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transport.go
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transport.go
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// Copyright (c) Mainflux
// SPDX-License-Identifier: Apache-2.0
package api
import (
"context"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"regexp"
"strings"
"time"
"github.com/mainflux/mainflux/pkg/errors"
"github.com/go-zoo/bone"
"github.com/mainflux/mainflux"
"github.com/mainflux/mainflux/coap"
log "github.com/mainflux/mainflux/logger"
"github.com/mainflux/mainflux/pkg/messaging"
"github.com/plgd-dev/go-coap/v2/message"
"github.com/plgd-dev/go-coap/v2/message/codes"
"github.com/plgd-dev/go-coap/v2/mux"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
const (
protocol = "coap"
authQuery = "auth"
startObserve = 0 // observe option value that indicates start of observation
)
var channelPartRegExp = regexp.MustCompile(`^/channels/([\w\-]+)/messages(/[^?]*)?(\?.*)?$`)
const (
numGroups = 3 // entire expression + channel group + subtopic group
channelGroup = 2 // channel group is second in channel regexp
)
var (
errMalformedSubtopic = errors.New("malformed subtopic")
errBadOptions = errors.New("bad options")
)
var (
logger log.Logger
service coap.Service
)
// MakeHandler returns a HTTP handler for API endpoints.
func MakeHTTPHandler() http.Handler {
b := bone.New()
b.GetFunc("/health", mainflux.Health(protocol))
b.Handle("/metrics", promhttp.Handler())
return b
}
// MakeCoAPHandler creates handler for CoAP messages.
func MakeCoAPHandler(svc coap.Service, l log.Logger) mux.HandlerFunc {
logger = l
service = svc
return handler
}
func sendResp(w mux.ResponseWriter, resp *message.Message) {
if err := w.Client().WriteMessage(resp); err != nil {
logger.Warn(fmt.Sprintf("Can't set response: %s", err))
}
}
func handler(w mux.ResponseWriter, m *mux.Message) {
resp := message.Message{
Code: codes.Content,
Token: m.Token,
Context: m.Context,
Options: make(message.Options, 0, 16),
}
msg, err := decodeMessage(m)
if err != nil {
logger.Warn(fmt.Sprintf("Error decoding message: %s", err))
resp.Code = codes.BadRequest
sendResp(w, &resp)
return
}
key, err := parseKey(m)
if err != nil {
logger.Warn(fmt.Sprintf("Error parsing auth: %s", err))
resp.Code = codes.Unauthorized
sendResp(w, &resp)
return
}
switch m.Code {
case codes.GET:
err = handleGet(m, w.Client(), msg, key)
case codes.POST:
err = service.Publish(context.Background(), key, msg)
default:
err = errors.ErrNotFound
}
if err != nil {
switch {
case err == errBadOptions:
resp.Code = codes.BadOption
case err == errors.ErrNotFound:
resp.Code = codes.NotFound
case errors.Contains(err, errors.ErrAuthorization),
errors.Contains(err, errors.ErrAuthentication):
resp.Code = codes.Unauthorized
default:
resp.Code = codes.InternalServerError
}
sendResp(w, &resp)
}
}
func handleGet(m *mux.Message, c mux.Client, msg messaging.Message, key string) error {
var obs uint32
obs, err := m.Options.Observe()
if err != nil {
logger.Warn(fmt.Sprintf("Error reading observe option: %s", err))
return errBadOptions
}
if obs == startObserve {
c := coap.NewClient(c, m.Token, logger)
return service.Subscribe(context.Background(), key, msg.Channel, msg.Subtopic, c)
}
return service.Unsubscribe(context.Background(), key, msg.Channel, msg.Subtopic, m.Token.String())
}
func decodeMessage(msg *mux.Message) (messaging.Message, error) {
if msg.Options == nil {
return messaging.Message{}, errBadOptions
}
path, err := msg.Options.Path()
if err != nil {
return messaging.Message{}, err
}
channelParts := channelPartRegExp.FindStringSubmatch(path)
if len(channelParts) < numGroups {
return messaging.Message{}, errMalformedSubtopic
}
st, err := parseSubtopic(channelParts[channelGroup])
if err != nil {
return messaging.Message{}, err
}
ret := messaging.Message{
Protocol: protocol,
Channel: channelParts[1],
Subtopic: st,
Payload: []byte{},
Created: time.Now().UnixNano(),
}
if msg.Body != nil {
buff, err := ioutil.ReadAll(msg.Body)
if err != nil {
return ret, err
}
ret.Payload = buff
}
return ret, nil
}
func parseKey(msg *mux.Message) (string, error) {
if obs, _ := msg.Options.Observe(); obs != 0 && msg.Code == codes.GET {
return "", nil
}
authKey, err := msg.Options.GetString(message.URIQuery)
if err != nil {
return "", err
}
vars := strings.Split(authKey, "=")
if len(vars) != 2 || vars[0] != authQuery {
return "", errors.ErrAuthorization
}
return vars[1], nil
}
func parseSubtopic(subtopic string) (string, error) {
if subtopic == "" {
return subtopic, nil
}
subtopic, err := url.QueryUnescape(subtopic)
if err != nil {
return "", errMalformedSubtopic
}
subtopic = strings.ReplaceAll(subtopic, "/", ".")
elems := strings.Split(subtopic, ".")
filteredElems := []string{}
for _, elem := range elems {
if elem == "" {
continue
}
if len(elem) > 1 && (strings.Contains(elem, "*") || strings.Contains(elem, ">")) {
return "", errMalformedSubtopic
}
filteredElems = append(filteredElems, elem)
}
subtopic = strings.Join(filteredElems, ".")
return subtopic, nil
}