Add update utility

updater/web/web.go

@@ -0,0 +1,133 @@
+package web
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"syscall"
+
+	"archive/zip"
+)
+
+var client = &http.Client{}
+
+// func DownloadText(url string) string {
+// 	response, err := client.Get(url)
+// 	if err != nil {
+// 		fmt.Println("Error while downloading", url, "-", err)
+// 		os.Exit(1)
+// 	}
+// 	defer response.Body.Close()
+
+// 	body, err := ioutil.ReadAll(response.Body)
+// 	if err != nil {
+// 		fmt.Print(err)
+// 		os.Exit(1)
+// 	}
+// 	return string(body)
+// }
+
+func Download(url string, target string) bool {
+	output, err := os.Create(target)
+	if err != nil {
+		fmt.Println("Error while creating", target, "-", err)
+		return false
+	}
+	defer output.Close()
+
+	response, err := client.Get(url)
+	if err != nil {
+		fmt.Println("Error while downloading", url, "-", err)
+	}
+	defer response.Body.Close()
+	c := make(chan os.Signal, 2)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+	go func() {
+		<-c
+		fmt.Println("Download interrupted.")
+		output.Close()
+		response.Body.Close()
+	}()
+	_, err = io.Copy(output, response.Body)
+	if err != nil {
+		fmt.Println("Error while downloading", url, "-", err)
+		return false
+	}
+	if response.Status[0:3] != "200" {
+		// fmt.Println("HTTP " + response.Status[0:3] + " " + url)
+		// fmt.Println("Download failed. Rolling Back.")
+		fmt.Println("ERROR: SOURCE NOT FOUND -> " + url)
+		os.RemoveAll(target)
+		return false
+	}
+
+	return true
+}
+
+func Unzip(src, dest string) error {
+	r, err := zip.OpenReader(src)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := r.Close(); err != nil {
+			panic(err)
+		}
+	}()
+
+	os.MkdirAll(dest, 0755)
+
+	// Closure to address file descriptors issue with all the deferred .Close() methods
+	extractAndWriteFile := func(f *zip.File) error {
+		rc, err := f.Open()
+		if err != nil {
+			return err
+		}
+		defer func() {
+			if err := rc.Close(); err != nil {
+				panic(err)
+			}
+		}()
+
+		path := filepath.Join(dest, f.Name)
+
+		// Check for ZipSlip (Directory traversal)
+		if !strings.HasPrefix(path, filepath.Clean(dest)+string(os.PathSeparator)) {
+			return fmt.Errorf("illegal file path: %s", path)
+		}
+
+		if f.FileInfo().IsDir() {
+			os.MkdirAll(path, f.Mode())
+		} else {
+			os.MkdirAll(filepath.Dir(path), f.Mode())
+			f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+			if err != nil {
+				return err
+			}
+			defer func() {
+				if err := f.Close(); err != nil {
+					panic(err)
+				}
+			}()
+
+			_, err = io.Copy(f, rc)
+			if err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	for _, f := range r.File {
+		err := extractAndWriteFile(f)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}