558 lines
12 KiB
Go
558 lines
12 KiB
Go
// Copyright (C) 2025 Marius Schellenberger
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package main
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import (
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"cmp"
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"errors"
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"flag"
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"fmt"
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"image"
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"image/color"
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"image/png"
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"iter"
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"net/http"
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"os"
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"slices"
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"sync"
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"time"
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)
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const (
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X = 82
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maxX = 574
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maxStart = 150
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Y = 431
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)
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func scale(img image.Image) int {
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startY := Y
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for y := Y; y > 0; y-- {
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col := img.At(X, y)
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if !isBlack(col) {
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startY = y
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break
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}
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}
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c := 0
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for y := startY; y > 0; y-- {
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col := img.At(X, y)
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if isWhite(col) {
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c = startY - y
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startY = y
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break
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}
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}
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for y := startY; y > 0; y-- {
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col := img.At(X, y)
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if !isWhite(col) {
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return (startY + c) - y
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}
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}
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return -1
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}
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func start(img image.Image) int {
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for x := X; x < maxStart; x++ {
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col := img.At(x, Y)
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if !isStart(col) {
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return x
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}
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}
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return -1
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}
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func uv(img image.Image, x, s int) float64 {
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start := Y
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end := Y
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for y := start; y > 0; y-- {
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col := img.At(x, y)
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if isBlack(col) || isWhite(col) {
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end = y - 1
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break
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}
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}
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v := start - end
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if v <= s {
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return float64(v) / float64(s)
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}
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return float64(v+s) / 2 / float64(s)
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}
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func getUV(img image.Image) (vals []float64) {
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s := scale(img)
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if s == -1 {
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return
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}
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x := start(img)
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if x == -1 {
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return
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}
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for ; x < maxX; x++ {
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col := img.At(x, Y)
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if isStop(col) {
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break
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}
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vals = append(vals, uv(img, x, s))
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}
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return
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}
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var tmp = `<!doctype html>
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<html>
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<head>
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<title>UV Index</title>
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<style>
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a, a:link, a:visited {
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color: #007d9c;
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}
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</style>
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<meta name="theme-color" content="#d6d6d6">
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</head>
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<body style="background-color:#d6d6d6;">
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<center>
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<h5 style="font-size:4em;">UV Index</h5>
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<h1 style="font-size:15em;color:#%s;">%s</h1>
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<h5 style="font-size:2em;">Updated: %s</h5>
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<h5 style="font-size:2em;">Server: %s</h5>
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<h5 style="font-size:3em;"><a href="/set">Location</a>: %s</h5>
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<footer>UV data copyright belongs to <a href="https://www.bfs.de/DE/themen/opt/uv/uv-index/aktuelle-tagesverlaeufe/aktuell_node.html" rel="nofollow noreferrer noopener" target="_blank">Bundesamt für Strahlenschutz</a><br>
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Use this service at your own risk.<br>
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I take no responsibility for missing or incorrect data.<br>
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© <a href="https://git.giftfish.de/ston1th/uvgo" rel="nofollow noreferrer noopener" target="_blank">uvgo</a> %s<br><br>
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</footer>
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</center>
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</body>
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</html>`
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func getColor(v float64) string {
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if v < 1.0 {
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return "006300"
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} else if v >= 1.0 && v <= 2.0 {
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return "00a014"
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} else if v >= 2.0 && v <= 3.0 {
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return "81c600"
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} else if v >= 3.0 && v <= 4.0 {
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return "fff800"
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} else if v >= 4.0 && v <= 5.0 {
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return "ffd100"
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} else if v >= 5.0 && v <= 6.0 {
