使用 Content-Type multipart/form-data POST 数据 [英] POST data using the Content-Type multipart/form-data
问题描述
我正在尝试使用 go 将图像从我的计算机上传到网站.通常,我使用向服务器发送文件和密钥的 bash 脚本:
I'm trying to upload images from my computer to a website using go. Usually, I use a bash script that sends a file and a key to the server:
curl -F "image"=@"IMAGEFILE" -F "key"="KEY" URL
它工作正常,但我正在尝试将此请求转换为我的 golang 程序.
it works fine, but I'm trying to convert this request into my golang program.
http://matt.aimonetti.net/posts/2013/07/01/golang-multipart-file-upload-example/
我尝试了这个链接和许多其他链接,但是,对于我尝试的每个代码,来自服务器的响应都是没有发送图像",我不知道为什么.如果有人知道上面的例子发生了什么.
I tried this link and many others, but, for each code that I try, the response from the server is "no image sent", and I've no idea why. If someone knows what's happening with the example above.
推荐答案
这是一些示例代码.
简而言之,您需要使用 mime/multipart
包 构建表单.
In short, you'll need to use the mime/multipart
package to build the form.
package main
import (
"bytes"
"fmt"
"io"
"mime/multipart"
"net/http"
"net/http/httptest"
"net/http/httputil"
"os"
"strings"
)
func main() {
var client *http.Client
var remoteURL string
{
//setup a mocked http client.
ts := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
b, err := httputil.DumpRequest(r, true)
if err != nil {
panic(err)
}
fmt.Printf("%s", b)
}))
defer ts.Close()
client = ts.Client()
remoteURL = ts.URL
}
//prepare the reader instances to encode
values := map[string]io.Reader{
"file": mustOpen("main.go"), // lets assume its this file
"other": strings.NewReader("hello world!"),
}
err := Upload(client, remoteURL, values)
if err != nil {
panic(err)
}
}
func Upload(client *http.Client, url string, values map[string]io.Reader) (err error) {
// Prepare a form that you will submit to that URL.
var b bytes.Buffer
w := multipart.NewWriter(&b)
for key, r := range values {
var fw io.Writer
if x, ok := r.(io.Closer); ok {
defer x.Close()
}
// Add an image file
if x, ok := r.(*os.File); ok {
if fw, err = w.CreateFormFile(key, x.Name()); err != nil {
return
}
} else {
// Add other fields
if fw, err = w.CreateFormField(key); err != nil {
return
}
}
if _, err = io.Copy(fw, r); err != nil {
return err
}
}
// Don't forget to close the multipart writer.
// If you don't close it, your request will be missing the terminating boundary.
w.Close()
// Now that you have a form, you can submit it to your handler.
req, err := http.NewRequest("POST", url, &b)
if err != nil {
return
}
// Don't forget to set the content type, this will contain the boundary.
req.Header.Set("Content-Type", w.FormDataContentType())
// Submit the request
res, err := client.Do(req)
if err != nil {
return
}
// Check the response
if res.StatusCode != http.StatusOK {
err = fmt.Errorf("bad status: %s", res.Status)
}
return
}
func mustOpen(f string) *os.File {
r, err := os.Open(f)
if err != nil {
panic(err)
}
return r
}
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