Drupal 7: I need a module to append a contact form to a node of a specific content type. The form should be configurable and permit to send an email with an attachment to the node author. The form should also have a captcha. The email must not be saved in the database.
Does such module exists or do i need to develop it ?
You should be able to achieve this through the combination of the webform module, CAPTCHA module and a custom module.
Webform defines it's own 'webform' content type, but it also allows you to make other content types webform enabled by visiting 'admin/config/content/webform' and selecting the appropriate content type.
The token module provides node tokens such as nid and title which can be included as a hidden form element, but annoyingly, doesn't include the author as a token.
On the email tab of your webform, it's possible to choose a form component as the email address to send the form results to. I would create a hidden field, leaving the default value blank and then it should be fairly easy to add the node author value to it in a custom module using hook_form_alter (form id can be found by viewing source and looking for the hidden input 'form_id'). You can then use this form component in the email tab to send the results to.
The only thing I can see causing an issue is that there isn't an easy way to stop webform recording the form result in the database - I would imagine this would be achievable in a custom module without too much hassle though.