Allow us to pass configuration options in a json file

Addresses #48

.gitignore

@@ -1,2 +1,3 @@
 .vscode/launch.json
 artifacts/*
+config.json

README.md

@@ -75,6 +75,20 @@ When using a cronjob, we are using file based locking to avoid multiple overlapp
 
 If you are running FediFetcher locally, my recommendation is to run it manually once, before turning on the cron job: The first run will be significantly slower than subsequent runs, and that will help you prevent overlapping during that first run.
 
+When running FediFetcher locally, it may be advantageous to supply a json file of configuration options, instead of supplying a long list of command line flags. To do so, create a json file with your configuration options, e.g.
+
+```json
+{
+  "server": "mstdn.thms.uk",
+  "access-token": "{token}",
+  "home-timeline-length": 200,
+  "max-followings": 80,
+  "from-notifications": 1
+}
+```
+
+and then run your script like so: `python find_posts.py --config=path/to/json`.
+
 *Note:* if you wish to run FediFetcher using Windows Task Scheduler, you can rename the script to the `.pyw` extension instead of `.py`, and it will run silently, without opening a console window.
 
 ### 2.3) Run FediFetcher from a container
@@ -110,6 +124,7 @@ Please find the list of all configuration options, including descriptions, below
 
 | Environment Variable Name | Command line flag | Required? | Notes |
 |:---------------------------------------------------|:----------------------------------------------------|-----------|:------|
+| -- | `--config` | No | You can use this to point to a JSON file containing your configuration options, instead of supplying configuration options as command line flags.
 | -- | `--access-token` | Yes | The access token. If using GitHub action, this needs to be provided as a Secret called  `ACCESS_TOKEN`. If running as a cron job or a container, you can supply this argument multiple times, to [fetch posts for multiple users](https://blog.thms.uk/2023/04/muli-user-support-for-fedifetcher) on your instance. |
 |`MASTODON_SERVER`|`--server`|Yes|The domain only of your mastodon server (without `https://` prefix) e.g. `mstdn.thms.uk`. |
 | `HOME_TIMELINE_LENGTH` | `--home-timeline-length` | No | Provide to fetch remote replies to posts in the API-Key owner's home timeline. Determines how many posts we'll fetch replies for. Recommended value: `200`.

find_posts.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 from datetime import datetime, timedelta
+import string
 from dateutil import parser
 import itertools
 import json
@@ -14,8 +15,9 @@
 
 argparser=argparse.ArgumentParser()
 
-argparser.add_argument('--server', required=True, help="Required: The name of your server (e.g. `mstdn.thms.uk`)")
-argparser.add_argument('--access-token', action="append", required=True, help="Required: The access token can be generated at https://<server>/settings/applications, and must have read:search, read:statuses and admin:read:accounts scopes. You can supply this multiple times, if you want tun run it for multiple users.")
+argparser.add_argument('-c','--config', required=False, type=str, help='Optionally provide a path to a JSON file containing configuration options. If not provided, options must be supplied using command line flags.')
+argparser.add_argument('--server', required=False, help="Required: The name of your server (e.g. `mstdn.thms.uk`)")
+argparser.add_argument('--access-token', action="append", required=False, help="Required: The access token can be generated at https://<server>/settings/applications, and must have read:search, read:statuses and admin:read:accounts scopes. You can supply this multiple times, if you want tun run it for multiple users.")
 argparser.add_argument('--reply-interval-in-hours', required = False, type=int, default=0, help="Fetch remote replies to posts that have received replies from users on your own instance in this period")
 argparser.add_argument('--home-timeline-length', required = False, type=int, default=0, help="Look for replies to posts in the API-Key owner's home timeline, up to this many posts")
 argparser.add_argument('--user', required = False, default='', help="Use together with --max-followings or --max-followers to tell us which user's followings/followers we should backfill")
@@ -750,6 +752,23 @@ def toJSON(self):
 
     arguments = argparser.parse_args()
 
+    if(arguments.config != None):
+        if os.path.exists(arguments.config):
+            with open(arguments.config, "r", encoding="utf-8") as f:
+                config = json.load(f)
+
+            for key in config:
+                setattr(arguments, key.lower().replace('-','_'), config[key])
+
+        else:
+            log(f"Config file {arguments.config} doesn't exist")
+            sys.exit(1)
+
+    if(arguments.server == None or arguments.access_token == None):
+        log("You must supply at least a server name and an access token")
+        sys.exit(1)
+
+
     runId = uuid.uuid4()
 
     if(arguments.on_start != None and arguments.on_start != ''):