Simplify response type check

readability/read.go

@@ -1128,14 +1128,14 @@ func FromURL(url *nurl.URL, timeout time.Duration) (Article, error) {
 	}
 	defer resp.Body.Close()
 
-	// If response is not HTML, stop process
-	mimeType, err := getMimeType(resp.Body)
-	if err != nil {
-		return Article{}, err
+	// Check content type. If not HTML, stop process
+	contentType := resp.Header.Get("Content-type")
+	if contentType == "" {
+		contentType = "application/octet-stream"
 	}
 
-	if !strings.HasPrefix(mimeType, "text/html") {
-		return Article{}, fmt.Errorf("URL must be a text/html, found %s", mimeType)
+	if !strings.HasPrefix(contentType, "text/html") {
+		return Article{}, fmt.Errorf("URL must be a text/html, found %s", contentType)
 	}
 
 	// Parse response body

readability/utils.go

@@ -3,8 +3,6 @@ package readability
 import (
 	"crypto/md5"
 	"fmt"
-	"io"
-	"net/http"
 	"os"
 	"strings"
 	"unicode/utf8"
@@ -70,17 +68,6 @@ func removeSeparator(str string, separators ...string) string {
 	return strings.Join(finalWords, " ")
 }
 
-func getMimeType(resp io.Reader) (string, error) {
-	buffer := make([]byte, 512)
-	_, err := resp.Read(buffer)
-	if err != nil {
-		return "", err
-	}
-
-	mimeType := http.DetectContentType(buffer)
-	return mimeType, nil
-}
-
 func normalizeText(str string) string {
 	return strings.Join(strings.Fields(str), " ")
 }