#!/usr/bin/env python3

from base64 import b64encode

from hashlib import sha256, sha384

from itertools import chain

from pathlib import Path

from shutil import which

from subprocess import run

def integrity_all(paths):

return { path: integrity(path) for path in paths }

def integrity(path):

with open(path, 'rb') as f:

return b64encode(sha384(f.read()).digest()).decode('utf-8')

def hash_str(s):

return sha256(s.encode('utf-8')).digest()

sass = which('sass')

babel = which('babel')

if sass is None:

print('warn: could not find sass in path. css will not be compiled')

if babel is None:

print('warn: could not find babel in path. js will not be compiled')

# web resources path

web_path = Path('webserver/web')

# all static js and css

files = list(chain(

web_path.glob('static/**/*.js'),

web_path.glob('static/**/*.css'),

))

src = {

}

# template files

templates = list(web_path.glob('templates/**/*.html.tera'))

# calculate old integrity hashes to potentially replace

old_integrity = integrity_all(files)

# compile css resources

if sass is not None:

for css in src['css']:

print(f'compiling {css}')

static_css = str(css).replace('scss', 'css').replace('/src/', '/static/')

run([sass, '-s', 'compressed', f'{css}:{static_css}'])

# compile js resources (assuming directories)

if babel is not None:

for js in src['js']:

print(f'compiling {js}')

static_js = str(js).replace('/src/', '/static/')

run([babel, '-s', 'true', '-d', static_js, str(js)])

# calculate new integrity hashes

new_integrity = integrity_all(files)

# determine which files changed

changed = {}

for name, ihash in new_integrity.items():

if name not in old_integrity or ihash == old_integrity[name]:

continue

changed[name] = (old_integrity[name], ihash)

# go through every template and replace change hashes if present

for template in templates:

# read in template

with open(template, 'r') as f:

content = f.read()

# calculate sha256 hash before replacing

before = hash_str(content)

# replace any changed hashes

for name, paths in changed.items():

(old, new) = paths

content = content.replace(old, new)

# calculate sha256 hash after replacing

after = hash_str(content)

# if no change, ignore

if before == after:

continue

# update the template with the replaced hashes

print(f'updating {template}')

with open(template, 'w') as f:

f.write(content)