/
app.go
248 lines (209 loc) · 6.34 KB
/
app.go
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package hello
import (
"encoding/json"
"fmt"
"math/rand"
"net/http"
"time"
"appengine"
"appengine/datastore"
)
type channelEntry struct {
PeerID string
}
type peerOffer struct {
SourceID string
Offer []byte
}
type peerOfferInfo struct {
SourceID string
Offer string
}
type iceCandidate struct {
Label string
ID string
Candidate string
SourceID string
}
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" +
"0123456789./"
func init() {
http.HandleFunc("/broker", brokerHandler)
}
func generatePeerId() string {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
b := make([]byte, 64)
for i := range b { b[i] = byte(letterBytes[r.Int() & 0x3f]) }
return string(b)
}
func makeRootChannelKey(c appengine.Context, channelId string) *datastore.Key {
return datastore.NewKey(c, "channelEntry", channelId, 0, nil)
}
func makeRootPeerKey(c appengine.Context, peerId string) *datastore.Key {
return datastore.NewKey(c, "peer", peerId, 0, nil)
}
func brokerHandler(w http.ResponseWriter, r *http.Request) {
c := appengine.NewContext(r)
if r.Method != "POST" {
http.Error(w, "Invalid request format", http.StatusBadRequest)
return
}
decoder := json.NewDecoder(r.Body)
var request struct {
Operation string
ChannelID string
SourcePeerID string
TargetPeerID string
Candidate *iceCandidate
Offer string
}
if err := decoder.Decode(&request); err != nil {
http.Error(w, fmt.Sprintf("Invalid request format: %s", err),
http.StatusBadRequest)
return
}
switch request.Operation {
case "join":
joinChannel(c, w, request.ChannelID)
return
case "add ice candidate":
addIceCandidate(c, w, request.SourcePeerID, request.TargetPeerID,
request.Candidate);
return
case "add offer":
addOffer(c, w, request.SourcePeerID, request.TargetPeerID, request.Offer)
return
case "get status":
queryPeerStatus(c, w, request.SourcePeerID, request.ChannelID)
return
default:
http.Error(w, fmt.Sprintf("Invalid operation: %s", request.Operation),
http.StatusBadRequest)
return
}
}
func joinChannel(c appengine.Context, w http.ResponseWriter, channelId string) {
if len(channelId) == 0 {
http.Error(w, "Invalid channel ID", http.StatusBadRequest)
return
}
peers, err := getPeersInChannel(c, channelId)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
parentKey := makeRootChannelKey(c, channelId)
newEntryKey := datastore.NewIncompleteKey(c, "channelEntry", parentKey)
newEntry := new(channelEntry)
newEntry.PeerID = generatePeerId()
if _, err := datastore.Put(c, newEntryKey, newEntry); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
encoder := json.NewEncoder(w)
encoder.Encode(struct {
PeerID string
Peers []string
}{ newEntry.PeerID, peers })
}
func addIceCandidate(c appengine.Context, w http.ResponseWriter,
sourcePeerId, targetPeerId string, candidate *iceCandidate) {
if candidate == nil || len(sourcePeerId) == 0 || len(targetPeerId) == 0 {
http.Error(w, "Invalid 'add ice candidate' request", http.StatusBadRequest);
return
}
parentKey := makeRootPeerKey(c, targetPeerId)
newCandidateKey := datastore.NewIncompleteKey(c, "iceCandidate", parentKey)
candidate.SourceID = sourcePeerId
if _, err := datastore.Put(c, newCandidateKey, candidate); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
encoder := json.NewEncoder(w)
encoder.Encode(struct{}{})
}
func addOffer(c appengine.Context, w http.ResponseWriter,
sourcePeerId, targetPeerId, offer string) {
if len(sourcePeerId) == 0 || len(targetPeerId) == 0 || len(offer) == 0 {
http.Error(w, "Invalid 'add offer' request", http.StatusBadRequest)
return
}
parentKey := makeRootPeerKey(c, targetPeerId)
newOfferKey := datastore.NewIncompleteKey(c, "peerOffer", parentKey)
newOffer := new(peerOffer)
newOffer.SourceID = sourcePeerId
newOffer.Offer = []byte(offer)
if _, err := datastore.Put(c, newOfferKey, newOffer); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
encoder := json.NewEncoder(w)
encoder.Encode(struct{}{})
}
func queryPeerStatus(
c appengine.Context, w http.ResponseWriter, peerId, channelId string) {
if len(peerId) == 0 || len(channelId) == 0 {
http.Error(w, "Invalid 'get status' request", http.StatusBadRequest)
return
}
peers, err := getPeersInChannel(c, channelId)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
candidates, err := getCandidatesForPeer(c, peerId)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
offers, err := getOffersForPeer(c, peerId)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
encoder := json.NewEncoder(w)
encoder.Encode(struct {
Peers []string
Candidates []iceCandidate
Offers []peerOfferInfo
}{ peers, candidates, offers })
}
func getPeersInChannel(
c appengine.Context, channelId string) ([]string, error) {
q := datastore.NewQuery("channelEntry").
Ancestor(makeRootChannelKey(c, channelId))
var channelEntries []channelEntry
if _, err := q.GetAll(c, &channelEntries); err != nil {
return nil, err
}
peerIds := make([]string, len(channelEntries))
for i := range channelEntries {
peerIds[i] = channelEntries[i].PeerID
}
return peerIds, nil
}
func getCandidatesForPeer(
c appengine.Context, peerId string) ([]iceCandidate, error) {
q := datastore.NewQuery("iceCandidate").
Ancestor(makeRootPeerKey(c, peerId))
var candidates []iceCandidate
if _, err := q.GetAll(c, &candidates); err != nil {
return nil, err
}
return candidates, nil
}
func getOffersForPeer(
c appengine.Context, peerId string) ([]peerOfferInfo, error) {
q := datastore.NewQuery("peerOffer").
Ancestor(makeRootPeerKey(c, peerId))
var offers []peerOffer
if _, err := q.GetAll(c, &offers); err != nil {
return nil, err
}
offerInfo := make([]peerOfferInfo, len(offers))
for i := range offers {
offerInfo[i].SourceID = offers[i].SourceID
offerInfo[i].Offer = string(offers[i].Offer)
}
return offerInfo, nil
}