working scrape of photos

scrape.js

@@ -1,8 +1,14 @@
 const puppeteer = require('puppeteer');
-const { pathOr, unionWith, prop, eqBy } = require('ramda');
+const { pathOr, unionWith, prop, eqBy, maxBy } = require('ramda');
 const parse_args = require('minimist');
+const url = require('url');
+const path = require('path');
+const fs = require('fs').promises;
+const gm = require('gm').subClass({ imageMagick: true });
 
 const graphql_endpoint = 'https://www.facebook.com/api/graphql/';
+const facebook_event_url = (event_id) =>
+  `https://www.facebook.com/events/${event_id}/`;
 
 const get_upcoming_events = pathOr(
   null,
@@ -32,6 +38,96 @@ const load_page = async (page, event_page) => {
   }
 };
 
+const load_event = async (page, event_id) => {
+  try {
+    const image_data = new Promise((resolve, reject) => {
+      const images = [];
+      page.on('response', async (response) => {
+        const response_url = response.request().url();
+        const { pathname } = new URL(response_url);
+        const ext = path.extname(pathname);
+        if (ext === '.jpg') {
+          const image = await response.buffer();
+          images.push(image);
+        }
+      });
+      page.on('domcontentloaded', async () => {
+        resolve(images);
+      });
+    });
+
+    await page.goto(facebook_event_url(event_id));
+    const images = await image_data;
+    const image = images.reduce((res, image) =>
+      maxBy((item) => item.length, res, image),
+    );
+    return { image };
+  } catch (e) {
+    console.error(e);
+  }
+};
+
+const write_image = (path, image) =>
+  fs.writeFile(path, image, { encoding: null });
+
+const gm_write = (image, path) => {
+  return new Promise((resolve, reject) =>
+    image.write(path, (err) => (!err ? resolve() : reject(err))),
+  );
+};
+
+const write_resized = async (image_path, original) => {
+  const image = gm(original);
+  const size = await new Promise((resolve, reject) => {
+    image.size((err, value) => (!err ? resolve(value) : resolve(null)));
+  });
+
+  if (size === null) {
+    throw new Error('Could not get image.');
+  }
+
+  let { height: y, width: x } = size;
+
+  if (y % 2 === 1) {
+    y = y + 1;
+  }
+
+  if (x % 2 === 1) {
+    x = x + 1;
+  }
+
+  image.resize(x, y);
+
+  if (y > x) {
+    const z = (y - x) / 2;
+    image.crop(x, x, 0, z);
+  }
+
+  if (y < x) {
+    const z = (x - y) / 2;
+    image.crop(y, y, z, 0);
+  }
+
+  return gm_write(image, image_path);
+};
+
+const save_images = async ({ image = null, event_id }) => {
+  if (image === null) {
+    return [];
+  }
+  const original_path = `./events/img/${event_id}.jpg`;
+  const resized_path = `./events/img/square-${event_id}.jpg`;
+  const original = write_image(original_path, image);
+  const resized_square = write_resized(resized_path, image);
+  try {
+    const res = await Promise.all([original, resized_square]);
+    return { original: original_path, square: resized_path };
+  } catch (err) {
+    console.error(err);
+    return { original: null };
+  }
+};
+
 const argv = parse_args(process.argv.slice(2));
 const page_ids = pathOr('', ['page_ids'], argv)
   .split(',')
@@ -69,20 +165,47 @@ const map_event = (edge) => {
 };
 
 (async () => {
+  fs.mkdir('./events/img', { recursive: true }).catch(console.error);
   const browser = await puppeteer.launch({
-    headless: true,
+    headless: false,
     args: ['--disable-dev-shm-usage'],
   });
 
   let events = [];
 
   for (let page_id of page_ids) {
-    const page = await browser.newPage();
-    const data = await load_page(page, page_id);
+    const facebook_page = await browser.newPage();
+    const data = await load_page(facebook_page, page_id);
     const edges = data.edges.map(map_event);
     events = merge_edges(edges, events);
-  }
 
-  console.log(JSON.stringify(events));
-  process.exit();
+    events = await Promise.all(
+      events.map(async (event) => {
+        const event_page = await browser.newPage();
+        const event_data = await load_event(event_page, event.event_id);
+        return {
+          ...event_data,
+          ...event,
+        };
+      }),
+    );
+
+    events = await Promise.all(
+      events.map(async (event) => {
+        const images = await save_images(event);
+        delete event.image;
+        return {
+          images,
+          ...event,
+        };
+      }),
+    );
+  }
+  console.log(events);
 })();
+
+/* (async () => {
+ *   const image_path = './events/img/439439046887956.jpg';
+ *   const image = await fs.readFile(image_path);
+ *   write_resized(image_path, image);
+ * })(); */