JSON-API with Go and MongoDB: Final Part

main.go

package main

import (
	"encoding/json"
	"log"
	"net/http"
	"reflect"
	"time"

	"github.com/gorilla/context"
	"github.com/julienschmidt/httprouter"
	"github.com/justinas/alice"
	"gopkg.in/mgo.v2"
	"gopkg.in/mgo.v2/bson"
)

// Repo

type Tea struct {
	Id       bson.ObjectId `json:"id,omitempty" bson:"_id,omitempty"`
	Name     string        `json:"name"`
	Category string        `json:"category"`
}

type TeasCollection struct {
	Data []Tea `json:"data"`
}

type TeaResource struct {
	Data Tea `json:"data"`
}

type TeaRepo struct {
	coll *mgo.Collection
}

func (r *TeaRepo) All() (TeasCollection, error) {
	result := TeasCollection{[]Tea{}}
	err := r.coll.Find(nil).All(&result.Data)
	if err != nil {
		return result, err
	}

	return result, nil
}

func (r *TeaRepo) Find(id string) (TeaResource, error) {
	result := TeaResource{}
	err := r.coll.FindId(bson.ObjectIdHex(id)).One(&result.Data)
	if err != nil {
		return result, err
	}

	return result, nil
}

func (r *TeaRepo) Create(tea *Tea) error {
	id := bson.NewObjectId()
	_, err := r.coll.UpsertId(id, tea)
	if err != nil {
		return err
	}

	tea.Id = id

	return nil
}

func (r *TeaRepo) Update(tea *Tea) error {
	err := r.coll.UpdateId(tea.Id, tea)
	if err != nil {
		return err
	}

	return nil
}

func (r *TeaRepo) Delete(id string) error {
	err := r.coll.RemoveId(bson.ObjectIdHex(id))
	if err != nil {
		return err
	}

	return nil
}

// Errors

type Errors struct {
	Errors []*Error `json:"errors"`
}

type Error struct {
	Id     string `json:"id"`
	Status int    `json:"status"`
	Title  string `json:"title"`
	Detail string `json:"detail"`
}

func WriteError(w http.ResponseWriter, err *Error) {
	w.Header().Set("Content-Type", "application/vnd.api+json")
	w.WriteHeader(err.Status)
	json.NewEncoder(w).Encode(Errors{[]*Error{err}})
}

var (
	ErrBadRequest           = &Error{"bad_request", 400, "Bad request", "Request body is not well-formed. It must be JSON."}
	ErrNotAcceptable        = &Error{"not_acceptable", 406, "Not Acceptable", "Accept header must be set to 'application/vnd.api+json'."}
	ErrUnsupportedMediaType = &Error{"unsupported_media_type", 415, "Unsupported Media Type", "Content-Type header must be set to: 'application/vnd.api+json'."}
	ErrInternalServer       = &Error{"internal_server_error", 500, "Internal Server Error", "Something went wrong."}
)

// Middlewares

func recoverHandler(next http.Handler) http.Handler {
	fn := func(w http.ResponseWriter, r *http.Request) {
		defer func() {
			if err := recover(); err != nil {
				log.Printf("panic: %+v", err)
				WriteError(w, ErrInternalServer)
			}
		}()

		next.ServeHTTP(w, r)
	}

	return http.HandlerFunc(fn)
}

func loggingHandler(next http.Handler) http.Handler {
	fn := func(w http.ResponseWriter, r *http.Request) {
		t1 := time.Now()
		next.ServeHTTP(w, r)
		t2 := time.Now()
		log.Printf("[%s] %q %v\n", r.Method, r.URL.String(), t2.Sub(t1))
	}

	return http.HandlerFunc(fn)
}

func acceptHandler(next http.Handler) http.Handler {
	fn := func(w http.ResponseWriter, r *http.Request) {
		if r.Header.Get("Accept") != "application/vnd.api+json" {
			WriteError(w, ErrNotAcceptable)
			return
		}

		next.ServeHTTP(w, r)
	}

	return http.HandlerFunc(fn)
}

func contentTypeHandler(next http.Handler) http.Handler {
	fn := func(w http.ResponseWriter, r *http.Request) {
		if r.Header.Get("Content-Type") != "application/vnd.api+json" {
			WriteError(w, ErrUnsupportedMediaType)
			return
		}

		next.ServeHTTP(w, r)
	}

	return http.HandlerFunc(fn)
}

func bodyHandler(v interface{}) func(http.Handler) http.Handler {
	t := reflect.TypeOf(v)

	m := func(next http.Handler) http.Handler {
		fn := func(w http.ResponseWriter, r *http.Request) {
			val := reflect.New(t).Interface()
			err := json.NewDecoder(r.Body).Decode(val)

			if err != nil {
				WriteError(w, ErrBadRequest)
				return
			}

			if next != nil {
				context.Set(r, "body", val)
				next.ServeHTTP(w, r)
			}
		}

		return http.HandlerFunc(fn)
	}

	return m
}

// Main handlers

type appContext struct {
	db *mgo.Database
}

func (c *appContext) teasHandler(w http.ResponseWriter, r *http.Request) {
	repo := TeaRepo{c.db.C("teas")}
	teas, err := repo.All()
	if err != nil {
		panic(err)
	}

