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support @include/@skip directives #23

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Merged
merged 2 commits into from
Jan 22, 2020
Merged

support @include/@skip directives #23

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9787510
support @include/@skip directives
zimuliu Jan 16, 2020
a974258
add test cases
zimuliu Jan 16, 2020
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33 changes: 32 additions & 1 deletion src/QueryComplexity.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -4,19 +4,22 @@

import {
getArgumentValues,
getDirectiveValues,
} from 'graphql/execution/values';

import {
ValidationContext,
FragmentDefinitionNode,
OperationDefinitionNode,
DirectiveNode,
FieldNode,
FragmentSpreadNode,
InlineFragmentNode,
assertCompositeType,
GraphQLField, isCompositeType, GraphQLCompositeType, GraphQLFieldMap,
GraphQLSchema, DocumentNode, TypeInfo,
visit, visitWithTypeInfo
visit, visitWithTypeInfo,
GraphQLDirective,
} from 'graphql';
import {
GraphQLUnionType,
Expand Down Expand Up @@ -102,6 +105,8 @@ export default class QueryComplexity {
options: QueryComplexityOptions;
OperationDefinition: Object;
estimators: Array<ComplexityEstimator>;
includeDirectiveDef: GraphQLDirective;
skipDirectiveDef: GraphQLDirective;

constructor(
context: ValidationContext,
Expand All @@ -115,6 +120,9 @@ export default class QueryComplexity {
this.complexity = 0;
this.options = options;

this.includeDirectiveDef = this.context.getSchema().getDirective('include');
this.skipDirectiveDef = this.context.getSchema().getDirective('skip');

if (!options.estimators) {
console.warn(
'DEPRECATION WARNING: Estimators should be configured in the queryComplexity options.'
Expand Down Expand Up @@ -183,6 +191,29 @@ export default class QueryComplexity {
(total: number, childNode: FieldNode | FragmentSpreadNode | InlineFragmentNode) => {
let nodeComplexity = 0;

let includeNode = true;
let skipNode = false;
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We only need one variable to determine if the node should be skipped/included, this avoids contradictory (temporary) values...

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@zimuliu zimuliu Jan 20, 2020 •
edited
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These two variables were created for a better alignment with the GraphQL standard:

Neither @Skip nor @include has precedence over the other. In the case that both the @Skip and @include directives are provided in on the same the field or fragment, it must be queried only if the @Skip condition is false and the @include condition is true. Stated conversely, the field or fragment must not be queried if either the @Skip condition is true or the @include condition is false.

from: http://spec.graphql.org/June2018/#sec--include

We can technically use a single variable, but it would be a bit harder to follow.


childNode.directives.forEach((directive: DirectiveNode) => {
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In case a server makes excessive use of directives it would iterate over all the directives, extract values, etc. regardless of whether it was already determined if we include or skip the field.

For example:

{
  field @skip(if: true) @otherDirective @otherDirective2 @etc
}

In this case, we could skip the evaluation of the last 3 directives. I'd use Array.find instead and find the directives that result in the exclusion of the field.

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@skip and @include can only be used in queries/mutations from the client, and not in schema definitions on the server side. The chance of multiple directives on a query is really rare. Also, as the directives are not sorted, the big O complexity is the same for both forEach and find. If we use forEach, we just need to scan directives in one pass to get the job done.

Directives from the standard:

directive @include(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
directive @skip(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT

const directiveName = directive.name.value;
switch (directiveName) {
case 'include': {
const values = getDirectiveValues(this.includeDirectiveDef, childNode, this.options.variables || {});
includeNode = values.if;
break;
}
case 'skip': {
const values = getDirectiveValues(this.skipDirectiveDef, childNode, this.options.variables || {});
skipNode = values.if;
break;
}
}
});

if (!includeNode || skipNode) {
return total;
}

switch (childNode.kind) {
case Kind.FIELD: {
const field = fields[childNode.name.value];
Expand Down
87 changes: 86 additions & 1 deletion src/__tests__/QueryComplexity-test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,91 @@ describe('QueryComplexity analysis', () => {
expect(complexity).to.equal(1);
});

it('should respect @include(if: false)', () => {
const ast = parse(`
query {
variableScalar(count: 10) @include(if: false)
}
`);

const complexity = getComplexity({
estimators: [
simpleEstimator({defaultComplexity: 1})
],
schema,
query: ast
});
expect(complexity).to.equal(0);
});

it('should respect @include(if: true)', () => {
const ast = parse(`
query {
variableScalar(count: 10) @include(if: true)
}
`);

const complexity = getComplexity({
estimators: [
simpleEstimator({defaultComplexity: 1})
],
schema,
query: ast
});
expect(complexity).to.equal(1);
});

it('should respect @skip(if: true)', () => {
const ast = parse(`
query {
variableScalar(count: 10) @skip(if: true)
}
`);

const complexity = getComplexity({
estimators: [
simpleEstimator({defaultComplexity: 1})
],
schema,
query: ast
});
expect(complexity).to.equal(0);
});

it('should respect @skip(if: false)', () => {
const ast = parse(`
query {
variableScalar(count: 10) @skip(if: false)
}
`);

const complexity = getComplexity({
estimators: [
simpleEstimator({defaultComplexity: 1})
],
schema,
query: ast
});
expect(complexity).to.equal(1);
});

it('should respect @skip(if: false) @include(if: true)', () => {
const ast = parse(`
query {
variableScalar(count: 10) @skip(if: false) @include(if: true)
}
`);

const complexity = getComplexity({
estimators: [
simpleEstimator({defaultComplexity: 1})
],
schema,
query: ast
});
expect(complexity).to.equal(1);
});

it('should calculate complexity with variables', () => {
const ast = parse(`
query Q($count: Int) {
Expand Down Expand Up @@ -341,7 +426,7 @@ describe('QueryComplexity analysis', () => {
});
expect(Number.isNaN(complexity)).to.equal(true);
});

it('should skip complexity calculation by directiveEstimator when no astNode available on field', () => {
const ast = parse(`
query {
Expand Down