import json import uuid as uuid_builder import os.path from os import path from threading import Lock from copy import deepcopy import logging import time import threading # Is there an existing library to ensure some data store (JSON etc) is in sync with CRUD methods? # Open a github issue if you know something :) # https://stackoverflow.com/questions/6190468/how-to-trigger-function-on-value-change class ChangeDetectionStore: lock = Lock() def __init__(self, datastore_path="/datastore", include_default_watches=True): self.needs_write = False self.datastore_path = datastore_path self.json_store_path = "{}/url-watches.json".format(self.datastore_path) self.stop_thread = False self.__data = { 'note': "Hello! If you change this file manually, please be sure to restart your changedetection.io instance!", 'watching': {}, 'tag': "0.25", 'settings': { 'headers': { 'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.66 Safari/537.36', 'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9', 'Accept-Encoding': 'gzip, deflate', # No support for brolti in python requests yet. 'Accept-Language': 'en-GB,en-US;q=0.9,en;' }, 'requests': { 'timeout': 15, # Default 15 seconds 'minutes_between_check': 3 * 60, # Default 3 hours 'workers': 10 # Number of threads, lower is better for slow connections } } } # Base definition for all watchers self.generic_definition = { 'url': None, 'tag': None, 'last_checked': 0, 'last_changed': 0, 'last_viewed': 0, # history key value of the last viewed via the [diff] link 'newest_history_key': "", 'title': None, 'previous_md5': "", 'uuid': str(uuid_builder.uuid4()), 'headers': {}, # Extra headers to send 'history': {} # Dict of timestamp and output stripped filename } if path.isfile('/source.txt'): with open('/source.txt') as f: # Should be set in Dockerfile to look for /source.txt , this will give us the git commit # # So when someone gives us a backup file to examine, we know exactly what code they were running. self.__data['build_sha'] = f.read() try: with open(self.json_store_path) as json_file: from_disk = json.load(json_file) # @todo isnt there a way todo this dict.update recursively? # Problem here is if the one on the disk is missing a sub-struct, it wont be present anymore. if 'watching' in from_disk: self.__data['watching'].update(from_disk['watching']) if 'settings' in from_disk: if 'headers' in from_disk['settings']: self.__data['settings']['headers'].update(from_disk['settings']['headers']) if 'requests' in from_disk['settings']: self.__data['settings']['requests'].update(from_disk['settings']['requests']) # Reinitialise each `watching` with our generic_definition in the case that we add a new var in the future. # @todo pretty sure theres a python we todo this with an abstracted(?) object! for uuid, watch in self.data['watching'].items(): _blank = deepcopy(self.generic_definition) _blank.update(watch) self.__data['watching'].update({uuid: _blank}) self.__data['watching'][uuid]['newest_history_key'] = self.get_newest_history_key(uuid) print("Watching:", uuid, self.__data['watching'][uuid]['url']) # First time ran, doesnt exist. except (FileNotFoundError, json.decoder.JSONDecodeError): if include_default_watches: print("Creating JSON store at", self.datastore_path) self.add_watch(url='http://www.quotationspage.com/random.php', tag='test') self.add_watch(url='https://news.ycombinator.com/', tag='Tech news') self.add_watch(url='https://www.gov.uk/coronavirus', tag='Covid') self.add_watch(url='https://changedetection.io', tag='Tech news') # Finally start the thread that will manage periodic data saves to JSON save_data_thread = threading.Thread(target=self.save_datastore).start() # Returns the newest key, but if theres only 1 record, then it's counted as not being new, so return 0. def get_newest_history_key(self, uuid): if len(self.__data['watching'][uuid]['history']) == 1: return 0 dates = list(self.__data['watching'][uuid]['history'].keys()) # Convert to int, sort and back to str again dates = [int(i) for i in dates] dates.sort(reverse=True) if len(dates): # always keyed as str return str(dates[0]) return 0 def set_last_viewed(self, uuid, timestamp): self.data['watching'][uuid].update({'last_viewed': str(timestamp)}) self.needs_write = True def update_watch(self, uuid, update_obj): with self.lock: # In python 3.9 we have the |= dict operator, but that still will lose data on nested structures... for dict_key, d in self.generic_definition.items(): if isinstance(d, dict): if update_obj is not None and dict_key in update_obj: self.__data['watching'][uuid][dict_key].update(update_obj[dict_key]) del (update_obj[dict_key]) self.__data['watching'][uuid].update(update_obj) self.__data['watching'][uuid]['newest_history_key'] = self.get_newest_history_key(uuid) self.needs_write = True @property def data(self): return self.__data def get_all_tags(self): tags = [] for uuid, watch in self.data['watching'].items(): # Support for comma separated list of tags. for tag in watch['tag'].split(','): tag = tag.strip() if tag not in tags: tags.append(tag) tags.sort() return tags def delete(self, uuid): with self.lock: del (self.__data['watching'][uuid]) self.needs_write = True def url_exists(self, url): # Probably their should be dict... for watch in self.data['watching']: if watch['url'] == url: return True return False def get_val(self, uuid, val): # Probably their should be dict... return self.data['watching'][uuid].get(val) def add_watch(self, url, tag): with self.lock: # @todo use a common generic version of this new_uuid = str(uuid_builder.uuid4()) _blank = deepcopy(self.generic_definition) _blank.update({ 'url': url, 'tag': tag, 'uuid': new_uuid }) self.data['watching'][new_uuid] = _blank # Get the directory ready output_path = "{}/{}".format(self.datastore_path, new_uuid) try: os.mkdir(output_path) except FileExistsError: print(output_path, "already exists.") self.sync_to_json() return new_uuid # Save some text file to the appropriate path and bump the history # result_obj from fetch_site_status.run() def save_history_text(self, uuid, result_obj, contents): output_path = "{}/{}".format(self.datastore_path, uuid) fname = "{}/{}-{}.stripped.txt".format(output_path, result_obj['previous_md5'], str(time.time())) with open(fname, 'w') as f: f.write(contents) f.close() # Update history with the stripped text for future reference, this will also mean we save the first # Should always be keyed by string(timestamp) self.update_watch(uuid, {"history": {str(result_obj["last_checked"]): fname}}) return fname def sync_to_json(self): print("Saving..") with open(self.json_store_path, 'w') as json_file: json.dump(self.__data, json_file, indent=4) logging.info("Re-saved index") self.needs_write = False # Thread runner, this helps with thread/write issues when there are many operations that want to update the JSON # by just running periodically in one thread, according to python, dict updates are threadsafe. def save_datastore(self): while True: if self.stop_thread: print("Shutting down datastore thread") return if self.needs_write: self.sync_to_json() time.sleep(1) # body of the constructor