graphql
Package graphql provides a GraphQL client implementation.
For more information, see package github.com/shurcooL/githubv4, which is a specialized version targeting GitHub GraphQL API v4. That package is driving the feature development.
Installation
go get github.com/shurcooL/graphqlUsage
Construct a GraphQL client, specifying the GraphQL server URL. Then, you can use it to make GraphQL queries and mutations.
client := graphql.NewClient("https://example.com/graphql", nil)
// Use client...Authentication
Some GraphQL servers may require authentication. The graphql package does not directly handle authentication. Instead, when creating a new client, you're expected to pass an http.Client that performs authentication. The easiest and recommended way to do this is to use the golang.org/x/oauth2 package. You'll need an OAuth token with the right scopes. Then:
import "golang.org/x/oauth2"
func main() {
src := oauth2.StaticTokenSource(
&oauth2.Token{AccessToken: os.Getenv("GRAPHQL_TOKEN")},
)
httpClient := oauth2.NewClient(context.Background(), src)
client := graphql.NewClient("https://example.com/graphql", httpClient)
// Use client...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 graphql.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 SkywalkerArguments 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 graphql.String
Height graphql.Float `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
// 1.72However, 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 graphql.String
Height graphql.Float `graphql:"height(unit: $unit)"`
} `graphql:"human(id: $id)"`
}Then, define a variables map with their values:
variables := map[string]any{
"id": graphql.ID(id),
"unit": starwars.LengthUnit("METER"),
}Finally, call client.Query providing variables:
err := client.Query(context.Background(), &q, variables)
if err != nil {
// Handle error.
}Inline Fragments
Some GraphQL queries contain inline fragments. You can use the graphql struct field tag to express them.
For example, to make the following GraphQL query:
{
hero(episode: "JEDI") {
name
... on Droid {
primaryFunction
}
... on Human {
height
}
}
}You can define this variable:
var q struct {
Hero struct {
Name graphql.String
Droid struct {
PrimaryFunction graphql.String
} `graphql:"... on Droid"`
Human struct {
Height graphql.Float
} `graphql:"... on Human"`
} `graphql:"hero(episode: \"JEDI\")"`
}Alternatively, you can define the struct types corresponding to inline fragments, and use them as embedded fields in your query:
type (
DroidFragment struct {
PrimaryFunction graphql.String
}
HumanFragment struct {
Height graphql.Float
}
)
var q struct {
Hero struct {
Name graphql.String
DroidFragment `graphql:"... on Droid"`
HumanFragment `graphql:"... on Human"`
} `graphql:"hero(episode: \"JEDI\")"`
}Then call client.Query:
err := client.Query(context.Background(), &q, nil)
if err != nil {
// Handle error.
}
fmt.Println(q.Hero.Name)
fmt.Println(q.Hero.PrimaryFunction)
fmt.Println(q.Hero.Height)
// Output:
// R2-D2
// Astromech
// 0Mutations
Mutations often require information that you can only find out by performing a query first. Let's suppose you've already done that.
For example, to make the following GraphQL mutation:
mutation($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 graphql.Int
Commentary graphql.String
} `graphql:"createReview(episode: $ep, review: $review)"`
}
variables := map[string]any{
"ep": starwars.Episode("JEDI"),
"review": starwars.ReviewInput{
Stars: graphql.Int(5),
Commentary: graphql.String("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 |
|---|---|
| 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. |