Rename downloader

Author: Drakirus

example/simpleDemo/engineDownloader.go

@@ -0,0 +1,301 @@
+package main
+
+import (
+	"archive/zip"
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Unzip will decompress a zip archive, moving all files and folders
+// within the zip file (parameter 1) to an output directory (parameter 2).
+func unzip(src string, dest string) ([]string, error) {
+
+	var filenames []string
+
+	r, err := zip.OpenReader(src)
+	if err != nil {
+		return filenames, err
+	}
+	defer r.Close()
+
+	for _, f := range r.File {
+
+		rc, err := f.Open()
+		if err != nil {
+			return filenames, err
+		}
+		defer rc.Close()
+
+		// Store filename/path for returning and using later on
+		fpath := filepath.Join(dest, f.Name)
+
+		// Check for ZipSlip. More Info: http://bit.ly/2MsjAWE
+		if !strings.HasPrefix(fpath, filepath.Clean(dest)+string(os.PathSeparator)) {
+			return filenames, fmt.Errorf("%s: illegal file path", fpath)
+		}
+
+		filenames = append(filenames, fpath)
+
+		if f.FileInfo().IsDir() {
+
+			// Make Folder
+			os.MkdirAll(fpath, os.ModePerm)
+
+		} else {
+
+			// Make File
+			if err = os.MkdirAll(filepath.Dir(fpath), os.ModePerm); err != nil {
+				return filenames, err
+			}
+
+			outFile, err := os.OpenFile(fpath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+			if err != nil {
+				return filenames, err
+			}
+
+			_, err = io.Copy(outFile, rc)
+
+			// Close the file without defer to close before next iteration of loop
+			outFile.Close()
+
+			if err != nil {
+				return filenames, err
+			}
+
+		}
+	}
+	return filenames, nil
+}
+
+func askForConfirmation() bool {
+	reader := bufio.NewReader(os.Stdin)
+
+	for {
+		fmt.Printf("Would you like to overwrite the previously downloaded engine [Y/n] : ")
+
+		response, err := reader.ReadString('\n')
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		response = strings.ToLower(strings.TrimSpace(response))
+
+		if response == "y" || response == "yes" || response == "" {
+			return true
+		} else if response == "n" || response == "no" {
+			return false
+		}
+	}
+}
+
+// Function to prind download percent completion
+func printDownloadPercent(done chan int64, path string, total int64) {
+
+	var stop = false
+
+	for {
+		select {
+		case <-done:
+			stop = true
+		default:
+
+			file, err := os.Open(path)
+			if err != nil {
+				log.Fatal(err)
+			}
+
+			fi, err := file.Stat()
+			if err != nil {
+				log.Fatal(err)
+			}
+
+			size := fi.Size()
+
+			if size == 0 {
+				size = 1
+			}
+
+			var percent float64 = float64(size) / float64(total) * 100
+
+			// We use `\033[2K\r` to avoid carriage return, it will print above previous.
+			fmt.Printf("\033[2K\r %.0f %% / 100 %%", percent)
+		}
+
+		if stop {
+			break
+		}
+
+		time.Sleep(time.Second)
+	}
+}
+
+// Function to download file with given path and url.
+func downloadFile(filepath string, url string) error {
+
+	// Print download url in case user needs it.
+	fmt.Printf("Downloading file from\n '%s'\n to '%s'\n\n", url, filepath)
+
+	if _, err := os.Stat(filepath); !os.IsNotExist(err) {
+		if !askForConfirmation() {
+			fmt.Printf("Leaving.\n")
+			os.Exit(0)
+		}
+	}
+	start := time.Now()
+
+	// Create the file
+	out, err := os.Create(filepath)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	// Get the data
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	size, err := strconv.Atoi(resp.Header.Get("Content-Length"))
+
+	done := make(chan int64)
+
+	go printDownloadPercent(done, filepath, int64(size))
+
+	// Write the body to file
+	n, err := io.Copy(out, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	done <- n
+
+	elapsed := time.Since(start)
+	log.Printf("\033[2K\rDownload completed in %s", elapsed)
+
+	return nil
+}
+
+func main() {
+	// Execute flutter command to retrieve the version
+	out, err := exec.Command("flutter", "--version").Output()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Get working directory
+	dir, err := os.Getwd()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	re := regexp.MustCompile(`Engine • revision (\w{10})`)
+	shortRevision := re.FindStringSubmatch(string(out))[1]
+
+	url := fmt.Sprintf("https://api.github.com/search/commits?q=%s", shortRevision)
+
+	// This part is used to retrieve the full hash
+	req, err := http.NewRequest("GET", os.ExpandEnv(url), nil)
+	if err != nil {
+		// handle err
+		log.Fatal(err)
+	}
+	req.Header.Set("Accept", "application/vnd.github.cloak-preview")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		// handle err
+		log.Fatal(err)
+	}
+
+	body, err := ioutil.ReadAll(resp.Body)
+	defer resp.Body.Close()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// We define a struct to build JSON object from the response
+	hashResponse := struct {
+		Items []struct {
+			Sha string `json:"sha"`
+		} `json:"items"`
+	}{}
+
+	err2 := json.Unmarshal(body, &hashResponse)
+	if err2 != nil {
+		// handle err
+		log.Fatal(err2)
+	}
+
+	var platform = "undefined"
+	var downloadURL = ""
+
+	// Retrieve the OS and set variable to retrieve correct flutter embedder
+	switch runtime.GOOS {
+	case "darwin":
+		platform = "darwin-x64"
+		downloadURL = fmt.Sprintf("https://storage.googleapis.com/flutter_infra/flutter/%s/%s/FlutterEmbedder.framework.zip", hashResponse.Items[0].Sha, platform)
+
+	case "linux":
+		platform = "linux-x64"
+		downloadURL = fmt.Sprintf("https://storage.googleapis.com/flutter_infra/flutter/%s/%s/%s-embedder", hashResponse.Items[0].Sha, platform, platform)
+
+	case "windows":
+		platform = "windows-x64"
+		downloadURL = fmt.Sprintf("https://storage.googleapis.com/flutter_infra/flutter/%s/%s/%s-embedder", hashResponse.Items[0].Sha, platform, platform)
+
+	default:
+		log.Fatal("OS not supported")
+	}
+
+	err3 := downloadFile(dir+"/.build/temp.zip", downloadURL)
+	if err3 != nil {
+		log.Fatal(err3)
+	} else {
+		fmt.Printf("Downloaded embedder for %s platform, matching version : %s\n", platform, hashResponse.Items[0].Sha)
+	}
+
+	_, err = unzip(".build/temp.zip", dir+"/.build/")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	switch platform {
+	case "darwin-x64":
+		_, err = unzip(".build/FlutterEmbedder.framework.zip", dir+"/FlutterEmbedder.framework")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+	case "linux-x64":
+		err := os.Rename(".build/libflutter_engine.so", dir+"/libflutter_engine.so")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+	case "windows-x64":
+		err := os.Rename(".build/flutter_engine.dll", dir+"/flutter_engine.dll")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+	}
+	fmt.Printf("Unzipped files and moved them to correct repository.\n")
+
+	fmt.Printf("Done.\n")
+
+}