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return "ffa600"
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} else if v >= 6.0 && v <= 7.0 {
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return "ff7200"
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} else if v >= 7.0 && v <= 8.0 {
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return "ff4a00"
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} else if v >= 8.0 && v <= 9.0 {
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return "ff0000"
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} else if v >= 9.0 && v <= 10.0 {
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return "ff0078"
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} else if v >= 10.0 {
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return "a80080"
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}
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return "000000"
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}
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var (
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locPage string
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version string
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listen string
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)
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func main() {
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flag.StringVar(&listen, "l", ":7878", "listen addr")
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flag.Parse()
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url := "https://uvi.bfs.de/Tagesgrafiken"
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generateLocPage()
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ic := &ImageCrawler{
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url: url,
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c: &http.Client{},
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m: make(map[string]*Image),
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}
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http.HandleFunc("/set", func(w http.ResponseWriter, r *http.Request) {
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if r.Method == "POST" {
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r.ParseForm()
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loc := r.PostForm.Get("loc")
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if _, ok := locations[loc]; ok {
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c := &http.Cookie{
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Name: "loc",
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Path: "/",
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Value: loc,
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Secure: true,
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HttpOnly: true,
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SameSite: http.SameSiteStrictMode,
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}
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http.SetCookie(w, c)
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http.Redirect(w, r, "/", http.StatusMovedPermanently)
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return
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}
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}
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w.Write([]byte(locPage))
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})
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http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
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cc := r.CookiesNamed("loc")
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var c *http.Cookie
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if len(cc) == 0 {
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c = &http.Cookie{
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Name: "loc",
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Path: "/",
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Value: "24",
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Secure: true,
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HttpOnly: true,
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SameSite: http.SameSiteStrictMode,
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}
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http.SetCookie(w, c)
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} else {
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c = cc[0]
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}
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loc := c.Value
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img, mod, err := ic.getImage(loc)
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mod = mod.Local()
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location := selectListReverse[loc]
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if err != nil {
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fmt.Fprintf(w, tmp,
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"000000",
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"Err",
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mod.Format(time.RFC1123),
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time.Now().Format(time.RFC1123),
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location,
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version,
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)
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return
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}
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vals := getUV(img)
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if len(vals) == 0 {
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fmt.Fprintf(w, tmp,
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"000000",
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"Err",
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mod.Format(time.RFC1123),
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time.Now().Format(time.RFC1123),
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location,
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version,
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)
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return
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}
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last := vals[len(vals)-1]
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fmt.Fprintf(w, tmp,
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getColor(last),
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fmt.Sprintf("%.2f", last),
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mod.Format(time.RFC1123),
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time.Now().Format(time.RFC1123),
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location,
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version,
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)
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})
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err := http.ListenAndServe(listen, nil)
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if err != nil {
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fatal(err)
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}
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}
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type ImageCrawler struct {
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mu sync.RWMutex
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url string
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c *http.Client
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m map[string]*Image
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}
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type Image struct {
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mu sync.RWMutex
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ic *ImageCrawler
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file string
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img image.Image
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etag string
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modified time.Time
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lastGet time.Time
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}
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func (ic *ImageCrawler) getImage(loc string) (img image.Image, mod time.Time, err error) {
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file, ok := locations[loc]
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if !ok {
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return nil, time.Time{}, errors.New("invalid location")
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}
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ic.mu.RLock()
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if i, ok := ic.m[loc]; ok {
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ic.mu.RUnlock()
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return i.getImage()
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}
