Question

我正在尝试编写一个后请求功能，该功能可以从golang服务器向客户端发送文件。该代码从此处开始有点混乱（golang POST data using the Content-Type multipart/form-data）。无论出于什么原因，我总是收到“找不到404页”的消息，即使通过邮递员完成的相同请求是到达终点并成功返回。这是奇怪的行为，我不确定如何调试。（出于测试目的，我已经对该URL进行了硬编码以使其打入本地运行的服务器。）

这是我的代码：

func PostUpload(values map[string]io.Reader, URL string){
    fmt.Println("inside PostUpload in outbound")
    client := &http.Client{}
    var err error

    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 {
                fmt.Println("there was an error")
                fmt.Println(err)
            }
        }
    w.Close()

    // Now that you have a form, you can submit it to your handler.
        // req, err := http.NewRequest("POST", URL, &b)
        req, err := http.NewRequest("POST", "http://127.0.0.1:5000/upload", &b)
    if err != nil {
                fmt.Println("there was an error on http.NewRequest in outbound post file upload")
                fmt.Println(err)
    }
    // Don't forget to set the content type, this will contain the boundary.
        req.Header.Set("Content-Type", w.FormDataContentType())


        requestDump, err := httputil.DumpRequest(req, true)
        if err != nil {
            fmt.Println(err)
        }
        fmt.Println(string(requestDump))


    // Submit the request
    resp, err := client.Do(req)
    if err != nil {
                fmt.Println("there was an error on client do in outbound post file upload")
                fmt.Println(err)
        }

        resp_body, _ := ioutil.ReadAll(resp.Body)
        var parsed map[string]interface{}
        err = json.Unmarshal(resp_body, &parsed)
        if err!=nil{
            if typeof(resp_body)=="[]uint8"{
                fmt.Println("received []uint8, converting and displaying")
                fmt.Print(string(resp_body))
            }else{
                fmt.Println("inside unmarshal error")
                fmt.Println(err)
            }
        }

    return
}

这是控制台中的输出：

api      | 21:16:09 app         | inside PostUpload in outbound
api      | 21:16:09 app         | POST /upload HTTP/1.1
api      | Host: 127.0.0.1:5000
api      | Content-Type: multipart/form-data; boundary=0ce8aee17e5d00524acd3875d8b4b41dba5f99d8a7796d56289e38f89c64
api      |
api      | --0ce8aee17e5d00524acd3875d8b4b41dba5f99d8a7796d56289e38f89c64
api      | Content-Disposition: form-data; name="file"; filename="/uploads/TIME^2019-01-26 21:16:09.413514444 +0000 UTCFILE^Any_Publishing.txt"
api      | Content-Type: application/octet-stream
api      |
api      | # © 2016 and later: Unicode, Inc. and others.
api      | # License & terms of use: http://www.unicode.org/copyright.html#License
api      | #
api      | # File: Any_Publishing.txt
api      | # Generated from CLDR
api      | #
api      |
api      | # Variables
api      | $single = \' ;
api      | $space = ' ' ;
api      | $double = \";
api      | $back = \` ;
api      |
api      | --0ce8aee17e5d00524acd3875d8b4b41dba5f99d8a7796d56289e38f89c64--
api      |
api      | 21:16:09 app         | received []uint8, converting and displaying
api      | 404 page not found

有人看到出了什么问题吗？

编辑：

有人建议注释掉req上的转储，因为它可能会消耗req，而将其保留为空。我尝试了与上面相同的结果。

有人提到他们想查看成功上传的curl请求，因此它是：

patientplatypus:~/Downloads:15:48:28$curl -X POST -F "file=@./catpic.jpg" http://127.0.0.1:5000/upload
file uploaded successfully!

带有-v标志的curl的完全转储：

patientplatypus:~/Downloads:15:48:42$curl -v -X POST -F "file=@./catpic.jpg" http://127.0.0.1:5000/upload
Note: Unnecessary use of -X or --request, POST is already inferred.
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 5000 (#0)
> POST /upload HTTP/1.1
> Host: 127.0.0.1:5000
> User-Agent: curl/7.54.0
> Accept: */*
> Content-Length: 264915
> Expect: 100-continue
> Content-Type: multipart/form-data; boundary=------------------------48411aa948b523e2
>
< HTTP/1.1 100 Continue
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Content-Type: text/html; charset=utf-8
< Content-Length: 27
< Server: Werkzeug/0.14.1 Python/3.6.5
< Date: Sat, 26 Jan 2019 22:12:19 GMT
<
* Closing connection 0
file uploaded successfully!

有人提到他们想查看我尝试访问的服务器，所以这里是：https://github.com/patientplatypus/pythonServer

Answer 1

该404错误字符串看起来与Go标准库生成的错误字符串相同：

https://github.com/golang/go/blob/902fc114272978a40d2e65c2510a18e870077559/src/net/http/fs.go#L630

确定要运行Flask应用程序吗？

Answer 2

从外观上看，您没有发出相同的请求。卷曲（感谢包含它）在go设置2时设置一个表单值。在curl中，它是“文件”，而在go中是“文件名”。我在输出的内容配置行中看到了这一点。使用-v进行卷曲可能还包含有关其发送f的更多信息。

Golang http.NewRequest总是返回404-邮递员还可以

2 个答案: