Comment by derriz

2 days ago

Yeah, I’ve always felt that the stream API is a leaky abstraction for providing access to networking. I understand the attraction of making network I/O look like local file access given the philosophy of UNIX.

The API should have been message oriented from the start. This would avoid having the network stack try to compensate for the behavior of the application layer. Then Nagel’s or something like it would just be a library available for applications that might need it.

The stream API is as annoying on the receiving end especially when wrapping (like TLS) is involved. Basically you have to code your layers as if the underlying network is handing you a byte at a time - and the application has to try to figure out where the message boundaries are - adding a great deal of complexity.

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derriz

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mgaunard  1 day ago

the whole point of TCP is that it is a stream of bytes, not of messages.

The problem is that this is not in practice quite what most applications need, but the Internet evolved towards UDP and TCP only.

So you can have message-based if you want, but then you have to do sequencing, gap filling or flow control yourself, or you can have the overkill reliable byte stream with limited control or visibility at the application level.

  • derriz  1 day ago

    For me, the “whole point” of TCP is to add various delivery guarantees on top of IP. It does not mandate or require a particular API. Of course, you can provide a stream API over TCP which suits many applications but it does not suit all and by forcing this abstraction over TCP you end up making message oriented applications (e.g request /response type protocols) more complex to implement than if you had simply exposed the message oriented reality of TCP via an API.

    • mgaunard  1 day ago

      TCP is not message-oriented. Retransmitted bytes can be at arbitrary offsets and do not need to align with the way the original transmission was fragmented or even an earlier retransmission.

      3 replies →

calineczka  2 days ago

> message oriented

Very well said. I think there is enormous complexity in many layers because we don't have that building block easily available.

  • mort96  1 day ago

    It's the main reason why I use websockets for a whole lot of things. I don't wanna build my own message chunking layer on top of TCP every time.