reddit: add support for authenticated requests

src/modules/processing/services/reddit.js

@@ -1,7 +1,61 @@
-import { maxVideoDuration } from "../../config.js";
+import { genericUserAgent, maxVideoDuration } from "../../config.js";
+import { getCookie, updateCookieValues } from "../cookie/manager.js";
+
+async function getAccessToken() {
+    /* "cookie" in cookiefile needs to contain:
+     * client_id, client_secret, refresh_token
+     * e.g. client_id=bla; client_secret=bla; refresh_token=bla
+     *
+     * you can get these by making a reddit app and
+     * authenticating an account against reddit's oauth2 api
+     * see: https://github.com/reddit-archive/reddit/wiki/OAuth2
+     * 
+     * any additional cookie fields are managed by this code and you
+     * should not touch them unless you know what you're doing. **/
+    const cookie = await getCookie('reddit');
+    if (!cookie) return;
+
+    const values = cookie.values(),
+          needRefresh = !values.access_token
+                        || !values.expiry
+                        || Number(values.expiry) > new Date().getTime();
+    if (!needRefresh) return values.access_token;
+
+    const data = await fetch('https://www.reddit.com/api/v1/access_token', {
+        method: 'POST',
+        headers: {
+            'authorization': `Basic ${Buffer.from(
+                [values.client_id, values.client_secret].join(':')
+            ).toString('base64')}`,
+            'content-type': 'application/x-www-form-urlencoded',
+            'user-agent': genericUserAgent,
+            'accept': 'application/json'
+        },
+        body: `grant_type=refresh_token&refresh_token=${encodeURIComponent(values.refresh_token)}`
+    }).then(r => r.json()).catch(_ => {});
+    if (!data) return;
+
+    const { access_token, refresh_token, expires_in } = data;
+    if (!access_token) return;
+
+    updateCookieValues(cookie, {
+        ...cookie.values(),
+        access_token, refresh_token,
+        expiry: new Date().getTime() + (expires_in * 1000),
+    });
+
+    return access_token;
+}
 
 export default async function(obj) {
-    let data = await fetch(`https://www.reddit.com/r/${obj.sub}/comments/${obj.id}/${obj.name}.json`).then((r) => { return r.json() }).catch(() => { return false });
+    const url = new URL(`https://www.reddit.com/r/${obj.sub}/comments/${obj.id}/${obj.title}.json`);
+
+    const accessToken = await getAccessToken()
+    if (accessToken) url.hostname = 'oauth.reddit.com';
+
+    let data = await fetch(
+        url, { headers: accessToken && { authorization: `Bearer ${accessToken}` } }
+    ).then((r) => { return r.json() }).catch(() => { return false });
     if (!data) return { error: 'ErrorCouldntFetch' };
 
     data = data[0]["data"]["children"][0]["data"];