Can I do something similar to pipelining on HTTP 2?

Question

Pipelining is a technique in HTTP/1.1 where multiple requests are sent at once without waiting for a response, on a keepalive connection. The responses are then returned in order by the server, without waiting for a round-trip-time between a response being sent and the next request being received.

HTTP/2 adds a feature called multiplexing, which similarly allows the client to send off multiple requests at once. In this case however, the server can send responses all at once.

Without control of the server, Can I achieve something similar to pipelining (i.e. receiving responses in order one-at-a-time without latency between responses) when using HTTP/2?

This would be useful when downloading many large files, without much available memory to buffer several partially-completed responses.

Answer 1

Without control of the server, Can I achieve something similar to pipelining (i.e. receiving responses in order one-at-a-time without latency between responses) when using HTTP/2?

No you cannot, unless the server cooperates (for example the server can be configured to handle requests sequentially or something similar).

As a side note, while request pipelining was allowed in HTTP/1.1, it has always been considered a bad idea and as such made irrelevant by all major implementations (i.e. browsers don't do it, servers don't really support it, etc.). The main problem is error handling and buggy proxy servers.

HTTP/2 allows a client to set priorities on requests so that requests are processed in priority order. However, this feature is optional and servers may not implement it, so again you need to carefully choose/configure the server in order to get the behavior you want.

If you can control a little the server side, for both HTTP/1.1 and HTTP/2, a better solution would be to ask the server for all the files in a single request, and have the server reply with a multipart response.