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package main
import (
"fmt"
"log"
"net/http"
"strings"
"sync"
"time"
)
var (
// outputMode is either HTML or RSS
outputMode string
// cache will hold all previous network calls and re-use within set timeframe
cache safeCache
// cacheTimeout sets the time in in seconds for how long a channel will be cached
cacheTimeout float64
)
func init() {
outputMode = "html"
cache = safeCache{v: make(map[string]*channel)}
cacheTimeout = 60 * 15 // seconds
}
type safeCache struct {
sync.Mutex
v map[string]*channel
}
type channel struct {
Title string
Link string
Name string
Time time.Time
Description string
Items []*post
}
func (c *channel) String() string {
var template string
switch outputMode {
case "html":
template = htmlRoot
case "rss":
template = rssRoot
}
var s string
s = strings.Replace(template, "{{title}}", c.Title, -1)
s = strings.Replace(s, "{{link}}", c.Link, -1)
s = strings.Replace(s, "{{description}}", c.Description, -1)
s = strings.Replace(s, "{{name}}", c.Name, -1)
var items string
for i := range c.Items {
item := c.Items[i].String()
item = strings.Replace(item, "{{link}}", c.Link, -1)
items += item
}
s = strings.Replace(s, "{{items}}", items, 1)
return s
}
type post struct {
Time time.Time
Link string
Content string
Images []*image // list of urls
}
type image struct {
Source string
Caption string
}
func (p *post) String() string {
var template string
switch outputMode {
case "html":
template = htmlItem
case "rss":
template = rssItem
}
var s string
// time format: Mon Jan 2 15:04:05 -0700 MST 2006
s = strings.Replace(template, "{{time}}", p.Time.Format("Mon, 2 Jan 2006 15:04:05"), 2)
s = strings.Replace(s, "{{content}}", p.Content, 1)
var imgs string
for i := range p.Images {
imgs += `<a href="` + p.Images[i].Source + `"><img src="` + p.Images[i].Source + `" title="` + p.Images[i].Caption + `"></a>`
}
s = strings.Replace(s, "{{images}}", imgs, 1)
return s
}
type handler struct{}
func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/favicon.ico" {
return
}
group := r.URL.Path[1:]
if strings.HasSuffix(group, ".rss") {
group = strings.TrimSuffix(group, ".rss")
outputMode = "rss"
}
c, ok := cache.v[group]
if !ok || time.Now().Sub(c.Time).Seconds() > cacheTimeout {
var err error
c, err = fetch(group)
if err != nil {
http.Error(w, fmt.Sprintf("error: %s", err), 400)
return
}
if c == nil || len(c.Items) < 1 {
http.Error(w, fmt.Sprintf("%s", "group not found"), 400)
return
}
c.Name = group
c.Time = time.Now()
cache.Lock()
cache.v[c.Name] = c
cache.Unlock()
}
fmt.Fprintf(w, "%s\n", c.String())
}
func fetch(group string) (c *channel, err error) {
if group == "" {
return
}
url := "https://www.facebook.com/pg/" + group + "/posts/"
log.Println("Fetching:", url)
resp, err := http.Get(url)
if err != nil {
return
}
defer resp.Body.Close()
c, err = parse(resp.Body)
if err != nil {
return
}
c.Link = url
return
}
func main() {
// clean the cache when channels have expired
go func() {
for {
time.Sleep(time.Duration(cacheTimeout) * time.Second)
for k, c := range cache.v {
if time.Now().Sub(c.Time).Seconds() > cacheTimeout {
cache.Lock()
delete(cache.v, k)
cache.Unlock()
log.Println("Removed from cache:", k)
}
}
}
}()
log.Println("Serving: http://localhost:1212")
http.ListenAndServe(":1212", handler{})
}
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