Extra script to make PlatformIO do compressed OTA updates for the ESP8266

compressed_ota.py

import gzip
import shutil
import os
Import("env")


def compressFirmware(source, target, env):
    """ Compress ESP8266 firmware using gzip for 'compressed OTA upload' """
    SOURCE_FILE = env.subst("$BUILD_DIR") + os.sep + env.subst("$PROGNAME") + ".bin"
    SOURCE_BAK = SOURCE_FILE + '.bak'
    do_compress = True
    if os.path.exists(SOURCE_FILE) and os.path.exists(SOURCE_BAK):
        src_mtime = os.stat(SOURCE_FILE).st_mtime
        bak_mtime = os.stat(SOURCE_BAK).st_mtime
        """ Recompress if .bin file is newer than .bak file """
        do_compress = (src_mtime > bak_mtime)

    if do_compress:
        print("Compressing firmware for upload...")
        shutil.move(SOURCE_FILE, SOURCE_BAK)
        with open(SOURCE_BAK, 'rb') as f_in:
            with gzip.open(SOURCE_FILE, 'wb') as f_out:
                shutil.copyfileobj(f_in, f_out)
        """ Set modification time on compressed file so incremental build works """
        shutil.copystat(SOURCE_BAK, SOURCE_FILE)

    if os.path.exists(SOURCE_BAK):
        ORG_FIRMWARE_SIZE = os.stat(SOURCE_BAK).st_size
        GZ_FIRMWARE_SIZE = os.stat(SOURCE_FILE).st_size

        print("Compression reduced firmware size to {:.0f}% (was {} bytes, now {} bytes)".format((GZ_FIRMWARE_SIZE / ORG_FIRMWARE_SIZE) * 100, ORG_FIRMWARE_SIZE, GZ_FIRMWARE_SIZE))

env.AddPreAction("upload", compressFirmware)

How can I use it to compress my own .bin files?

@ozanpalaz Do you mean run this script standalone? It's specifically designed to work in conjunction with PlatformIO (to be called automatically during the upload process, hence the AddPreAction hook at the bottom of the file), so that won't be possible without some modification. It would require you to so something like remove Import("env"), change env.subst() calls to point to variables, and then have a main function that runs the function, and ensures the variables are loaded with valid info.