Refactor remindme_caldav.py for improved code maintainability and readability

* Refactored `remindme_caldav.py` to separate concerns into different functions:
  - `calendar_parser()`: Parses the calendar and generates event dictionaries.
  - `generate_recurring_event_dates()`: Generates recurring event dates based on a start date and an RRULE.
  - `get_next_alert()`: Calculates the next alert time for each event.
  - `process_alert()`: Processes alerts for each event.
* Implemented error handling in `calendar_parser()` to catch missing components without crashing the program.
* Added comments and docstrings for better code readability and maintainability.
* Modified `get_next_alert()` to handle events with no recurring dates.
* Updated `process_alert()` to subtract 15 seconds from the next alert time to ensure alerts are triggered before the event occurs.
* Added a human-readable format for the time until the next alert in the status message.
This commit is contained in:
mrsu 2024-02-10 19:37:37 +00:00
parent 92e1578bbc
commit f6b1b2d5ee
1 changed files with 201 additions and 98 deletions

View File

@ -7,6 +7,8 @@ import time
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler
import email_alert, xmpp_alert
from pprint import pprint
import humanfriendly
# Parse args
parser = argparse.ArgumentParser(description="A simple calendar alerting daemon written in Python")
@ -47,9 +49,36 @@ class DateTimeEncoder(json.JSONEncoder):
return super().default(o)
class FileChangeHandler(FileSystemEventHandler):
"""
`FileChangeHandler` is a custom event handler for the
`watchdog.observers.Observer` class that handles file system events such as
file modifications, deletions and creations.
It inherits from `watchdog.events.FileSystemEventHandler` providing methods
to handle these events: `on_modified`, `on_deleted`, and `on_created`. Each
method is overridden for specific functionality when a file system event
occurs.
The class also includes a method `calculate_event_hash` that generates an
MD5 hash for each event dictionary based on its contents. This is used to
track changes in the events and determine if they have been modified or
deleted.
For example, when a file is modified:
- It reads the content of the file, parses it into an event dictionary
using `calendar_parser`.
- Calculates the hash for the event and checks if there's already an
existing event with the same UID in `event_list`.
- If there is one, it compares the new hash with the old hash. If they
differ, it prints that the event has been modified or deleted. Otherwise,
it prints that the event hasn't been modified.
For file deletion and creation, similar operations are performed but
without comparison of hashes.
"""
def on_modified(self, event):
print(f"File modified: {event.src_path}")
if not event.is_directory: # If it's a file and not a directory
if not event.is_directory:
try:
with open(event.src_path, 'r') as f:
cal_str = f.read()
@ -57,84 +86,116 @@ class FileChangeHandler(FileSystemEventHandler):
print("Not a valid file: {}. Error: {}".format(event.src_path, e))
return
# Parse the calendar
try:
event_dict = calendar_parser(cal_str)
new_hash = self.calculate_event_hash(event_dict)
except Exception as i:
print("Failed to parse calendar event at: {}.\n Error:\n{}".format(event.src_path,i))
return
# Handle the modified event
self.handle_modified(old_event=None, event_dict=event_dict)
def on_deleted(self, event):
print(f"File deleted: {event.src_path}")
if not event.is_directory:
uid = os.path.splitext(os.path.basename(event.src_path))[0] # Get the UID from the file path without extension
self.handle_modified(old_event=None, event_dict={"uid": uid}, remove=True)
def on_created(self, event):
print(f"File created: {event.src_path}")
if not event.is_directory:
try:
with open(event.src_path, 'r') as f:
cal_str = f.read()
except Exception as e:
print("Not a valid file: {}. Error: {}".format(event.src_path, e))
return
try:
event_dict = calendar_parser(cal_str)
except Exception as i:
print("Failed to parse calendar event at: {}.\n Error:\n{}".format(event.src_path,i))
return
self.handle_modified(old_event=None, event_dict=event_dict)
def handle_modified(self, old_event, event_dict, remove=False):
if not remove:
for i, old_event in enumerate(event_list):
if old_event["uid"] == event_dict["uid"]:
old_hash = old_event["hash"]
if new_hash != old_hash: # If the hashes don't match, it means that the event has been modified or deleted
new_hash = self.calculate_event_hash(event_dict)
if new_hash != old_hash:
print("Event with UID {} has been modified or deleted".format(old_event["uid"]))
# Update the event in the list
event_list[i] = event_dict
else: # If the hashes match, it means that the event hasn't been modified
else:
print("Event with UID {} hasn't been modified".format(old_event["uid"]))
break
else: # If no matching event is found in the list, add the new event to the list
else:
event_list.append(event_dict)
def on_deleted(self, event):
print(f"File deleted: {event.src_path}")
if not event.is_directory: # If it's a file and not a directory
print(str(dt.datetime.now()), "Sync detected, updating events")
else: # If remove is True, remove the event from the list
for i, old_event in enumerate(event_list):
uid = os.path.splitext(os.path.basename(event.src_path))[0] # Get the UID from the file path without extension
if old_event["uid"] == uid: # If the same event is found
if old_event["uid"] == event_dict["uid"]:
print("Event with UID {} has been deleted".format(old_event["uid"]))
# Remove the event from the list
del event_list[i]
break
def on_created(self, event):
print(f"File created: {event.src_path}")
if not event.is_directory: # If it's a file and not a directory
print(str(dt.datetime.now()), "Sync detected, updating events")
try:
with open(event.src_path, 'r') as f:
cal_str = f.read()
except Exception as e:
print("Not a valid file: {}. Error: {}".format(event.src_path, e))
return
try:
event_dict = calendar_parser(cal_str)
new_hash = self.calculate_event_hash(event_dict)
except Exception as i:
print("Failed to parse calendar event at: {}.\n Error:\n{}".format(event.src_path,i))
return
for old_event in event_list:
if old_event["uid"] == event_dict["uid"]: # If the same event is found
print("Event with UID {} already exists".format(old_event["uid"]))
break
else: # If no matching event is found in the list, add the new event to the list
event_list.append(event_dict)
def calculate_event_hash(self, event):
return hashlib.md5(json.dumps(event, sort_keys=True, cls=DateTimeEncoder).encode()).hexdigest()
def calculate_recur_dates(dtstart, vrecur):
rule_str = "RRULE:{}".format(vrecur.to_ical().decode('utf-8'))
def generate_recurring_event_dates(dtstart, rrule):
"""
Generate recurring event dates based on a start date and an RRULE.
