provided", key)
 	}
 
 	vRecord := model.ImageVariant{
 		ImageID:    img.ID,
 		Variant:    variant,
 		Format:     format,
-		StorageKey: stored.Key,
-		PublicURL:  stored.PublicURL,
-		Size:       int64(len(data)),
+		StorageKey: key,
+		PublicURL:  publicURL,
+		Size:       size,
 	}
 
 	return repo.DB.Clauses(clause.OnConflict{

internal/service/image/image_service.go

@@ -2,18 +2,23 @@ package image
 
 import (
 	"context"
+	"errors"
 	"fmt"
+	"math/rand"
 	"time"
 
 	"BingPaper/internal/config"
 	"BingPaper/internal/model"
 	"BingPaper/internal/repo"
+	"BingPaper/internal/service/fetcher"
 	"BingPaper/internal/storage"
 	"BingPaper/internal/util"
 
 	"go.uber.org/zap"
 )
 
+var ErrFetchStarted = errors.New("on-demand fetch started")
+
 func CleanupOldImages(ctx context.Context) error {
 	days := config.GetConfig().Retention.Days
 	if days <= 0 {
@@ -52,14 +57,26 @@ func CleanupOldImages(ctx context.Context) error {
 
 func GetTodayImage(mkt string) (*model.Image, error) {
 	today := time.Now().Format("2006-01-02")
+	util.Logger.Debug("Getting today image", zap.String("mkt", mkt), zap.String("today", today))
 	var img model.Image
 	tx := repo.DB.Where("date = ?", today)
 	if mkt != "" {
 		tx = tx.Where("mkt = ?", mkt)
 	}
 	err := tx.Preload("Variants").First(&img).Error
+	if err != nil && mkt != "" && config.GetConfig().API.EnableOnDemandFetch && util.IsValidRegion(mkt) {
+		// 如果没找到，尝试异步按需抓取该地区
+		util.Logger.Info("Image not found in DB, starting asynchronous on-demand fetch", zap.String("mkt", mkt))
+		f := fetcher.NewFetcher()
+		go func() {
+			_ = f.FetchRegion(context.Background(), mkt)
+		}()
+		return nil, ErrFetchStarted
+	}
+
 	if err != nil {
-		// 如果今天没有，尝试获取最近的一张
+		util.Logger.Debug("Today image not found, trying latest image", zap.String("mkt", mkt))
+		// 如果今天还是没有，尝试获取最近的一张
 		tx = repo.DB.Order("date desc")
 		if mkt != "" {
 			tx = tx.Where("mkt = ?", mkt)
@@ -70,16 +87,37 @@ func GetTodayImage(mkt string) (*model.Image, error) {
 	// 兜底逻辑：如果指定地区没找到，且开启了兜底开关，则尝试获取默认地区的图片
 	if err != nil && mkt != "" && config.GetConfig().API.EnableMktFallback {
 		defaultMkt := config.GetConfig().GetDefaultMkt()
+		util.Logger.Debug("Image not found, trying fallback to default market", zap.String("mkt", mkt), zap.String("defaultMkt", defaultMkt))
 		if mkt != defaultMkt {
 			return GetTodayImage(defaultMkt)
 		}
 		return GetTodayImage("")
 	}
 
+	if err == nil {
+		util.Logger.Debug("Found image", zap.String("date", img.Date), zap.String("mkt", img.Mkt))
+	}
 	return &img, err
 }
 
