## org.springframework.web.servlet.support
Interface RequestDataValueProcessor

    public interface RequestDataValueProcessor

A contract for inspecting and potentially modifying request data values such as URL query parameters or form field values before they are rendered by a view or before a redirect.

Implementations may use this contract for example as part of a solution to provide data integrity, confidentiality, protection against cross-site request forgery (CSRF), and others or for other tasks such as automatically adding a hidden field to all forms and URLs.

View technologies that support this contract can obtain an instance to delegate to via `RequestContext.getRequestDataValueProcessor()`.

Since:
  3.1
Author:
  Rossen Stoyanchev

Method Summary
`Map<String,String>` `getExtraHiddenFields(HttpServletRequest request)` Invoked after all form fields have been rendered.
`String` `processAction(HttpServletRequest request, String action)` Invoked when a new form action is rendered.
`String` `processFormFieldValue(HttpServletRequest request, String name, String value, String type)` Invoked when a form field value is rendered.
`String` `processUrl(HttpServletRequest request, String url)` Invoked when a URL is about to be rendered or redirected to.

Method Detail

### processAction

    String processAction(HttpServletRequest request,
                         String action)

  Invoked when a new form action is rendered.

  Parameters:
    `request` - the current request
    `action` - the form action
  Returns:
    the action to use, possibly modified

### processFormFieldValue

    String processFormFieldValue(HttpServletRequest request,
                                 String name,
                                 String value,
                                 String type)

  Invoked when a form field value is rendered.

  Parameters:
    `request` - the current request
    `name` - the form field name
    `value` - the form field value
    `type` - the form field type ("text", "hidden", etc.)
  Returns:
    the form field value to use, possibly modified

### getExtraHiddenFields

    Map<String,String> getExtraHiddenFields(HttpServletRequest request)

  Invoked after all form fields have been rendered.

  Parameters:
    `request` - the current request
  Returns:
    additional hidden form fields to be added, or `null`

### processUrl

    String processUrl(HttpServletRequest request,
                      String url)

  Invoked when a URL is about to be rendered or redirected to.

  Parameters:
    `request` - the current request
    `url` - the URL value
  Returns:
    the URL to use, possibly modified