#61 add gzip

close #61

Author: zhengchun

query.go

@@ -5,6 +5,8 @@ package htmlquery
 
 import (
 	"bufio"
+	"compress/gzip"
+	"compress/zlib"
 	"fmt"
 	"io"
 	"net/http"
@@ -88,15 +90,42 @@ func QuerySelectorAll(top *html.Node, selector *xpath.Expr) []*html.Node {
 	return elems
 }
 
-// LoadURL loads the HTML document from the specified URL.
+// LoadURL loads the HTML document from the specified URL. Default enabling gzip on a HTTP request.
 func LoadURL(url string) (*html.Node, error) {
-	resp, err := http.Get(url)
+	req, err := http.NewRequest("GET", url, nil)
 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
+	// Enable gzip compression.
+	req.Header.Add("Accept-Encoding", "gzip")
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	var reader io.ReadCloser
+
+	defer func() {
+		if reader != nil {
+			reader.Close()
+		}
+	}()
+
+	switch resp.Header.Get("Content-Encoding") {
+	case "gzip":
+		reader, err = gzip.NewReader(resp.Body)
+		if err != nil {
+			return nil, err
+		}
+	case "deflate":
+		reader, err = zlib.NewReader(resp.Body)
+		if err != nil {
+			return nil, err
+		}
+	default:
+		reader = resp.Body
+	}
 
-	r, err := charset.NewReader(resp.Body, resp.Header.Get("Content-Type"))
+	r, err := charset.NewReader(reader, resp.Header.Get("Content-Type"))
 	if err != nil {
 		return nil, err
 	}

query_test.go

@@ -1,6 +1,7 @@
 package htmlquery
 
 import (
+	"compress/gzip"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -80,6 +81,21 @@ func TestLoadURL(t *testing.T) {
 	}
 }
 
+func TestLoadURLWithGzipResponse(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Content-Encoding", "gzip")
+		gz := gzip.NewWriter(w)
+		defer gz.Close()
+		fmt.Fprint(gz, htmlSample)
+	}))
+	defer ts.Close()
+
+	_, err := LoadURL(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestLoadDoc(t *testing.T) {
 	tempHTMLdoc, err := ioutil.TempFile("", "sample_*.html")
 	if err != nil {