图片压缩

internal/apps/upload/file_server.go

@@ -5,15 +5,22 @@
 package upload
 
 import (
+	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
+	"io"
 	"net/http"
+	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 
 	"github.com/Rain-kl/Wavelet/internal/apps/oauth"
 	"github.com/Rain-kl/Wavelet/internal/common"
 	"github.com/Rain-kl/Wavelet/internal/db"
+	"github.com/Rain-kl/Wavelet/internal/logger"
 	"github.com/Rain-kl/Wavelet/internal/model"
 	"github.com/Rain-kl/Wavelet/internal/storage"
 	"github.com/gin-gonic/gin"
@@ -26,6 +33,8 @@ import (
 // @Tags upload
 // @Produce octet-stream
 // @Param id path string true "文件 ID"
+// @Param compress query string false "是否启用压缩 (传任意非空值代表启用，非图片文件将被忽略)"
+// @Param level query string false "压缩质量等级 (low, medium, high)，默认为 high"
 // @Success 200 {file} file "成功获取文件内容"
 // @Failure 400 {object} util.ResponseAny "文件 ID 格式错误"
 // @Failure 401 {object} util.ResponseAny "未登录"
@@ -33,24 +42,16 @@ import (
 // @Failure 500 {object} util.ResponseAny "服务内部错误"
 // @Router /f/{id} [get]
 func ServeFileByID(c *gin.Context) {
-	c.Header("X-Content-Type-Options", "nosniff")
-	c.Header("Content-Security-Policy", "sandbox")
-
-	idStr := c.Param("id")
-	uploadID, err := strconv.ParseUint(idStr, 10, 64)
+	upload, err := getUploadRecordByID(c)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid upload ID"})
-		return
-	}
-
-	var upload model.Upload
-	if err := db.DB(c.Request.Context()).
-		Where("id = ? AND status IN (?, ?)", uploadID, model.UploadStatusPending, model.UploadStatusUsed).
-		First(&upload).Error; err != nil {
 		if errors.Is(err, gorm.ErrRecordNotFound) {
 			c.AbortWithStatus(http.StatusNotFound)
 			return
 		}
+		if _, ok := err.(*strconv.NumError); ok {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid upload ID"})
+			return
+		}
 		c.AbortWithStatus(http.StatusInternalServerError)
 		return
 	}
@@ -61,6 +62,87 @@ func ServeFileByID(c *gin.Context) {
 		return
 	}
 
+	ServeUpload(c, upload)
+}
+
+// getUploadRecordByID 从请求路径参数中解析文件 ID 并从数据库中检索处于 Pending 或 Used 状态的上传记录。
+// 同时会自动设置通用的安全响应头。
+func getUploadRecordByID(c *gin.Context) (*model.Upload, error) {
+	c.Header("X-Content-Type-Options", "nosniff")
+	c.Header("Content-Security-Policy", "sandbox")
+
+	idStr := c.Param("id")
+	uploadID, err := strconv.ParseUint(idStr, 10, 64)
+	if err != nil {
+		return nil, err
+	}
+
+	var upload model.Upload
+	if err := db.DB(c.Request.Context()).
+		Where("id = ? AND status IN (?, ?)", uploadID, model.UploadStatusPending, model.UploadStatusUsed).
+		First(&upload).Error; err != nil {
+		return nil, err
+	}
+
+	return &upload, nil
+}
+
+// ServeUpload 将已存在的文件内容读取并流式响应给客户端，支持本地和 S3/CDN 驱动，并可选支持 WebP 图片压缩与本地缓存。
+func ServeUpload(c *gin.Context, upload *model.Upload) {
+	compressStr := c.Query("compress")
+	isImage := strings.HasPrefix(strings.ToLower(upload.MimeType), "image/") || isImageExtension(strings.ToLower(upload.Extension))
+
+	if compressStr == "" || !isImage {
+		serveOriginal(c, upload)
+		return
+	}
+
+	// Map level parameter to standard options
+	level := strings.ToLower(c.Query("level"))
+	if level != "low" && level != "medium" && level != "high" {
+		level = "high"
+	}
+
+	// Local cache path for the compressed webp image
+	cachePath := filepath.Join("uploads", "cache", fmt.Sprintf("compressed_%d_%s.webp", upload.ID, level))
+
+	// Check if the compressed file already exists in cache
+	if _, err := os.Stat(cachePath); err == nil {
+		c.Header("Content-Type", "image/webp")
+		c.File(cachePath)
+		return
+	}
+
+	// Cache miss: retrieve original file content
+	origBytes, err := getOriginalFileBytes(c.Request.Context(), upload)
+	if err != nil {
+		logger.ErrorF(c.Request.Context(), "failed to retrieve original file bytes for compression: %v", err)
+		serveOriginal(c, upload)
+		return
+	}
+
+	// Compress to WebP
+	webpBytes, err := CompressImageToWebP(bytes.NewReader(origBytes), level)
+	if err != nil {
+		logger.ErrorF(c.Request.Context(), "failed to compress image to WebP: %v", err)
+		serveOriginal(c, upload)
+		return
+	}
+
+	// Ensure cache directory exists and write cached file
+	if err := os.MkdirAll(filepath.Dir(cachePath), cacheDirPerm); err != nil {
+		logger.ErrorF(c.Request.Context(), "failed to create cache directory: %v", err)
+	} else if err := os.WriteFile(cachePath, webpBytes, cacheFilePerm); err != nil {
+		logger.ErrorF(c.Request.Context(), "failed to write compressed cache file: %v", err)
+	}
+
+	// Serve compressed WebP
+	c.Header("Content-Type", "image/webp")
+	c.Data(http.StatusOK, "image/webp", webpBytes)
+}
+
+// serveOriginal 原始文件的流式响应逻辑
+func serveOriginal(c *gin.Context, upload *model.Upload) {
 	if upload.StorageDriver == "local" || (upload.StorageDriver == "" && !storage.IsEnabled()) {
 		c.File(upload.FilePath)
 		return
@@ -86,6 +168,27 @@ func ServeFileByID(c *gin.Context) {
 	c.DataFromReader(http.StatusOK, obj.ContentLength, obj.ContentType, obj.Body, nil)
 }
 
+// getOriginalFileBytes 获取原始文件所有字节
+func getOriginalFileBytes(ctx context.Context, upload *model.Upload) ([]byte, error) {
+	if upload.StorageDriver == "local" || (upload.StorageDriver == "" && !storage.IsEnabled()) {
+		return os.ReadFile(upload.FilePath)
+	}
+
+	// Retrieve file from S3 (via CDN if configured)
+	obj, err := storage.GetObjectViaCache(ctx, upload.FilePath)
+	if err != nil {
+		return nil, err
+	}
+
+	// Cachefile
+	if obj.CachePath != "" {
+		return os.ReadFile(obj.CachePath)
+	}
+
+	defer func() { _ = obj.Body.Close() }()
+	return io.ReadAll(obj.Body)
+}
+
 // checkFileAccessPermission 校验文件是否可以被当前请求访问
 func checkFileAccessPermission(c *gin.Context, uploadType string) error {
 	var sc model.SystemConfig