Lua

Resolve an Absolute Remote Path with SFTP RealPath

Demonstrates the Chilkat SFtp.RealPath method, which asks the server to canonicalize a path and returns the resulting absolute remote path. The first argument is the original path and the second is an optional compose path (SFTP v5 or later); pass an empty string when no composition is needed.

Background: The server — not the client — owns the remote filesystem's layout, so path canonicalization must happen on the server. RealPath resolves ., .., and symbolic links into a single absolute path, which is the reliable way to learn the session's home directory (canonicalize .) or to turn a relative path into an absolute one before storing or displaying it. On SFTP v5 and later, the compose path can additionally join or override the original.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the SFtp.RealPath method, which asks the server to canonicalize a path and
-- returns the resulting absolute remote path.  The 1st argument is the original path and the
-- 2nd is an optional compose path (SFTP v5+), which may be an empty string.

local sftp = chilkat.SFtp.new()

-- Step 1: Connect the SSH transport.  Port 22 is the usual port.
local port = 22
local success = sftp:connect("sftp.example.com", port)
if not success then
    print(sftp.last_error_text)
    return
end

-- Normally you would not hard-code the password in source.  You should instead obtain it
-- from an interactive prompt, environment variable, or a secrets vault.
local password = "mySshPassword"

success = sftp:authenticate_pw("mySshLogin", password)
if not success then
    print(sftp.last_error_text)
    return
end

-- Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
-- file or directory operations.
success = sftp:initialize_sftp()
if not success then
    print(sftp.last_error_text)
    return
end

-- Resolve "." to the absolute path of the session's default (home) directory.  No compose path
-- is needed, so the 2nd argument is an empty string.
local homeDir = sftp:real_path(".", "")
if not sftp.last_method_success then
    print(sftp.last_error_text)
    return
end

print("Home directory: " .. homeDir)

-- Canonicalize a relative path with "..", resolving it to an absolute path.
local resolved = sftp:real_path("subdir/../otherdir", "")
if not sftp.last_method_success then
    print(sftp.last_error_text)
    return
end

print("Resolved path: " .. resolved)

sftp:disconnect()