This PR is the final change, where all backends are now purely implemented with async interfaces.
The code changes here replace the LIST call with an async version. This affect all backends (and then some) but the changes are mostly mechanical rewrites of the code.
In many places, the backeds were already prepared for async output, in other some glue was needed.
To reduce the scope of this change, some backends simply report a synchronous result as an async list.
* Fixed nullability warnings in `Utility.cs`
* Fixed a number of nullability issues and warnings
* More nullable fixes
* Fixed the overwrite issue
* Fixed additional nullability issues
* Removed additional nullability issues
* More nullability fixes and added some xmldoc
* Added more xmldocs and removed an unused argument
* Removed more warnings
Changed the strategy to use absolute paths for all operations, to avoid cases where a silent reconnect would end up in a different folder.
Add backwards compatible option to use CWD style relative operations.
Added support for detecting the SSL certificate hash when there is a certificate error.
With this change, ftp-passive, ftp-regular and use-ssl parameters found on existing FTP Backend configurations will be respected and exhibit the same behavior. They are marked as deprecated so they will issue warning messages when used prompting users to refer to new parameters.
For this change, what was known as the alternate FTP client which uses FluentFTP library now officially replaces the FTP Backend which still used the deprecated FtpWebrequest.
To mantain compatibility with existing configurations, both ftp and aftp targets and configuration prefixes are accepted.
Without await, the using statement can dispose the Stream before the
call to PutAsync completes, resulting in an ObjectDisposedException.
This fixes#4556.
By changing to IEnumerable, it is possible to iterate only a portion of the list, which is useful when not all entries are needed (e.g., when testing a connection).
All existing backends have been updated, and any which were able to be changed to yield return results in a straightforward way now do.
Many backends had a try/catch in the List() method. Due to the fact that yield returns can't be placed within a try/catch block, these have been refactored to either scope the try/catch to the parts that (should) be the only places throwing exceptions, so that exceptions are still caught and handled.
Note that lazy evaluation may cause some changes in behavior - exceptions that were previously thrown at the point of invokation of List() may now be thrown while it is being enumerated.
I believe this will not be problematic though, as the only well-known exception seems to be FolderMissingException, which should be thrown by Test(), but TestList() attempts to enumerate the list to force this exception.
Any places that require the legacy behavior can get it by simply converting the lazy enumerable to a List()
Kenneth Skovhede