From 02a5292f2fd9ec911914e628a4cd1fee454e5a99 Mon Sep 17 00:00:00 2001
From: Zach Fuller <zach.fuller1222@gmail.com>
Date: Wed, 3 Apr 2024 17:53:56 -0700
Subject: [PATCH] Feat/13 create alt sizes for uploaded files (#15)

* Logging with Slog + Fixed Get File (#8)

* logging with slog

* added path prefix to file being returned

* Added default cors config (#14)

* setup empty func 'createAltSizes' that will be called at the end of 'saveFile'

* removed a couple comments

* new file to house functions for resizing uploaded files

* printing out dimensions of src file

* creating new image with half-sized dimensions. wip: copying over image contents to resized img

* successfully copied image using same dimensions

* able to create image at 1/4 the og dimensions

* renamed functions, now creates 2 alts sizes on file upload

* fixed file prefix
---
 main.go    | 10 +++------
 resizer.go | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 7 deletions(-)
 create mode 100644 resizer.go

diff --git a/main.go b/main.go
index 22c121e..b2db088 100644
--- a/main.go
+++ b/main.go
@@ -39,6 +39,7 @@ type UploadedFiles struct {
 }
 
 const FilePrefix = "/opt/picloud/uploads/"
+
 // const FilePrefix = "uploads/" // localhost
 
 // global var initialized before API to store info on the server's uploaded files
@@ -46,7 +47,6 @@ var uploadedFiles UploadedFiles
 
 func loadFileMetadata() UploadedFiles {
 	var files UploadedFiles
-	// check if file exists
 	if _, err := os.Stat("metadata.json"); err == nil {
 		data, err := os.ReadFile("metadata.json")
 		if err != nil {
@@ -71,7 +71,6 @@ func loadFileMetadata() UploadedFiles {
 }
 
 func writeFileMetadata() {
-	// write file metadata to file
 	data, err := json.Marshal(uploadedFiles)
 	if err != nil {
 		panic(err)
@@ -82,7 +81,6 @@ func writeFileMetadata() {
 	}
 }
 
-// buildLink returns a link to be used in the FileMetadata struct on initialization
 func buildLink(rawFilename string) string {
 	return fmt.Sprintf("http://pi.local:1234/file/%s", url.QueryEscape(rawFilename))
 }
@@ -120,6 +118,7 @@ func saveFile(c echo.Context) error {
 	tags := form.Value["tags"]
 	uploadedFiles.Files = append(uploadedFiles.Files, FileMetadata{Name: file.Filename, Tags: tags, Link: buildLink(file.Filename)})
 	go writeFileMetadata()
+	go createAltSizes(file.Filename)
 	return c.String(http.StatusOK, fmt.Sprintf("File %s uploaded successfully!", file.Filename))
 }
 
@@ -206,7 +205,6 @@ func getAvif(c echo.Context) error {
 		slog.Error("Error decoding image")
 		return err
 	}
-	slog.Debug("Image decoded successfully")
 
 	// encode the img as avif file
 	err = avif.Encode(dstFile, img, nil)
@@ -222,14 +220,11 @@ func getAvif(c echo.Context) error {
 
 // e.GET("/files", listFiles)
 func listFiles(c echo.Context) error {
-	// list all available files
 	return c.JSON(http.StatusOK, uploadedFiles)
 }
 
 // e.GET("/files/search", searchFiles)
 func searchFiles(c echo.Context) error {
-	// search for files by tag
-	// get the tag from the request
 	tag := c.QueryParam("tag")
 	// search for the tag in the uploadedFiles
 	var foundFiles []FileMetadata
@@ -274,6 +269,7 @@ func main() {
 			return nil
 		},
 	}))
+	e.Use(middleware.CORS())
 	e.GET("/", func(c echo.Context) error {
 		return c.String(http.StatusOK, "Hello, World!")
 	})
diff --git a/resizer.go b/resizer.go
new file mode 100644
index 0000000..6d17b19
--- /dev/null
+++ b/resizer.go
@@ -0,0 +1,64 @@
+package main
+
+import (
+	"fmt"
+	"image"
+	"image/jpeg"
+	"log/slog"
+	"os"
+)
+
+func writeNewImg(img *image.Image, scale int, filename string) error {
+	// create destination file
+	dstFile, err := os.Create(fmt.Sprintf("%s-%d.jpeg", filename, scale))
+	if err != nil {
+		return err
+	}
+	defer dstFile.Close()
+
+	// create new image
+	maxX := (*img).Bounds().Dx() / scale
+	maxY := (*img).Bounds().Dy() / scale
+	// newImg := image.NewRGBA((*img).Bounds())
+	newImg := image.NewRGBA(image.Rect(0, 0, maxX, maxY))
+	fmt.Printf("New image bounds: %v\n", newImg.Bounds())
+
+	for y := range (*newImg).Bounds().Dy() {
+		for x := range (*newImg).Bounds().Dx() {
+			newImg.Set(x, y, (*img).At(x*scale, y*scale))
+		}
+	}
+
+	err = jpeg.Encode(dstFile, newImg, nil)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func createAltSizes(srcPath string) {
+	slog.Info(fmt.Sprintf("Creating alt sizes for %s", srcPath))
+	srcFile, err := os.Open(srcPath)
+	if err != nil {
+		panic(err)
+	}
+	defer srcFile.Close()
+
+	img, err := jpeg.Decode(srcFile)
+	if err != nil {
+		slog.Error("Error decoding image")
+		panic(err)
+	}
+
+	filename := srcFile.Name()
+	// Create medium img at 1/4 size
+	err = writeNewImg(&img, 4, filename)
+	if err != nil {
+		panic(err)
+	}
+	// Create icon image at 1/10 size
+	err = writeNewImg(&img, 10, filename)
+	if err != nil {
+		panic(err)
+	}
+}