HTTP/2 Server Push: Difference between revisions

Revision as of 16:27, 26 November 2018

Revision as of 12:12, 19 February 2019

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* HEADERS frame. As its name implies, this type of frame carries HTTP headers . When sent by the browser to the server, it signals that a request is being made. When sent by the server to the browser, it signals that a response to a previous request or push promise is being sent.

* PUSH_PROMISE frame. This frame is sent by the server to the browser to start pushing a resource. It also contains HTTP headers. However, the kind of headers present in a PUSH_PROMISE frame are headers that would normally be present in a request . This is different from the response headers that a server would normally send. The request URL, for example, is present in the PUSH_PROMISE frame as the HTTP/2-specific :path pseudo-header, as is the :authority pseudo-header to indicate a host. Other headers that may be present in a PUSH_PROMISE and that some browsers use are cache headers, for example, if-none-match.

* DATA frames. These frames are sent in either direction to carry the actual content of a resource or the contents that the browser POSTs or PUTs to the server.

* RST_STREAM frames. These frames serve many purposes. One of them is having the browser signal to the server that a pushed stream is not needed.