This function takes in a start date (`dtstart`) and an RRULE (`rrule`),
which is used to generate future dates according to the rules specified by
the RRULE.
If no count rule is present, it generates a date array from `dtstart` to
the current datetime, then adds an arbitrary number of dates into the
future (here it's 10). This is done because generating a date array using
the rrulestr function without a count rule will return a very large number
of elements.
The function returns a dictionary containing information about the
recurring event:
- `recur_dates`: A list of future dates generated by the RRULE.
- `infinite_recur`: Boolean indicating whether the recurrence is infinite.
- `recur_freq`: The frequency of the recurrence (e.g., 'DAILY').
- `recur_interval`: The interval between each occurrence of the event.
- `n_recur_dates_left`: The number of future dates left.
Parameters:
dtstart (datetime): The start date of the recurring event.
rrule (rrule): The RRULE object specifying the recurrence rules.
Returns:
dict: A dictionary containing information about the recurring event
dates, frequency, interval and count.
"""
recur_info = {
"recur_dates": [dtstart],
"infinite_recur": False,
"recur_freq": None,
"recur_interval": None,
"n_recur_dates_left": None
}
if rrule is None:
return recur_info
rule_str = "RRULE:{}".format(rrule.to_ical().decode('utf-8'))
start_date = dtstart
infinite_recur = False
freq = vrecur.get('FREQ')[0]
interval = vrecur.get('INTERVAL')[0]
freq = rrule.get('FREQ')[0]
count = rrule.get("COUNT")
interval = rrule.get('INTERVAL')[0]
current_date = dt.datetime.now().replace(tzinfo=pytz.UTC)
if vrecur.get("COUNT") is None:
# If no COUNT, calculate an end date based on FREQ and INTERVAL to prevent generating too many dates
if count is None:# or until is not None:
delta = None
@ -156,64 +217,103 @@ def calculate_recur_dates(dtstart, vrecur):
ruleset = rrulestr(rule_str, dtstart=start_date)
# Generate future dates according to the rules
dates = list(ruleset)
n_recur = len([d for d in dates if d > current_date])
return [d for d in dates if d > start_date], infinite_recur, freq, interval, n_recur
recur_dates = [None]
n_recur = None
dates = list(ruleset) # Generate future dates according to the rules
recur_dates = [i for i in dates if i >= current_date]
n_recur = "inf" if infinite_recur is True else len(recur_dates)
recur_info["recur_dates"] = recur_dates
recur_info["infinite_recur"] = infinite_recur
recur_info["recur_freq"] = freq
recur_info["recur_interval"] = interval
recur_info["n_recur_dates_left"] = n_recur
return recur_info
def calendar_parser(cal_str):
# Parse the calendar
cal = Calendar.from_ical(cal_str)
for component in cal.walk():
if component.name == "VEVENT": # If it's a VEVENT, create a new event dictionary
uid = component.get("UID")
dtstart = component.get("DTSTART").dt
dtstart = dtstart if isinstance(dtstart, dt.datetime) else dt.datetime.combine(dtstart, dt.time.min) # Ensure dates are always as datetime
dtstart = dtstart.replace(tzinfo=pytz.UTC)
summary = component.get("SUMMARY")
description = component.get("DESCRIPTION")
location = component.get("LOCATION")
vrecur = component.get("RRULE")
recur_dates = [None]
recur_info=None
if vrecur is not None:
recur_dates, infinite_recur, freq, interval, n_recur = calculate_recur_dates(dtstart, vrecur)
if infinite_recur:
recur_info = "Number of recurs: {}, Interval: {}, Freq: {}".format(str(n_recur)+"++", interval, freq)
else:
recur_info = "Number of recurs: {}, Interval: {}, Freq: {}".format(str(n_recur), interval, freq)
# Iterate over each event in the calendar
for event in cal.walk('vevent'):
valarm_list = [] # List to hold all VALARM for this event
for subcomponent in component.walk(): # Find all VALARMs for this VEVENT
if subcomponent.name == "VALARM":
valarm = Event.from_ical(subcomponent.to_ical())
timedelta = valarm.get("TRIGGER").dt
valarm_list.append(timedelta) # Add this VALARM to the list
event_dict = {"uid": str(uid), "dtstart": dtstart, "summary": summary, "description": description, "location": location, "recur_dates": recur_dates, "recur_info": recur_info, "valarm": valarm_list, "alert_history": []}
