Question

Based on the documentation, %s will be replaced by field name when setting error messages.

If you include %s in your error string, it will be replaced with the
“human” name you used for your field when you set your rules.

Is there a way to have multiple %s in the string and define them differently?

Answer 1

This is the line in the form validation library that creates the error message:

// Build the error message
$message = sprintf($line, $this->_translate_fieldname($row['label']), $param);

• $line: The error message template, for example “The % field is invalid”
• $this->_translate_fieldname($row['label']): The field’s label
• $param: The parameter passed the the validation function, if any, max_length[5] would pass “5”

So that’s the extent of what the form validation class does for you. If you need more flexibility you’ll have to prepare the error message yourself ^{<– might be useful} beforehand with the extra variables already populated.

It might be interesting to extend the form validation class via core/MY_form_validation.php and work this functionality in. Unfortunately this line is contained in the main function _execute which is very big and messy, and from looking at it now, you’d need to overload some other functions as well. I started to write an example but it actually looks like a chore. You might be better off using:

$this->form_validation->set_message('rule_name', 'Your custom message here');

More on setting error messages: http://ellislab.com/codeigniter/user_guide/libraries/form_validation.html#settingerrors