Download and unzip gh

commands/update.go

@@ -1,7 +1,17 @@
 package commands
 
 import (
+	"archive/zip"
+	"fmt"
+	"github.com/jingweno/gh/github"
+	"github.com/jingweno/gh/utils"
+	"io"
+	"io/ioutil"
+	"net/http"
 	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
 )
 
 var cmdUpdate = &Command{
@@ -16,5 +26,115 @@ Examples:
 }
 
 func update(cmd *Command, args *Args) {
+	err := doUpdate()
+	utils.Check(err)
 	os.Exit(0)
 }
+
+func doUpdate() (err error) {
+	client := github.NewClient(github.GitHubHost)
+	releases, err := client.Releases(github.NewProject("jingweno", "gh", github.GitHubHost))
+	if err != nil {
+		err = fmt.Errorf("Error fetching releases: %s", err)
+		return
+	}
+
+	latestRelease := releases[0]
+	tagName := latestRelease.TagName
+	version := strings.TrimPrefix(tagName, "v")
+	downloadURL := fmt.Sprintf("https://github.com/jingweno/gh/releases/download/%s/gh_%s-snapshot_%s_%s.zip", tagName, version, runtime.GOOS, runtime.GOARCH)
+	path, err := downloadFile(downloadURL)
+	if err != nil {
+		err = fmt.Errorf("Can't download update %s to %s", downloadURL, path)
+		return
+	}
+
+	exec, err := unzipExecutable(path)
+	if err != nil {
+		err = fmt.Errorf("Can't unzip gh executable: %s", err)
+		return
+	}
+
+	fmt.Println(exec)
+
+	//https://github.com/jingweno/gh/releases/download/v0.26.0/gh_0.26.0-snapshot_darwin_amd64.zip
+
+	return
+}
+
+func unzipExecutable(path string) (exec string, err error) {
+	rc, err := zip.OpenReader(path)
+	if err != nil {
+		err = fmt.Errorf("Can't open zip file %s: %s", path, err)
+		return
+	}
+	defer rc.Close()
+
+	dir := filepath.Dir(path)
+	for _, file := range rc.File {
+		frc, e := file.Open()
+		if e != nil {
+			err = fmt.Errorf("Can't open zip entry %s when reading: %s", file.Name, err)
+			return
+		}
+		defer frc.Close()
+
+		if !strings.HasPrefix(file.Name, "gh") {
+			continue
+		}
+
+		dest := filepath.Join(dir, filepath.Base(file.Name))
+		f, e := os.Create(dest)
+		if e != nil {
+			err = e
+			return
+		}
+		defer f.Close()
+
+		copied, e := io.Copy(f, frc)
+		if e != nil {
+			err = e
+			return
+		}
+
+		if uint32(copied) != file.UncompressedSize {
+			err = fmt.Errorf("Zip entry %s is corrupted", file.Name)
+			return
+		}
+
+		exec = f.Name()
+
+		break
+	}
+
+	if exec == "" {
+		err = fmt.Errorf("No gh executable is found")
+	}
+
+	return
+}
+
+func downloadFile(url string) (path string, err error) {
+	dir, err := ioutil.TempDir("", "gh-update")
+	if err != nil {
+		return
+	}
+
+	file, err := os.Create(filepath.Join(dir, filepath.Base(url)))
+	if err != nil {
+		return
+	}
+	defer file.Close()
+
+	resp, err := http.Get(url)
+	defer resp.Body.Close()
+
+	_, err = io.Copy(file, resp.Body)
+	if err != nil {
+		return
+	}
+
+	path = file.Name()
+
+	return
+}