nestjs graphql query/mutation complexity - nestjs

Question

I'm trying to implement query complexity for my nestjs v8 graphql queries, but I can't find a fully working example...
Following the docs (https://docs.nestjs.com/graphql/complexity) I created my ComplexityPlugin
import { GraphQLSchemaHost } from '#nestjs/graphql';
import { Plugin } from '#nestjs/apollo';
import {
ApolloServerPlugin,
BaseContext,
GraphQLRequestContext,
GraphQLRequestListener,
} from 'apollo-server-plugin-base';
import { GraphQLError } from 'graphql';
import {
fieldExtensionsEstimator,
getComplexity,
simpleEstimator,
} from 'graphql-query-complexity';
#Plugin()
export class ComplexityPlugin implements ApolloServerPlugin {
constructor(private gqlSchemaHost: GraphQLSchemaHost) {}
requestDidStart(
requestContext: GraphQLRequestContext<BaseContext>,
): void | GraphQLRequestListener<BaseContext> {
const maxComplexity = 20;
const { schema } = this.gqlSchemaHost;
return {
async didResolveOperation({ request, document }) {
const complexity = getComplexity({
schema,
operationName: request.operationName,
query: document,
variables: request.variables,
estimators: [
fieldExtensionsEstimator(),
simpleEstimator({ defaultComplexity: 1 }),
],
});
if (complexity > maxComplexity) {
throw new GraphQLError(
`Query is too complex: ${complexity}. Maximum allowed complexity: ${maxComplexity}`,
);
}
console.log('Query Complexity:', complexity);
},
};
}
}
then added in my module as a provider
and then in my app.module.ts -> imports ->
GraphQLModule.forRoot({
...
plugins: [new ComplexityPlugin()],
...
}),
but new ComplexityPlugin() expects a GraphQLSchemaHost object as parameter... now what?
If I don't add it as a plugin into GraphQLModule.forRoot, I get this error:
TypeError: Class extends value undefined is not a constructor or null
at Object.<anonymous> (/home/johnykes/code/my-service/node_modules/#nestjs/apollo/dist/services/plugins-explorer.service.js:6:48)
at Module._compile (node:internal/modules/cjs/loader:1105:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
at Module.load (node:internal/modules/cjs/loader:981:32)
at Function.Module._load (node:internal/modules/cjs/loader:822:12)
at Module.require (node:internal/modules/cjs/loader:1005:19)
at require (node:internal/modules/cjs/helpers:102:18)
at Object.<anonymous> (/home/johnykes/code/my-service/node_modules/#nestjs/apollo/dist/drivers/apollo-federation.driver.js:9:36)
at Module._compile (node:internal/modules/cjs/loader:1105:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
at Module.load (node:internal/modules/cjs/loader:981:32)
at Function.Module._load (node:internal/modules/cjs/loader:822:12)
at Module.require (node:internal/modules/cjs/loader:1005:19)
at require (node:internal/modules/cjs/helpers:102:18)
at Object.<anonymous> (/home/johnykes/code/my-service/node_modules/#nestjs/apollo/dist/drivers/index.js:4:22)
at Module._compile (node:internal/modules/cjs/loader:1105:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
at Module.load (node:internal/modules/cjs/loader:981:32)
at Function.Module._load (node:internal/modules/cjs/loader:822:12)
at Module.require (node:internal/modules/cjs/loader:1005:19)
at require (node:internal/modules/cjs/helpers:102:18)
at Object.<anonymous> (/home/johnykes/code/my-service/node_modules/#nestjs/apollo/dist/index.js:5:22)

Answer 1

From the docs you could just add the ComplexityPlugin as a provider in the providers array.

Answer 2

My colleague just found the solution:
npm i package "graphql-query-complexity": "...,
create plugin
import { Plugin } from '#nestjs/graphql';
import {
ApolloServerPlugin,
GraphQLRequestListener,
GraphQLServiceContext,
} from 'apollo-server-plugin-base';
import { GraphQLError, GraphQLSchema } from 'graphql';
import {
fieldExtensionsEstimator,
getComplexity,
simpleEstimator,
} from 'graphql-query-complexity';
#Plugin()
export class ComplexityPlugin implements ApolloServerPlugin {
private schema: GraphQLSchema;
constructor() {}
async serverWillStart(service: GraphQLServiceContext) {
this.schema = service.schema;
}
async requestDidStart(): Promise<GraphQLRequestListener> {
const maxComplexity = 100;
const schema = this.schema;
return {
async didResolveOperation({ request, document }) {
const complexity = getComplexity({
schema,
operationName: request.operationName,
query: document,
variables: request.variables,
estimators: [
fieldExtensionsEstimator(),
simpleEstimator({ defaultComplexity: 1 }),
],
});
if (complexity > maxComplexity) {
throw new GraphQLError(
`Query is too complex: ${complexity}. Maximum allowed complexity: ${maxComplexity}`,
);
}
},
};
}
}
in app.module.ts, add:
import { ComplexityPlugin } from './modules/common/complexity.plugin';
...
GraphQLModule.forRoot({
...
plugins: [new ComplexityPlugin()],
formatError: (error: GraphQLError) => {
const graphQLFormattedError: GraphQLFormattedError = {
...error,
message:
error.extensions?.exception?.response?.message || error.message,
};
console.error(graphQLFormattedError);
return {
...graphQLFormattedError,
extensions: { ...graphQLFormattedError.extensions, exception: null },
};
},
}),
in your graphql input args, add:
import { IsOptional, Max } from 'class-validator';
...
#IsOptional()
#Max(100)
#Field(() => Int, { nullable: true, description: 'Paginate first' })
public first?: number = 10;
...