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https://github.com/4catalyzer/graphql-validation-complexity
Query complexity validation for GraphQL.js
https://github.com/4catalyzer/graphql-validation-complexity
Last synced: about 20 hours ago
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Query complexity validation for GraphQL.js
- Host: GitHub
- URL: https://github.com/4catalyzer/graphql-validation-complexity
- Owner: 4Catalyzer
- License: mit
- Created: 2017-06-20T21:49:19.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2024-10-10T15:46:05.000Z (2 months ago)
- Last Synced: 2024-10-12T18:27:05.529Z (2 months ago)
- Language: JavaScript
- Size: 1.09 MB
- Stars: 342
- Watchers: 6
- Forks: 24
- Open Issues: 19
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# graphql-validation-complexity [![Travis][build-badge]][build] [![npm][npm-badge]][npm]
Query complexity validation for GraphQL.js.
[![Codecov][codecov-badge]][codecov]
## Usage
```js
import { createComplexityLimitRule } from 'graphql-validation-complexity';
const ComplexityLimitRule = createComplexityLimitRule(1000);
// Then use this rule with validate() or other validation APIs.
```
For example, with `express-graphql` or Apollo Server, pass the complexity limit rule to `validationRules`.
```js
const graphqlMiddleware = graphqlHTTP({
schema,
validationRules: [createComplexityLimitRule(1000)],
});
const apolloServer = new ApolloServer({
schema,
validationRules: [createComplexityLimitRule(1000)],
});
```
You can provide a configuration object with custom global costs for scalars and objects as `scalarCost` and `objectCost` respectively, and a custom cost factor for lists as `listFactor`.
```js
const ComplexityLimitRule = createComplexityLimitRule(1000, {
scalarCost: 1,
objectCost: 10, // Default is 0.
listFactor: 20, // Default is 10.
});
```
You can also set custom costs and cost factors as field definition extensions with the `getCost` and `getCostFactor` callbacks.
```js
const expensiveField = {
type: ExpensiveItem,
extensions: {
getCost: () => 50,
},
};
const expensiveList = {
type: new GraphQLList(MyItem),
extensions: {
getCostFactor: () => 100,
},
};
```
You can also define these via field directives in the SDL.
```graphql
directive @cost(value: Int) on FIELD_DEFINITION
directive @costFactor(value: Int) on FIELD_DEFINITION
type CustomCostItem {
expensiveField: ExpensiveItem @cost(value: 50)
expensiveList: [MyItem] @costFactor(value: 100)
}
```
The configuration object also supports an `onCost` callback for logging query costs and a `formatErrorMessage` callback for customizing error messages. `onCost` will be called for every query with its cost. `formatErrorMessage` will be called with the cost whenever a query exceeds the complexity limit, and should return a string containing the error message.
```js
const ComplexityLimitRule = createComplexityLimitRule(1000, {
onCost: (cost) => {
console.log('query cost:', cost);
},
formatErrorMessage: (cost) =>
`query with cost ${cost} exceeds complexity limit`,
});
```
The configuration object also supports a `createError` callback for creating a custom `GraphQLError`. `createError` will be called with the cost and the document node whenever an error occurs. `formatErrorMessage` will be ignored when `createError` is specified.
```js
const ComplexityLimitRule = createComplexityLimitRule(1000, {
createError(cost, documentNode) {
const error = new GraphQLError('custom error', [documentNode]);
error.meta = { cost };
return error;
},
});
```
By default, the validation rule applies a custom, lower cost factor for lists of introspection types, to prevent introspection queries from having unreasonably high costs. You can adjust this by setting `introspectionListFactor` on the configuration object.
```js
const ComplexityLimitRule = createComplexityLimitRule(1000, {
introspectionListFactor: 10, // Default is 2.
});
```
[build-badge]: https://img.shields.io/travis/4Catalyzer/graphql-validation-complexity/master.svg
[build]: https://travis-ci.org/4Catalyzer/graphql-validation-complexity
[npm-badge]: https://img.shields.io/npm/v/graphql-validation-complexity.svg
[npm]: https://www.npmjs.org/package/graphql-validation-complexity
[codecov-badge]: https://img.shields.io/codecov/c/github/4Catalyzer/graphql-validation-complexity/master.svg
[codecov]: https://codecov.io/gh/4Catalyzer/graphql-validation-complexity