JS based easy Field Validations in Rails
Most of you will disagree with this post to use Javascript based form validations in Rails. However this is an attempt to simplify integration of DEXAGOGO - Really easy field validations in Rails. This is one of the most structured and easy validation technique written by Andrew Tetlaw and team. (Demo)
To use it in Rails, copy simple_validation.rb in application lib directory and add following lines to config/environment.rb file.
Download and Import validation.js along with prototype.js in layout from here.
Two methods are introduced to render forms.
- validated_form_for
- validated_remote_form_for
Usage:
:class attribute refers to validation rule (or combination of rules) and :title attribute is the validation message. Details of all rules are available at http://tetlaw.id.au/view/javascript/really-easy-field-validation
File Upload: Validating Extensions
I was searching for a way to validate a file against an allowed set of extensions before uploading. My application uses file_column plugin to store video files and I am using mongrel_upload_progress to track the upload. The maximum file size allowed is 50Mb so there was a need to have validation at both client as well as server side.
Model Validation
Client Side javascript validation
mongrel_upload_progress plugin uses following code to submit the form in a hidden iframe. Modify submitUploadForm method as shown:
The advantages of this approach are:
File is validated at both sides to avoid unnecessary uploading of file before model validation. Good for big files.
In case JS is disabled, the file is still validated.
