pdf-diff server edition

.gitignore

@@ -15,4 +15,6 @@
 # vendor/
 
 *.pdf
-generated/
+generated/
+data/
+pdf-diff

README.md

@@ -42,6 +42,15 @@ go build
 
 Once ran, the images are created in the folder `generated`.
 
+#### Available flags
+
+A list of common flags that you can use via `pdf-diff` is provided in the following table.
+
+Name | Description
+-- | --
+`color` | this flag can be used to specify the background color that is composed for highlighting pdf differences
+`server` | this flag can be used to enable a web ui
+
 ### Contact
 
 If you wish to use this for your project, go ahead. If you have any issues or improvements, feel free to open a new [ISSUE](https://github.com/serhack/pdf-diff/issues). Lastly, if you have a good algorithm to implement or just to discuss about any other tools for editor, you can [email me]([email protected]).

main.go

@@ -21,6 +21,7 @@ type Pixel struct {
 }
 
 var rmaster, gmaster, bmaster float64
+var hash1 string
 
 func rgbaToPixel(r uint32, g uint32, b uint32, a uint32) Pixel {
 	return Pixel{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8), false}
@@ -34,19 +35,30 @@ func CreatePNG(PDFPath string) {
 	folderName := ComputeSha256(PDFPath)
 
 	// Checks if a folder with the name sha256(file) already exists
-	if _, err := os.Stat(folderName); err == nil {
+	if _, err := os.Stat("data/" + folderName); err == nil {
 		return
 	}
 
 	// If not, probably we never met this pdf. Create the folder
-	err := os.Mkdir(folderName, os.ModePerm)
+	err := os.Mkdir("data/" +folderName, os.ModePerm)
 	if err != nil {
 		panic(err)
 	}
 
+	file, err := os.Create("data/" + folderName + "/.tmp")
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close()
+
 	// Create the images
-	cmd, _ := exec.Command("pdftoppm", "-png", PDFPath, folderName+"/png_gen").Output()
+	cmd, _ := exec.Command("pdftoppm", "-png", PDFPath, "data/" + folderName+"/png_gen").Output()
 	fmt.Println(cmd)
+
+	err = os.Remove("data/" + folderName + ".tmp")
+	if err != nil {
+		panic(err)
+	}
 }
 
 func RetrievePixel(fileName string) ([][]Pixel, int, int) {
@@ -136,7 +148,7 @@ func CompareSingleImage(path1 string, path2 string, i int) {
 	}
 
 	// Create the file under "generated" folder
-	f, err := os.Create("generated/image-" + strconv.Itoa(i) + ".png")
+	f, err := os.Create("data/generated/" + hash1 + "/image-" + strconv.Itoa(i) + ".png")
 	if err != nil {
 		panic(err)
 	}
@@ -181,15 +193,32 @@ func Compare(PDF1 string, PDF2 string) {
 	// Compares the two files
 
 	shaPDF1 := ComputeSha256(PDF1)
+	hash1 = shaPDF1
 	shaPDF2 := ComputeSha256(PDF2)
 
-	if _, err := os.Stat("generated"); errors.Is(err, os.ErrNotExist) {
-		err := os.Mkdir("generated", os.ModePerm)
+	if _, err := os.Stat("data"); errors.Is(err, os.ErrNotExist) {
+		err := os.Mkdir("data", os.ModePerm)
 		if err != nil {
 			panic(err)
 		}
 	}
 
+	if _, err := os.Stat("data/generated"); errors.Is(err, os.ErrNotExist) {
+		err := os.Mkdir("data/generated", os.ModePerm)
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	if _, err := os.Stat("data/generated/" + shaPDF1); errors.Is(err, os.ErrNotExist) {
+		err := os.Mkdir("data/generated/" + shaPDF1, os.ModePerm)
+		if err != nil {
+			panic(err)
+		}
+	} else {
+		return
+	}
+
 	i := 1
 	k := 1
 	for {
@@ -200,8 +229,8 @@ func Compare(PDF1 string, PDF2 string) {
 		o := fmt.Sprintf("%d", k)
 		s := fmt.Sprintf("%0"+o+"d", i)
 