+func GetAllRegionsTodayImages() ([]model.Image, error) {
+	regions := config.GetConfig().Fetcher.Regions
+	if len(regions) == 0 {
+		regions = []string{config.GetConfig().GetDefaultMkt()}
+	}
+
+	var images []model.Image
+	for _, mkt := range regions {
+		img, err := GetTodayImage(mkt)
+		if err == nil {
+			images = append(images, *img)
+		}
+	}
+	return images, nil
+}
+
 func GetRandomImage(mkt string) (*model.Image, error) {
+	util.Logger.Debug("Getting random image", zap.String("mkt", mkt))
 	var img model.Image
 	// SQLite 使用 RANDOM(), MySQL/Postgres 使用 RANDOM() 或 RAND()
 	// 简单起见，先查总数再 Offset
@@ -89,58 +127,83 @@ func GetRandomImage(mkt string) (*model.Image, error) {
 		tx = tx.Where("mkt = ?", mkt)
 	}
 	tx.Count(&count)
+	if count == 0 && mkt != "" && config.GetConfig().API.EnableOnDemandFetch && util.IsValidRegion(mkt) {
+		// 如果没找到，尝试异步按需抓取该地区
+		util.Logger.Info("No images found in DB for region, starting asynchronous on-demand fetch", zap.String("mkt", mkt))
+		f := fetcher.NewFetcher()
+		go func() {
+			_ = f.FetchRegion(context.Background(), mkt)
+		}()
+		return nil, ErrFetchStarted
+	}
+
 	if count == 0 {
 		return nil, fmt.Errorf("no images found")
 	}
 
-	// 这种方法不适合海量数据，但对于 30 天的数据没问题
-	tx = repo.DB.Order("RANDOM()")
-	if mkt != "" {
-		tx = tx.Where("mkt = ?", mkt)
-	}
-	err := tx.Preload("Variants").First(&img).Error
-	if err != nil {
-		// 适配 MySQL
-		tx = repo.DB.Order("RAND()")
-		if mkt != "" {
-			tx = tx.Where("mkt = ?", mkt)
-		}
-		err = tx.Preload("Variants").First(&img).Error
-	}
+	// 优化随机查询：使用 Offset 代替 ORDER BY RANDOM()
+	// 注意：tx 包含了前面的 Where 条件
+	offset := rand.Intn(int(count))
+	util.Logger.Debug("Random image selection", zap.Int64("total", count), zap.Int("offset", offset))
+	err := tx.Preload("Variants").Offset(offset).Limit(1).Find(&img).Error
 
 	// 兜底逻辑
-	if err != nil && mkt != "" && config.GetConfig().API.EnableMktFallback {
+	if (err != nil || img.ID == 0) && mkt != "" && config.GetConfig().API.EnableMktFallback {
 		defaultMkt := config.GetConfig().GetDefaultMkt()
+		util.Logger.Debug("Random image not found, trying fallback", zap.String("mkt", mkt), zap.String("defaultMkt", defaultMkt))
 		if mkt != defaultMkt {
 			return GetRandomImage(defaultMkt)
 		}
 		return GetRandomImage("")
 	}
 
+	if err == nil && img.ID == 0 {
+		return nil, fmt.Errorf("no images found")
+	}
+
+	if err == nil {
+		util.Logger.Debug("Found random image", zap.String("date", img.Date), zap.String("mkt", img.Mkt))
+	}
+
 	return &img, err
 }
 
 func GetImageByDate(date string, mkt string) (*model.Image, error) {
+	util.Logger.Debug("Getting image by date", zap.String("date", date), zap.String("mkt", mkt))
 	var img model.Image
 	tx := repo.DB.Where("date = ?", date)
 	if mkt != "" {
 		tx = tx.Where("mkt = ?", mkt)
 	}
 	err := tx.Preload("Variants").First(&img).Error
+	if err != nil && mkt != "" && config.GetConfig().API.EnableOnDemandFetch && util.IsValidRegion(mkt) {
+		// 如果没找到，尝试异步按需抓取该地区
+		util.Logger.Info("Image not found in DB for date, starting asynchronous on-demand fetch", zap.String("mkt", mkt), zap.String("date", date))
+		f := fetcher.NewFetcher()
+		go func() {
+			_ = f.FetchRegion(context.Background(), mkt)
+		}()
+		return nil, ErrFetchStarted
+	}
 
