ResourceExt does not canonicalize URLs

[heaths]

The Key Vault ResourceExt does not canonicalize URLs, such that "https://my-vault.vault.azure.net//secrets/my-secret" fails with "missing collection". I believe other languages' SDKs handle this already. Unfortunately, it seems url::Url does not canonicalize like .NET's System.Url does.

FWIW, in the past when I first proposed these parsing APIs to the Key Vault v-team, I investigated and the service does indeed canonicalize URLs itself such that it treats "//" as "/".

[heaths]

Actually, I take that back. .NET does not canonicalized empty segments: https://github.com/Azure/azure-sdk-for-net/blob/e1740e156e022898b196325f6b65f502d7b69287/sdk/keyvault/Azure.Security.KeyVault.Shared/src/KeyVaultIdentifier.cs#L46. Url.TryParse does indeed return them e.g.,

$url = ''
[Uri]::TryCreate('https://my-vault.vault.azure.net//secrets/my-secret', 'Absolute', [ref] $url)
# True
$url.Segments
# / / secrets/ my-secret

This means .NET is likely parsing such identifiers into the wrong properties of the KeyVaultIdentifier. /cc @JonathanCrd @chlowell (in case other languages don't handle this either).