Friday, August 15, 2008

Input Validation with ESAPI - Very Important

I just committed a new concrete class into the ESAPI core called org.owasp.esapi.ValidationErrorList.

ValidationErrorList will allow you to attempt groups of validation checks in a non blocking way.

I also added a variant of many org.owasp.esapi.Validator functions that will accept a ValidationErrorList as an argument instead of throwing a ValidaitonException. These ValidationErrorList variants will populate the ValidationErrorList with the ValidationException, hashed by the context.

To actually submit and collect errors for an entire validation group, your controller code would look something like:

ValidationErrorList() errorList = new ValidationErrorList();.
String name = getValidInput("Name", form.getName(), "SomeESAPIRegExName1", 255, false, errorList);
String address = getValidInput("Address", form.getAddress(), "SomeESAPIRegExName2", 255, false, errorList);
Integer weight = getValidInteger("Weight", form.getWeight(), 1, 1000000000, false, errorList);
Integer sortOrder = getValidInteger("Sort Order", form.getSortOrder(), -100000, +100000, false, errorList);
request.setAttribute(errorList , "ERROR_LIST");

Then later in your view layer, you would be able to display all of error messages via a helper function like:

public static ValidationErrorList getErrors() {
HttpServletRequest request = ESAPI.httpUtilities().getCurrentRequest();
ValidationErrorList errors = new ValidationErrorList();
if (request.getAttribute(Constants.ERROR_LIST) != null) {
errors = (ValidationErrorList)request.getAttribute("ERROR_LIST");
return errors;

And even check if a specific UI component is in error via calls like:


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