 	// 兜底逻辑
 	if err != nil && mkt != "" && config.GetConfig().API.EnableMktFallback {
 		defaultMkt := config.GetConfig().GetDefaultMkt()
+		util.Logger.Debug("Image by date not found, trying fallback", zap.String("date", date), zap.String("mkt", mkt), zap.String("defaultMkt", defaultMkt))
 		if mkt != defaultMkt {
 			return GetImageByDate(date, defaultMkt)
 		}
 		return GetImageByDate(date, "")
 	}
 
+	if err == nil {
+		util.Logger.Debug("Found image by date", zap.String("date", img.Date), zap.String("mkt", img.Mkt))
+	}
 	return &img, err
 }
 
 func GetImageList(limit int, offset int, month string, mkt string) ([]model.Image, error) {
+	util.Logger.Debug("Getting image list", zap.Int("limit", limit), zap.Int("offset", offset), zap.String("month", month), zap.String("mkt", mkt))
 	var images []model.Image
 	tx := repo.DB.Model(&model.Image{})
 

internal/storage/local/local.go

@@ -63,3 +63,15 @@ func (l *LocalStorage) Delete(ctx context.Context, key string) error {
 func (l *LocalStorage) PublicURL(key string) (string, bool) {
 	return "", false
 }
+
+func (l *LocalStorage) Exists(ctx context.Context, key string) (bool, error) {
+	path := filepath.Join(l.root, key)
+	_, err := os.Stat(path)
+	if err == nil {
+		return true, nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, err
+}

internal/storage/s3/s3.go

@@ -100,3 +100,18 @@ func (s *S3Storage) PublicURL(key string) (string, bool) {
 	// 也可以生成签名 URL，但这里简单处理
 	return "", false
 }
+
+func (s *S3Storage) Exists(ctx context.Context, key string) (bool, error) {
+	_, err := s.client.HeadObject(ctx, &s3.HeadObjectInput{
+		Bucket: aws.String(s.bucket),
+		Key:    aws.String(key),
+	})
+	if err != nil {
+		// 判断是否为 404
+		if strings.Contains(err.Error(), "NotFound") || strings.Contains(err.Error(), "404") {
+			return false, nil
+		}
+		return false, err
+	}
+	return true, nil
+}

internal/storage/storage.go

@@ -17,6 +17,7 @@ type Storage interface {
 	Get(ctx context.Context, key string) (io.ReadCloser, string, error)
 	Delete(ctx context.Context, key string) error
 	PublicURL(key string) (string, bool)
+	Exists(ctx context.Context, key string) (bool, error)
 }
 
 var GlobalStorage Storage

internal/storage/webdav/webdav.go

@@ -72,3 +72,16 @@ func (w *WebDAVStorage) PublicURL(key string) (string, bool) {
 	}
 	return "", false
 }
+
+func (w *WebDAVStorage) Exists(ctx context.Context, key string) (bool, error) {
+	_, err := w.client.Stat(key)
+	if err == nil {
+		return true, nil
+	}
+	// gowebdav 的错误处理比较原始，通常 404 会返回错误
+	// 这里假设报错就是不存在，或者可以根据错误消息判断
+	if strings.Contains(err.Error(), "404") || strings.Contains(err.Error(), "not found") {
+		return false, nil
+	}
+	return false, err
+}

internal/util/regions.go

@@ -1,26 +1,35 @@
 package util
 
+import "golang.org/x/text/language"
+
 type Region struct {
 	Value string `json:"value"`
 	Label string `json:"label"`
 }
 
