Setting hostname part of redirect uri (callback) is important part to get correct, because authorization servers often expect a verbatim match between what has been registered, and what is sent as part of authorization request. This commit clarifies and improves specifying the hostname part. Historically the callback host was fixed to "127.0.0.1" which has its drawbacks (and can be outright wrong). The situation was later improved by using "localhost" hostname, which correctly maps to both IPv4 and IPv6 interfaces. However, there are authorization servers which require the use of IP literals, and reject "localhost". To address these issues, this commit consists of: - Map Any, AnyIPv4, and AnyIPv6 to "localhost". This mapping is logical because "localhost" will work then independent of what the actual used address is - Map IPv4 and IPv6 loopback addresses (LocalHost, LocalHostIPv6) to their IP literals 127.0.0.1 and ::1 These are well-known IP literal addresses, and mapping them to "localhost" does not bring an advantage - If user has provided a string literal, use that directly - Change default address to "LocalHost", which maps to hostname "127.0.0.1". This, in part, undoes the changed behavior where the default changed to "localhost". With this change, users that don't define callback address shouldn't notice a difference to the very original behavior All in all these changes should improve the compatibility with various authorization servers and provide more flexibility to users. Amends: fd49b7f6543e7b49be7847624c64ee86c4272ccd Amends: 4e03167088181bf513adcfb8aac93fb8efb3f420 [ChangeLog][QOAuthHttpServerReplyHandler] Changed and clarified callback hostname handling (especially localhost vs. 127.0.0.1) Pick-to: 6.8 Fixes: QTBUG-130159 Change-Id: I25dfb996d10f95fe60bdb4f46ea848edcb2528be Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>