fraud detection added

assets/templates/form.html

@@ -22,6 +22,7 @@
             </fieldset>
         </form>
         <footer>
+            <a href="/">&#8962; notehub</a> &middot;
             <a href="https://github.com/chmllr/NoteHub">source code</a> &middot;
             <a href="/TOS.md">terms of service</a>
         </footer>

assets/templates/note.html

@@ -8,6 +8,7 @@
         <link href="/style.css" rel="stylesheet" type="text/css" />
     </head>
     <body>
+        {{.Ads}}
         <article>
             {{.Content}}
         </article>

server.go

@@ -7,6 +7,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/url"
+	"os"
 	"sync"
 
 	"database/sql"
@@ -17,7 +18,10 @@ import (
 	"github.com/labstack/gommon/log"
 )
 
-var stats = &sync.Map{}
+var (
+	stats = &sync.Map{}
+	ads   []byte
+)
 
 type Template struct{ templates *template.Template }
 
@@ -35,6 +39,15 @@ func main() {
 	}
 	defer db.Close()
 
+	adsFName := os.Getenv("ADS")
+	if adsFName != "" {
+		var err error
+		ads, err = ioutil.ReadFile(adsFName)
+		if err != nil {
+			e.Logger.Errorf("couldn't read file %q: %v", adsFName, err)
+		}
+	}
+
 	e.Renderer = &Template{templates: template.Must(template.ParseGlob("assets/templates/*.html"))}
 
 	e.File("/favicon.ico", "assets/public/favicon.ico")
@@ -61,6 +74,9 @@ func main() {
 			}
 		}
 		defer stats.Store(n.ID, views+1)
+		if n.Fraud() {
+			n.Ads = mdTmplHTML(ads)
+		}
 		c.Logger().Debugf("/%q requested; response code: %d", n.ID, code)
 		return c.Render(code, "Note", n)
 	})

storage.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"html/template"
+	"math"
 	"math/rand"
 	"net/http"
 	"regexp"
@@ -25,6 +26,7 @@ func init() {
 const (
 	idLength            = 5
 	statsSavingInterval = 1 * time.Minute
+	fraudThreshold      = 7
 )
 
 var (
@@ -39,6 +41,7 @@ var (
 	rexpNewLine        = regexp.MustCompile("[\n\r]")
 	rexpNonAlphaNum    = regexp.MustCompile("[`~!@#$%^&*_|+=?;:'\",.<>{}\\/]")
 	rexpNoScriptIframe = regexp.MustCompile("<.*?(iframe|script).*?>")
+	rexpLink           = regexp.MustCompile("(ht|f)tp://[^\\s]+")
 
 	errorUnathorised = errors.New("id or password is wrong")
 	errorBadRequest  = errors.New("password is empty")
@@ -48,7 +51,7 @@ type Note struct {
 	ID, Title, Text, Password string
 	Published, Edited         time.Time
 	Views                     int
-	Content                   template.HTML
+	Content, Ads              template.HTML
 }
 
 func errPage(code int, details ...string) Note {
@@ -203,3 +206,10 @@ var mdRenderer = markdown.New(markdown.HTML(true))
 func mdTmplHTML(content []byte) template.HTML {
 	return template.HTML(mdRenderer.RenderToString(content))
 }
+
+func (n *Note) Fraud() bool {
+	stripped := rexpLink.ReplaceAllString(n.Text, "")
+	l1 := len(n.Text)
+	l2 := len(stripped)
+	return int(math.Ceil(100*float64(l1-l2)/float64(l1))) > fraudThreshold
+}