Enable getting and deleting symbolic links

src/Renci.SshNet/ISftpClient.cs

@@ -491,6 +491,18 @@ public interface ISftpClient : IBaseClient, IDisposable
         /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
         void DeleteFile(string path);
 
+        /// <summary>
+        /// Deletes remote symbolic link specified by path.
+        /// </summary>
+        /// <param name="path">File to be deleted path.</param>
+        /// <exception cref="ArgumentException"><paramref name="path"/> is <b>null</b> or contains only whitespace characters.</exception>
+        /// <exception cref="SshConnectionException">Client is not connected.</exception>
+        /// <exception cref="SftpPathNotFoundException"><paramref name="path"/> was not found on the remote host.</exception>
+        /// <exception cref="SftpPermissionDeniedException">Permission to delete the file was denied by the remote host. <para>-or-</para> A SSH command was denied by the server.</exception>
+        /// <exception cref="SshException">A SSH error where <see cref="Exception.Message"/> is the message from the remote host.</exception>
+        /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
+        void DeleteSymbolicLink(string path);
+
         /// <summary>
         /// Asynchronously deletes remote file specified by path.
         /// </summary>
@@ -580,6 +592,20 @@ public interface ISftpClient : IBaseClient, IDisposable
         /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
         bool Exists(string path);
 
+        /// <summary>
+        /// Checks whether symbolic link exists;
+        /// </summary>
+        /// <param name="path">The path.</param>
+        /// <returns>
+        /// <c>true</c> if directory or file exists; otherwise <c>false</c>.
+        /// </returns>
+        /// <exception cref="ArgumentException"><paramref name="path"/> is <b>null</b> or contains only whitespace characters.</exception>
+        /// <exception cref="SshConnectionException">Client is not connected.</exception>
+        /// <exception cref="SftpPermissionDeniedException">Permission to perform the operation was denied by the remote host. <para>-or-</para> A SSH command was denied by the server.</exception>
+        /// <exception cref="SshException">A SSH error where <see cref="Exception.Message"/> is the message from the remote host.</exception>
+        /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
+        bool SymbolicLinkExists(string path);
+
         /// <summary>
         /// Gets reference to remote file or directory.
         /// </summary>
@@ -593,6 +619,19 @@ public interface ISftpClient : IBaseClient, IDisposable
         /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
         ISftpFile Get(string path);
 
+        /// <summary>
+        /// Gets reference to remote symbolic link.
+        /// </summary>
+        /// <param name="path">The path.</param>
+        /// <returns>
+        /// A reference to <see cref="ISftpFile"/> file object.
+        /// </returns>
+        /// <exception cref="SshConnectionException">Client is not connected.</exception>
+        /// <exception cref="SftpPathNotFoundException"><paramref name="path"/> was not found on the remote host.</exception>
+        /// <exception cref="ArgumentNullException"><paramref name="path" /> is <b>null</b>.</exception>
+        /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
+        ISftpFile GetSymbolicLink(string path);
+
         /// <summary>
         /// Gets the <see cref="SftpFileAttributes"/> of the file on the path.
         /// </summary>

src/Renci.SshNet/Sftp/ISftpSession.cs

@@ -35,10 +35,11 @@ internal interface ISftpSession : ISubsystemSession
         /// Resolves a given path into an absolute path on the server.
         /// </summary>
         /// <param name="path">The path to resolve.</param>
+        /// <param name="getRealPath">Boolean determining whether to get the ral path.</param>
         /// <returns>
         /// The absolute path.
         /// </returns>
-        string GetCanonicalPath(string path);
+        string GetCanonicalPath(string path, bool getRealPath = true);
 
         Task<string> GetCanonicalPathAsync(string path, CancellationToken cancellationToken);
 

src/Renci.SshNet/Sftp/SftpSession.cs

@@ -89,13 +89,20 @@ internal void SendMessage(SftpMessage sftpMessage)
         /// Resolves a given path into an absolute path on the server.
         /// </summary>
         /// <param name="path">The path to resolve.</param>
+        /// <param name="getRealPath">Boolean determining whether to get the real path.</param>
         /// <returns>
         /// The absolute path.
         /// </returns>
-        public string GetCanonicalPath(string path)
+        public string GetCanonicalPath(string path, bool getRealPath = true)
         {
             var fullPath = GetFullRemotePath(path);
 
