Improvements to image endpoints (#96)

- Removed `AltText` from Image definition since it is no longer used.
- Added `Maps` to check for valid file types and content types to make
use of O(1) checks for Sets/Maps.

Author: AlDu2407

admin-app/image.go

@@ -6,14 +6,21 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
-	"slices"
 
 	"github.com/fossoreslp/go-uuid-v4"
 	"github.com/gin-gonic/gin"
 	"github.com/matheusgomes28/urchin/common"
 	"github.com/rs/zerolog/log"
 )
 
+var allowed_extensions = map[string]bool{
+	".jpeg": true, ".jpg": true, ".png": true,
+}
+
+var allowed_content_types = map[string]bool{
+	"image/jpeg": true, "image/png": true, "image/gif": true,
+}
+
 // TODO : need these endpoints
 // r.POST("/images", postImageHandler(&database))
 // r.DELETE("/images", deleteImageHandler(&database))
@@ -38,9 +45,9 @@ func postImageHandler(app_settings common.AppSettings) func(*gin.Context) {
 		}
 
 		file := file_array[0]
-		allowed_types := []string{"image/jpeg", "image/png", "image/gif"}
 		file_content_type := file.Header.Get("content-type")
-		if !slices.Contains(allowed_types, file_content_type) {
+		_, ok := allowed_content_types[file_content_type]
+		if !ok {
 			log.Error().Msgf("file type not supported")
 			c.JSON(http.StatusBadRequest, common.MsgErrorRes("file type not supported"))
 			return
@@ -60,10 +67,10 @@ func postImageHandler(app_settings common.AppSettings) func(*gin.Context) {
 			return
 		}
 
-		allowed_extensions := []string{"jpeg", "jpg", "png"}
 		ext := filepath.Ext(file.Filename)
 		// check ext is supported
-		if ext == "" && slices.Contains(allowed_extensions, ext) {
+		_, ok = allowed_extensions[ext]
+		if ext == "" || !ok {
 			log.Error().Msgf("file extension is not supported %v", err)
 			c.JSON(http.StatusBadRequest, common.ErrorRes("file extension is not supported", err))
 			return

app/image.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"os"
 	"path"
-	"slices"
 	"strconv"
 
 	"github.com/gin-gonic/gin"
@@ -14,9 +13,18 @@ import (
 	"github.com/rs/zerolog/log"
 )
 
+// Since there are no builtin sets in go, we are using a map to improve the performance when checking for valid extensions
+// by creating a map with the valid extensions as keys and using an existence check.
+var valid_extensions = map[string]bool{
+	".jpg":  true,
+	".jpeg": true,
+	".png":  true,
+	".gif":  true,
+}
+
 func imagesHandler(c *gin.Context, app_settings common.AppSettings, database database.Database) ([]byte, error) {
 	// TODO: Implement rendering.
-	pageNum := 0 // Default to page 0
+	pageNum := 1 // Default to page 0
 	if pageNumQuery := c.Param("num"); pageNumQuery != "" {
 		num, err := strconv.Atoi(pageNumQuery)
 		if err == nil && num > 0 {
@@ -27,7 +35,7 @@ func imagesHandler(c *gin.Context, app_settings common.AppSettings, database dat
 	}
 
 	limit := 10 // or whatever limit you want
-	offset := max((pageNum-1)*limit, 0)
+	offset := (pageNum - 1) * limit
 
 	// Get all the files inside the image directory
 	files, err := os.ReadDir(app_settings.ImageDirectory)
@@ -38,9 +46,7 @@ func imagesHandler(c *gin.Context, app_settings common.AppSettings, database dat
 
 	// Filter all the non-images out of the list
 	valid_images := make([]common.Image, 0)
-	valid_extensions := []string{".jpg", ".jpeg", ".png", ".gif"}
 	for n, file := range files {
-
 		// TODO : This is surely not the best way
 		//        to implement pagination in for loops
 		if n >= limit {
@@ -53,16 +59,19 @@ func imagesHandler(c *gin.Context, app_settings common.AppSettings, database dat
 
 		filename := file.Name()
 		ext := path.Ext(file.Name())
-		if slices.Contains(valid_extensions, ext) {
-
-			image := common.Image{
-				Uuid:    filename[:len(filename)-len(ext)],
-				Name:    filename,
-				AltText: "undefined", // TODO : perhaps remove this
-				Ext:     ext,
-			}
-			valid_images = append(valid_images, image)
+		// Checking for the existence of a value in a map takes O(1) and therefore it's faster than
+		// iterating over a string slice
+		_, ok := valid_extensions[ext]
+		if !ok {
+			continue
+		}
+
+		image := common.Image{
+			Uuid: filename[:len(filename)-len(ext)],
+			Name: filename,
+			Ext:  ext,
 		}
+		valid_images = append(valid_images, image)
 	}
 
 	index_view := views.MakeImagesPage(valid_images, app_settings.AppNavbar.Links)
@@ -89,10 +98,9 @@ func imageHandler(c *gin.Context, app_settings common.AppSettings, database data
 	name := filename[:len(filename)-len(ext)]
 
 	image := common.Image{
-		Uuid:    name,
-		Name:    filename,
-		AltText: "undefined",
-		Ext:     ext,
+		Uuid: name,
+		Name: filename,
+		Ext:  ext,
 	}
 	index_view := views.MakeImagePage(image, app_settings.AppNavbar.Links)
 	html_buffer := bytes.NewBuffer(nil)

common/image.go

@@ -1,8 +1,7 @@
 package common
 
 type Image struct {
-	Uuid    string `json:"uuid"`
-	Name    string `json:"name"`
-	AltText string `json:"alt_text"`
-	Ext     string `json:"extension"`
+	Uuid string `json:"uuid"`
+	Name string `json:"name"`
+	Ext  string `json:"extension"`
 }

views/image.templ

@@ -23,8 +23,7 @@ templ MakeImagePage(image Image, links []Link) {
         <main>
             <article>
             <h3>{ image.Name }</h3>
-            <img src={fmt.Sprintf("/images/data/%s", image.Name)} alt={image.AltText} />
-            <p>{ image.AltText }</p>
+            <img src={fmt.Sprintf("/images/data/%s", image.Name)} />
             </article>
         </main>
         <a href={templ.URL("/images")}>Back</a>

views/images.templ

@@ -48,7 +48,7 @@ templ MakeImagesPage(images []Image, links []Link) {
                     for _, image := range images {
                         <a href={templ.URL("/images/" + image.Name)}>
                             <div>
-                                <img src={fmt.Sprintf("/images/data/%s", image.Name)} alt={image.AltText} />
+                                <img src={fmt.Sprintf("/images/data/%s", image.Name)} />
                                 <span>{image.Name}</span>
                             </div>
                         </a>