actix-http: h1: stop pipelining when not reading full requests #3721
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The existing pipelining behavior of the h1 dispatcher can cause client timeouts if the entire request body isn't read. It puts the dispatcher into a state where it refuses to read more (payload dropped) but there are still bytes in the buffer from the request body. This solution adds the SHUTDOWN flag in addition to the FINISHED flag when completing a response when both the following are true: 1. There are no messages in `this.messages` 2. There is still a payload in `this.payload` This combination implies two things. First, that we have not parsed a pipelined request after the request we have just responded to. Second, that the current request payload has not been fed an EOF. Because there are no pipelined requests, we know that the current request payload belongs to the request we have just responded to, and because the request payload has not been fed an EOF, we know we never finished reading it. When this occurs, adding the SHUTDOWN flag to the dispatcher triggers a `flush` and a `poll_shutdown` on the IO resource on the next poll.
robjtede
approved these changes
Aug 29, 2025
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An alternate solution to #3715
The existing pipelining behavior of the h1 dispatcher can cause client timeouts if the entire request body isn't read. It puts the dispatcher into a state where it refuses to read more (payload dropped) but there are still bytes in the buffer from the request body.
This solution adds the SHUTDOWN flag in addition to the FINISHED flag when completing a response when both the following are true:
this.messagesthis.payloadThis combination implies two things. First, that we have not parsed a pipelined request after the request we have just responded to. Second, that the current request payload has not been fed an EOF. Because there are no pipelined requests, we know that the current request payload belongs to the request we have just responded to, and because the request payload has not been fed an EOF, we know we never finished reading it.
When this occurs, adding the SHUTDOWN flag to the dispatcher triggers a
flushand apoll_shutdownon the IO resource on the next poll.PR Type
Bug Fix
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