ntfy/server/server.go
2021-11-05 13:46:27 -04:00

434 lines
12 KiB
Go

package server
import (
"bytes"
"context"
"embed"
_ "embed" // required for go:embed
"encoding/json"
firebase "firebase.google.com/go"
"firebase.google.com/go/messaging"
"fmt"
"google.golang.org/api/option"
"heckel.io/ntfy/config"
"io"
"log"
"net"
"net/http"
"regexp"
"strconv"
"strings"
"sync"
"time"
)
// TODO add "max messages in a topic" limit
// TODO implement "since=<ID>"
// Server is the main server
type Server struct {
config *config.Config
topics map[string]*topic
visitors map[string]*visitor
firebase subscriber
messages int64
cache cache
mu sync.Mutex
}
// errHTTP is a generic HTTP error for any non-200 HTTP error
type errHTTP struct {
Code int
Status string
}
func (e errHTTP) Error() string {
return fmt.Sprintf("http: %s", e.Status)
}
const (
messageLimit = 512
)
var (
topicRegex = regexp.MustCompile(`^/[^/]+$`)
jsonRegex = regexp.MustCompile(`^/[^/]+/json$`)
sseRegex = regexp.MustCompile(`^/[^/]+/sse$`)
rawRegex = regexp.MustCompile(`^/[^/]+/raw$`)
staticRegex = regexp.MustCompile(`^/static/.+`)
//go:embed "index.html"
indexSource string
//go:embed static
webStaticFs embed.FS
errHTTPBadRequest = &errHTTP{http.StatusBadRequest, http.StatusText(http.StatusBadRequest)}
errHTTPNotFound = &errHTTP{http.StatusNotFound, http.StatusText(http.StatusNotFound)}
errHTTPTooManyRequests = &errHTTP{http.StatusTooManyRequests, http.StatusText(http.StatusTooManyRequests)}
)
func New(conf *config.Config) (*Server, error) {
var firebaseSubscriber subscriber
if conf.FirebaseKeyFile != "" {
var err error
firebaseSubscriber, err = createFirebaseSubscriber(conf)
if err != nil {
return nil, err
}
}
cache, err := createCache(conf)
if err != nil {
return nil, err
}
topics, err := cache.Topics()
if err != nil {
return nil, err
}
for _, t := range topics {
if firebaseSubscriber != nil {
t.Subscribe(firebaseSubscriber)
}
}
return &Server{
config: conf,
cache: cache,
firebase: firebaseSubscriber,
topics: topics,
visitors: make(map[string]*visitor),
}, nil
}
func createCache(conf *config.Config) (cache, error) {
if conf.CacheFile != "" {
return newSqliteCache(conf.CacheFile)
}
return newMemCache(), nil
}
func createFirebaseSubscriber(conf *config.Config) (subscriber, error) {
fb, err := firebase.NewApp(context.Background(), nil, option.WithCredentialsFile(conf.FirebaseKeyFile))
if err != nil {
return nil, err
}
msg, err := fb.Messaging(context.Background())
if err != nil {
return nil, err
}
return func(m *message) error {
_, err := msg.Send(context.Background(), &messaging.Message{
Topic: m.Topic,
Data: map[string]string{
"id": m.ID,
"time": fmt.Sprintf("%d", m.Time),
"event": m.Event,
"topic": m.Topic,
"message": m.Message,
},
})
return err
}, nil
}
func (s *Server) Run() error {
go func() {
ticker := time.NewTicker(s.config.ManagerInterval)
for {
<-ticker.C
s.updateStatsAndExpire()
}
}()
return s.listenAndServe()
}
func (s *Server) listenAndServe() error {
log.Printf("Listening on %s", s.config.ListenHTTP)
http.HandleFunc("/", s.handle)
return http.ListenAndServe(s.config.ListenHTTP, nil)
}
func (s *Server) handle(w http.ResponseWriter, r *http.Request) {
if err := s.handleInternal(w, r); err != nil {
if e, ok := err.(*errHTTP); ok {
s.fail(w, r, e.Code, e)
} else {
s.fail(w, r, http.StatusInternalServerError, err)
}
}
}
func (s *Server) handleInternal(w http.ResponseWriter, r *http.Request) error {
if r.Method == http.MethodGet && r.URL.Path == "/" {
return s.handleHome(w, r)
} else if r.Method == http.MethodHead && r.URL.Path == "/" {
return s.handleEmpty(w, r)
} else if r.Method == http.MethodGet && staticRegex.MatchString(r.URL.Path) {
return s.handleStatic(w, r)
} else if r.Method == http.MethodOptions {
return s.handleOptions(w, r)
