问题描述
我正在尝试执行以下操作。
|Upload file in HTML post file form|
|
⌄
|Server A forwards the multipart request|
|
⌄
|Server B receives and stores the file from the forwarded multipart request|
|
⌄
|Server A receives response from Server B when Server B is done|
在服务器 A 上处理多部分请求很简单,但是当我尝试在服务器 B 上处理转发的请求时,它失败并显示 multipart: NextPart: EOF
。
我正在尝试创建单独的前端/后端服务。前端只处理 UI 相关的处理,而后端实际上会对文件做一些处理,因此需要多部分请求转发。
服务器A上的转发代码如下。 解决方案已从此处获取。 https://stackoverflow.com/a/34725635/6569715
func forwardRequest(address string,path string,r *http.Request) (interface{},error) {
body,err := IoUtil.ReadAll(r.Body)
if err != nil {
return nil,err
}
r.Body = IoUtil.nopCloser(bytes.NewReader(body))
proxyReq,err := http.NewRequest(r.Method,fmt.Sprintf("%s%s",address,path),bytes.NewReader(body))
if err != nil {
return nil,err
}
for header,values := range r.Header {
for _,value := range values {
proxyReq.Header.Add(header,value)
}
}
client := &http.Client{}
resp,err := client.Do(proxyReq)
if err != nil {
return nil,err
}
defer resp.Body.Close()
return resp,nil
}
以及服务器 B 上处理转发请求的代码:
func testMultiPart(w http.ResponseWriter,r *http.Request) {
if err := r.ParseMultipartForm(10 << 20); err != nil {
err = errors.Wrap(errors.WithStack(err),"Backend: Failed to parse form")
w.WriteHeader(http.StatusInternalServerError)
fmt.Fprint(w,fmt.Sprintf("{\"error\":\"%s\"}",err.Error())
return
}
}
感谢任何帮助。
解决方法
我设法让它发挥作用。我相信这只是我自己没有正确填写 URI 的错误。无论如何,我都会发布我的解决方案中的片段以供将来参考。
客户端html文件表单部分:
<form action="/test-main/file-test" enctype="multipart/form-data" method="post">
<label for="file-upload">Upload your file :</label>
<input type="file" id="file-upload" name="file-upload" accept="image/*">
</form>
服务器 A 代码:
import (
"net/http"
"errors"
"fmt"
"log"
"io/ioutil"
"bytes"
"github.com/gorilla/mux"
)
func fileUpload(w http.ResponseWriter,r *http.Request) {
body,err := ioutil.ReadAll(r.Body)
if err != nil {
return log.Fatal(err)
}
r.Body = ioutil.NopCloser(bytes.NewReader(body))
// If Server A and B are separate docker images,you may need to use their docker subnet IP,like below.
proxyReq,err := http.NewRequest(r.Method,fmt.Sprintf("http://172.18.0.2:8082%s",r.RequestURI),bytes.NewReader(body))
if err != nil {
return log.Fatal(err)
}
for header,values := range r.Header {
for _,value := range values {
proxyReq.Header.Add(header,value)
}
}
client := &http.Client{}
resp,err := client.Do(proxyReq)
if err != nil {
return log.Fatal(err)
}
defer resp.Body.Close()
respBody,err := ioutil.ReadAll(resp.Body)
if err != nil {
return log.Fatal(err)
}
// Process Server B response
// ...
}
func createRouter() *mux.Router {
r := mux.NewRouter()
testPath := r.PathPrefix("/test-main").Subrouter()
testPath.HandleFunc("/file-test",fileUpload)
return r
}
func main() {
// Create Server and Route Handlers
srv := &http.Server{
Handler: createRouter(),Addr: ":8081",ReadTimeout: 30 * time.Second,WriteTimeout: 30 * time.Second,}
// Start Server
go func() {
log.Println("Starting Server")
if err := srv.ListenAndServe(); err != nil {
log.Fatal(err)
}
}()
}
和服务器 B 代码:
import (
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"github.com/gorilla/mux"
)
func uploadFile(w http.ResponseWriter,r *http.Request) {
if err := r.ParseMultipartForm(10 << 20); err != nil {
log.Fatal(err)
}
file,handler,err := r.FormFile("file-upload")
if err == http.ErrMissingFile {
return nil
}
if err != nil {
log.Fatal(err)
}
fmt.Printf("Uploaded File: %+v\n",handler.Filename)
fmt.Printf("File Size: %+v\n",handler.Size)
fmt.Printf("MIME Header: %+v\n",handler.Header)
defer file.Close()
// Create file
dst,err := os.Create(fmt.Sprintf("/some-destination-folder/%s",handler.Filename))
if err != nil {
log.Fatal(err)
}
// Copy the uploaded file to the created file on the file system.
if _,err := io.Copy(dst,file); err != nil {
if err2 := dst.Close(); err2 != nil {
log.Fatal(err)
}
log.Fatal(err)
}
dst.Close()
return nil
}
func (c *Controller) createRouter() *mux.Router {
r := mux.NewRouter()
testPath := r.PathPrefix("/test-main").Subrouter()
testPath.HandleFunc("/file-test",uploadFile)
return r
}
func main() {
// Create Server and Route Handlers
srv := &http.Server{
Handler: createRouter(),Addr: ":8082",}
// Start Server
go func() {
log.Println("Starting Server")
if err := srv.ListenAndServe(); err != nil {
log.Fatal(err)
}
}()
}
祝未来的读者好运。