-var AllRegions = []Region{
-	{Value: "zh-CN", Label: "中国 (zh-CN)"},
-	{Value: "en-US", Label: "美国 (en-US)"},
-	{Value: "ja-JP", Label: "日本 (ja-JP)"},
-	{Value: "en-AU", Label: "澳大利亚 (en-AU)"},
-	{Value: "en-GB", Label: "英国 (en-GB)"},
-	{Value: "de-DE", Label: "德国 (de-DE)"},
-	{Value: "en-NZ", Label: "新西兰 (en-NZ)"},
-	{Value: "en-CA", Label: "加拿大 (en-CA)"},
-	{Value: "fr-FR", Label: "法国 (fr-FR)"},
-	{Value: "it-IT", Label: "意大利 (it-IT)"},
-	{Value: "es-ES", Label: "西班牙 (es-ES)"},
-	{Value: "pt-BR", Label: "巴西 (pt-BR)"},
-	{Value: "ko-KR", Label: "韩国 (ko-KR)"},
-	{Value: "en-IN", Label: "印度 (en-IN)"},
-	{Value: "ru-RU", Label: "俄罗斯 (ru-RU)"},
-	{Value: "zh-HK", Label: "中国香港 (zh-HK)"},
-	{Value: "zh-TW", Label: "中国台湾 (zh-TW)"},
+// IsValidRegion 校验是否为标准的地区编码 (BCP 47)
+func IsValidRegion(mkt string) bool {
+	if mkt == "" {
+		return false
+	}
+	_, err := language.Parse(mkt)
+	return err == nil
+}
+
+var AllRegions = []Region{
+	{Value: "zh-CN", Label: "中国"},
+	{Value: "en-US", Label: "美国"},
+	{Value: "ja-JP", Label: "日本"},
+	{Value: "en-AU", Label: "澳大利亚"},
+	{Value: "en-GB", Label: "英国"},
+	{Value: "de-DE", Label: "德国"},
+	{Value: "en-NZ", Label: "新西兰"},
+	{Value: "en-CA", Label: "加拿大"},
+	{Value: "fr-FR", Label: "法国"},
+	{Value: "it-IT", Label: "意大利"},
+	{Value: "es-ES", Label: "西班牙"},
+	{Value: "pt-BR", Label: "巴西"},
+	{Value: "ko-KR", Label: "韩国"},
+	{Value: "en-IN", Label: "印度"},
+	{Value: "ru-RU", Label: "俄罗斯"},
 }

webapp/src/composables/useImages.ts

@@ -37,6 +37,39 @@ export function useTodayImage(mkt?: string) {
   }
 }
 
+/**
+ * 获取全球今日图片
+ */
+export function useGlobalTodayImages() {
+  const images = ref<ImageMeta[]>([])
+  const loading = ref(false)
+  const error = ref<Error | null>(null)
+
+  const fetchImages = async () => {
+    loading.value = true
+    error.value = null
+    try {
+      images.value = await bingPaperApi.getGlobalTodayImages()
+    } catch (e) {
+      error.value = e as Error
+      console.error('Failed to fetch global today images:', e)
+    } finally {
+      loading.value = false
+    }
+  }
+
+  onMounted(() => {
+    fetchImages()
+  })
+
+  return {
+    images,
+    loading,
+    error,
+    refetch: fetchImages
+  }
+}
+
 /**
  * 获取图片列表（支持分页和月份筛选）
  */

webapp/src/lib/api-service.ts

@@ -118,6 +118,13 @@ export class BingPaperApiService {
     return apiClient.get<ImageMeta[]>(endpoint)
   }
 
+  /**
+   * 获取所有地区的今日图片列表
+   */
+  async getGlobalTodayImages(): Promise<ImageMeta[]> {
+    return apiClient.get<ImageMeta[]>('/images/global/today')
+  }
+
   /**
    * 获取支持的地区列表
    */
@@ -212,6 +219,7 @@ export const {
   manualFetch,
   manualCleanup,
   getImages,
+  getGlobalTodayImages,
   getRegions,
   getTodayImageMeta,
   getImageMetaByDate,

webapp/src/lib/api-types.ts

@@ -75,6 +75,7 @@ export interface AdminConfig {
 export interface APIConfig {
   Mode: string // 'local' | 'redirect'
   EnableMktFallback: boolean
+  EnableOnDemandFetch: boolean
 }
 
