Request callbacks added.

Recover from all panics and continue scraping.
Only parse HTML if response is HTML.

response.go

@@ -4,14 +4,15 @@ import (
 	"github.com/PuerkitoBio/goquery"
 	"net/http"
 	"net/url"
+	"strings"
 )
 
 // Response type wraps http.Response
 // Contains parsed response data and Geziyor functions.
 type Response struct {
 	*http.Response
-	Body []byte
-	Doc  *goquery.Document
+	Body    []byte
+	DocHTML *goquery.Document
 
 	Geziyor *Geziyor
 	Exports chan interface{}
@@ -27,3 +28,13 @@ func (r *Response) JoinURL(relativeURL string) string {
 	joinedURL := r.Response.Request.URL.ResolveReference(parsedRelativeURL)
 	return joinedURL.String()
 }
+
+func (r *Response) isHTML() bool {
+	contentType := r.Header.Get("Content-Type")
+	for _, htmlContentType := range []string{"text/html", "application/xhtml+xml", "application/vnd.wap.xhtml+xml"} {
+		if strings.Contains(contentType, htmlContentType) {
+			return true
+		}
+	}
+	return false
+}