How to check if input file is empty?

Question

go

simple form

<form action="/upload" method="POST" enctype="multipart/form-data">
            <input type="file" name="file">
            <input type="submit" value="Submit">
</form>

How to check if the submitted form is empty? Or that specifically input name="file" is not set when submitting the form?
fmt.Println(r.PostFormValue("file")) produces an empty string even if I submit a file.

Answer 1

try
in ok it will be true if the field was sent when sending and false if the field was not in the request,
just don't forget to parse the request body with

const maxMemory = 32 << 20 // 32 MB
r.ParseMultipartForm(maxMemory)