go 实现图片服务器缓存
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func blackHandler(w http.ResponseWriter, r *http.Request) {
key := "black"
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
}
}
m := image.NewRGBA(image.Rect(0, 0, 240, 240))
black := color.RGBA{0, 0, 0, 255}
draw.Draw(m, m.Bounds(), &image.Uniform{black}, image.ZP, draw.Src)
var img image.Image = m
writeImage(w, &img)
}