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package main
import (
"encoding/json"
"fmt"
"log"
"net/http"
"net/url"
"os"
"regexp"
"strings"
"sync"
"time"
)
var (
long = regexp.MustCompile(`(.{72}\S*)\s+`)
file, requests *os.File
m sync.Mutex
)
func wrap(s string) string {
return strings.ReplaceAll(long.ReplaceAllString(
strings.ReplaceAll(s, "\r", ""), "$1\n"), "\n", "\n ")
}
func handler(w http.ResponseWriter, r *http.Request) {
defer r.Body.Close()
if err := r.ParseForm(); err != nil {
w.WriteHeader(http.StatusBadRequest)
return
}
text := r.FormValue("text")
if len(text) > 64<<10 {
w.WriteHeader(http.StatusBadRequest)
return
}
m.Lock()
defer m.Unlock()
j, _ := json.Marshal(struct {
URI string
Headers http.Header
Form url.Values
}{
URI: r.RequestURI,
Headers: r.Header,
Form: r.Form,
})
if s, err := file.Stat(); err != nil {
log.Fatalln(err)
} else if s.Size()+int64(len(text)) > 64<<20 {
w.WriteHeader(http.StatusInternalServerError)
} else if r.Form.Has("submit") {
// <input type="submit"> should not be named, and thus received.
//
// If this is not enough to filter out most spammers, consider also:
// - Header: "Origin" should not be missing for POST.
// - Header: "Accept" should not be "*/*".
// - Header: "Accept-Language" and "Accept-Encoding" should be present.
// - Form: _charset_ should not be kept verbatim,
// seeing as Safari/Chromium/Firefox all pass UTF-8,
// in accordance with HTML5.
w.WriteHeader(http.StatusTeapot)
} else {
fmt.Fprintf(file, "%s %s\n %s\n",
time.Now().Local().Format(time.RFC1123), r.RequestURI, wrap(text))
if err := file.Sync(); err != nil {
log.Fatalln(err)
}
// To help filter out spammers.
fmt.Fprintf(requests, "%s\n", j)
if err := requests.Sync(); err != nil {
log.Fatalln(err)
}
fmt.Fprintln(w, "Saved.")
}
}
func main() {
if len(os.Args) != 3 {
log.Fatalf("Usage: %s BIND DB\n", os.Args[0])
}
var err error
if file, err = os.OpenFile(os.Args[2],
os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644); err != nil {
log.Fatalln(err)
}
if requests, err = os.OpenFile(os.Args[2]+".requests",
os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644); err != nil {
log.Fatalln(err)
}
http.HandleFunc("/", handler)
log.Fatalln(http.ListenAndServe(os.Args[1], nil))
}
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