Mainflux.mainflux/manager/api/transport.go

package api

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"net/url"
	"strconv"

	kithttp "github.com/go-kit/kit/transport/http"
	"github.com/go-zoo/bone"
	"github.com/mainflux/mainflux"
	"github.com/mainflux/mainflux/manager"
	"github.com/prometheus/client_golang/prometheus/promhttp"
)

var errUnsupportedContentType = errors.New("unsupported content type")
var errInvalidQueryParams = errors.New("invalid query params")

// MakeHandler returns a HTTP handler for API endpoints.
func MakeHandler(svc manager.Service) http.Handler {
	opts := []kithttp.ServerOption{
		kithttp.ServerErrorEncoder(encodeError),
	}

	r := bone.New()

	r.Post("/users", kithttp.NewServer(
		registrationEndpoint(svc),
		decodeCredentials,
		encodeResponse,
		opts...,
	))

	r.Post("/tokens", kithttp.NewServer(
		loginEndpoint(svc),
		decodeCredentials,
		encodeResponse,
		opts...,
	))

	r.Post("/clients", kithttp.NewServer(
		addClientEndpoint(svc),
		decodeClientCreation,
		encodeResponse,
		opts...,
	))

	r.Put("/clients/:id", kithttp.NewServer(
		updateClientEndpoint(svc),
		decodeClientUpdate,
		encodeResponse,
		opts...,
	))

	r.Delete("/clients/:id", kithttp.NewServer(
		removeClientEndpoint(svc),
		decodeView,
		encodeResponse,
		opts...,
	))

	r.Get("/clients/:id", kithttp.NewServer(
		viewClientEndpoint(svc),
		decodeView,
		encodeResponse,
		opts...,
	))

	r.Get("/clients", kithttp.NewServer(
		listClientsEndpoint(svc),
		decodeList,
		encodeResponse,
		opts...,
	))

	r.Post("/channels", kithttp.NewServer(
		createChannelEndpoint(svc),
		decodeChannelCreation,
		encodeResponse,
		opts...,
	))

	r.Put("/channels/:id", kithttp.NewServer(
		updateChannelEndpoint(svc),
		decodeChannelUpdate,
		encodeResponse,
		opts...,
	))

	r.Delete("/channels/:id", kithttp.NewServer(
		removeChannelEndpoint(svc),
		decodeView,
		encodeResponse,
		opts...,
	))

	r.Get("/channels/:id", kithttp.NewServer(
		viewChannelEndpoint(svc),
		decodeView,
		encodeResponse,
		opts...,
	))

	r.Get("/channels", kithttp.NewServer(
		listChannelsEndpoint(svc),
		decodeList,
		encodeResponse,
		opts...,
	))

	r.Put("/channels/:chanId/clients/:clientId", kithttp.NewServer(
		connectEndpoint(svc),
		decodeConnection,
		encodeResponse,
		opts...,
	))

	r.Delete("/channels/:chanId/clients/:clientId", kithttp.NewServer(
		disconnectEndpoint(svc),
		decodeConnection,
		encodeResponse,
		opts...,
	))

	r.Get("/access-grant", kithttp.NewServer(
		identityEndpoint(svc),
		decodeIdentity,
		encodeResponse,
		opts...,
	))

	r.Get("/channels/:id/access-grant", kithttp.NewServer(
		canAccessEndpoint(svc),
		decodeView,
		encodeResponse,
		opts...,
	))

	r.GetFunc("/version", mainflux.Version())
	r.Handle("/metrics", promhttp.Handler())

	return r
}

func decodeIdentity(_ context.Context, r *http.Request) (interface{}, error) {
	req := identityReq{
		key: r.Header.Get("Authorization"),
	}

	return req, nil
}

func decodeCredentials(_ context.Context, r *http.Request) (interface{}, error) {
	if r.Header.Get("Content-Type") != contentType {
		return nil, errUnsupportedContentType
	}

	var user manager.User
	if err := json.NewDecoder(r.Body).Decode(&user); err != nil {
		return nil, err
	}

	return userReq{user}, nil
}

func decodeClientCreation(_ context.Context, r *http.Request) (interface{}, error) {
	if r.Header.Get("Content-Type") != contentType {
		return nil, errUnsupportedContentType
	}

	var client manager.Client
	if err := json.NewDecoder(r.Body).Decode(&client); err != nil {
		return nil, err
	}

	req := addClientReq{
		key:    r.Header.Get("Authorization"),
		client: client,
	}