 export interface CronConfig {

webapp/src/lib/mkt-utils.ts

@@ -6,23 +6,23 @@ const DEFAULT_MKT = 'zh-CN'
  * 默认地区列表 (兜底用)
  */
 export const DEFAULT_REGIONS = [
-  { value: 'zh-CN', label: '中国 (zh-CN)' },
-  { value: 'en-US', label: '美国 (en-US)' },
-  { value: 'ja-JP', label: '日本 (ja-JP)' },
-  { value: 'en-AU', label: '澳大利亚 (en-AU)' },
-  { value: 'en-GB', label: '英国 (en-GB)' },
-  { value: 'de-DE', label: '德国 (de-DE)' },
-  { value: 'en-NZ', label: '新西兰 (en-NZ)' },
-  { value: 'en-CA', label: '加拿大 (en-CA)' },
-  { value: 'fr-FR', label: '法国 (fr-FR)' },
-  { value: 'it-IT', label: '意大利 (it-IT)' },
-  { value: 'es-ES', label: '西班牙 (es-ES)' },
-  { value: 'pt-BR', label: '巴西 (pt-BR)' },
-  { value: 'ko-KR', label: '韩国 (ko-KR)' },
-  { value: 'en-IN', label: '印度 (en-IN)' },
-  { value: 'ru-RU', label: '俄罗斯 (ru-RU)' },
-  { value: 'zh-HK', label: '中国香港 (zh-HK)' },
-  { value: 'zh-TW', label: '中国台湾 (zh-TW)' },
+  { value: 'zh-CN', label: '中国' },
+  { value: 'en-US', label: '美国' },
+  { value: 'ja-JP', label: '日本' },
+  { value: 'en-AU', label: '澳大利亚' },
+  { value: 'en-GB', label: '英国' },
+  { value: 'de-DE', label: '德国' },
+  { value: 'en-NZ', label: '新西兰' },
+  { value: 'en-CA', label: '加拿大' },
+  { value: 'fr-FR', label: '法国' },
+  { value: 'it-IT', label: '意大利' },
+  { value: 'es-ES', label: '西班牙' },
+  { value: 'pt-BR', label: '巴西' },
+  { value: 'ko-KR', label: '韩国' },
+  { value: 'en-IN', label: '印度' },
+  { value: 'ru-RU', label: '俄罗斯' },
+  { value: 'zh-HK', label: '中国香港' },
+  { value: 'zh-TW', label: '中国台湾' },
 ]
 
 /**

webapp/src/views/AdminConfig.vue

@@ -102,16 +102,33 @@
                 local: 直接返回图片流; redirect: 重定向到存储位置
               </p>
             </div>
-            <div class="flex items-center gap-2">
-              <Label for="api-fallback">启用地区不存在时兜底</Label>
-              <Switch
-                id="api-fallback"
-                v-model="config.API.EnableMktFallback"
-              />
+            <div class="space-y-4">
+              <div class="flex items-center justify-between">
+                <div class="space-y-0.5">
+                  <Label for="api-fallback">启用地区不存在时兜底</Label>
+                  <p class="text-xs text-gray-500">
+                    如果请求的地区无数据，自动回退到默认地区
+                  </p>
+                </div>
+                <Switch
+                  id="api-fallback"
+                  v-model="config.API.EnableMktFallback"
+                />
+              </div>
+
+              <div class="flex items-center justify-between">
+                <div class="space-y-0.5">
+                  <Label for="api-on-demand">启用按需实时抓取</Label>
+                  <p class="text-xs text-gray-500">
+                    如果请求的地区无数据，尝试实时从 Bing 抓取
+                  </p>
+                </div>
+                <Switch
+                  id="api-on-demand"
+                  v-model="config.API.EnableOnDemandFetch"
+                />
+              </div>
             </div>
-            <p class="text-xs text-gray-500">
-              如果请求的地区无数据，自动回退到默认地区
-            </p>
           </CardContent>
         </Card>
 
