Avoid Uri creation in HttpRuleParser.IsValidHostName

[geoffkizer]

This function validates the given host name by actually trying to create a Uri object and seeing if it fails. It also has to construct and allocate a string to pass to the Uri.TryCreate method.

We should be able to validate a hostname directly, without actually constructing a Uri.

The main place this is used is when setting the Host property on the request message headers.

[ghost]

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Issue Details

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This function validates the given host name by actually trying to create a Uri object and seeing if it fails. It also has to construct and allocate a string to pass to the Uri.TryCreate method.

We should be able to validate a hostname directly, without actually constructing a Uri.

The main place this is used is when setting the Host property on the request message headers.

Author:	geoffkizer
Assignees:	-
Labels:	area-System.Net, untriaged
Milestone:	-

[ghost]

Tagging subscribers to this area: @dotnet/ncl
See info in area-owners.md if you want to be subscribed.

Issue Details

---

This function validates the given host name by actually trying to create a Uri object and seeing if it fails. It also has to construct and allocate a string to pass to the Uri.TryCreate method.

We should be able to validate a hostname directly, without actually constructing a Uri.

The main place this is used is when setting the Host property on the request message headers.

Author:	geoffkizer
Assignees:	-
Labels:	area-System.Net.Http, untriaged
Milestone:	-

[MihaZupan]

And since the test Uri we use also contains a user info ("u@"), we'll end up allocating a substring for that as well.