Serverless Web Differ

中文文档

A serverless web browser which crawls websites and compares pages by schedule, with Serverless, AWS Lambda, Headless Chrome and Selenium!

What it can do | Prerequisites | Configuration | Deploy

What it can do

• Runs headless chrome in a serverless environement.
• Finds web elements with xpath and compares it.
• Send notifications/emails if something has changed.

Prerequisites

0. You need to have a aws account, aws_access_key_id and aws_secret_access_key. If you don't an account yet, go to here to sign up for one, and then follow the instructions here to get the key_id and access key.
1. Install node and make sure npm is available in your path.
2. Install docker from here.
3. Install Serverless: npm install -g serverless
4. Configure serverless with aws, using the aws_access_key_id and aws_secret_access_key from step 0: sls config credentials -p aws -k aws_access_key_id -s aws_secret_access_key
5. Clone this project: git clone https://github.com/LeiShi1313/serverless-web-differ.git
6. Install the dependencies: cd serverless-web-differ && npm install

Configuration

There are couple of things you need to configure before actually make the function running in the cloud. First you need to create a file called config.yml and copy/paste everything from config.yml.example. Inside the config.yml:

• events: This is the place you can define what is the frequency the function runs, you can read more from here. But most of the time, you want one entry like - schedule: rate(1 hour) or - schedule: cron(0 * * * ? *), which both means run the function every hour.
• server_chan/sendgrid/ifttt/pushbullet: There are the pre-defined ways to notify you if something has changed on the websites you interested. You can read the comments to find out how to get the security keys.
• websites: This is the main configuration part. websites can have multiple entries, and each one represents a website you want to periodically check. url and xpath is easy to understand, if you don't know how to get the xpath, try search xpath [THE BROWSER YOU ARE USING], you should be able to find a lot of informations. For original, actually it can be absent if you are expecting a web element will appear, otherwise the function will compare the EXACT text from original and the web element of the web page by xpath.

Deploy

This is simple, when everything is all set, run:

sls deploy

and 🎉🎉🎉

TODO

• Add Chinese ver. README.
• For each website, deploy a lambda function instead of visiting all websites in one function.
• Make notify.py another lambda function.
• Add more ways to notify.
• Maybe move notify.py to another project and make a submodule here?
• Provide a headerless chrome docker image
• Options for other cloud provider: Google Cloud, Aliyun, etc