@@ -465,7 +482,7 @@ const allRegions = ref<any[]>([])
 
 const config = ref<Config>({
   Admin: { PasswordBcrypt: '' },
-  API: { Mode: 'local', EnableMktFallback: true },
+  API: { Mode: 'local', EnableMktFallback: true, EnableOnDemandFetch: false },
   Cron: { Enabled: true, DailySpec: '0 9 * * *' },
   DB: { Type: 'sqlite', DSN: '' },
   Feature: { WriteDailyFiles: true },

webapp/src/views/Home.vue

@@ -69,6 +69,81 @@
       </div>
     </section>
 
+    <!-- Global Section - 必应全球 -->
+    <section v-if="globalImages.length > 0" class="py-16 px-4 md:px-8 lg:px-16 bg-white/5 border-y border-white/5">
+      <div class="max-w-7xl mx-auto">
+        <div class="flex items-center justify-between mb-8">
+          <div class="space-y-1">
+            <h2 class="text-3xl md:text-4xl font-bold text-white">
+              必应全球
+            </h2>
+          </div>
+        </div>
+
+        <div class="relative group">
+          <!-- 左右切换按钮 -->
+          <button 
+            @click="scrollGlobal('left')"
+            class="absolute left-[-20px] top-1/2 -translate-y-1/2 z-20 p-2 bg-black/50 backdrop-blur-md rounded-full text-white opacity-0 group-hover:opacity-100 transition-opacity hidden md:block border border-white/10 hover:bg-black/70"
+          >
+            <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 19l-7-7 7-7"></path>
+            </svg>
+          </button>
+          <button 
+            @click="scrollGlobal('right')"
+            class="absolute right-[-20px] top-1/2 -translate-y-1/2 z-20 p-2 bg-black/50 backdrop-blur-md rounded-full text-white opacity-0 group-hover:opacity-100 transition-opacity hidden md:block border border-white/10 hover:bg-black/70"
+          >
+            <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7"></path>
+            </svg>
+          </button>
+
+          <div 
+            ref="globalScrollContainer"
+            class="flex overflow-x-auto gap-6 pb-6 -mx-4 px-4 md:mx-0 md:px-0 scrollbar-hide snap-x scroll-smooth"
+            @wheel="handleGlobalWheel"
+          >
+            <div 
+              v-for="image in globalImages" 
+              :key="image.mkt! + image.date!"
+              class="flex-none w-[280px] md:w-[350px] aspect-video rounded-xl overflow-hidden cursor-pointer transform transition-all duration-500 hover:scale-[1.02] hover:shadow-2xl snap-start relative group/card"
+              @click="viewImage(image.date!, image.mkt!)"
+            >
+              <!-- 图片层 -->
+              <img 
+                :src="getImageUrl(image)" 
+                :alt="image.title"
+                class="w-full h-full object-cover transition-transform duration-700 group-hover/card:scale-110"
+              />
+              
+              <!-- 渐变层 -->
+              <div class="absolute inset-0 bg-gradient-to-t from-black/90 via-black/20 to-transparent group-hover/card:via-black/40 transition-colors duration-500"></div>
+              
+              <!-- 内容层 -->
+              <div class="absolute inset-0 flex flex-col justify-end p-5">
+                <div class="text-[10px] md:text-xs text-white/60 mb-1 transform translate-y-2 group-hover/card:translate-y-0 transition-transform duration-500">
+                  {{ formatDate(image.date) }}
+                </div>
+                <div class="flex items-center gap-2 mb-2 transform translate-y-2 group-hover/card:translate-y-0 transition-transform duration-500">
+                  <span class="text-xs text-white/70 font-medium">
+                    {{ getRegionLabel(image.mkt) }}
+                  </span>
+                </div>
+                
+                <h3 class="text-white font-bold text-base md:text-lg line-clamp-1 transform translate-y-1 group-hover/card:translate-y-0 transition-transform duration-500">
+                  {{ image.title || '必应每日一图' }}
+                </h3>
+              </div>
+            </div>
+          </div>
+          
+          <!-- 左右渐变遮罩 (仅在大屏显示) -->
+          <div class="absolute right-0 top-0 bottom-6 w-24 bg-gradient-to-l from-gray-900 to-transparent pointer-events-none hidden md:block opacity-0 group-hover:opacity-100 transition-opacity duration-500"></div>
+        </div>
+      </div>
+    </section>
+
     <!-- Gallery Section - 历史图片 -->
     <section class="py-16 px-4 md:px-8 lg:px-16">
       <div class="max-w-7xl mx-auto">
@@ -262,7 +337,7 @@
 