+            if (!getRealPath)
+            {
+                // getRealPath set to false allows us to get a reference to the symbolic link itself and not to the file it points to.
+                return fullPath;
+            }
+
             var canonizedPath = string.Empty;
 
             var realPathFiles = RequestRealPath(fullPath, nullOnError: true);
@@ -152,7 +159,6 @@ public string GetCanonicalPath(string path)
         public async Task<string> GetCanonicalPathAsync(string path, CancellationToken cancellationToken)
         {
             var fullPath = GetFullRemotePath(path);
-
             var canonizedPath = string.Empty;
             var realPathFiles = await RequestRealPathAsync(fullPath, nullOnError: true, cancellationToken).ConfigureAwait(false);
             if (realPathFiles != null)

src/Renci.SshNet/SftpClient.cs

@@ -737,6 +737,38 @@ public ISftpFile Get(string path)
             return new SftpFile(_sftpSession, fullPath, attributes);
         }
 
+        /// <summary>
+        /// Gets reference to remote symbolic link.
+        /// </summary>
+        /// <param name="path">The path.</param>
+        /// <returns>
+        /// A reference to <see cref="ISftpFile"/> file object.
+        /// </returns>
+        /// <exception cref="SshConnectionException">Client is not connected.</exception>
+        /// <exception cref="SftpPathNotFoundException"><paramref name="path"/> was not found on the remote host.</exception>
+        /// <exception cref="ArgumentNullException"><paramref name="path" /> is <b>null</b>.</exception>
+        /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
+        public ISftpFile GetSymbolicLink(string path)
+        {
+            CheckDisposed();
+
+            if (path is null)
+            {
+                throw new ArgumentNullException(nameof(path));
+            }
+
+            if (_sftpSession is null)
+            {
+                throw new SshConnectionException("Client not connected.");
+            }
+
+            var fullPath = _sftpSession.GetCanonicalPath(path, false);
+
+            var attributes = _sftpSession.RequestLStat(fullPath);
+
+            return new SftpFile(_sftpSession, fullPath, attributes);
+        }
+
         /// <summary>
         /// Checks whether file or directory exists;
         /// </summary>
@@ -793,6 +825,45 @@ public bool Exists(string path)
             }
         }
 
+        /// <summary>
+        /// Checks whether symbolic link exists;
+        /// </summary>
+        /// <param name="path">The path.</param>
+        /// <returns>
+        /// <c>true</c> if directory or file exists; otherwise <c>false</c>.
+        /// </returns>
+        /// <exception cref="ArgumentException"><paramref name="path"/> is <b>null</b> or contains only whitespace characters.</exception>
+        /// <exception cref="SshConnectionException">Client is not connected.</exception>
+        /// <exception cref="SftpPermissionDeniedException">Permission to perform the operation was denied by the remote host. <para>-or-</para> A SSH command was denied by the server.</exception>
+        /// <exception cref="SshException">A SSH error where <see cref="Exception.Message"/> is the message from the remote host.</exception>
+        /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
+        public bool SymbolicLinkExists(string path)
+        {
+            CheckDisposed();
+
+            if (string.IsNullOrWhiteSpace(path))
+            {
+                throw new ArgumentException("path");
+            }
+
+            if (_sftpSession is null)
+            {
+                throw new SshConnectionException("Client not connected.");
+            }
+
+            var fullPath = _sftpSession.GetCanonicalPath(path, false);
+
+            try
+            {
+                _ = _sftpSession.RequestLStat(fullPath);
+                return true;
+            }
+            catch (SftpPathNotFoundException)
+            {
+                return false;
+            }
+        }
+
         /// <summary>
         /// Downloads remote file specified by the path into the stream.
         /// </summary>
@@ -1479,6 +1550,20 @@ public void Delete(string path)
             file.Delete();
         }
 
+        /// <summary>
+        /// Deletes the specified symbolic link.
+        /// </summary>
+        /// <param name="path">The name of the file or directory to be deleted. Wildcard characters are not supported.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="path"/> is <b>null</b>.</exception>
+        /// <exception cref="SshConnectionException">Client is not connected.</exception>
+        /// <exception cref="SftpPathNotFoundException"><paramref name="path"/> was not found on the remote host.</exception>
+        /// <exception cref="ObjectDisposedException">The method was called after the client was disposed.</exception>
+        public void DeleteSymbolicLink(string path)
+        {
+            var symLink = GetSymbolicLink(path);
+            symLink.Delete();
+        }
+
         /// <summary>
         /// Returns the date and time the specified file or directory was last accessed.
         /// </summary>