Lua Requires Chilkat v11.0.0+

Transfer a File using Sockets (TLS or non-TLS)

See more Socket/SSL/TLS Examples

Demonstrates how to two programs, one a socket writer and the other a socket reader, can transfer a file. The connection can be TLS or a regular non-encrypted TCP connection. Lua

local chilkat = require("chilkat")

-- This example requires the Chilkat API to have been previously unlocked.
-- See Global Unlock Sample for sample code.

-- On the sending side, we'll load the file into a BinData object and send.
-- On the receiving side, we'll read from the socket connection into a BinData, and save to a file.
-- This example assumes the file is not crazy-large, and that the entire contents
-- can fit into memory.
-- (If the file is too large for memory, there are other ways to send. It just involves streaming or
-- sending the file chunk-by-chunk..)

-- This section of code is for the sender.
local bdToSend = chilkat.BinData.new()
local success = bdToSend:load_file("somePath/someFile.dat")
-- Assume success for the example...

local sndSock = chilkat.Socket.new()
local bUseTls = true
local port = 5555
local maxWaitMs = 5000
success = sndSock:connect("some_domain_or_ip.com", port, bUseTls, maxWaitMs)
-- Assume success for the example...

-- Tell the receiver how many bytes are coming.
local numBytes = bdToSend.num_bytes
local bBigEndian = true
success = sndSock:send_int32(numBytes, bBigEndian)

-- Send the file data (sends the entire contents of bdToSend).
success = sndSock:send_bd(bdToSend, 0, 0)

-- Get an acknowledgement.
success = sndSock:receive_int32(bBigEndian)
if not success then
    print(sndSock.last_error_text)
    return
end

-- Did the receiver get the correct number of bytes?
if sndSock.received_int ~= numBytes then
    print("The receiver did not acknowledge with the correct number of bytes.")
    return
end

print("File sent!")

-- ------------------------------------------------------------------------------------
-- The code below is for the receiving side (running on some other computer..)

local listenSock = chilkat.Socket.new()

success = listenSock:bind_and_listen(5555, 25)
if not success then
    print(listenSock.last_error_text)
    return
end

-- Get the next incoming connection
-- Wait a maximum of 20 seconds (20000 millisec)
local rcvSock = chilkat.Socket.new()
success = listenSock:accept_next(20000, rcvSock)
if not success then
    print(listenSock.last_error_text)
    return
end

-- The sender will first send the big-endian integer for the number of bytes
-- that are forthcoming..
success = rcvSock:receive_int32(bBigEndian)
if not success then
    print(rcvSock.last_error_text)
    return
end

local numBytesComing = rcvSock.received_int

-- Receive that many bytes..
local bdReceived = chilkat.BinData.new()
success = rcvSock:receive_bd_n(numBytesComing, bdReceived)
if not success then
    print(rcvSock.last_error_text)
    return
end

-- Acknowledge the sender by sending back the number of bytes we received.
success = rcvSock:send_int32(bdReceived.num_bytes, bBigEndian)

-- Close the connection.
maxWaitMs = 20
rcvSock:close(maxWaitMs)

-- Save the received data to a file.
success = bdReceived:write_file("somePath/someFile.dat")
-- Assume success for the example...

print("File received!")