we now set etag and cache-control in http header. Etag is set to the md5 key... (d48eb18d) · Commits · blackheaven / tinygraphs

app-backend/main.go

+2 −2

Original line number	Diff line number	Diff line
		@@ -23,8 +23,8 @@ func main() {

		r.HandleFunc("/grid/?", grid.H6X6)
		r.HandleFunc("/grid/[0-8]/?", grid.Color)
		r.HandleFunc("/grid/square/[0-8]/[a-zA-Z0-9]+/?", grid.SquareColor)
		r.HandleFunc("/grid/square/[a-zA-Z0-9]+/?", grid.Square)
		r.HandleFunc("/grid/square/[0-8]/[a-zA-Z0-9]+/?", grid.SquareColor) // cached
		r.HandleFunc("/grid/square/[a-zA-Z0-9]+/?", grid.Square) //cached

		r.HandleFunc("/grid/random/?", grid.Random)
		r.HandleFunc("/grid/random/[0-8]/?", grid.RandomColor)

controllers/grid/square.go

+39 −9

Original line number	Diff line number	Diff line
		@@ -13,15 +13,32 @@ import (
		"log"
		"net/http"
		"strconv"
		"strings"
		)

		// gridColorHandler is the handler for /grid/square/[0-9]+/?
		// Square is the handler for /grid/square/[A-Za-z0-9]+/?
		// build a 6x6 grid with alternate colors based on the number passed in the url
		func Square(w http.ResponseWriter, r *http.Request) {
		id, err := misc.PermalinkString(r, 3)
		if err != nil {

		if id, err := misc.PermalinkString(r, 3); err != nil {
		log.Printf("error when extracting permalink id: %v", err)
		} else {

		h := md5.New()
		io.WriteString(h, id)
		key := fmt.Sprintf("%x", h.Sum(nil)[:])

		e := `"` + key + `"`
		w.Header().Set("Etag", e)
		w.Header().Set("Cache-Control", "max-age=2592000") // 30 days

		if match := r.Header.Get("If-None-Match"); match != "" {
		if strings.Contains(match, e) {
		w.WriteHeader(http.StatusNotModified)
		return
		}
		}

		colorMap := tgColors.MapOfColorPatterns()
		bg, err1 := background(r)
		if err1 != nil {
		@@ -32,10 +49,8 @@ func Square(w http.ResponseWriter, r *http.Request) {
		fg = colorMap[0][1]
		}
		size := size(r)

		m := image.NewRGBA(image.Rect(0, 0, size, size))
		h := md5.New()
		io.WriteString(h, id)
		key := fmt.Sprintf("%x", h.Sum(nil)[:])
		draw.Square(m, key, bg, fg)
		var img image.Image = m
		write.Image(w, &img)
		@@ -50,12 +65,27 @@ func SquareColor(w http.ResponseWriter, r *http.Request) {
		log.Printf("error when extracting permalink id: %v", err)
		} else {
		if id, err1 := misc.PermalinkString(r, 4); err1 == nil {
		size := size(r)
		m := image.NewRGBA(image.Rect(0, 0, size, size))
		colorMap := tgColors.MapOfColorPatterns()

		h := md5.New()
		io.WriteString(h, id)
		key := fmt.Sprintf("%x", h.Sum(nil)[:])
		strId := strconv.FormatInt(colorId, 10)

		e := `"` + key + `-` + strId + `"`
		w.Header().Set("Etag", e)
		w.Header().Set("Cache-Control", "max-age=2592000") // 30 days

		if match := r.Header.Get("If-None-Match"); match != "" {
		if strings.Contains(match, e) {
		w.WriteHeader(http.StatusNotModified)
		return
		}
		}

		size := size(r)
		m := image.NewRGBA(image.Rect(0, 0, size, size))
		colorMap := tgColors.MapOfColorPatterns()

		draw.Square(m, key, colorMap[int(colorId)][0], colorMap[int(colorId)][1])
		var img image.Image = m
		write.Image(w, &img)