Lua

Read Text at a String Offset from a Remote SFTP File

Demonstrates the Chilkat SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte offset as a decimal string. The arguments are the handle, the offset string, the maximum number of bytes, and the charset.

Background: The string-offset read exists for the same reason as its write counterpart: it lets code in languages without convenient 64-bit integers still address positions in very large files by supplying the offset as text. Functionally it is identical to the int64 version.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte
-- offset as a decimal string.  The 1st argument is the handle, the 2nd is the offset string, the
-- 3rd is the maximum number of bytes, and the 4th is the charset.

local sftp = chilkat.SFtp.new()

-- Connect, authenticate, and initialize the SFTP subsystem.
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

success = sftp:initialize_sftp()
if not success then
    print(sftp.last_error_text)
    return
end

local handle = sftp:open_file("subdir/hugefile.dat", "readOnly", "openExisting")
if not sftp.last_method_success then
    print(sftp.last_error_text)
    return
end

-- Supplying the offset as a string is convenient in languages without a native 64-bit integer.
local offset = "5000000000"
local numBytes = 6
local text = sftp:read_file_text64s(handle, offset, numBytes, "utf-8")
if not sftp.last_method_success then
    print(sftp.last_error_text)
    return
end

print(text)

success = sftp:close_handle(handle)
if not success then
    print(sftp.last_error_text)
    return
end

sftp:disconnect()