Gin-Gonic File upload mime error

Question

I'm creating an API in go with gin-gonic package, and I'm stuck with the file upload handler. Here is my code:

func postPicture(c *gin.Context) {
    id, ok := c.Params.Get("fileId")
    if !ok {...} // Err Handling
    user, ok := c.Params.Get("user")
    if !ok {...} // Err Handling
    file, _, err := c.Request.FormFile("file") // Here is the bug
    if err != nil {
        Common.Debug("Error: " + err.Error())
        c.JSON(http.StatusBadRequest, Common.JsonError{"Error", err.Error()})
        return
    } // Err Handling

    path := "./Files/" + user + "/pictures"
    filename := id + ".jpg"
    if _, err := os.Stat(path); os.IsNotExist(err) {
        os.Mkdir(path, 0755)
    }
    out, err := os.Create(path + "/" + filename)
    if err != nil {...} // Err Handling
    defer out.Close()

    _, err = io.Copy(out, file)
    if err != nil {...} // Err Handling
    c.JSON(http.StatusAccepted, gin.H{})

}

The error is on c.Request.FormFile(), it returns me "mime: invalid media parameter" whatever the request is. I tried the following:

curl -X POST --form upload=C:\Users\meiche_j\Pictures\Capture.PNG -H "Content-Type: multipart/form-data;boundary=???" "http://127.0.0.1:3003/postFiles/picture/58cbb5627067500f58834f69/fileIdTest"


curl -X POST --form upload=C:\Users\meiche_j\Pictures\Capture.PNG -H "Content-Type: multipart/form-data;boundary=???;Content-Disposition: attachment; filename=file" "http://127.0.0.1:3003/postFiles/picture/58cbb5627067500f58834f69/fileIdTest"


curl -X POST --form upload=C:\Users\meiche_j\Pictures\Capture.PNG -H "Content-Type: multipart/form-data;boundary=???;Content-Disposition: form-data; filename=file" "http://127.0.0.1:3003/postFiles/picture/58cbb5627067500f58834f69/fileIdTest"

I don't think the error is in the code, but I can't find what request headers are missing, any idea?

Answer 1

You make multiple little mistake in your code and in your test:

1. You should use the correct key in c.Request.FormFile("file"), here you use file as key but you use upload in your curl request as key --form upload=...

2. You should use the @ in your curl request : curl -X POST --form upload=@C:\Users\meiche_j\Pictures\Capture.PNG to indicate that you want to transfer the content of the file and not only the path

3. You should avoid putting by yourself the boundary parameter in your curl request and do a curl request like

   curl -X POST -F upload=@pathtoyourfile -H 'Content-Type: multipart/form-data' "http://127.0.0.1:3003/postFiles/picture/58cbb5627067500f58834f69/fileIdTest"
   

Hope this has been usefull