It encapsulates a number of features and functionality for generating HTTP responses in your application.It also assists in testing, as it can be mocked/stubbed allowing you to inspect headers that will be sent.Using a URL Session has a step-by-step list of events that occur when a session is performing a task, and which delegate methods are called as a result.On the other hand, if you don’t need any of the features provided by a delegate, you can use this API without providing one by passing Important The session object keeps a strong reference to the delegate until your app exits or explicitly invalidates the session.To take advantage of this header, you must either call the header to indicate the date and time at which the resource was modified for the last time.Setting this header helps Cake PHP tell caching clients whether the response was modified or not based on their cache.
The tasks in a session also share a common delegate that lets you provide and obtain information when various events occur—when authentication fails, when data arrives from the server, when data is ready to be cached, and so on.
API, your app creates one or more sessions, each of which coordinates a group of related data transfer tasks.
For example, if you’re creating a web browser, your app might create one session per tab or window, or one session for interactive use and another for background downloads.
Within each session, your app adds a series of tasks, each of which represents a request for a specific URL (following HTTP redirects, if necessary).
The tasks within a given URL session share a common , which defines connection behavior, such as the maximum number of simultaneous connections to make to a single host, whether to allow connections over a cellular network, and so on.