Optimize HttpDateParser.TryStringToDate#34860
Merged
stephentoub merged 2 commits intodotnet:masterfrom Apr 12, 2020
Merged
Conversation
When HttpResponseMessage headers are enumerated, even though SocketsHttpHandler adds headers with TryAddWithoutValidation, the enumeration ends up validating them (that's something to be discussed and follow-up on separately). As part of that, it validates the Date header that's required of most responses. It does so using DateTimeOffset.TryParseExact, but using a long list of allowed formats as well as options that knock TryParseExact's processing off the fast path. Since most responses are going to contain a date using RFC1123 format (aka "r"), we just try that first, in a way that will generally result in hitting the optimized "r" code path which is much faster.
|
Tagging @dotnet/ncl as an area owner. If you would like to be tagged for a label, please notify danmosemsft. |
scalablecory
approved these changes
Apr 12, 2020
MihaZupan
approved these changes
Apr 12, 2020
davidsh
approved these changes
Apr 12, 2020
danmoseley
reviewed
Apr 12, 2020
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
When HttpResponseMessage headers are enumerated, even though SocketsHttpHandler adds headers with TryAddWithoutValidation, the enumeration ends up validating them (that's something to be discussed and follow-up on separately). As part of that, it validates the Date header that's required of most responses. It does so using DateTimeOffset.TryParseExact, but using a long list of allowed formats as well as options that knock TryParseExact's processing off the fast path. Since most responses are going to contain a date using RFC1123 format (aka "r"), we just try that first, in a way that will generally result in hitting the optimized "r" code path which is much faster.
cc: @davidsh, @scalablecory