I am developing a Marketing(mostly email) extension for Magento, which requires that the users and products be imported into another third-party tool. How do I export this data from Magento to send it to our tool? What is the correct way to do it? Right now, I am forcing the Magento store owner to generate consumer key and consumer secret(after giving a bunch of permissions), and then go through the OAuth flow on the third party tool. But it is too tedious a process. I want to simplify it, by the extension taking care of the export/import automatically. How best can it be done?
You could start by having a look at the Magento API, which gives you a bunch of options to get data out of the box. If you are not happy with these functions, you can extend the api and add more methods by overwriting the Core API with a custom module.
Another thing you could do is export your data into a csv and have the extenal tool pick it up from there. You could make a CRON job for that.