} else if (r.Method == http.MethodPut || r.Method == http.MethodPost) && topicRegex.MatchString(r.URL.Path) {
return s.withRateLimit(w, r, s.handlePublish)
} else if r.Method == http.MethodGet && jsonRegex.MatchString(r.URL.Path) {
return s.withRateLimit(w, r, s.handleSubscribeJSON)
} else if r.Method == http.MethodGet && sseRegex.MatchString(r.URL.Path) {
return s.withRateLimit(w, r, s.handleSubscribeSSE)
} else if r.Method == http.MethodGet && rawRegex.MatchString(r.URL.Path) {
return s.withRateLimit(w, r, s.handleSubscribeRaw)
}
return errHTTPNotFound
}
func (s *Server) handleHome(w http.ResponseWriter, r *http.Request) error {
_, err := io.WriteString(w, indexSource)
return err
}
func (s *Server) handleEmpty(w http.ResponseWriter, r *http.Request) error {
return nil
}
func (s *Server) handleStatic(w http.ResponseWriter, r *http.Request) error {
http.FileServer(http.FS(webStaticFs)).ServeHTTP(w, r)
return nil
}
func (s *Server) handlePublish(w http.ResponseWriter, r *http.Request, v *visitor) error {
t, err := s.topic(r.URL.Path[1:])
if err != nil {
return err
}
reader := io.LimitReader(r.Body, messageLimit)
b, err := io.ReadAll(reader)
if err != nil {
return err
}
m := newDefaultMessage(t.id, string(b))
if err := t.Publish(m); err != nil {
return err
}
if err := s.cache.AddMessage(m); err != nil {
return err
}
w.Header().Set("Access-Control-Allow-Origin", "*") // CORS, allow cross-origin requests
if err := json.NewEncoder(w).Encode(m); err != nil {
return err
}
s.mu.Lock()
s.messages++
s.mu.Unlock()
return nil
}
func (s *Server) handleSubscribeJSON(w http.ResponseWriter, r *http.Request, v *visitor) error {
encoder := func(msg *message) (string, error) {
var buf bytes.Buffer
if err := json.NewEncoder(&buf).Encode(&msg); err != nil {
return "", err
}
return buf.String(), nil
}
return s.handleSubscribe(w, r, v, "json", "application/stream+json", encoder)
}
func (s *Server) handleSubscribeSSE(w http.ResponseWriter, r *http.Request, v *visitor) error {
encoder := func(msg *message) (string, error) {
var buf bytes.Buffer
if err := json.NewEncoder(&buf).Encode(&msg); err != nil {
return "", err
}
if msg.Event != messageEvent {
return fmt.Sprintf("event: %s\ndata: %s\n", msg.Event, buf.String()), nil // Browser's .onmessage() does not fire on this!
}
return fmt.Sprintf("data: %s\n", buf.String()), nil
}
return s.handleSubscribe(w, r, v, "sse", "text/event-stream", encoder)
}
func (s *Server) handleSubscribeRaw(w http.ResponseWriter, r *http.Request, v *visitor) error {
encoder := func(msg *message) (string, error) {
if msg.Event == messageEvent { // only handle default events
return strings.ReplaceAll(msg.Message, "\n", " ") + "\n", nil
}
return "\n", nil // "keepalive" and "open" events just send an empty line
}
return s.handleSubscribe(w, r, v, "raw", "text/plain", encoder)
}
func (s *Server) handleSubscribe(w http.ResponseWriter, r *http.Request, v *visitor, format string, contentType string, encoder messageEncoder) error {
if err := v.AddSubscription(); err != nil {
return errHTTPTooManyRequests
}
defer v.RemoveSubscription()
t, err := s.topic(strings.TrimSuffix(r.URL.Path[1:], "/"+format)) // Hack
if err != nil {
return err
}
since, err := parseSince(r)
if err != nil {
return err
}
poll := r.URL.Query().Has("poll")
sub := func(msg *message) error {
m, err := encoder(msg)
if err != nil {
return err
}
if _, err := w.Write([]byte(m)); err != nil {
return err
}
if fl, ok := w.(http.Flusher); ok {
fl.Flush()
}
return nil
}
w.Header().Set("Access-Control-Allow-Origin", "*") // CORS, allow cross-origin requests
w.Header().Set("Content-Type", contentType)
if poll {
return s.sendOldMessages(t, since, sub)
}
subscriberID := t.Subscribe(sub)
defer t.Unsubscribe(subscriberID)
