core/installer/server/form.go

package server

import (
	"fmt"
	"net/url"
)

func GetFormValue(v url.Values, name string) (string, error) {
	items, ok := v[name]
	if !ok || len(items) != 1 {
		return "", fmt.Errorf("%s not found", name)
	}
	return items[0], nil
}