forked from markpasc/cares
/
pshb.go
238 lines (206 loc) · 6.39 KB
/
pshb.go
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package main
import (
"bytes"
"crypto/hmac"
"crypto/sha1"
"database/sql"
"encoding/hex"
"fmt"
//"github.com/moovweb/gokogiri/xml"
"io/ioutil"
"net/http"
"net/url"
"strconv"
"strings"
"time"
)
type Subscription struct {
Id uint64
Url string
LeaseUntil time.Time
Secret sql.NullString
Created time.Time
}
func (s *Subscription) Notify(feed string) {
// Don't notify if the subscription expired.
if s.LeaseUntil.Before(time.Now().UTC()) {
return
}
buf := bytes.NewBufferString(feed)
req, err := http.NewRequest("POST", s.Url, buf)
if err != nil {
// ...?!?
logr.Errln("Error creating new HTTP request to notify subscriber:", err.Error())
return
}
req.Header.Set("Content-Type", "application/atom+xml")
if s.Secret.Valid {
sign := hmac.New(sha1.New, []byte(s.Secret.String))
sign.Write([]byte(feed))
hashData := make([]byte, 40, 0) // actually too long, it's 40 hex chars
hash := sign.Sum(hashData)
signature := fmt.Sprintf("sha1=%s", hex.EncodeToString(hash))
req.Header.Set("X-Hub-Signature", signature)
}
resp, _ := http.DefaultClient.Do(req)
resp.Body.Close()
}
func (s *Subscription) Save() error {
if s.Id == 0 {
return db.Insert(s)
}
_, err := db.Update(s)
return err
}
func ActiveSubscriptions() ([]*Subscription, error) {
rows, err := db.Select(Subscription{},
"SELECT id, url, leaseuntil, secret, created FROM subscription WHERE leaseuntil > $1",
time.Now().UTC())
if err != nil {
return nil, err
}
clouds := make([]*Subscription, len(rows))
for i, row := range rows {
clouds[i] = row.(*Subscription)
}
return clouds, nil
}
func NotifySubscribers(feed string) {
logr.Debugln("Sending PubSubHubbub notifications")
subs, err := ActiveSubscriptions()
if err != nil {
logr.Errln("Error finding pubsubhubbub subscribers:", err.Error())
return
}
for _, sub := range subs {
go sub.Notify(feed)
}
}
type SubscribeRequest struct {
Mode string
Topic string
CallbackUrl *url.URL
LeaseUntil time.Time
Secret string
VerifyToken string
}
type UnverifiedResponse string
func (u UnverifiedResponse) Error() string {
return string(u)
}
func (req *SubscribeRequest) Verify() error {
challenge := "yup"
query := req.CallbackUrl.Query()
query.Set("hub.mode", req.Mode)
query.Set("hub.topic", req.Topic)
query.Set("hub.challenge", challenge)
if req.Mode == "subscribe" {
leaseDuration := req.LeaseUntil.Sub(time.Now().UTC())
leaseSecondsStr := strconv.Itoa(int(leaseDuration / time.Second))
query.Set("hub.lease_seconds", leaseSecondsStr)
}
if req.VerifyToken != "" {
query.Set("hub.verify_token", req.VerifyToken)
}
verifyUrl := *req.CallbackUrl // verifyUrl is not a pointer
verifyUrl.RawQuery = query.Encode()
resp, err := http.Get(verifyUrl.String())
if err != nil {
return fmt.Errorf("Unexpected HTTP error verifying request")
}
// Ideally we would search progressively, such as by using
// regexp.MatchReader(RuneReadifier(resp.Body))... but we'd have to
// implement RuneReadifier.
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return err
}
if !bytes.Contains(body, []byte(challenge)) {
return UnverifiedResponse("Response body did not contain the verification token")
}
subSecret := sql.NullString{req.Secret, req.Secret != ""}
sub := &Subscription{0, req.CallbackUrl.String(), req.LeaseUntil, subSecret, time.Now().UTC()}
err = db.Insert(sub)
if err != nil {
return err
}
return nil
}
func hub(w http.ResponseWriter, r *http.Request) {
logr.Debugln("Yay, a pubsubhubbub request!")
if r.Method != "POST" {
w.Header().Set("Allow", "POST")
http.Error(w, "POST is required", http.StatusMethodNotAllowed)
return
}
verifyModes := r.Form["hub.verify"]
canVerifySync, canVerifyAsync := false, false
for _, verifyMode := range verifyModes {
if verifyMode == "sync" {
canVerifySync = true
} else if verifyMode == "async" {
canVerifyAsync = true
}
}
if !canVerifyAsync && !canVerifySync {
logr.Debugln("Subscriber asked for verification modes", verifyModes, "so couldn't subscribe them")
http.Error(w, fmt.Sprintf("None of your requested verification modes (%s) are supported", strings.Join(verifyModes, ",")), http.StatusBadRequest)
return
}
topic := r.FormValue("hub.topic")
// TODO: ssl?
if topic != fmt.Sprintf("http://%s/atom", r.Host) {
logr.Debugln("Subscriber asked for a subscription to", topic, "so couldn't subscribe them")
http.Error(w, fmt.Sprintf("Your requested subscription topic %s is not tracked by this hub", topic), http.StatusBadRequest)
return
}
callback := r.FormValue("hub.callback")
callbackUrl, err := url.Parse(callback)
if err != nil {
logr.Debugln("Subscriber asked for a subscription with callback", callback, "which doesn't parse as an url:", err.Error())
http.Error(w, fmt.Sprintf("Could not parse your callback URL %s", callback), http.StatusBadRequest)
return
}
if callbackUrl.Scheme != "http" && callbackUrl.Scheme != "https" {
logr.Debugln("Subscriber asked for a subscription with callback", callback, "which has unknown scheme", callbackUrl.Scheme)
http.Error(w, fmt.Sprintf("Your callback URL's scheme %s is not supported", callbackUrl.Scheme), http.StatusBadRequest)
return
}
if callbackUrl.Fragment != "" {
logr.Debugln("Subscriber asked for a subscription with callback", callback, "which has a fragment", callbackUrl.Fragment)
http.Error(w, fmt.Sprintf("Your callback URL has a fragment (%s) which is not supported", callbackUrl.Fragment), http.StatusBadRequest)
return
}
leaseUntil := time.Now().UTC()
leaseSecondsStr := r.FormValue("hub.lease_seconds")
if leaseSecondsStr != "" {
leaseSeconds, err := strconv.Atoi(leaseSecondsStr)
if err != nil {
logr.Debugln("Subscriber asked for a subscription with lease seconds", leaseSecondsStr, "so didn't subscribe")
http.Error(w, fmt.Sprintf("Could not parse your requested lease seconds (%s)", leaseSecondsStr), http.StatusBadRequest)
return
}
leaseUntil = leaseUntil.Add(time.Duration(leaseSeconds) * time.Second)
} else {
leaseUntil = leaseUntil.AddDate(0, 1, 0) // one month
}
req := &SubscribeRequest{
r.FormValue("hub.mode"),
topic,
callbackUrl,
leaseUntil,
r.FormValue("hub.secret"),
r.FormValue("hub.verify_token"),
}
if canVerifyAsync {
go req.Verify()
w.WriteHeader(http.StatusAccepted)
return
}
err = req.Verify()
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
w.WriteHeader(http.StatusNoContent)
}