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ic.mu.RUnlock()
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ic.mu.Lock()
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i := &Image{
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ic: ic,
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file: file,
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}
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ic.m[loc] = i
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ic.mu.Unlock()
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return i.getImage()
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}
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func (i *Image) getImage() (img image.Image, mod time.Time, err error) {
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i.mu.RLock()
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if !i.lastGet.IsZero() &&
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time.Now().Sub(i.lastGet) < time.Minute*3 {
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defer i.mu.RUnlock()
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return i.img, i.modified, nil
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}
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i.mu.RUnlock()
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req, err := http.NewRequest("GET", i.ic.url+"/"+i.file, nil)
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if err != nil {
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return
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}
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i.mu.RLock()
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if !i.modified.IsZero() {
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req.Header.Set("if-modified-since", i.modified.Format(time.RFC1123))
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}
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if i.etag != "" {
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req.Header.Set("if-none-match", i.etag)
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}
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i.mu.RUnlock()
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resp, err := i.ic.c.Do(req)
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if err != nil {
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return
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}
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defer resp.Body.Close()
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if resp.StatusCode == http.StatusNotModified {
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i.mu.RLock()
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defer i.mu.RUnlock()
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return i.img, i.modified, nil
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}
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if resp.StatusCode == http.StatusOK {
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img, err = png.Decode(resp.Body)
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if err != nil {
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return
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}
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i.mu.Lock()
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i.img = img
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modTime, err := time.Parse(time.RFC1123, resp.Header.Get("last-modified"))
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if err == nil {
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i.modified = modTime
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}
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i.etag = resp.Header.Get("etag")
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i.lastGet = time.Now()
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defer i.mu.Unlock()
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return i.img, i.modified, nil
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}
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i.mu.RLock()
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defer i.mu.RUnlock()
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if i.img != nil {
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return i.img, i.modified, nil
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}
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return nil, time.Time{}, errors.New("error getting image")
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}
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func isWhite(col color.Color) bool {
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col = color.RGBAModel.Convert(col)
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c, ok := col.(color.RGBA)
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if !ok {
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return false
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}
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if c.R == 255 &&
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c.G == 255 &&
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c.B == 255 {
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return true
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}
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return false
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}
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func isBlack(col color.Color) bool {
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col = color.RGBAModel.Convert(col)
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c, ok := col.(color.RGBA)
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if !ok {
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return false
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}
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if c.R == 0 &&
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c.G == 0 &&
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c.B == 0 {
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return true
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}
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return false
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}
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func isStop(col color.Color) bool {
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col = color.RGBAModel.Convert(col)
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c, ok := col.(color.RGBA)
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if !ok {
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return false
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}
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if c.R == 241 &&
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c.G == 241 &&
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c.B == 241 {
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return true
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}
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if c.R == 88 &&
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c.G == 88 &&
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c.B == 88 {
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return true
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}
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return false
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}
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func isStart(col color.Color) bool {
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col = color.RGBAModel.Convert(col)
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c, ok := col.(color.RGBA)
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if !ok {
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return false
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}
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if c.R == 241 &&
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c.G == 241 &&
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c.B == 241 {
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return true
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}
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if c.R == 214 &&
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c.G == 214 &&
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c.B == 214 {
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return true
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}
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if c.R == 0 &&
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c.G == 0 &&
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c.B == 0 {
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return true
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}
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return false
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}
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func fatal(err error) {
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if err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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}