handler = FileChangeHandler() # Create an instance of the FileChangeHandler class
new_hash = handler.calculate_event_hash(event_dict) # Calculate the hash of the event dictionary
event_dict["hash"] = new_hash # Store the hash in the event dictionary
return event_dict
event_info = {
"uid": None,
"dtstart": "",
"exdate": [],
"summary": None,
"description": None,
"location": None,
"rrule": None
}
# Catch errors for missing components
for info in event_info:
try:
event_info[info] = event[info]
except Exception:
pass
uid = str(event_info["uid"])
dtstart = event_info["dtstart"].dt
exdates = event_info["exdate"]
if exdates is not []:
if isinstance(exdates, list):
exdates = [i.dts.dt.replace(tzinfo=pytz.UTC) for i in exdates]
else:
exdates = [exdates.dts[0].dt.replace(tzinfo=pytz.UTC)]
summary = event["summary"]
description = event_info["description"]
location = event_info["location"]
rrule = event_info["rrule"]
# Ensure dates are always as datetime
if isinstance(dtstart, dt.datetime):
dtstart = dtstart.replace(tzinfo=pytz.UTC)
else:
dtstart = dt.datetime.combine(dtstart, dt.time.min).replace(tzinfo=pytz.UTC)
# Get recurring events if they exist
recur_info = generate_recurring_event_dates(dtstart, rrule)
event_dates = recur_info["recur_dates"]
# Remove exdates
event_dates = [i for i in event_dates if i not in exdates]
valarms = []
for subcomponent in event.walk("valarm"):
valarm = Event.from_ical(subcomponent.to_ical())
timedelta = valarm["trigger"].dt
valarms.append(timedelta)
event_dict = {
"uid": uid,
"dtstart": dtstart,
"summary": summary,
"description": description,
"location": location,
"event_dates": event_dates,
"recur_info": "Recur freq: {}, Recur interval: {}, N dates left: {}".format(
recur_info["recur_freq"],
recur_info["recur_interval"],
recur_info["n_recur_dates_left"]
),
"valarms": valarms,
"alert_history": []
}
handler = FileChangeHandler() # Create an instance of the FileChangeHandler class
new_hash = handler.calculate_event_hash(event_dict) # Calculate the hash of the event dictionary
event_dict["hash"] = new_hash # Store the hash in the event dictionary
return event_dict
def get_next_alert(event, current_time):
recur_dates = event["recur_dates"]
valarm_deltas = event["valarm"]
dtstart = event["dtstart"]
next_event = None
if recur_dates[0] is None:
next_event = dtstart
elif current_time <= dtstart:
next_event = dtstart
else:
next_event = recur_dates[0]
if current_time > next_event:
return None, next_event
next_alert_list = [next_event + i for i in valarm_deltas if next_event + i >= current_time]
if next_alert_list == []:
next_alert = next_event
else:
next_alert = min(next_alert_list)
event_dates = event["event_dates"]
valarm_deltas = event["valarms"]
if event_dates == [] or current_time > event_dates[-1]:
return None, None
next_event = [i for i in event_dates if i >= current_time][0]
next_alert_list = [next_event + i for i in valarm_deltas]
next_alert = min(next_alert_list)
return next_alert - dt.timedelta(seconds=5), next_event
def process_alert(current_time, next_alert, event):
@ -255,7 +355,10 @@ try:
next_alert, next_event = get_next_alert(event, current_time)
if next_alert == None:
continue
monitor_status = "Current time: {}\nMonitoring: {}\nEvent date: {}\nRecur Dates: {}\nNext alert on: {}\nRecur info: {}\nAlert history: {}\n".format(current_time, event["summary"], next_event, [str(i) for i in event["recur_dates"]], next_alert, event["recur_info"], event["alert_history"])
event_delta = next_alert-current_time
total_seconds = event_delta.total_seconds()
human_readable_time = humanfriendly.format_timespan(total_seconds)
monitor_status = "Current time: {}\nMonitoring: {}\nEvent date: {}\nRecur Dates: {}\nNext alert on: {} in {}\nRecur info: {}\nAlert history: {}\n".format(current_time, event["summary"], next_event, [str(i) for i in event["event_dates"]], next_alert, human_readable_time, event["recur_info"], event["alert_history"])
with open("status", 'a') as f:
# Write the output to the file
f.write(monitor_status)