/
handlers.go
262 lines (207 loc) · 5.87 KB
/
handlers.go
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package main
import (
"fmt"
"io"
"io/ioutil"
"mime"
"net/http"
"github.com/gobridge/gopherbot/workqueue"
"github.com/rs/zerolog"
"github.com/valyala/fastjson"
)
const maxBodySize = 2 * 1024 * 1024 // 2 MB
type handler struct {
l *zerolog.Logger
q workqueue.Q
}
func (s *handler) handleNotFound(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusNotFound)
}
func (s *handler) handleRUOK(w http.ResponseWriter, r *http.Request) {
_, _ = io.WriteString(w, "imok")
}
func getJSONString(document *fastjson.Value, key string) (string, error) {
if !document.Exists(key) {
return "", fmt.Errorf("failed to get field %s: key does not exist", key)
}
v, err := document.Get(key).StringBytes()
if err != nil {
return "", fmt.Errorf("failed to get field %s: %w", key, err)
}
s := make([]byte, len(v))
copy(s, v)
return string(s), nil
}
func getJSONInt64(document *fastjson.Value, key string) (int64, error) {
if !document.Exists(key) {
return -1, fmt.Errorf("failed to get field %s: key does not exist", key)
}
v, err := document.Get(key).Int64()
if err != nil {
return -1, fmt.Errorf("failed to get field %s: %w", key, err)
}
return v, nil
}
func requestValues(document *fastjson.Value) (eventType, eventID string, eventTimestamp int64, err error) {
eventType, err = getJSONString(document, "type")
if err != nil {
return "", "", 0, fmt.Errorf("failed to get type field: %w", err)
}
if eventType == "url_verification" {
return
}
eventID, err = getJSONString(document, "event_id")
if err != nil {
return "", "", 0, fmt.Errorf("failed to get event_id field")
}
eventTimestamp, err = getJSONInt64(document, "event_time")
if err != nil {
return "", "", 0, fmt.Errorf("failed to get event_time field: %w", err)
}
return
}
func urlVerification(w http.ResponseWriter, r *http.Request, document *fastjson.Value, logger zerolog.Logger) {
challenge, err := getJSONString(document, "challenge")
if err != nil {
logger.Error().
Err(err).
Msg("failed URL verification")
w.WriteHeader(http.StatusUnprocessableEntity)
return
}
w.Header().Set("Content-Type", "plain/text")
fmt.Fprint(w, challenge)
}
func wqEventType(event *fastjson.Value) (workqueue.Event, error) {
eventType, err := getJSONString(event, "type")
if err != nil {
return "", fmt.Errorf("failed to get type field: %w", err)
}
switch eventType {
case "message":
if !event.Exists("channel_type") {
return workqueue.SlackMessageChannel, nil
}
ct, _ := getJSONString(event, "channel_type")
switch ct {
case "app_home":
return workqueue.SlackMessageAppHome, nil
case "channel":
return workqueue.SlackMessageChannel, nil
case "group":
return workqueue.SlackMessageGroup, nil
case "im":
return workqueue.SlackMessageIM, nil
case "mpim":
return workqueue.SlackMessageMPIM, nil
default:
return workqueue.SlackMessageChannel, nil
}
case "team_join":
return workqueue.SlackTeamJoin, nil
case "member_joined_channel":
return workqueue.SlackChannelJoin, nil
default:
return "", fmt.Errorf("unknown type %s", eventType)
}
}
func (s *handler) handleSlackEvent(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
lc := s.l.With().Str("context", "event_handler")
rid, ok := ctxRequestID(ctx)
if ok {
lc = lc.Str("request_id", rid)
}
logger := lc.Logger()
if r.Method != http.MethodPost {
logger.Info().
Str("http_method", r.Method).
Msg("unexpected HTTP method")
w.Header().Set("Allow", http.MethodPost)
w.WriteHeader(http.StatusMethodNotAllowed)
return
}
mt, _, err := mime.ParseMediaType(r.Header.Get("Content-Type"))
if err != nil {
logger.Error().
Err(err).
Msg("failed to parse Content-Type")
w.Header().Set("Accept", "application/json; charset=utf-8")
w.WriteHeader(http.StatusBadRequest)
return
}
if mt != "application/json" {
logger.Error().
Str("content_type", mt).
Msg("content type was not JSON")
w.Header().Set("Accept", "application/json; charset=utf-8")
w.WriteHeader(http.StatusUnsupportedMediaType)
return
}
body, err := ioutil.ReadAll(io.LimitReader(r.Body, maxBodySize))
if err != nil {
logger.Error().
Err(err).
Msg("failed to read request body")
w.WriteHeader(http.StatusInternalServerError)
return
}
document, err := fastjson.ParseBytes(body)
if err != nil {
logger.Error().
Err(err).
Msg("failed to unmarshal JSON document")
w.WriteHeader(http.StatusUnprocessableEntity)
return
}
eventType, eventID, eventTimestamp, err := requestValues(document)
if err != nil {
logger.Error().
Err(err).
Msg("failed to parse values from JSON document")
w.WriteHeader(http.StatusUnprocessableEntity)
return
}
if eventType == "url_verification" {
urlVerification(w, r, document, logger)
return
}
logger = logger.With().Str("event_type", eventType).Str("event_id", eventID).Int64("event_time", eventTimestamp).Logger()
if !document.Exists("event") {
logger.Error().
Str("error", "event field does not exist").
Msg("failed to unmarshal JSON document")
w.WriteHeader(http.StatusUnprocessableEntity)
return
}
event := document.Get("event")
et, err := wqEventType(event)
if err != nil {
logger.Error().
Err(err).
Msg("failed to determine event type")
w.WriteHeader(http.StatusUnprocessableEntity)
return
}
obj, err := event.Object()
if err != nil {
logger.Error().
Err(err).
Msg("failed to convert event field to object")
w.WriteHeader(http.StatusUnprocessableEntity)
return
}
object := obj.MarshalTo(make([]byte, 0, 4*1024))
err = s.q.Publish(et, eventTimestamp, eventID, rid, object)
if err != nil {
logger.Error().Err(err).Msg("failed to publish event to workqueue")
w.WriteHeader(http.StatusInternalServerError)
return
}
logger.Debug().
Str("event_type", string(et)).
Int64("event_timestamp", eventTimestamp).
Str("event_id", eventID).
Bool("object_has_len", len(object) > 0).
Msg("published event")
}