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func generateLocPage() {
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loc := `<!doctype html><html>
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<head>
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<title>UV Index Change Location</title>
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<meta name="theme-color" content="#d6d6d6">
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</head>
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<body style="background-color:#d6d6d6;">
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<center>
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<h5 style="font-size:4em;">Change Location</h5>
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<form action="/set" method="post">
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<select name="loc" style="font-size:5em;margin-bottom:50px;">`
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for k, v := range sortedMap(selectList) {
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loc += `<option value="` + v + `">` + k + `</option>`
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}
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loc += `</select><br><input type="submit" style="font-size:5em;" value="Change"></input></form></center></body></html>`
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locPage = loc
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}
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var locations = map[string]string{
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"0": "EEr_Andernach_today.png",
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"1": "EEr_Berlin_Potsdamer_Platz_today.png",
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"2": "EEr_Bonn_today.png",
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"3": "EEr_Boesel_B_today.png",
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"4": "EEr_Chieming_today.png",
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"5": "EEr_Cuxhaven_B_today.png",
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"6": "EEr_Dortmund_today.png",
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"7": "EEr_Duderstadt_B_today.png",
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"8": "EEr_Eckernfoerde_today.png",
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"9": "EEr_Fichtelberg_today.png",
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"10": "EEr_Friedrichshafen_today.png",
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"11": "EEr_Genthin_today.png",
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"12": "EEr_Giessen-Wettenberg_today.png",
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"13": "EEr_Goerlitz_today.png",
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"14": "EEr_Groemitz_today.png",
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"15": "EEr_Hamburg_today.png",
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"16": "EEr_Hohenpeissenberg_today.png",
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"17": "EEr_Kassel_today.png",
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"18": "EEr_Klippeneck_today.png",
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"19": "EEr_Kulmbach_today.png",
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"20": "EEr_Langen_today.png",
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"21": "EEr_Lindenberg_today.png",
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"22": "EEr_Lueneburg_today.png",
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"23": "EEr_Melpitz_today.png",
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"24": "EEr_Muenchen_today.png",
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"25": "EEr_Norderney_today.png",
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"26": "EEr_Belm-Osnabrueck_today.png",
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"27": "EEr_Salzgitter_today.png",
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"28": "EEr_Sankt Augustin_today.png",
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"29": "EEr_Schauinsland_today.png",
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"30": "EEr_Schweinfurt_Wasserlosen_today.png",
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"31": "EEr_Stuttgart_today.png",
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"32": "EEr_Sylt_Tinnum_today.png",
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"33": "EEr_Tholey_today.png",
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"34": "EEr_Todendorf_today.png",
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"35": "EEr_Waldhof_Falkenstein_today.png",
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"36": "EEr_Waldmuenchen_today.png",
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"37": "EEr_Wasserkuppe bei Fulda_today.png",
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"38": "EEr_Weissenburg_today.png",
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"39": "EEr_Wurmberg_B_today.png",
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"40": "EEr_Zingst_today.png",
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"41": "EEr_Zirchow_today.png",
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"42": "EEr_Schneefernerhaus_today.png",
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}
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var selectList = map[string]string{
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"Andernach": "0",
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"Berlin": "1",
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"Bonn": "2",
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"Bösel": "3",
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"Chieming": "4",
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"Cuxhaven": "5",
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"Dortmund": "6",
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"Duderstadt": "7",
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"Eckernförde": "8",
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"Fichtelberg": "9",
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"Friedrichshafen": "10",
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"Genthin": "11",
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"Gießen": "12",
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"Görlitz": "13",
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"Grömitz": "14",
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"Hamburg": "15",
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"Hohenpeißenberg": "16",
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"Kassel": "17",
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"Klippeneck": "18",
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"Kulmbach": "19",
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"Langen": "20",
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"Lindenberg": "21",
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"Lüneburg": "22",
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"Melpitz": "23",
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"München": "24",
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"Norderney": "25",
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"Osnabrück": "26",
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"Salzgitter": "27",
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"Sankt Augustin": "28",
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"Schauinsland": "29",
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"Schweinfurt": "30",
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"Stuttgart": "31",
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"Sylt (Westerland)": "32",
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"Tholey": "33",
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"Todendorf": "34",
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"Waldhof": "35",
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"Waldmünchen": "36",
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"Wasserkuppe": "37",
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"Weißenburg": "38",
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"Wurmberg": "39",
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"Zingst": "40",
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"Zirchow": "41",
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"Zugspitze (Schneefernerhaus)": "42",
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}
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|
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var selectListReverse = reverseMap(selectList)
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|
|
func reverseMap[K, V comparable](v map[K]V) map[V]K {
|
|
m := make(map[V]K)
|
|
for k, v := range v {
|
|
m[v] = k
|
|
}
|
|
return m
|
|
}
|
|
|
|
func sortedMap[K cmp.Ordered, V any](m map[K]V) iter.Seq2[K, V] {
|
|
a := make([]K, len(m))
|
|
i := 0
|
|
for k := range m {
|
|
a[i] = k
|
|
i++
|
|
}
|
|
slices.Sort(a)
|
|
return func(yield func(K, V) bool) {
|
|
for _, k := range a {
|
|
v := m[k]
|
|
if !yield(k, v) {
|
|
return
|
|
}
|
|
}
|
|
}
|
|
}
|