if err := sub(newOpenMessage(t.id)); err != nil { // Send out open message
return err
}
if err := s.sendOldMessages(t, since, sub); err != nil {
return err
}
for {
select {
case <-r.Context().Done():
return nil
case <-time.After(s.config.KeepaliveInterval):
v.Keepalive()
if err := sub(newKeepaliveMessage(t.id)); err != nil { // Send keepalive message
return err
}
}
}
}
func (s *Server) sendOldMessages(t *topic, since time.Time, sub subscriber) error {
if since.IsZero() {
return nil
}
messages, err := s.cache.Messages(t.id, since)
if err != nil {
return err
}
for _, m := range messages {
if err := sub(m); err != nil {
return err
}
}
return nil
}
func parseSince(r *http.Request) (time.Time, error) {
if !r.URL.Query().Has("since") {
return time.Time{}, nil
}
if since, err := strconv.ParseInt(r.URL.Query().Get("since"), 10, 64); err == nil {
return time.Unix(since, 0), nil
}
if d, err := time.ParseDuration(r.URL.Query().Get("since")); err == nil {
return time.Now().Add(-1 * d), nil
}
return time.Time{}, errHTTPBadRequest
}
func (s *Server) handleOptions(w http.ResponseWriter, r *http.Request) error {
w.Header().Set("Access-Control-Allow-Origin", "*") // CORS, allow cross-origin requests
w.Header().Set("Access-Control-Allow-Methods", "GET, PUT, POST")
return nil
}
func (s *Server) topic(id string) (*topic, error) {
s.mu.Lock()
defer s.mu.Unlock()
if _, ok := s.topics[id]; !ok {
if len(s.topics) >= s.config.GlobalTopicLimit {
return nil, errHTTPTooManyRequests
}
s.topics[id] = newTopic(id, time.Now())
if s.firebase != nil {
s.topics[id].Subscribe(s.firebase)
}
}
return s.topics[id], nil
}
func (s *Server) updateStatsAndExpire() {
s.mu.Lock()
defer s.mu.Unlock()
// Expire visitors from rate visitors map
for ip, v := range s.visitors {
if v.Stale() {
delete(s.visitors, ip)
}
}
// Prune cache
if err := s.cache.Prune(s.config.CacheDuration); err != nil {
log.Printf("error pruning cache: %s", err.Error())
}
// Prune old messages, remove subscriptions without subscribers
var subscribers, messages int
for _, t := range s.topics {
subs := t.Subscribers()
msgs, err := s.cache.MessageCount(t.id)
if err != nil {
log.Printf("cannot get stats for topic %s: %s", t.id, err.Error())
continue
}
if msgs == 0 && (subs == 0 || (s.firebase != nil && subs == 1)) { // Firebase is a subscriber!
delete(s.topics, t.id)
continue
}
subscribers += subs
messages += msgs
}
// Print stats
log.Printf("Stats: %d message(s) published, %d topic(s) active, %d subscriber(s), %d message(s) buffered, %d visitor(s)",
s.messages, len(s.topics), subscribers, messages, len(s.visitors))
}
func (s *Server) withRateLimit(w http.ResponseWriter, r *http.Request, handler func(w http.ResponseWriter, r *http.Request, v *visitor) error) error {
v := s.visitor(r)
if err := v.RequestAllowed(); err != nil {
return err
}
return handler(w, r, v)
}
// visitor creates or retrieves a rate.Limiter for the given visitor.
// This function was taken from https://www.alexedwards.net/blog/how-to-rate-limit-http-requests (MIT).
func (s *Server) visitor(r *http.Request) *visitor {
s.mu.Lock()
defer s.mu.Unlock()
remoteAddr := r.RemoteAddr
ip, _, err := net.SplitHostPort(remoteAddr)
if err != nil {
ip = remoteAddr // This should not happen in real life; only in tests.
}
if s.config.BehindProxy && r.Header.Get("X-Forwarded-For") != "" {
ip = r.Header.Get("X-Forwarded-For")
}
v, exists := s.visitors[ip]
if !exists {
s.visitors[ip] = newVisitor(s.config)
return s.visitors[ip]
}
v.seen = time.Now()
return v
}
func (s *Server) fail(w http.ResponseWriter, r *http.Request, code int, err error) {
log.Printf("[%s] %s - %d - %s", r.RemoteAddr, r.Method, code, err.Error())
w.WriteHeader(code)
io.WriteString(w, fmt.Sprintf("%s\n", http.StatusText(code)))
}