fix: thumbnail should show last thumbnail in server in any condition

internal/http/response/file.go

@@ -9,10 +9,12 @@ import (
 	"github.com/go-shiori/shiori/internal/model"
 )
 
-// SendFile sends file to client with caching header
-func SendFile(c *gin.Context, storageDomain model.StorageDomain, path string) {
-	c.Header("Cache-Control", "public, max-age=86400")
+type SendFileOptions struct {
+	Headers []http.Header
+}
 
+// SendFile sends file to client with caching header
+func SendFile(c *gin.Context, storageDomain model.StorageDomain, path string, options *SendFileOptions) {
 	if !storageDomain.FileExists(path) {
 		c.AbortWithStatus(http.StatusNotFound)
 		return
@@ -24,8 +26,17 @@ func SendFile(c *gin.Context, storageDomain model.StorageDomain, path string) {
 		return
 	}
 
+	c.Header("Cache-Control", "public, max-age=86400")
 	c.Header("ETag", fmt.Sprintf("W/%x-%x", info.ModTime().Unix(), info.Size()))
 
+	if options != nil {
+		for _, header := range options.Headers {
+			for key, value := range header {
+				c.Header(key, value[0])
+			}
+		}
+	}
+
 	// TODO: Find a better way to send the file to the client from the FS, probably making a
 	// conversion between afero.Fs and http.FileSystem to use c.FileFromFS.
 	fileContent, err := storageDomain.FS().Open(path)

internal/http/routes/bookmark.go

@@ -165,7 +165,23 @@ func (r *BookmarkRoutes) bookmarkThumbnailHandler(c *gin.Context) {
 		return
 	}
 
-	response.SendFile(c, r.deps.Domains.Storage, model.GetThumbnailPath(bookmark))
+	etag := "w/" + model.GetThumbnailPath(bookmark) + "-" + bookmark.ModifiedAt
+
+	// Check if the client's ETag matches the current ETag
+	if c.GetHeader("If-None-Match") == etag {
+		c.Status(http.StatusNotModified)
+		return
+	}
+
+	options := &response.SendFileOptions{
+		Headers: []http.Header{
+			{"Cache-Control": {"no-cache , must-revalidate"}},
+			{"Last-Modified": {bookmark.ModifiedAt}},
+			{"ETag": {etag}},
+		},
+	}
+
+	response.SendFile(c, r.deps.Domains.Storage, model.GetThumbnailPath(bookmark), options)
 }
 
 func (r *BookmarkRoutes) bookmarkEbookHandler(c *gin.Context) {
@@ -185,5 +201,5 @@ func (r *BookmarkRoutes) bookmarkEbookHandler(c *gin.Context) {
 
 	// TODO: Potentially improve this
 	c.Header("Content-Disposition", `attachment; filename="`+bookmark.Title+`.epub"`)
-	response.SendFile(c, r.deps.Domains.Storage, model.GetEbookPath(bookmark))
+	response.SendFile(c, r.deps.Domains.Storage, model.GetEbookPath(bookmark), nil)
 }