Without await, the using statement can dispose the Stream before the
call to PutAsync completes, resulting in an ObjectDisposedException.
This fixes#4556.
.NET 5 moves the responsibility to the operating system, and since
SSH.NET currently relies on the ECDsaCng class, we will simply interpret
all exceptions to mean lack of ECDSA support.
It's possible that our test will no longer be valid (e.g., due to
changes in SSH.NET), so we don't want the backend to fail if our test
is no longer valid.
SSH.NET relies on the System.Security.Cryptography.ECDsaCng class for
ECDSA algorithms, which is not implemented in Mono (as of 6.12.0.144).
This prevents clients from connecting if one of the ECDSA algorithms is
chosen as the host key algorithm. In the event that this causes a
connection failure, we will prevent the client from advertising support
for ECDSA algorithms and make another connection attempt.
Related forum discussion:
https://forum.duplicati.com/t/release-2-0-6-1-beta-2021-sftp-failure-synology/12358
If the user specifies a path with multiple directories that do not
exist, the SftpClient.CreateDirectory method does not create all the
missing parent directories. As such, we have to do so ourselves.
This addresses issue #2080.
The removed code was introduced in revision ba58651e5a ("Fix for
CreateFolder with SSH"), presumably to fix an issue where some SSH
backends did not like the trailing slash when creating new folders.
However, since we are not using the output argument of the call to
Substring, these statements have no effect.
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()
InvariantCulture is useful when comparing / sorting human language strings in a culturely correct way. It handles things like accented letters in a way that makes sense to humans (e.g., 'a' should be sorted next to 'á', rather than after 'z').
Ordinal looks just at the raw code points of the characters. As such, it is recommended for use in cases when comparing system strings (file paths, command line parameters, config settings, etc.). Since it doesn't need to use the culture specific sorting rules, this method can often be faster.
For more information, see https://stackoverflow.com/questions/492799/difference-between-invariantculture-and-ordinal-string-comparison (and other related questions)
Was an backup canceled, a restart doesn't work. The problem was that a non existing file caused an failure. This fix handles this situation for the ssh and googledocs backend.
Kenneth Skovhede