GraphQL

GraphQL Complexity Limit Policy

This policy allows you to add a limit for the depth and a limit for the complexity of a GraphQL query.

Configuration

The configuration shows how to configure the policy in the 'policies.json' document.


config/policies.json
{
  "name": "my-graphql-complexity-limit-inbound-policy",
  "policyType": "graphql-complexity-limit-inbound",
  "handler": {
    "export": "GraphQLComplexityLimitInboundPolicy",
    "module": "$import(@zuplo/graphql)",
    "options": {
      "useComplexityLimit": {
        "complexityLimit": 10
      },
      "useDepthLimit": {
        "ignore": []
      }
    }
  }
}

Policy Configuration

name <string> - The name of your policy instance. This is used as a reference in your routes.
policyType <string> - The identifier of the policy. This is used by the Zuplo UI. Value should be graphql-complexity-limit-inbound.
handler.export <string> - The name of the exported type. Value should be GraphQLComplexityLimitInboundPolicy.
handler.module <string> - The module containing the policy. Value should be $import(@zuplo/graphql).
handler.options <object> - The options for this policy. See Policy Options below.

Policy Options

The options for this policy are specified below. All properties are optional unless specifically marked as required.

useComplexityLimit (required) <object> - No description available.
- complexityLimit <number> - The maximum complexity a query is allowed to have.
- endpointUrl <string> - The endpoint URL to use for the complexity calculation.
useDepthLimit (required) <object> - No description available.
- depthLimit <number> - The maximum depth a query is allowed to have.
- ignore <string[]> - The fields to ignore when calculating the depth of a query.

Using the Policy

Depth Limit

Limit the depth a GraphQL query is allowed to query for.

maxDepth - Number of levels a GraphQL query is allowed to query for.

This allows you to limit the depth of a GraphQL query. This is useful to prevent DoS attacks on your GraphQL server.

Code
{
  # Level 0
  me {
    # Level 1
    name
    friends {
      # Level 2
      name
      friends {
        # Level 3
        name
        # ...
      }
    }
  }
}

Complexity Limit

Example:

maxComplexity - Maximum complexity allowed for a query.

Code
{
  me {
    name  # Complexity +1
    age   # Complexity +1
    email # Complexity +1
    friends {
      name   # Complexity +1
      height # Complexity +1
    }
  }
}
# Total complexity = 5