	w.Header().Set("Content-Type", "application/vnd.api+json")
	json.NewEncoder(w).Encode(teas)
}

func (c *appContext) teaHandler(w http.ResponseWriter, r *http.Request) {
	params := context.Get(r, "params").(httprouter.Params)
	repo := TeaRepo{c.db.C("teas")}
	tea, err := repo.Find(params.ByName("id"))
	if err != nil {
		panic(err)
	}

	w.Header().Set("Content-Type", "application/vnd.api+json")
	json.NewEncoder(w).Encode(tea)
}

func (c *appContext) createTeaHandler(w http.ResponseWriter, r *http.Request) {
	body := context.Get(r, "body").(*TeaResource)
	repo := TeaRepo{c.db.C("teas")}
	err := repo.Create(&body.Data)
	if err != nil {
		panic(err)
	}

	w.Header().Set("Content-Type", "application/vnd.api+json")
	w.WriteHeader(201)
	json.NewEncoder(w).Encode(body)
}

func (c *appContext) updateTeaHandler(w http.ResponseWriter, r *http.Request) {
	params := context.Get(r, "params").(httprouter.Params)
	body := context.Get(r, "body").(*TeaResource)
	body.Data.Id = bson.ObjectIdHex(params.ByName("id"))
	repo := TeaRepo{c.db.C("teas")}
	err := repo.Update(&body.Data)
	if err != nil {
		panic(err)
	}

	w.WriteHeader(204)
	w.Write([]byte("\n"))
}

func (c *appContext) deleteTeaHandler(w http.ResponseWriter, r *http.Request) {
	params := context.Get(r, "params").(httprouter.Params)
	repo := TeaRepo{c.db.C("teas")}
	err := repo.Delete(params.ByName("id"))
	if err != nil {
		panic(err)
	}

	w.WriteHeader(204)
	w.Write([]byte("\n"))
}

// Router

type router struct {
	*httprouter.Router
}

func (r *router) Get(path string, handler http.Handler) {
	r.GET(path, wrapHandler(handler))
}

func (r *router) Post(path string, handler http.Handler) {
	r.POST(path, wrapHandler(handler))
}

func (r *router) Put(path string, handler http.Handler) {
	r.PUT(path, wrapHandler(handler))
}

func (r *router) Delete(path string, handler http.Handler) {
	r.DELETE(path, wrapHandler(handler))
}

func NewRouter() *router {
	return &router{httprouter.New()}
}

func wrapHandler(h http.Handler) httprouter.Handle {
	return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
		context.Set(r, "params", ps)
		h.ServeHTTP(w, r)
	}
}

func main() {
	session, err := mgo.Dial("localhost")
	if err != nil {
		panic(err)
	}
	defer session.Close()
	session.SetMode(mgo.Monotonic, true)

	appC := appContext{session.DB("test")}
	commonHandlers := alice.New(context.ClearHandler, loggingHandler, recoverHandler, acceptHandler)
	router := NewRouter()
	router.Get("/teas/:id", commonHandlers.ThenFunc(appC.teaHandler))
	router.Put("/teas/:id", commonHandlers.Append(contentTypeHandler, bodyHandler(TeaResource{})).ThenFunc(appC.updateTeaHandler))
	router.Delete("/teas/:id", commonHandlers.ThenFunc(appC.deleteTeaHandler))
	router.Get("/teas", commonHandlers.ThenFunc(appC.teasHandler))
	router.Post("/teas", commonHandlers.Append(contentTypeHandler, bodyHandler(TeaResource{})).ThenFunc(appC.createTeaHandler))
	http.ListenAndServe(":8080", router)
}

Nice article. Thanks for writing it.

But I noticed there are a couple errors in your handlers. These two lines for example

https://gist.github.com/nmerouze/2e26a02d23c4c62173fd#file-main-go-L229-L230

Calling w.Header().Set(...) after calling w.WriteHeader(...) does not effect the response on the wire. The godoc for "net/http" is explicit about this.

Thanks for catching the problem @bmatsuo

Aren't you supposed to Copy the MongoDB session per request?

@nmerouze out of interest have you moved on to Elixir?

Thanks for sharing!

please help, i have probeleum how to save consume api result to mongo
my code its error !!!

package main

import (
"encoding/json"
"fmt"
"bytes"
"io/ioutil"
"net/http"
//"mydb"
"gopkg.in/mgo.v2"
"gopkg.in/mgo.v2/bson"
)

type Response struct {
StatusCode int json:"statusCode"
Headers map[string]string json:"headers"
Body string json:"body"
}

type Passanger struct {
bson.ObjectId json:"id" bson:"_id"
Title string json:"title" bson:"title"
Image string json:"image" bson:"image"
Price string json:"price" bson:"price"
Rating string json:"rating" bson:"rating"
}

