'Proceed to Checkout' Event for Magento?

Question

I've just started putting together a Magento module which bypasses the whole Magento checkout process and instead sends the cart details to a 3rd party fulfilment company via XML-RPC.

Not getting anywhere fast and could use a bit of guidance. My understanding is that I should create the module with an observer based on the event triggered by proceeding to checkout. Trouble is I can't work out which event that would be, I've been through the whole massive list here;

http://www.nicksays.co.uk/magento_events_cheat_sheet/

I've tried;

checkout_submit_all_after - fires after order processed successfully

checkout_cart_add_product_complete - fires after product added to cart

checkout_cart_save_before - fires after product added to cart

checkout_type_onepage_save_order - can't get this to fire at all

checkout_onepage_controller_success_action - fires after order processed successfully

I don't know if this means I'll have to create a custom event or if there is an entirely different and much better alternative to what I'm doing. Building and sending the XML I will leave to another question (starting to realise I may have my hands pretty full here) but any tips there gratefully appreciated too.

Thanks for any help.

Answer 1

controller_action_predispatch_checkout_onepage_index should be the event you're looking for. All controllers inherit the preDispatch method which fires a generic event for predispatch, and a specific event based on the requested action path. The controller you want lives in the checkout module and is called onepage with a default action of index.

Review Mage_Core_Controller_Varien_Action::preDispatch() to see the relevant code