How to get information from another domain?

Question

Yii

In general, there are two sites on different domains, but they look into the same database. It is necessary to carry out cross-authorization, i.e. if a person is logged in on site1 under user1, then when going to site2, he should automatically be logged in under user1 there as well.
How to do it, what are the options?
Can it be done simply?
Why, when requesting from site2 to site1 via file_get_contents(" http://site1 "), I don't get information that the user is logged in to site1 under user1?

Answer 1

Because the browser on site2 does not send cookies from site1.
Otherwise it would be a security disaster.
Cross-domain authorization is done through a third-party authorization service. Or through authorization on the top-level domain.
For example, site2.domain.rf and site1.domain.rf are authorized through domain.rf, which redirects to the desired site