gzip web content before image creation ( python script for PlatformIO )

gzip_web_content.py

# SCRIPT TO GZIP CRITICAL FILES FOR ACCELERATED WEBSERVING
# see also https://community.platformio.org/t/question-esp32-compress-files-in-data-to-gzip-before-upload-possible-to-spiffs/6274/10
#

# todo : add minify js 
# todo : exclude files with _ at begginging

Import( 'env', 'projenv' )

import os
import gzip
import shutil
import glob

# HELPER TO GZIP A FILE
def gzip_file( src_path, dst_path ):
    with open( src_path, 'rb' ) as src, gzip.open( dst_path, 'wb' ) as dst:
        for chunk in iter( lambda: src.read(4096), b"" ):
            dst.write( chunk )

def gzip_webfiles( source, target, env ):
    
    # FILETYPES 
    filetypes_to_gzip = [ 'css', 'html', 'js', 'ico']

    print( '\nGZIP: INITIATED GZIP FOR SPIFFS...\n' )

    
    data_dir = env.get('PROJECT_DATA_DIR')
    data_src_dir = os.path.join(env.get('PROJECT_DIR'), 'data_src')

    if(os.path.exists(data_dir) and not os.path.exists(data_src_dir) ):
        print('GZIP:  "data" dir exists, "data_src" not found.')
        print('GZIP:  renaming "' + data_dir + '" to "' + data_src_dir + '"')
        os.rename(data_dir, data_src_dir)
        
    if(os.path.exists(data_dir)):
        print('GZIP:   Deleting data dir ' + data_dir)
        shutil.rmtree(data_dir)
        
    print('GZIP:   Re-creating empty data dir ' + data_dir)
    os.mkdir(data_dir)

    # DETERMINE FILES TO COMPRESS
    files_to_gzip = []
    for extension in filetypes_to_gzip:
        files_to_gzip.extend(glob.glob(os.path.join(data_src_dir, '*.' + extension)))

    print('GZIP:  files to gzip: ' + str(files_to_gzip))
    
    
    all_files = glob.glob(os.path.join(data_src_dir, '*.*'))
    files_to_copy = list(set(all_files) - set(files_to_gzip))

    print('GZIP:  files to copy: ' + str(files_to_copy))
    
    for file in files_to_copy:
        print('GZIP:   Copying file: ' + file + ' to data dir')
        shutil.copy(file, data_dir)
        
    # COMPRESS AND MOVE FILES
    was_error = False
    try:
        for source_file_path in files_to_gzip:
            print( 'GZIP: ZIPPING... ' + source_file_path )
            target_file_path = os.path.join( data_dir, os.path.basename( source_file_path ) + '.gz' )
            # CHECK IF FILE ALREADY EXISTS
            if os.path.exists( target_file_path ):
                print( 'GZIP: REMOVING... ' + target_file_path )
                os.remove( target_file_path )

            # print( 'GZIP: GZIPPING FILE...\n' + source_file_path + ' TO...\n' + target_file_path + "\n\n" )
            print( 'GZIP: GZIPPED... ' + target_file_path + "\n" )
            gzip_file( source_file_path, target_file_path )
    except IOError as e:
        was_error = True
        print( 'GZIP: FAILED TO COMPRESS FILE: ' + source_file_path )
        # print( 'GZIP: EXCEPTION... {}'.format( e ) )
    if was_error:
        print( 'GZIP: FAILURE/INCOMPLETE.\n' )
    else:
        print( 'GZIP: SUCCESS/COMPRESSED.\n' )

# IMPORTANT, this needs to be added to call the routine
env.AddPreAction( '$BUILD_DIR/spiffs.bin', gzip_webfiles )

platformio.ini

; ^^^ here some other settings ^^^

extra_scripts =
    post:src/gzip_web_content.py