Do not allocate String to check if HTTP message is keep alive #402
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Sources/NIOHTTP1/HTTPTypes.swift
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| if connection == "close" { | ||
| return false | ||
| if !self.headers.isEmpty { |
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this seems superfluous as you iterate self.headers just after that. If this is empty, the loop won't do anything either.
Sources/NIOHTTP1/HTTPTypes.swift
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| } | ||
| return connection == "keep-alive" | ||
| // HTTP 1.1 use keep-alive by default if not otherwise told. | ||
| return version.major == 1 && version.minor == 1 |
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this should be version.minor >= 1 as RFC says to treat 1.x where x>=1 like 1.1
Sources/NIOHTTP1/HTTPTypes.swift
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| @@ -18,6 +18,8 @@ let crlf: StaticString = "\r\n" | |||
| let headerSeparator: StaticString = ": " | |||
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| private let connectionUtf8 = "connection".utf8 | |||
| private let closeUtf8 = "close".utf8 | |||
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I think these global variables do nothing (in the good case) and cause a slowdown if the compiler isn't able to optimise it. Just put them where you use them
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@weissi hmm I would have thought its actually better as .utf8 should only be called once ? Maybe I should make these static ?
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@normanmaurer .utf8 is a function that needs to be inlined. If you want to cache the bytes straight, you'll need to do Array("close".utf8)
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ah ok... then let me just do what you said first.
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that should be pretty fast in 4.1 and really fast in 4.2
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only using StaticStrings would be faster but we unfortunately don't support them yet for headers (which we should fix)
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@weissi on my to do list for this week ;)
Sources/NIOHTTP1/HTTPTypes.swift
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| if !self.headers.isEmpty { | ||
| for header in self.headers { | ||
| if self.buffer.equalCaseInsensitiveASCII(view: connectionUtf8, at: header.name) { | ||
| if self.buffer.equalCaseInsensitiveASCII(view: closeUtf8, at: header.value) { |
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technically this isn't a correct implementation, right? could be connection: keep-alive, foobar no?
I know, it's not worse than the previous implementation either but the fast path is anyway that there is no connection header
| @@ -18,6 +18,8 @@ let crlf: StaticString = "\r\n" | |||
| let headerSeparator: StaticString = ": " | |||
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please change the allocation counter test limits and reduce according to the number of allocs saved
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@weissi let me see if it changes anything (as it will only if we actual have a connection header).
| return false | ||
| for header in self.headers { | ||
| if self.buffer.equalCaseInsensitiveASCII(view: "connection".utf8, at: header.name) { | ||
| if self.buffer.equalCaseInsensitiveASCII(view: "close".utf8, at: header.value) { |
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I don't think this is quite right, though to be fair this has never been quite right. Strictly speaking I think this will fail if the header is Connection: close, some-other-header-name, when it should not. Additionally, neither close nor keep-alive strictly have to be first.
Do we want to add some tolerance for that, or set it as a contributor friendly issue and let the community tackle it?
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@Lukasa yes, commented on that one too but I'd be happy with a follow-up.
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@Lukasa cool with me merging ? |
Motivation: We can check if a HTTP message is using keep alive without any allocation. Modifications: Directly act on the internal storage of HTTPHeaders to find out if keep alive is used or not. Result: Less allocations
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Motivation:
We can check if a HTTP message is using keep alive without any allocation.
Modifications:
Directly act on the internal storage of HTTPHeaders to find out if keep alive is used or not.
Result:
Less allocations