jacoz/gqlgen-constraint-directive

Constraint directive for gqlgen

Package

This package allows you to define constraints to your input parameters directly in the graphql schema.

Requirements

• go >= 1.18
• 99designs/gqlgen >= 0.17
• go-playground/validator >= 10
• go-playground/universal-translator >= 0.18

Setup

1. Add this library to your go project with:

go get -u github.com/jacoz/gqlgen-constraint-directive
go mod tidy

2. Add to your schema.graphqls file the directive and then use it like the example below:

directive @constraint(constraint: String!) on INPUT_FIELD_DEFINITION | ARGUMENT_DEFINITION

# ...

input SearchInput {
    offset: Int! @constraint(constraint: "min=0")
    limit: Int! @constraint(constraint: "max=50")
}

3. Regenerate the graphql schema with the command

go run github.com/99designs/gqlgen generate

4. Define your validator and your translator (optional). In case you already are using a validator and a translator in your project, you can pass them as parameters, you can pass nil otherwise.

constraintDirective := gqlgen_constraint_directive.New(nil, nil)

// or

constraintDirective := gqlgen_constraint_directive.New(yourValidator, yourTranslator)

5. Load the directive into your graphql server configuration:

c := generated.Config{}
c.Directives.Constraint = constraintDirective.Contraint

Validators

You can find all the available validators in the validator package