README.md

FORK

NOTE: This internal package is a fork of https://github.com/shurcooL/graphql

Shurcool's excellent, MIT-licensed work was needlessly tied to an HTTP client, causing some unnecessary complexity downstream. This fork simply strips the HTTP support, and exposes the underlying marshalling/encoding machinery directly.

Docs below have been revised, since the Client struct no longer exists. However, the the reflective encoding stuff is mostly unchanged. See the github.com/deref/graphql-go/encoding package for the public interface.

One critical change is improved scalar support. In particular, custom wrapper types are no longer required for representing GraphQL's String, Boolean, Float, and Int types. You can use corresponding Go types directly, provided they can represent the same range of values. That is, any integer type that fits in a 64-bit float can be used. The machine-specific int type may be truncated. Similar goes for floating point values. Other custom scalar types support both encoding and decoding by implementing Go's standard json.Marshaler and json.Unmarshaler interfaces.

Simple Query

To make a GraphQL query, you need to define a corresponding Go type.

For example, to make the following GraphQL query:

query {
	me {
		name
	}
}

You can define this variable:

var query struct {
	Me struct {
		Name string
	}
}

Then call client.Query, passing a pointer to it:

err := client.Query(context.Background(), &query, nil)
if err != nil {
	// Handle error.
}
fmt.Println(query.Me.Name)

// Output: Luke Skywalker

Arguments and Variables

Often, you'll want to specify arguments on some fields. You can use the graphql struct field tag for this.

For example, to make the following GraphQL query:

{
	human(id: "1000") {
		name
		height(unit: METER)
	}
}

You can define this variable:

var q struct {
	Human struct {
		Name   string
		Height float64 `graphql:"height(unit: METER)"`
	} `graphql:"human(id: \"1000\")"`
}

Then call client.Query:

err := client.Query(context.Background(), &q, nil)
if err != nil {
	// Handle error.
}
fmt.Println(q.Human.Name)
fmt.Println(q.Human.Height)

// Output:
// Luke Skywalker
// 1.72

However, that'll only work if the arguments are constant and known in advance. Otherwise, you will need to make use of variables. Replace the constants in the struct field tag with variable names:

var q struct {
	Human struct {
		Name   string
		Height float64 `graphql:"height(unit: $unit)"`
	} `graphql:"human(id: $id)"`
}

Then, define a variables map with their values:

variables := map[string]interface{}{
	"id":   graphql.ID(id),
	"unit": starwars.LengthUnit("METER"),
}

Finally, call client.Query providing variables:

err := client.Query(context.Background(), &q, variables)
if err != nil {
	// Handle error.
}

Inline Fragments

Some GraphQL queries contain inline fragments. You can use the graphql struct field tag to express them.

For example, to make the following GraphQL query:

{
	hero(episode: "JEDI") {
		name
		... on Droid {
			primaryFunction
		}
		... on Human {
			height
		}
	}
}

You can define this variable:

var q struct {
	Hero struct {
		Name  string
		Droid struct {
			PrimaryFunction string
		} `graphql:"... on Droid"`
		Human struct {
			Height float64
		} `graphql:"... on Human"`
	} `graphql:"hero(episode: \"JEDI\")"`
}

Alternatively, you can define the struct types corresponding to inline fragments, and use them as embedded fields in your query:

type (
	DroidFragment struct {
		PrimaryFunction string
	}
	HumanFragment struct {
		Height float64
	}
)

var q struct {
	Hero struct {
		Name          string
		DroidFragment `graphql:"... on Droid"`
		HumanFragment `graphql:"... on Human"`
	} `graphql:"hero(episode: \"JEDI\")"`
}

Then call client.Query:

err := client.Query(context.Background(), &q, nil)
if err != nil {
	// Handle error.
}
fmt.Println(q.Hero.Name)
fmt.Println(q.Hero.PrimaryFunction)
fmt.Println(q.Hero.Height)

// Output:
// R2-D2
// Astromech
// 0

Mutations

Mutations often require information that you can only find out by performing a query first. Let's suppose you've already done that.

For example, to make the following GraphQL mutation:

mutation($ep: Episode!, $review: ReviewInput!) {
	createReview(episode: $ep, review: $review) {
		stars
		commentary
	}
}
variables {
	"ep": "JEDI",
	"review": {
		"stars": 5,
		"commentary": "This is a great movie!"
	}
}

You can define:

var m struct {
	CreateReview struct {
		Stars      int
		Commentary string
	} `graphql:"createReview(episode: $ep, review: $review)"`
}
variables := map[string]interface{}{
	"ep": starwars.Episode("JEDI"),
	"review": starwars.ReviewInput{
		Stars:      5,
		Commentary: "This is a great movie!",
	},
}

Then call client.Mutate:

err := client.Mutate(context.Background(), &m, variables)
if err != nil {
	// Handle error.
}
fmt.Printf("Created a %v star review: %v\n", m.CreateReview.Stars, m.CreateReview.Commentary)

// Output:
// Created a 5 star review: This is a great movie!

Directories

Path	Synopsis
example/graphqldev	graphqldev is a test program currently being used for developing graphql package.
ident	Package ident provides functions for parsing and converting identifier names between various naming convention.
internal/jsonutil	Package jsonutil provides a function for decoding JSON into a GraphQL query data structure.

License

• MIT License