I am working with E-Commerce module of Drupal 7. I want to redirect Add to Cart button link to product page only those products which have attribute otherwise I want to add product direct to cart.
Using Drupal Rules Module:
To redirect directly to checkout after a user clicks 'add to cart'
- Admin -> Configure -> Rules -> Add New Rule
- Give it a title of 'Add to Cart - Redirect to Checkout'
- Set React on event to: After adding a product to the cart
- Add new Action - set this to 'Page redirect'
- Give it a value of 'checkout' and save.
Now when users click your add to cart button, they will be taken directly to checkout. Alternatively, you can send them to /cart by change the value in step 5.
Add a hook form alter that changes the add to cart form to add another #submit callback. In this callback, add your logic to check attributes, if you need to redirect, set $form_state['redirect']
See https://drupal.stackexchange.com/a/128001/42761 for more on how to alter the form