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Best practices and cosmetics

This commit is contained in:
Julien Dessaux 2020-01-08 15:45:37 +01:00
parent ca3d486bdf
commit e917e2c9d2

96
main.go
View file

@ -11,12 +11,15 @@ import (
"net/http"
"os"
"os/exec"
"path"
"time"
)
var level = 4
var width = 550
var delay = 8 // delay in hours, so that I can see daylight on my wallpaper during the day!
const (
level = 4
width = 550
delay = 8 // delay in hours, so that I can see daylight on my wallpaper during the day!
)
type latestData struct {
Date string `json:"date"`
@ -25,14 +28,23 @@ type latestData struct {
func main() {
// Define work directory and files
var home = os.Getenv("HOME")
var work_dir = home + "/.himawari"
var image_file = work_dir + "/latest.png"
var dat_file = work_dir + "/data"
var (
home = os.Getenv("HOME")
workDir = path.Join(home, ".himawari")
imageFile = path.Join(workDir, "/latest.png")
dataFile = path.Join(workDir, "/data")
data []byte
err error
oldData = new(latestData)
initData = new(latestData)
t time.Time
location *time.Location
output *image.RGBA
out *os.File
)
// Read the last date from dat_file if it exists
data, err := ioutil.ReadFile(dat_file)
oldData := new(latestData)
// Read the last date from dataFile if it exists
data, err = ioutil.ReadFile(dataFile)
if err != nil {
data = nil
} else {
@ -43,14 +55,16 @@ func main() {
}
// Get the data about the last image
initData := new(latestData)
err = getJson("http://himawari8-dl.nict.go.jp/himawari8/img/D531106/latest.json", initData)
err = getJSON("http://himawari8-dl.nict.go.jp/himawari8/img/D531106/latest.json", initData)
if err != nil {
log.Fatal("error getting json :", err)
log.Fatal("error getting json data from himawari server: ", err)
}
location, _ := time.LoadLocation("Asia/Tokyo")
t, _ := time.ParseInLocation("2006-01-02 15:04:05", initData.Date, location)
location, err = time.LoadLocation("Asia/Tokyo")
if err != nil {
log.Fatal("error loading Asia/Tokyo time zone data: ", err)
}
t, _ = time.ParseInLocation("2006-01-02 15:04:05", initData.Date, location)
if oldData != nil && oldData.Date == initData.Date {
log.Print("No new image, keeping the old one")
os.Exit(0)
@ -58,72 +72,70 @@ func main() {
t = t.Add(time.Duration(-delay) * time.Hour)
// Get all the chunks from the latest image and assemble them
output := image.NewRGBA(image.Rect(0, 0, level*width, level*width))
output = image.NewRGBA(image.Rect(0, 0, level*width, level*width))
for x := 0; x < level; x++ {
for y := 0; y < level; y++ {
url := fmt.Sprintf("http://himawari8.nict.go.jp/img/D531106/%dd/%d/%s_%d_%d.png",
level, width, t.Format("2006/01/02/150405"), x, y)
var buff image.Image
err = getPng(url, &buff)
err = getPNG(url, &buff)
if err != nil {
err = getPng(url, &buff)
err = getPNG(url, &buff)
if err != nil {
log.Fatal("Error getting png :", url)
}
}
draw.Draw(output, image.Rect(x*width, y*width, (x+1)*width, (y+1)*width), buff, image.Point{0, 0}, draw.Src)
}
}
// Write output to file
out, err := os.Create(image_file)
out, err = os.Create(imageFile)
if err != nil {
err := os.Mkdir(work_dir, 0755)
err := os.Mkdir(workDir, 0755)
if err != nil {
log.Fatal("error creating :", err)
log.Fatal("error creating output directory:", err)
}
out, err = os.Create(image_file)
out, err = os.Create(imageFile)
if err != nil {
log.Fatal("error creating :", err)
log.Fatal("error creating output file:", err)
}
}
defer out.Close()
err = png.Encode(out, output)
if err != nil {
log.Fatal("Error writing output:", err)
log.Fatal("Error writing output file:", err)
}
// Write dat file
buff, err := json.Marshal(initData)
ioutil.WriteFile(dat_file, buff, 0644)
ioutil.WriteFile(dataFile, buff, 0644)
// Exec feh
cmd := exec.Command("feh", "--bg-max", image_file)
cmd := exec.Command("feh", "--bg-max", imageFile)
err = cmd.Run()
if err != nil {
log.Fatal("Error launching feh :", err)
}
}
func getJson(url string, target interface{}) error {
r, err := http.Get(url)
if err != nil {
return err
func getJSON(url string, target interface{}) (err error) {
var r *http.Response
r, err = http.Get(url)
if err == nil {
defer r.Body.Close()
err = json.NewDecoder(r.Body).Decode(target)
}
defer r.Body.Close()
return json.NewDecoder(r.Body).Decode(target)
return
}
func getPng(url string, image *image.Image) error {
r, err := http.Get(url)
if err != nil {
return err
func getPNG(url string, image *image.Image) (err error) {
var r *http.Response
r, err = http.Get(url)
if err == nil {
defer r.Body.Close()
*image, err = png.Decode(r.Body)
}
defer r.Body.Close()
*image, err = png.Decode(r.Body)
return err
return
}