POST data using the Content-Type multipart/form-data

Question

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         


        

Answer 1

After having to decode the accepted answer for this question for use in my unit testing I finally ended up with the follow refactored code:

func createMultipartFormData(t *testing.T, fieldName, fileName string) (bytes.Buffer, *multipart.Writer) {
    var b bytes.Buffer
    var err error
    w := multipart.NewWriter(&b)
    var fw io.Writer
    file := mustOpen(fileName)
    if fw, err = w.CreateFormFile(fieldName, file.Name()); err != nil {
        t.Errorf("Error creating writer: %v", err)
    }
    if _, err = io.Copy(fw, file); err != nil {
        t.Errorf("Error with io.Copy: %v", err)
    }
    w.Close()
    return b, w
}

func mustOpen(f string) *os.File {
    r, err := os.Open(f)
    if err != nil {
        pwd, _ := os.Getwd()
        fmt.Println("PWD: ", pwd)
        panic(err)
    }
    return r
}

Now it should be pretty easy to use:

    b, w := createMultipartFormData(t, "image","../luke.png")

    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())