-		s_pdf1 := shaPDF1 + "/png_gen-" + s + ".png"
-		s_pdf2 := shaPDF2 + "/png_gen-" + s + ".png"
+		s_pdf1 := "data/" +shaPDF1 + "/png_gen-" + s + ".png"
+		s_pdf2 := "data/" + shaPDF2 + "/png_gen-" + s + ".png"
 
 		if _, err := os.Stat(s_pdf1); errors.Is(err, os.ErrNotExist) {
 			k++
@@ -232,21 +261,27 @@ func main() {
 	// flags
 
 	color := flag.String("color", "ff2010", "hex value for the background color for highlighting")
+	enableServer := flag.Bool("server", false, "flag to enable local server for pdf-diff")
+
 	flag.Parse()
 
-	arguments := flag.Args()
+	if !*enableServer {
+		arguments := flag.Args()
 
-	if len(arguments) < 2 {
-		fmt.Println("pdf-diff: highlights the differences between two pdf files.")
-		fmt.Println("Usage: pdf-diff pdf-file-1 pdf-file-2 [-color] hex-color")
-		fmt.Println()
-		flag.PrintDefaults()
-		os.Exit(1)
-	}
+		if len(arguments) < 2 {
+			fmt.Println("pdf-diff: highlights the differences between two pdf files.")
+			fmt.Println("Usage: pdf-diff pdf-file-1 pdf-file-2 [-color] hex-color")
+			fmt.Println()
+			flag.PrintDefaults()
+			os.Exit(1)
+		}
 
-	hexToRGB(*color)
-	CreatePNG(arguments[0])
-	CreatePNG(arguments[1])
-	Compare(arguments[0], arguments[1])
+		hexToRGB(*color)
+		CreatePNG(arguments[0])
+		CreatePNG(arguments[1])
+		Compare(arguments[0], arguments[1])
+	} else {
+		StartServer()
+	}
 
 }

server.go

@@ -0,0 +1,217 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"html/template"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type DiffImage struct {
+	Number   int    // page number
+	Filename string // file1
+}
+
+type ResultPage struct {
+	Hash1       string
+	Hash2       string
+	Differences []DiffImage
+}
+
+func indexController(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		fmt.Println("A new request has been made on / but the method " + r.Method + " was not supported.")
+		return
+	}
+
+	// TODO (idea): list pdf on upload folders
+
+	// Display the compare page
+	t, _ := template.ParseFiles("templates/index.html")
+	t.Execute(w, nil)
+
+}
+
+func compareController(w http.ResponseWriter, r *http.Request) {
+	// Set a limit of 32 MB per request
+	r.Body = http.MaxBytesReader(w, r.Body, 32<<20)
+
+	if r.Method == "GET" {
+		// Redirect to index page
+		http.Redirect(w, r, "/", http.StatusMovedPermanently)
+	} else if r.Method == "POST" {
+		parseErr := r.ParseMultipartForm(32 << 20)
+		if parseErr != nil {
+			http.Error(w, "failed to parse multipart message", http.StatusBadRequest)
+			return
+		}
+
+		if len(r.MultipartForm.File) != 2 {
+			http.Error(w, "two file pdfs per comparision", http.StatusBadRequest)
+			return
+		}
+
+		// Grab the two PDF(s) from the form
+		pdfFile1 := r.MultipartForm.File["pdf-1"]
+		pdfFile2 := r.MultipartForm.File["pdf-2"]
+
+		// Check if the two files are PDF
+
+		file1, err := pdfFile1[0].Open()
+		if err != nil {
+			panic(err)
+		}
+		defer file1.Close()
+
+		buff := make([]byte, 512)
+		if _, err = file1.Read(buff); err != nil {
+			panic(err)
+		}
+
+		var pdf1hash string
+
+		if http.DetectContentType(buff) == "application/pdf" {
+			out, err := os.Create("data/uploads/" + filepath.Clean(pdfFile1[0].Filename))
+			if err != nil {
+				panic(err)
+			}
+			_, err = file1.Seek(0, io.SeekStart)
+			if err != nil {
+				panic(err)
+			}
+			io.Copy(out, file1)
+			pdf1hash = ComputeSha256("data/uploads/" + filepath.Clean(pdfFile1[0].Filename))
+		}
+
+		file2, err := pdfFile2[0].Open()
+		if err != nil {
+			panic(err)
+		}
+		defer file2.Close()
+		if _, err = file2.Read(buff); err != nil {
+			panic(err)
+		}
+
+		var pdf2hash string
+
+		if http.DetectContentType(buff) == "application/pdf" {
+			// Write them in upload folder
+			out, err := os.Create("data/uploads/" + filepath.Clean(pdfFile2[0].Filename))
+			if err != nil {
+				panic(err)
+			}
+			_, err = file2.Seek(0, io.SeekStart)
+			if err != nil {
+				panic(err)
+			}
+			io.Copy(out, file2)
+			pdf2hash = ComputeSha256("data/uploads/" + filepath.Clean(pdfFile2[0].Filename))
+		}
+
+		fmt.Println("Starting a new job....")
+
+		// Start the job
+
+		hexToRGB("ff2010")
+		go CreatePNG("data/uploads/" + filepath.Clean(pdfFile1[0].Filename))
+		go CreatePNG("data/uploads/" + filepath.Clean(pdfFile2[0].Filename))
+		go Compare("data/uploads/"+filepath.Clean(pdfFile1[0].Filename), "data/uploads/"+filepath.Clean(pdfFile2[0].Filename))
+
+		// Redirect to result page
+		http.Redirect(w, r, "/compare/"+pdf1hash+"-"+pdf2hash, http.StatusMovedPermanently)
+
+	} else {
+		fmt.Println("A new request has been made on /compare but the method " + r.Method + " was not supported.")
+		return
+	}
+
+}
+
+func retrieveFilesController(w http.ResponseWriter, r *http.Request) {
+	slug := r.URL.Path[len("/compare/"):]
+	if len(slug) == 0 {
+		http.Redirect(w, r, "/", http.StatusMovedPermanently)
+		return
+	}
+	hashes := strings.Split(slug, "-")
+	fmt.Printf("%s ", hashes[0])
+	fmt.Printf("%s \n", hashes[1])
+
+	// Checks if the folder were already created
+
+	if _, err := os.Stat("data/generated/" + hashes[0]); errors.Is(err, os.ErrNotExist) {
+		http.Error(w, "The two pdfs ("+hashes[0]+", "+hashes[1]+") were not compared.", http.StatusNotFound)
+		return
+	}
+
+	if _, err := os.Stat("data/" + hashes[0] + "/.tmp"); errors.Is(err, os.ErrExist) {
+		http.Error(w, "The images are being created. It should take a few seconds.", http.StatusOK)
+		return
+	}
+
+	if _, err := os.Stat("data/generated/" + hashes[0] + "/.tmp"); errors.Is(err, os.ErrExist) {
+		http.Error(w, "pdf-diff takes a while to generate all the images.", http.StatusOK)
+		return
+	}
+
+	// Checks the result generated
+
+	// List all the images given a filename (e.g. filename-1.png)
+
+	f, err := os.Open("data/generated/" + hashes[0])
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	files, err := f.Readdir(0)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	i := 0
+	var differences []DiffImage
+
+	for _, v := range files {
+		single := DiffImage{
+			Number:   i,
+			Filename: v.Name(),
+		}
+		differences = append(differences, single)
+		i++
+	}
+
+	structure := ResultPage{
+		Hash1:       hashes[0],
+		Hash2:       hashes[1],
+		Differences: differences,
+	}
+
+	t := template.Must(template.ParseFiles("templates/result.html"))
+	if err != nil {
+		panic(err)
+	}
+
+	err = t.Execute(w, structure)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func StartServer() {
+
+	http.HandleFunc("/", indexController)
+	http.HandleFunc("/compare", compareController)
+	http.HandleFunc("/compare/", retrieveFilesController)
+
+	http.Handle("/results/", http.StripPrefix("/results/", http.FileServer(http.Dir("./data"))))
+
+	err := http.ListenAndServe(":8080", nil)
+	if err != nil {
+		panic(err)
+	}
+
+}