4 ms·

It will never get out-of-sync because TCP guarantees that the bytes will be delivered in the same order they've arrived. The best approach is typically put a l

It will never get out-of-sync because TCP guarantees that the bytes will be delivered in the same order they've arrived. The best approach is typically put a length in front of every message. The good things about that approach are: 1. The receiver can allocate buffer that is exactly the size it needs to fit the message. 2. The receiver can check whether the message is too long before seeing the entire message. The only disadvantage is that you have to know the length of all messages in advance.

kccqzy 6y ago
Definitely be sure to check the length though. Imagine a mistaken client trying to send HTTP, but of course the first four bytes "HTTP" when interpreted as a 32-bit integer, whichever endian, is an absurdly large buffer.
- nucleardog 6y ago
  I mean, at this point you're effectively defining a new network protocol (or, you will be shortly once you implement ways to work around all the other issues you're going to run into). I'd go all-in from the start and start every packet with a magic string/byte sequence of your own, a length, and probably a version code just to make it extensible. Or see if there's an existing protocol you can abuse for what you want. If it's transactional, you get a pretty big ecosystem of battle-tested clients/servers/proxies/etc if you use HTTP.
- userbinator 6y ago
  A 16-bit length (64k max message size) is usually sufficient, or even 24-bit (16M max) if you really feel the need, but 32 bits is far more than should be needed for parsing messages in memory; it would be fine for a streaming application, however (in which case a 64-bit length wouldn't be a bad idea either.)
  - kccqzy 6y ago
    Good advice. I was actually referring to this: https://rachelbythebay.com/w/2016/02/21/malloc/ https://rachelbythebay.com/w/2016/02/21/malloc/ I read this article a long time ago, and yet I made a similar mistake in my own code.

kccqzy 6y ago

Definitely be sure to check the length though. Imagine a mistaken client trying to send HTTP, but of course the first four bytes "HTTP" when interpreted as a 32-bit integer, whichever endian, is an absurdly large buffer.

nucleardog 6y ago
I mean, at this point you're effectively defining a new network protocol (or, you will be shortly once you implement ways to work around all the other issues you're going to run into). I'd go all-in from the start and start every packet with a magic string/byte sequence of your own, a length, and probably a version code just to make it extensible. Or see if there's an existing protocol you can abuse for what you want. If it's transactional, you get a pretty big ecosystem of battle-tested clients/servers/proxies/etc if you use HTTP.
userbinator 6y ago
A 16-bit length (64k max message size) is usually sufficient, or even 24-bit (16M max) if you really feel the need, but 32 bits is far more than should be needed for parsing messages in memory; it would be fine for a streaming application, however (in which case a 64-bit length wouldn't be a bad idea either.)
- kccqzy 6y ago
  Good advice. I was actually referring to this: https://rachelbythebay.com/w/2016/02/21/malloc/ https://rachelbythebay.com/w/2016/02/21/malloc/ I read this article a long time ago, and yet I made a similar mistake in my own code.