150 lines
3.2 KiB
Go
150 lines
3.2 KiB
Go
package websub
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"log"
|
|
"net/http"
|
|
"net/url"
|
|
"strings"
|
|
|
|
"p83.nl/go/ekster/pkg/rss"
|
|
|
|
"p83.nl/go/ekster/pkg/linkheader"
|
|
|
|
"p83.nl/go/ekster/pkg/jsonfeed"
|
|
"willnorris.com/go/microformats"
|
|
)
|
|
|
|
// GetHubURL finds the HubURL for topic
|
|
func GetHubURL(client *http.Client, topic string) (string, error) {
|
|
hubURL, err := parseLinkHeaders(client, topic)
|
|
if err == nil {
|
|
return hubURL, nil
|
|
}
|
|
|
|
hubURL, err = parseBodyLinks(client, topic)
|
|
if err == nil {
|
|
return hubURL, nil
|
|
}
|
|
|
|
return "", fmt.Errorf("no hub url found for topic %s", topic)
|
|
}
|
|
|
|
func isFeedContentType(contentType string) bool {
|
|
if strings.HasPrefix(contentType, "application/rss+xml") {
|
|
return true
|
|
}
|
|
if strings.HasPrefix(contentType, "application/atom+xml") {
|
|
return true
|
|
}
|
|
if strings.HasPrefix(contentType, "application/xml") {
|
|
return true
|
|
}
|
|
if strings.HasPrefix(contentType, "text/xml") {
|
|
return true
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
func parseBodyLinks(client *http.Client, topic string) (string, error) {
|
|
resp, err := client.Get(topic)
|
|
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
defer resp.Body.Close()
|
|
|
|
contentType := resp.Header.Get("Content-Type")
|
|
if isFeedContentType(contentType) {
|
|
body, err := ioutil.ReadAll(resp.Body)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
feed, err := rss.Parse(body)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
if feed.HubURL != "" {
|
|
return feed.HubURL, nil
|
|
}
|
|
return "", fmt.Errorf("no WebSub hub url found in the RSS feed")
|
|
} else if strings.HasPrefix(contentType, "text/html") {
|
|
topicURL, _ := url.Parse(topic)
|
|
md := microformats.Parse(resp.Body, topicURL)
|
|
if hubs, e := md.Rels["hub"]; e {
|
|
if len(hubs) >= 1 {
|
|
return hubs[0], nil
|
|
}
|
|
}
|
|
return "", fmt.Errorf("no WebSub hub url found in HTML <link> elements")
|
|
} else if strings.HasPrefix(contentType, "application/json") {
|
|
var feed jsonfeed.Feed
|
|
dec := json.NewDecoder(resp.Body)
|
|
err := dec.Decode(&feed)
|
|
if err != nil {
|
|
log.Printf("error while parsing json feed: %s\n", err)
|
|
return "", err
|
|
}
|
|
|
|
for _, v := range feed.Hubs {
|
|
if v.Type == "WebSub" {
|
|
return v.URL, nil
|
|
}
|
|
}
|
|
|
|
return "", fmt.Errorf("no WebSub hub url found in jsonfeed")
|
|
}
|
|
|
|
return "", fmt.Errorf("unknown content type of response: %s", resp.Header.Get("Content-Type"))
|
|
}
|
|
|
|
func parseLinkHeaders(client *http.Client, topic string) (string, error) {
|
|
resp, err := client.Head(topic)
|
|
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
defer resp.Body.Close()
|
|
|
|
if headers, e := resp.Header["Link"]; e {
|
|
links := linkheader.ParseMultiple(headers)
|
|
for _, link := range links {
|
|
if link.Rel == "hub" {
|
|
return link.URL, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
return "", fmt.Errorf("no hub url found in HTTP Link headers")
|
|
}
|
|
|
|
// Subscribe subscribes topicURL on hubURL
|
|
func Subscribe(client *http.Client, hubURL, topicURL, callbackURL, secret string, leaseSeconds int) error {
|
|
hub, err := url.Parse(hubURL)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
q := hub.Query()
|
|
q.Add("hub.mode", "subscribe")
|
|
q.Add("hub.callback", callbackURL)
|
|
q.Add("hub.topic", topicURL)
|
|
q.Add("hub.secret", secret)
|
|
q.Add("hub.lease_seconds", fmt.Sprintf("%d", leaseSeconds))
|
|
hub.RawQuery = ""
|
|
|
|
res, err := client.PostForm(hub.String(), q)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
defer res.Body.Close()
|
|
|
|
return nil
|
|
}
|