SmartFTP FTP Library
ISFTPServerState Interface Reference

import "sfFTPLib.idl";

Public Member Functions

HRESULT IsExtension ([in] BSTR extension, [out, retval] VARIANT_BOOL *retval)
 Checks if the connected server supports a specific SFTP protocol extension.

Properties

BSTR EOL [get]
 Retrieves the line ending sequence explicitly reported by the server's operating system.
ISFTPVendorId VendorId [get]
 Retrieves the software identification data reported by the remote SFTP server.

Member Function Documentation

◆ IsExtension()

HRESULT ISFTPServerState::IsExtension ( [in] BSTR extension,
[out, retval] VARIANT_BOOL * retval )

Checks if the connected server supports a specific SFTP protocol extension.

The Mechanism: During the initial version negotiation (Handshake), the server sends a list of supported extensions (Name-Data pairs). These extensions define capabilities beyond the standard SFTP protocol version.

Usage (Feature Detection): Before attempting to use advanced features, use this method to verify support. For example:

  • Check "fsync@openssh.com" before calling Flush on a file.
  • Check "hardlink@openssh.com" before attempting to create hard links.
  • Check "check-file" (or "check-file-name") to see if the server supports remote checksums/hashing.

Format: Extension names are typically formatted as name (standard IETF extensions) or name@domain (vendor-specific extensions). The comparison is case-sensitive.

Parameters
[in]extensionThe exact name of the extension to query (e.g., "posix-rename@openssh.com").
[out]retvalReturns VARIANT_TRUE if the server advertised this extension; otherwise VARIANT_FALSE.

Property Documentation

◆ EOL

BSTR ISFTPServerState::EOL
getproperty

Retrieves the line ending sequence explicitly reported by the server's operating system.

The Negotiation: In SFTP protocol versions 4, 5, and 6, the server can include a newline extension in its version packet. This informs the client exactly which character sequence defines the end of a line (e.g., \n for Unix/Linux, \r\n for Windows).

Usage: This value is used to automatically configure text-mode transfers. If the connection's ISFTPConnection::ServerLineTerminator property is empty (the default), the component uses this value to perform the correct translation.

Protocol Limitations (OpenSSH): SFTP Version 3 (used by standard OpenSSH) does not support this extension. In those cases, this property may return an empty string or a default value (usually \n) inferred from the server's OS string.

Parameters
[out]retvalReceives the server's newline string (e.g., "\n" or "\r\n").

◆ VendorId

ISFTPVendorId ISFTPServerState::VendorId
getproperty

Retrieves the software identification data reported by the remote SFTP server.

The Source: This object is populated automatically during the SFTP Protocol Version Exchange. It reflects the data found in the vendor-id extension structure within the SSH_FXP_VERSION packet sent by the server.

Usage: Read this property to fingerprint the server implementation (e.g., "Bitvise"). This is critical for applying compatibility workarounds. For example, if VendorName is "LegacyServer" and ProductVersion is "1.0", you might choose to disable newer features like CopyFile or CheckFile that are known to be broken on that version.

OpenSSH Note: Standard OpenSSH servers (and many strictly RFC-compliant v3 servers) do not send this extension. In those cases, this object will contain empty strings and 0 values.

Parameters
[out]retvalReceives the ISFTPVendorId object containing the server's reported identity.
The documentation for this interface was generated from the following file: