Server Load Balancer:AScript

What is AScript?

AScript provides easy-to-learn syntax and many functions that allow you to create custom ALB configurations.

AScript provides encapsulation-free functions, built-in variables, and the if-else statement. You can use variables and functions to create custom forwarding rules. This way, your business can quickly adapt to changes.

For details about the AScript syntax, see AScript syntax.

Use scenarios

• Hotlink protection

  You can use AScript to customize authentication algorithms, User-Agent (UA) blacklists, and Referer whitelists. AScript allows you to customize the authentication logic and authenticate requests based on request parameters, cookies, or algorithms. This helps you protect your resources against attacks.

• Access control based on whitelists or blacklists

  You can use AScript to configure an IP blacklist or whitelist to control access from clients.

• Request and response header customization

  You can use AScript to modify variables, such as request and response headers, based on your business requirements.

• Request rewrites and redirects

  You can use AScript to rewrite request URIs and file extensions, add URI prefixes, and perform 302 redirects. This way, you can rewrite requests or redirect them to the desired resources.

  A common use case is that your website supports different languages. With Ascript, requests destined for the website can be redirected to the URLs that point to the content written in the requested language. For example, requests that require English or German are redirected from the China site to the English or German site, respectively.

Billing

For information about how the number of rule evaluations affects the Load Balancer Capacity Unit (LCU) fee, see Billing rules.

How it works