title: Uniform Resource Identifier validation using python flask
body: <p>I am pretty new to flask, i wonder how to properly validate a Uniform Resource Identifier in flask.</p>
  
  <pre><code>email = EmailField('Email Address', validators=[DataRequired()])
  #this is not enough validation for url
  url = EmailField('Uniform Resource Identifier', validators=[DataRequired()])
  password = PasswordField('Password', validators=[DataRequired(), Email()])
  </code></pre>