validators.go

package main

import (
	"regexp"
)

// isLegitUsername returns true iff the given string represents
// a username using our allowed set of characters
func isLegitUsername(username string) bool {
	usernameRegex, _ := regexp.Compile("^[a-zA-Z0-9_-]+$")
	return usernameRegex.MatchString(username)
}

// isLegitPassword returns true iff the relevant string is non-empty
func isLegitPassword(password string) bool {
	return password != ""
}

// isLegitEmailAddress returns true iff the given string looks
// more or less like an email address.
func isLegitEmailAddress(address string) bool {
	// Reference for this chaos regexp:
	// https://github.com/asaskevich/govalidator/blob/master/patterns.go
	emailRegex, _ := regexp.Compile("^(((([a-zA-Z]|\\d|[!#\\$%&'\\*\\+\\-\\/=\\?\\^_`{\\|}~]|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])+(\\.([a-zA-Z]|\\d|[!#\\$%&'\\*\\+\\-\\/=\\?\\^_`{\\|}~]|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])+)*)|((\\x22)((((\\x20|\\x09)*(\\x0d\\x0a))?(\\x20|\\x09)+)?(([\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x7f]|\\x21|[\\x23-\\x5b]|[\\x5d-\\x7e]|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])|(\\([\\x01-\\x09\\x0b\\x0c\\x0d-\\x7f]|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}]))))*(((\\x20|\\x09)*(\\x0d\\x0a))?(\\x20|\\x09)+)?(\\x22)))@((([a-zA-Z]|\\d|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])|(([a-zA-Z]|\\d|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])([a-zA-Z]|\\d|-|\\.|_|~|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])*([a-zA-Z]|\\d|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])))\\.)+(([a-zA-Z]|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])|(([a-zA-Z]|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])([a-zA-Z]|\\d|-|\\.|_|~|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])*([a-zA-Z]|[\\x{00A0}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFEF}])))\\.?$")
	return emailRegex.MatchString(address)
}