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Merge pull request #91 from graphql-go/examples-todo
Adds todo example.
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# Go GraphQL ToDo example | ||
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An example that consists of basic core GraphQL queries and mutations. | ||
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To run the example navigate to the example directory by using your shell of choice. | ||
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``` | ||
cd examples/todo | ||
``` | ||
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Run the example, it will spawn a GraphQL HTTP endpoint | ||
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``` | ||
go run main.go | ||
``` | ||
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Execute queries via shell. | ||
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``` | ||
// To get single ToDo item by ID | ||
curl -g 'http://localhost:8080/graphql?query={todo(id:"b"){id,text,done}}' | ||
// To create a ToDo item | ||
curl -g 'http://localhost:8080/graphql?query=mutation+_{createTodo(text:"My+new+todo"){id,text,done}}' | ||
// To get a list of ToDo items | ||
curl -g 'http://localhost:8080/graphql?query={todoList{id,text,done}}' | ||
``` |
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package main | ||
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import ( | ||
"encoding/json" | ||
"fmt" | ||
"math/rand" | ||
"net/http" | ||
"time" | ||
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"github.com/graphql-go/graphql" | ||
) | ||
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type Todo struct { | ||
ID string `json:"id"` | ||
Text string `json:"text"` | ||
Done bool `json:"done"` | ||
} | ||
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var TodoList []Todo | ||
var letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ") | ||
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func RandStringRunes(n int) string { | ||
b := make([]rune, n) | ||
for i := range b { | ||
b[i] = letterRunes[rand.Intn(len(letterRunes))] | ||
} | ||
return string(b) | ||
} | ||
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func init() { | ||
todo1 := Todo{ID: "a", Text: "A todo not to forget", Done: false} | ||
todo2 := Todo{ID: "b", Text: "This is the most important", Done: false} | ||
todo3 := Todo{ID: "c", Text: "Please do this or else", Done: false} | ||
TodoList = append(TodoList, todo1, todo2, todo3) | ||
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rand.Seed(time.Now().UnixNano()) | ||
} | ||
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// define custom GraphQL ObjectType `todoType` for our Golang struct `Todo` | ||
// Note that | ||
// - the fields in our todoType maps with the json tags for the fields in our struct | ||
// - the field type matches the field type in our struct | ||
var todoType = graphql.NewObject(graphql.ObjectConfig{ | ||
Name: "Todo", | ||
Fields: graphql.Fields{ | ||
"id": &graphql.Field{ | ||
Type: graphql.String, | ||
}, | ||
"text": &graphql.Field{ | ||
Type: graphql.String, | ||
}, | ||
"done": &graphql.Field{ | ||
Type: graphql.Boolean, | ||
}, | ||
}, | ||
}) | ||
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// root mutation | ||
var rootMutation = graphql.NewObject(graphql.ObjectConfig{ | ||
Name: "RootMutation", | ||
Fields: graphql.Fields{ | ||
/* | ||
curl -g 'http://localhost:8080/graphql?query=mutation+_{createTodo(text:"My+new+todo"){id,text,done}}' | ||
*/ | ||
"createTodo": &graphql.Field{ | ||
Type: todoType, // the return type for this field | ||
Args: graphql.FieldConfigArgument{ | ||
"text": &graphql.ArgumentConfig{ | ||
Type: graphql.NewNonNull(graphql.String), | ||
}, | ||
}, | ||
Resolve: func(params graphql.ResolveParams) (interface{}, error) { | ||
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// marshall and cast the argument value | ||
text, _ := params.Args["text"].(string) | ||
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// figure out new id | ||
newId := RandStringRunes(8) | ||
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// perform mutation operation here | ||
// for e.g. create a Todo and save to DB. | ||
newTodo := Todo{ | ||
ID: newId, | ||
Text: text, | ||
Done: false, | ||
} | ||
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TodoList = append(TodoList, newTodo) | ||
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// return the new Todo object that we supposedly save to DB | ||
// Note here that | ||
// - we are returning a `Todo` struct instance here | ||
// - we previously specified the return Type to be `todoType` | ||
// - `Todo` struct maps to `todoType`, as defined in `todoType` ObjectConfig` | ||
return newTodo, nil | ||
}, | ||
}, | ||
}, | ||
}) | ||
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// root query | ||
// we just define a trivial example here, since root query is required. | ||
// Test with curl | ||
// curl -g 'http://localhost:8080/graphql?query={lastTodo{id,text,done}}' | ||
var rootQuery = graphql.NewObject(graphql.ObjectConfig{ | ||
Name: "RootQuery", | ||
Fields: graphql.Fields{ | ||
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/* | ||
curl -g 'http://localhost:8080/graphql?query={todo(id:"b"){id,text,done}}' | ||
*/ | ||
"todo": &graphql.Field{ | ||
Type: todoType, | ||
Args: graphql.FieldConfigArgument{ | ||
"id": &graphql.ArgumentConfig{ | ||
Type: graphql.String, | ||
}, | ||
}, | ||
Resolve: func(params graphql.ResolveParams) (interface{}, error) { | ||
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idQuery, isOK := params.Args["id"].(string) | ||
if isOK { | ||
// Search for el with id | ||
for _, todo := range TodoList { | ||
if todo.ID == idQuery { | ||
return todo, nil | ||
} | ||
} | ||
} | ||
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return Todo{}, nil | ||
}, | ||
}, | ||
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"lastTodo": &graphql.Field{ | ||
Type: todoType, | ||
Description: "Last todo added", | ||
Resolve: func(params graphql.ResolveParams) (interface{}, error) { | ||
return TodoList[len(TodoList)-1], nil | ||
}, | ||
}, | ||
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/* | ||
curl -g 'http://localhost:8080/graphql?query={todoList{id,text,done}}' | ||
*/ | ||
"todoList": &graphql.Field{ | ||
Type: graphql.NewList(todoType), | ||
Description: "List of todos", | ||
Resolve: func(p graphql.ResolveParams) (interface{}, error) { | ||
return TodoList, nil | ||
}, | ||
}, | ||
}, | ||
}) | ||
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// define schema, with our rootQuery and rootMutation | ||
var schema, _ = graphql.NewSchema(graphql.SchemaConfig{ | ||
Query: rootQuery, | ||
Mutation: rootMutation, | ||
}) | ||
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func executeQuery(query string, schema graphql.Schema) *graphql.Result { | ||
result := graphql.Do(graphql.Params{ | ||
Schema: schema, | ||
RequestString: query, | ||
}) | ||
if len(result.Errors) > 0 { | ||
fmt.Printf("wrong result, unexpected errors: %v", result.Errors) | ||
} | ||
return result | ||
} | ||
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func main() { | ||
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http.HandleFunc("/graphql", func(w http.ResponseWriter, r *http.Request) { | ||
result := executeQuery(r.URL.Query()["query"][0], schema) | ||
json.NewEncoder(w).Encode(result) | ||
}) | ||
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fmt.Println("Now server is running on port 8080") | ||
fmt.Println("Get single todo: curl -g 'http://localhost:8080/graphql?query={todo(id:\"b\"){id,text,done}}'") | ||
fmt.Println("Create new todo: curl -g 'http://localhost:8080/graphql?query=mutation+_{createTodo(text:\"My+new+todo\"){id,text,done}}'") | ||
fmt.Println("Load todo list: curl -g 'http://localhost:8080/graphql?query={todoList{id,text,done}}'") | ||
http.ListenAndServe(":8080", nil) | ||
} |