Uploading a file with FTP

Latest update: March 2015

In this tutorial, we’ll cover uploading a file to an FTP server. We’ll put together a simple script that, when run, uploads all files in a directory. It should also log what it’s doing to a file. Note: If your FlashAir card is currently mounted on a PC, it may be unable to write the log file.

Lets get started!

First, fill out some of the variables we are going to use. You’ll need to use your server’s info.

local logfile   = "/FTPLog.txt"     -- Where to log output on the FA
local folder    = "/Upload"         -- What folder to upload files from
local server    = ""     -- The FTP server's IP
local serverDir = "/"               -- The path on the FTP server to use.
local user      = "ftp"             -- FTP username
local passwd    = "abc123"          -- FTP passwd

Next, we should assemble our variables into a convenient URL we’ll use to upload.

-- Assemble our FTP command string
-- example: "ftp://user:pass@"
local ftpstring = "ftp://"..user..":"..passwd.."@"..server..serverDir

Then create the log file…​

-- Open the log file
local outfile = io.open(logfile, "w")

-- Write a header
outfile:write("File list: \n")

Remember to close it at the end!

--Close our log file

Ok, we’re ready to start! We’ll be using LuaFileSystem (lfs) to scan the upload directory, and the fa.ftp to perform the upload itself. The results are output to the log file - although some output will also be displayed if you run the script from your web browser.

-- For each file in folder...
for file in lfs.dir(folder) do
    -- Get that file's attributes
    attr = lfs.attributes(folder .. "/" .. file)
    print( "Found "..attr.mode..": " .. file )

    -- Don't worry about directories (yet)
    if attr.mode == "file" then
        --Attempt to upload the file!
        --ex ftp("put", "ftp://user:pass@", "Upload/test.jpg")
        response = fa.ftp("put", ftpstring..file, folder .. "/" .. file)

        --Check to see if it worked, and log the result!
        if response ~= nil then
            outfile:write("" .. file .. "... Success!\n")
            print("Fail :(")
            outfile:write("" .. file .. "...Fail :(\n")

That’s it! Pretty easy eh?

All sample code on this page is licensed under BSD 2-Clause License