Add executable examples (graph-gophers#567)

Author: pavelnikolov

examples_test.go

@@ -0,0 +1,154 @@
+package graphql_test
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+
+	"github.com/graph-gophers/graphql-go"
+	"github.com/graph-gophers/graphql-go/example/starwars"
+)
+
+type Resolver struct {
+	post *Post
+}
+
+func (r *Resolver) Post() *Post {
+	return r.post
+}
+
+type Post struct {
+	id    graphql.ID
+	title string
+}
+
+func (p *Post) ID() graphql.ID {
+	return p.id
+}
+
+func (p *Post) Title() string {
+	return p.title
+}
+
+func ExampleID() {
+	schemaString := `
+		schema {
+			query: Query
+		}
+
+		type Query {
+			post: Post!
+		}
+
+		type Post {
+			id: ID!
+			title: String!
+		}
+	`
+
+	resolver := &Resolver{
+		post: &Post{
+			id:    graphql.ID("5"),
+			title: "title",
+		},
+	}
+
+	schema := graphql.MustParseSchema(schemaString, resolver)
+
+	query := `
+		query {
+			post {
+				id
+				title
+			}
+		}
+	`
+
+	res := schema.Exec(context.Background(), query, "", nil)
+
+	enc := json.NewEncoder(os.Stdout)
+	enc.SetIndent("", "  ")
+	err := enc.Encode(res)
+	if err != nil {
+		panic(err)
+	}
+	// output:
+	// {
+	//   "data": {
+	//     "post": {
+	//       "id": "5",
+	//       "title": "title"
+	//     }
+	//   }
+	// }
+}
+
+func ExampleMaxDepth() {
+	schema := graphql.MustParseSchema(starwars.Schema, &starwars.Resolver{}, graphql.MaxDepth(3))
+
+	// this query has a depth of 4
+	query := `
+	  query {
+	    hero(episode:EMPIRE) { # level 1
+	      name                 # level 2
+	      friends { 
+	        name               # level 3
+	        friends { 
+	          id               # level 4 - this would exceed the max depth
+	        }
+	      }
+	    }
+	  }`
+
+	res := schema.Exec(context.Background(), query, "", nil)
+
+	enc := json.NewEncoder(os.Stdout)
+	enc.SetIndent("", "  ")
+	err := enc.Encode(res)
+	if err != nil {
+		panic(err)
+	}
+	// output:
+	// {
+	//   "errors": [
+	//     {
+	//       "message": "Field \"id\" has depth 4 that exceeds max depth 3",
+	//       "locations": [
+	//         {
+	//           "line": 8,
+	//           "column": 12
+	//         }
+	//       ]
+	//     }
+	//   ]
+	// }
+}
+
+func ExampleMaxQueryLength() {
+	schema := graphql.MustParseSchema(starwars.Schema, &starwars.Resolver{}, graphql.MaxQueryLength(50))
+
+	// this query has a length of 53
+	query := `{
+	  hero(episode:EMPIRE) {
+	    id
+	    name
+	  }
+	}`
+
+	res := schema.Exec(context.Background(), query, "", nil)
+
+	enc := json.NewEncoder(os.Stdout)
+	enc.SetIndent("", "  ")
+	err := enc.Encode(res)
+	if err != nil {
+		panic(err)
+	}
+	// output:
+	// {
+	//   "errors": [
+	//     {
+	//       "message": "query length 53 exceeds the maximum allowed query length of 50 bytes"
+	//     }
+	//   ]
+	// }
+}