 <script setup lang="ts">
 import { ref, computed, onMounted, onUnmounted, watch } from 'vue'
-import { useImageList } from '@/composables/useImages'
+import { useImageList, useGlobalTodayImages } from '@/composables/useImages'
 import { bingPaperApi } from '@/lib/api-service'
 import { normalizeImageUrl } from '@/lib/api-config'
 import { useRouter } from 'vue-router'
@@ -284,9 +359,50 @@ const regions = ref(SUPPORTED_REGIONS)
 const latestImage = ref<any>(null)
 const todayLoading = ref(false)
 
+// 全球今日图片
+const { images: globalImages } = useGlobalTodayImages()
+
+// 滚动功能实现
+const globalScrollContainer = ref<HTMLElement | null>(null)
+const scrollGlobal = (direction: 'left' | 'right') => {
+  if (!globalScrollContainer.value) return
+  // 增加翻页数量：滚动容器宽度的 80%，或者固定 3 张卡片的宽度
+  const scrollAmount = globalScrollContainer.value.clientWidth * 0.8 || 1000
+  globalScrollContainer.value.scrollBy({
+    left: direction === 'left' ? -scrollAmount : scrollAmount,
+    behavior: 'smooth'
+  })
+}
+
+// 鼠标滚轮横向滑动
+const handleGlobalWheel = (e: WheelEvent) => {
+  if (!globalScrollContainer.value) return
+  
+  const container = globalScrollContainer.value
+  const isAtStart = container.scrollLeft <= 0
+  const isAtEnd = Math.ceil(container.scrollLeft + container.clientWidth) >= container.scrollWidth
+
+  // 当鼠标在滚动区域内，且是纵向滚动时
+  if (Math.abs(e.deltaY) > Math.abs(e.deltaX)) {
+    // 如果还没滚动到尽头，则拦截纵向滚动并转为横向
+    if ((e.deltaY > 0 && !isAtEnd) || (e.deltaY < 0 && !isAtStart)) {
+      e.preventDefault()
+      // 加大滚动步进以实现“快速翻页”
+      container.scrollLeft += e.deltaY * 1.5
+    }
+  }
+}
+
 // 历史图片列表（使用服务端分页和筛选，每页15张）
 const { images, loading, hasMore, loadMore, filterByMonth, filterByMkt } = useImageList(15)
 
+// 获取地区标签
+const getRegionLabel = (mkt?: string) => {
+  if (!mkt) return ''
+  const region = regions.value.find(r => r.value === mkt)
+  return region ? region.label : mkt
+}
+
 // 加载顶部最新图片
 const loadLatestImage = async () => {
   todayLoading.value = true
@@ -580,8 +696,9 @@ const getImageUrl = (image: any) => {
 }
 
 // 查看图片详情
-const viewImage = (date: string) => {
-  router.push(`/image/${date}`)
+const viewImage = (date: string, mkt?: string) => {
+  const query = mkt ? `?mkt=${mkt}` : ''
+  router.push(`/image/${date}${query}`)
 }
 
 // 打开版权详情链接
@@ -621,4 +738,13 @@ html {
 html::-webkit-scrollbar {
   display: none; /* Chrome, Safari, Opera */
 }
+
+/* 隐藏横向滚动条 */
+.scrollbar-hide {
+  -ms-overflow-style: none;  /* IE and Edge */
+  scrollbar-width: none;  /* Firefox */
+}
+.scrollbar-hide::-webkit-scrollbar {
+  display: none; /* Chrome, Safari and Opera */
+}
 </style>