feat: add hackernews project in kittehub (#123)

This PR addresses ENG-1025. Project tracks articles from Hacker News
based on user-provided topic and sends updates to a designated Slack
channel. The main functionality includes:
• Slash Command Integration: Users can specify a topic to monitor
directly from Slack.
• Real-Time Updates: The bot fetches new articles every two minutes and
posts any updates to Slack.
• Hacker News API Integration: Uses the Algolia-powered Hacker News API
to search for articles by keyword.
• Slack Integration: Sends article details (title and URL) to the
specified Slack channel.

Since we’re updating the README to focus on cloud deployment, I did not
place significant emphasis on the README file

---------

Co-authored-by: Daniel Abraham <[email protected]>
Co-authored-by: Pasha Fateev <[email protected]>

hackernews/README.md

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+---
+title: Hacker News Alerts in Slack 
+description: Track Hacker News articles by topic and send updates to Slack
+integrations: ["slack"]
+categories: ["Office Automation"]
+---
+
+# Hacker News Alerts in Slack
+
+This project monitors Hacker News for new articles matching a specific topic, fetching their details in real-time. It compares the latest results with previously fetched articles to identify new ones and sends their title and URL as notifications to a Slack channel.
+
+## How It Works
+
+1. Extract the topic from the Slack app mention.
+2. Add the topic to the Hacker News search query (check out [Algolia's REST API](https://www.algolia.com/doc/api-reference/rest-api) for more details).
+3. Return all the new articles related to the topic that were published since the last check.
+
+## Deployment & Configuration
+
+#### Cloud Usage (Recommended)
+
+- Initialize your connection with Slack through the UI
+
+#### Prerequisites
+
+- [Install AutoKitteh](https://docs.autokitteh.com/get_started/install)
+- Set up required integrations:
+  - [Slack](https://docs.autokitteh.com/integrations/slack)
+
+#### Installation Steps
+
+1. Clone the repository:
+   ```shell
+   git clone https://github.com/autokitteh/kittehub.git
+   cd kittehub/hackernews
+   ```
+
+2. Start the AutoKitteh server:
+   ```shell
+   ak up --mode dev
+   ```
+
+3. Deploy the project:
+   ```shell
+   ak deploy --manifest autokitteh.yaml
+   ```
+
+   The output will show your connection IDs, which you'll need for the next step. Look for lines like:
+   ```shell
+   [exec] create_connection "hackernews_alert/slack_connection": con_01je39d6frfdtshstfg5qpk8sz created
+   ```
+
+   In this example, `con_01je39d6frfdtshstfg5qpk8sz` is the connection ID.
+
+4. Initialize your connections using the CLI:
+   ```shell
+   ak connection init slack_connection <connection ID>
+   ```
+
+## Trigger Workflow
+
+- Type `@your-slack-app topic` in the Slack channel you set in the environment variable, replacing `topic` with what you want to search for, to start tracking articles
+- The workflow runs automatically every two minutes after deployment

hackernews/autokitteh.yaml

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+# This YAML file is a declarative manifest that describes the setup of an
+# AutoKitteh project that monitors Hacker News for a specific topic.
+
+version: v1
+
+project:
+  name: hackernews_alert
+  vars:
+    - name: POLLING_INTERVAL_SECS
+      value: 120
+  connections:
+    - name: slack_connection
+      integration: slack
+  triggers:
+    - name: slack_slash_command
+      connection: slack_connection
+      event_type: app_mention
+      call: program.py:on_slack_command

hackernews/program.py

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+"""Monitor Hacker News for new articles on a specific topic, and post updates to a Slack channel."""
+
+import os
+import requests
+import time
+import urllib.parse
+
+from autokitteh.slack import slack_client
+
+
+API_URL = "http://hn.algolia.com/api/v1/search_by_date?tags=story&page=0&query="
+POLLING_INTERVAL_SECS = int(os.getenv("POLLING_INTERVAL_SECS"))
+
+slack = slack_client("slack_connection")
+
+
+def on_slack_command(event):
+    """Workflow's entry-point.
+    Extracts a topic from a Slack command, monitors for new articles,
+    and posts updates to `SLACK_CHANNEL`.
+    """
+    topic = event.data.text.split(" ", 1)[-1].strip()
+    slack.chat_postMessage(
+        channel=event.data.channel,
+        text=f"Waiting for new articles on the topic: `{topic}`.",
+    )
+    current_articles = set()
+    fetch_articles(topic, current_articles)
+
+    # NOTE: For low-traffic topics, it might take a while for new articles to be published,
+    # so users may experience delays in receiving notifications.
+    while True:
+        all_articles = set(current_articles)
+        fetch_articles(topic, all_articles)
+        new_articles = all_articles - current_articles
+
+        for article in new_articles:
+            _, title, url = article
+            slack_message = f"Title: {title}, URL: {url if url else 'No URL'}"
+            slack.chat_postMessage(channel=event.data.channel, text=slack_message)
+        current_articles.update(new_articles)
+
+        time.sleep(POLLING_INTERVAL_SECS)
+
+
+def fetch_articles(topic, all_articles):
+    encoded_query = urllib.parse.quote(topic)
+    full_url = f"{API_URL}{encoded_query}"
+    hits = requests.get(full_url).json().get("hits", [])
+
+    # Extract some of the article fields from the API response.
+    for article in hits:
+        object_id = article["objectID"]
+        title = article["title"]
+        url = article.get("url")
+        all_articles.add((object_id, title, url))