mockimg.go

package main

import (
	"image"
	"image/color"
	"image/draw"
	"image/png"
	"net/http"
	"regexp"
	"strconv"
)

// http://localhost:8080/100x100.png とかで100x100の画像を返す
var mockimgRegexp = regexp.MustCompile(`^.*/([0-9]+)x([0-9]+).png$`)

func mockimg(w http.ResponseWriter, r *http.Request) {
	matches := mockimgRegexp.FindStringSubmatch(r.RequestURI)
	width, height := int64(150), int64(150)
	if len(matches) == 3 {
		width, _ = strconv.ParseInt(matches[1], 10, 32)
		height, _ = strconv.ParseInt(matches[2], 10, 32)
	}

	img := image.NewRGBA(image.Rect(0, 0, int(width), int(height)))
	gray := &image.Uniform{color.RGBA{128, 128, 128, 255}}
	draw.Draw(img, img.Bounds(), gray, image.ZP, draw.Src)
	png.Encode(w, img)
}

func main() {
	http.HandleFunc("/", mockimg)
	http.ListenAndServe(":8080", nil)
}