dongyou6795
2016-12-14 14:08
浏览 356
已采纳

在Golang中从base64渲染图像

I would like to render an image from base64 in golang (here the twitter icon)

package main

import (
    base64 "encoding/base64"
    "fmt"
    "io"
    "net/http"
    "strconv"
)

func pix(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hi there, I love %s!", r.URL.Path[1:])
    var cookie *http.Cookie
    cookie, err := r.Cookie("csrftoken")
    if err != nil {
        fmt.Printf("error")
        fmt.Println(err)
    }
    fmt.Printf(cookie.Value)
    w.Header().Set("Content-Type", "image/jpeg")
    p, err := base64.StdEncoding.DecodeString("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")
    if err != nil {
        http.Error(w, "internal error", 500)
        return
    }
    w.Header().Set("Content-Length", strconv.Itoa(len(p))) //len(dec)
    io.WriteString(w, string(p))
}

func main() {
    http.HandleFunc("/pix/", pix)
    err := http.ListenAndServe(":9080", nil)
    if err != nil {
        fmt.Println(err)
    }
}

But it doesn't display anything and when I try to go to the URL; it downloads a file that contains error. Anyone have any idea why this is?

图片转代码服务由CSDN问答提供 功能建议

我想在golang（此处为twitter图标）中从base64渲染图像 \ n 

 包main 
 
import（
 base64“ encoding / base64” 
“ fmt” 
“ io” 
“ net / http” 
“ strconv” 
）
 \  nfunc pix（w http.ResponseWriter，r * http.Request）{
 fmt.Fprintf（w，“嗨，我爱％s！”，r.URL.Path [1：]）
 var cookie * http  .Cookie 
 Cookie，错误：= r.Cookie（“ csrftoken”）
，如果错误！= nil {
 fmt.Printf（“ error”）
 fmt.Println（err）
} 
 fmt。 的printf（cookie.Value）
 w.Header（）设置（ “内容类型”， “图像/ JPEG”）\ NP，ERR：= base64.StdEncoding.DecodeString（“iVBORw0KGgoAAAANSUhEUgAAADIAAAAyCAIAAACRXR / mAAADMUlEQVRYw + 2YTUgUYRjHZzOJIoNA + rrUyYNIRQgRHaLo4qFDBEGeunSxS9TFU0QEnhIh6IvokrUzO2uamRmbG6XmR / mVaKZpZVbYvvO143zszsxOz  + yahNm + 785sITEP72F3Z + ADH8 / ZF5 + PpagwtxKXj + VJ + Vg的+ LO / LY + W + WI4KpddKwWIQFUSF97nNLcLGZt75SiOHchEXfskDVmYjlowpiEoei3UT2ljcFJOpOd169C1Z2SuvgsdpB7cgzB16EV / byGM2xDIVPxQujKmBDF / 2m2l0vFvmEin7N2v8kiiP  iOeGlGHRvP1RdxA9eYtGR7pk2Pf6lI7RCoP2RaWkZWe3fsFc18hvesAHPGEFUc24ltnx3kyiCJwfRMs6dTXLdSIjO9Osal18qzKfE5V9coDxhlU7qS3uOyiaB55JDtkS2TKoLCLaOLPS4b02pQdCHiUfRKf653 / d2kjZN6f10jYxI2EnrGk5H + 2WsVi6ZZ8fVSmGQKaYyyFuR6ugmUtVrJo2C7HokeGq8447sYpOPBbo3XFzKC95626sZlz905sUM9XLGbXvtKtTOhZrQDApkhNNkiAOPo / viojh2YSZsj1aF2eQ5n2stuomNQjiiGQanrFufdCXP8gu8tbhjridJ6saVPKExXJrwlwfb3pnAg2Ut0tEBZFI8gza81Tik15DCDIoINQ7aQdBo90RMfrdwNaWLFY9opJGkBQrhCA / HXspQ8W1XHkN6vfWFiGH9ouwhdpJUFuy2JX3eg6uyqENpNHZYcUd02jcLMI2WO67UwZVv1G1HLMq3L83KuEbLPdY7IL2L42p0MMQiuzkq / ncwucOi6qPbWkWoPfCUsENpweUnP1EmE4XGhgagT72RyXolkSCHBbTU3By3fgJj8VyJW3CmSHl8oTWMJuYUUizVvtcsuyJ6J4J663CMLevXar / lJgnKNSgbphzKjriTn5i0F8eX9ODXnEzf6JHvjGtv + aNGdWCOEKnJRmpr5oFVQV8WTWglIKHMlPhv5uqQ1xGYfB5fRMPo + n2VmFbi7ChiS9oWBhZvXrI01TNLg7yPxt51v9rxMfysXwsH8vH + G + wfgDUr + 5LcyNV4AAAAABJRU5ErkJggg ==“）
如果犯错！=零{
 http.Error（W， ”内部错误“，500）  
 return 
} 
 w.Header（）。Set（“ Content-Length”，strconv.Itoa（len（p）））// len（dec）
 io.WriteStr  ing（w，string（p））
} 
 
func main（）{
 http.HandleFunc（“ / pix /”，pix）
 err：= http.ListenAndServe（“：9080”，nil）  
 if err！= nil {
 fmt.Println（err）
} 
} 
   
 
 
但是它什么也不显示，当我尝试时 转到URL； 它会下载包含错误的文件。 有人知道为什么会这样吗？
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1条回答 默认 最新

  • doudu161481 2016-12-14 14:17
    已采纳

    You are writing data to client other than the image. Specifically, this line:

    fmt.Fprintf(w, "Hi there, I love %s!", r.URL.Path[1:])

    You browser tries to render the content as a JPEG, but fails because of this extra data, so it prompts you to download it instead. Remove it and the picture will be displayed correctly.

    You should also follow @Mellow Marmot's suggestion and use w.Write(p) instead of io.WriteString(w, string(p)).

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