	return req, nil
}

func decodeClientUpdate(_ context.Context, r *http.Request) (interface{}, error) {
	if r.Header.Get("Content-Type") != contentType {
		return nil, errUnsupportedContentType
	}

	var client manager.Client
	if err := json.NewDecoder(r.Body).Decode(&client); err != nil {
		return nil, err
	}

	req := updateClientReq{
		key:    r.Header.Get("Authorization"),
		id:     bone.GetValue(r, "id"),
		client: client,
	}

	return req, nil
}

func decodeChannelCreation(_ context.Context, r *http.Request) (interface{}, error) {
	if r.Header.Get("Content-Type") != contentType {
		return nil, errUnsupportedContentType
	}

	var channel manager.Channel
	if err := json.NewDecoder(r.Body).Decode(&channel); err != nil {
		return nil, err
	}

	req := createChannelReq{
		key:     r.Header.Get("Authorization"),
		channel: channel,
	}

	return req, nil
}

func decodeChannelUpdate(_ context.Context, r *http.Request) (interface{}, error) {
	if r.Header.Get("Content-Type") != contentType {
		return nil, errUnsupportedContentType
	}

	var channel manager.Channel
	if err := json.NewDecoder(r.Body).Decode(&channel); err != nil {
		return nil, err
	}

	req := updateChannelReq{
		key:     r.Header.Get("Authorization"),
		id:      bone.GetValue(r, "id"),
		channel: channel,
	}

	return req, nil
}

func decodeView(_ context.Context, r *http.Request) (interface{}, error) {
	req := viewResourceReq{
		key: r.Header.Get("Authorization"),
		id:  bone.GetValue(r, "id"),
	}

	return req, nil
}

func decodeList(_ context.Context, r *http.Request) (interface{}, error) {

	q, err := url.ParseQuery(r.URL.RawQuery)
	if err != nil {
		return nil, err
	}
	offset := 0
	limit := 10

	n := len(q)
	if n == 0 {
		req := listResourcesReq{
			key:    r.Header.Get("Authorization"),
			offset: offset,
			limit:  limit,
		}
		return req, nil
	}

	if n > 2 {
		return nil, errInvalidQueryParams
	}

	off, lmt := q["offset"], q["limit"]

	if len(off) > 1 || len(lmt) > 1 {
		return nil, errInvalidQueryParams
	}

	if len(off) == 1 {
		offset, err = strconv.Atoi(off[0])
		if err != nil {
			return nil, err
		}
	}

	if len(lmt) == 1 {
		limit, err = strconv.Atoi(lmt[0])
		if err != nil {
			return nil, err
		}
	}
	req := listResourcesReq{
		key:    r.Header.Get("Authorization"),
		offset: offset,
		limit:  limit,
	}

	return req, nil
}

func decodeConnection(_ context.Context, r *http.Request) (interface{}, error) {
	req := connectionReq{
		key:      r.Header.Get("Authorization"),
		chanId:   bone.GetValue(r, "chanId"),
		clientId: bone.GetValue(r, "clientId"),
	}

	return req, nil
}

func encodeResponse(_ context.Context, w http.ResponseWriter, response interface{}) error {
	w.Header().Set("Content-Type", contentType)

	if ar, ok := response.(apiRes); ok {
		for k, v := range ar.headers() {
			w.Header().Set(k, v)
		}

		w.WriteHeader(ar.code())

		if ar.empty() {
			return nil
		}
	}

	return json.NewEncoder(w).Encode(response)
}

func encodeError(_ context.Context, err error, w http.ResponseWriter) {
	w.Header().Set("Content-Type", contentType)

	switch err {
	case manager.ErrMalformedEntity:
		w.WriteHeader(http.StatusBadRequest)
	case manager.ErrUnauthorizedAccess:
		w.WriteHeader(http.StatusForbidden)
	case manager.ErrNotFound:
		w.WriteHeader(http.StatusNotFound)
	case manager.ErrConflict:
		w.WriteHeader(http.StatusConflict)
	case errUnsupportedContentType:
		w.WriteHeader(http.StatusUnsupportedMediaType)
	case io.ErrUnexpectedEOF:
		w.WriteHeader(http.StatusBadRequest)
	case io.EOF:
		w.WriteHeader(http.StatusBadRequest)
	default:
		switch err.(type) {
		case *json.SyntaxError:
			w.WriteHeader(http.StatusBadRequest)
		case *json.UnmarshalTypeError:
			w.WriteHeader(http.StatusBadRequest)
		default:
			w.WriteHeader(http.StatusInternalServerError)
		}
	}
}