TransferEncoding.md

File Transfer Encoding

NodeMCU-Tool uses hex or base64 encoding to transfer the files binary safe.

To use the base64 mode, you have to include the native encode module into your firmware - this will speed up the file transfer by factor 4..10!

File Upload Helper Function

The following lua code is used to decode the stream on the NodeMCU Module. In case the encoder.fromBase64 function is available it will be used.

Original Version

-- Base64 Module available ?
if encoder and encoder.fromBase64 then
    -- Use build-in BASE64 Decoder
    _G.__nmtwrite = function(s) 
        file.write(encoder.fromBase64(s))
    end
    print("b")
else
    -- Use classic HEX Decoder
    _G.__nmtwrite = function(s) 
        for c in s:gmatch('..') do 
            file.write(string.char(tonumber(c, 16))) 
        end 
    end
    print("h") 
end

Compressed Version

if encoder and encoder.fromBase64 then _G.__nmtwrite = function(s) file.write(encoder.fromBase64(s)) 
end print('b') else _G.__nmtwrite = function(s) for c in s:gmatch('..') 
do file.write(string.char(tonumber(c, 16))) end end print('h') end

File Download Helper Function

The following lua code is used to encode the stream on the NodeMCU Module. In case the encoder.toBase64 function is available it will be used.

Original Version

function __nmtread()
    -- flag to indicate base64 encoding
    local b64 = encoder and encoder.toBase64

    while true do

        -- Base64 Chunk length (without padding): 6bits per character => for n bytes 4*(n/3) chars required
        c = file.read(b64 and 240 or 1)

        -- No more data available
        if c == nil then 
            print('') 
            break 
        end 

        -- Base64 or hex encoding ?
        uart.write(0, b64 and encoder.toBase64(c) or string.format('%02X', string.byte(c)))
    end

    -- final delimiter
    print('')
end

Compressed Version

function __nmtread()local b = encoder and encoder.toBase64 while true do c = file.read(b and 240 or 1) 
if c==nil then print('')break end uart.write(0, b and encoder.toBase64(c) 
or string.format('%02X', string.byte(c)))end print('') end