//type Passanger struct {
//ID bson.ObjectId bson:"_id,omitempty"
//Title string
//Image string
//Price string
//Rating string
//}

var (
IsDrop = true
)

type Adapter func(http.Handler) http.Handler
func Adapt(h http.Handler, adapters ...Adapter) http.Handler {
for _, adapter := range adapters {
h = adapter(h)
}
return h
}

func main() {
fmt.Println("Starting the application...")

url := "http://" 
fmt.Println("URL:>", url)


jsonData := map[string]string{}
jsonValue, _ := json.Marshal(jsonData)
req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonValue))
req.Header.Set("Content-Type", "application/json")

// req.Header.Set("Authorization", strAuthorization)

client := &http.Client{}

response, err := client.Do(req)

var info map[string]interface{}
var infodata string

if err != nil {
    fmt.Printf("The HTTP request failed with error %s\n", err)
} else {
    data, _ := ioutil.ReadAll(response.Body)
	//defer response.Body.Close()
	//json.Unmarshal(data, &info)
    fmt.Printf("ALTEA Response: %s\n", string(data))	    		
}


fmt.Println("Save Data To Database...")


session, err := mgo.Dial("localhost")
if err != nil {
	panic(err)
}

defer session.Close()

session.SetMode(mgo.Monotonic, true)

// Drop Database
if IsDrop {
	err = session.DB("test").DropDatabase()
	if err != nil {
		panic(err)
	}
}

// Collection Passanger
c := session.DB("flylist").C("passanger")

// Index
index := mgo.Index{
	Key:        []string{"title", "image", "price", "rating"},
	Unique:     true,
	DropDups:   true,
	Background: true,
	Sparse:     true,
}

err = c.EnsureIndex(index)
if err != nil {
	panic(err)
}


// Insert Datas
infodata = info["data"].(map[string]interface{})["id"].(string)
//konversi:= []byte(info)
err = c.Insert(&Passanger{Title: string(infodata[0]), Image: string(infodata[1]), Price: string(infodata[2]), Rating: string(infodata[3])})
if err != nil {
	panic(err)

}

// Query All
var results []Passanger
err = c.Find(bson.M{"name": "Ale"}).Sort("-timestamp").All(&results)

if err != nil {
	panic(err)
}
fmt.Println("Results All: ", results)

}

Please help Me ,!

Please help , i have problem when try to save consume api result to mongodb, the code it's error

package main

import (
"encoding/json"
"fmt"
"bytes"
"io/ioutil"
"net/http"
//"mydb"
"gopkg.in/mgo.v2"
"gopkg.in/mgo.v2/bson"
)

type Response struct {
StatusCode int json:"statusCode"
Headers map[string]string json:"headers"
Body string json:"body"
}

type Passanger struct {
bson.ObjectId json:"id" bson:"_id"
Title string json:"title" bson:"title"
Image string json:"image" bson:"image"
Price string json:"price" bson:"price"
Rating string json:"rating" bson:"rating"
}

//type Passanger struct {
//ID bson.ObjectId bson:"_id,omitempty"
//Title string
//Image string
//Price string
//Rating string
//}

var (
IsDrop = true
)

type Adapter func(http.Handler) http.Handler
func Adapt(h http.Handler, adapters ...Adapter) http.Handler {
for _, adapter := range adapters {
h = adapter(h)
}
return h
}

func main() {
fmt.Println("Starting the application...")

url := "http://" 
fmt.Println("URL:>", url)


jsonData := map[string]string{}
jsonValue, _ := json.Marshal(jsonData)
req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonValue))
req.Header.Set("Content-Type", "application/json")

// req.Header.Set("Authorization", strAuthorization)

client := &http.Client{}

response, err := client.Do(req)

var info map[string]interface{}
var infodata string

if err != nil {
    fmt.Printf("The HTTP request failed with error %s\n", err)
} else {
    data, _ := ioutil.ReadAll(response.Body)
	//defer response.Body.Close()
	//json.Unmarshal(data, &info)
    fmt.Printf("ALTEA Response: %s\n", string(data))	    		
}


fmt.Println("Save Data To Database...")


session, err := mgo.Dial("localhost")
if err != nil {
	panic(err)
}

defer session.Close()

session.SetMode(mgo.Monotonic, true)

// Drop Database
if IsDrop {
	err = session.DB("test").DropDatabase()
	if err != nil {
		panic(err)
	}
}

// Collection Passanger
c := session.DB("flylist").C("passanger")

// Index
index := mgo.Index{
	Key:        []string{"title", "image", "price", "rating"},
	Unique:     true,
	DropDups:   true,
	Background: true,
	Sparse:     true,
}

err = c.EnsureIndex(index)
if err != nil {
	panic(err)
}


// Insert Datas
infodata = info["data"].(map[string]interface{})["id"].(string)
//konversi:= []byte(info)
err = c.Insert(&Passanger{Title: string(infodata[0]), Image: string(infodata[1]), Price: string(infodata[2]), Rating: string(infodata[3])})
if err != nil {
	panic(err)

}

// Query All
var results []Passanger
err = c.Find(bson.M{"name": "Ale"}).Sort("-timestamp").All(&results)

if err != nil {
	panic(err)
}
fmt.Println("Results All: ", results)

}

Please correct my code, thanks alot before