perf(connector): add reddit API authentication to speed up fetching

This aligns better with ethics and massively increases rate limits.

example.env

@@ -1,5 +1,7 @@
 # API Keys
 YOUTUBE_API_KEY=
+REDDIT_CLIENT_ID=
+REDDIT_CLIENT_SECRET=
 
 # Database
 POSTGRES_USER=

server/connectors/reddit_api.py

@@ -1,6 +1,10 @@
 import requests
 import logging
 import time
+import os
+
+from dotenv import load_dotenv
+from requests.auth import HTTPBasicAuth
 
 from dto.post import Post
 from dto.user import User
@@ -9,6 +13,8 @@ from server.connectors.base import BaseConnector
 
 logger = logging.getLogger(__name__)
 
+CLIENT_ID = os.getenv("REDDIT_CLIENT_ID")
+CLIENT_SECRET = os.getenv("REDDIT_CLIENT_SECRET")
 
 class RedditAPI(BaseConnector):
     source_name: str = "reddit"
@@ -18,6 +24,8 @@ class RedditAPI(BaseConnector):
 
     def __init__(self):
         self.url = "https://www.reddit.com/"
+        self.token = None
+        self.token_expiry = 0
 
     # Public Methods #
     def get_new_posts_by_search(
@@ -172,8 +180,43 @@ class RedditAPI(BaseConnector):
         user.karma = user_data["total_karma"]
         return user
     
+    def _get_token(self):
+        if self.token and time.time() < self.token_expiry:
+            return self.token
+
+        logger.info("Fetching new Reddit access token...")
+
+        auth = HTTPBasicAuth(CLIENT_ID, CLIENT_SECRET)
+
+        data = {
+            "grant_type": "client_credentials"
+        }
+
+        headers = {
+            "User-Agent": "python:ethnography-college-project:0.1 (by /u/ThisBirchWood)"
+        }
+
+        response = requests.post(
+            "https://www.reddit.com/api/v1/access_token",
+            auth=auth,
+            data=data,
+            headers=headers,
+        )
+
+        response.raise_for_status()
+        token_json = response.json()
+
+        self.token = token_json["access_token"]
+        self.token_expiry = time.time() + token_json["expires_in"] - 60
+
+        logger.info(
+            f"Obtained new Reddit access token (expires in {token_json['expires_in']}s)"
+        )
+
+        return self.token
+
     def _fetch_post_overviews(self, endpoint: str, params: dict) -> dict:
-        url = f"{self.url}{endpoint}"
+        url = f"https://oauth.reddit.com/{endpoint.lstrip('/')}"
         max_retries = 15
         backoff = 1  # seconds
 
@@ -182,7 +225,8 @@ class RedditAPI(BaseConnector):
                 response = requests.get(
                     url,
                     headers={
-                        "User-agent": "python:ethnography-college-project:0.1 (by /u/ThisBirchWood)"
+                        "User-agent": "python:ethnography-college-project:0.1 (by /u/ThisBirchWood)",
+                        "Authorization": f"Bearer {self._get_token()}",
                     },
                     params=params,
                 )