How to Install Limit Payload Size

The integration uses an function to check the Content-Length header of request data and block payloads exceeding a set limit.

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Limit Payload Size is a serverless integration available at Azion Marketplace.

The integration employs a function to evaluate request data and deny payloads that exceed a predefined limit. The function validates the request payload size by checking the Content-Length header. The Content-Length header is required, making it safe to read instead of always reading the body. The users are safeguarded against attempts to change the header’s value in this way, and reading the Content-Length header is the best course of action from a performance standpoint.

Getting the integration

To install the integration, follow these steps:

  1. Access Azion Console > Marketplace.
  2. On the Marketplace homepage, select the integration’s card.
  3. Once the integration’s page opens, click the Install button.

You’ll see a message indicating that your integration was successfully installed.

You can search any integration by browsing through the cards, using the filters, or typing a keyword in the search bar.

Configuring the integration

This is an firewall integration, so, you’ll have to instantiate the integration on the Firewall page. Follow the steps below to do this.

Setting up a firewall

To instantiate the Limit Payload Size integration, follow the steps:

  1. On the Products menu, select Firewall in the SECURE section.
  2. Click the + Firewall button.
  3. Give an easy to remember name to your firewall.
  4. Click the Functions switch to enable functions on your firewall.
  5. Click the Save button.

Done. Now you’ve instantiated the firewall for your function.

Setting up the Firewall function

To instantiate the Limit Payload Size integration, while still on the Firewall page:

  1. Select the Functions Instances tab.
  2. Click the + Function Instance button.
  3. Give an easy to remember name to your instance.
  4. On the dropdown menu, select the Limit Payload Size function.
  • This action will load the Arguments tab.
  1. On the Arguments tab, add the parameters.

For this integration, you only have to pass one argument in the Args JSON file:

{
"max_content_length": "10kb"
}

Some information about how this integration works:

  • The max_content_length is the maximum size of the payload you’ll accept.
  • This field accepts bytes, kilobytes, and megabytes as argument.
  • If you don’t specify the unit of the payload size, it’ll be assumed as bytes.
  • If you don’t pass any argument, the function will bypass the execution.
  • Whenever the size exceeds the threshold set by the user, the integration will return a 403 error.
  1. Click the Save button.

Setting up the Firewall Rules Engine

To finish, you have to set up the Rules Engine to configure the behavior and the criteria to run the function.

Still on the Firewall page:

  1. Select the Rules Engine tab.
  2. Click the + Rule Engine button.
  3. Give a name to the rule.
  4. Select a criteria to run and catch the domains that you want to run the integration on.
  • Example: if Host matches yourdomain.com.
  1. Below, select a behavior to the criteria. In this case, it’ll be Run Function.
    • Select the adequate function according to the name you gave it during the instantiation step.
  2. Click the Save button.

On the Console, you must now configure your domain so your firewall protects it.

  1. On the Products menu, select Workloads.
  2. Click on the domain you want to protect with your Limit Payload Size function.
  3. In the Settings section, click on the Firewall selector and choose the firewall you created.
  4. Click the Save button.

Done. Now the Limit Payload Size integration is running for every request made to the domain you indicated.