Do not use charset.NewReader if the body is a valid UTF-8 document

go.mod

@@ -11,9 +11,9 @@ require (
 	github.com/prometheus/client_golang v1.8.0
 	github.com/rylans/getlang v0.0.0-20200505200108-4c3188ff8a2d
 	github.com/stretchr/testify v1.6.1 // indirect
-	github.com/tdewolff/minify/v2 v2.9.9 // indirect
+	github.com/tdewolff/minify/v2 v2.9.10 // indirect
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
-	golang.org/x/net v0.0.0-20200625001655-4c5254603344
+	golang.org/x/net v0.0.0-20201029221708-28c70e62bb1d
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
 	google.golang.org/appengine v1.6.6 // indirect
 	google.golang.org/protobuf v1.25.0 // indirect

go.sum

@@ -289,8 +289,8 @@ github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/tdewolff/minify v1.1.0 h1:nxHQi1ML+g3ZbZHffiZ6eC7vMqNvSRfX3KB5Y5y/kfw=
 github.com/tdewolff/minify v2.3.6+incompatible h1:2hw5/9ZvxhWLvBUnHE06gElGYz+Jv9R4Eys0XUzItYo=
-github.com/tdewolff/minify/v2 v2.9.9 h1:5POLhoyTEWNNHADzlwH83AhvpKVAdpS7fOfaWIOWOTw=
-github.com/tdewolff/minify/v2 v2.9.9/go.mod h1:U1Nc+/YBSB0FPEarqcgkYH3Ep4DNyyIbOyl5P4eWMuo=
+github.com/tdewolff/minify/v2 v2.9.10 h1:p+ifTTl+JMFFLDYNAm7nxQ9XuCG10HTW00wlPAZ7aoE=
+github.com/tdewolff/minify/v2 v2.9.10/go.mod h1:U1Nc+/YBSB0FPEarqcgkYH3Ep4DNyyIbOyl5P4eWMuo=
 github.com/tdewolff/parse/v2 v2.5.5 h1:b7ICJa4I/54JQGEGgTte8DiyJPKcC5g8V773QMzkeUM=
 github.com/tdewolff/parse/v2 v2.5.5/go.mod h1:WzaJpRSbwq++EIQHYIRTpbYKNA3gn9it1Ik++q4zyho=
 github.com/tdewolff/test v1.0.6/go.mod h1:6DAvZliBAAnD7rhVgwaM7DE5/d9NMOAJ09SqYqeK4QE=
@@ -346,6 +346,8 @@ golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7/go.mod h1:z5CRVTTTmAJ677TzLL
 golang.org/x/net v0.0.0-20200202094626-16171245cfb2/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200625001655-4c5254603344 h1:vGXIOMxbNfDTk/aXCmfdLgkrSV+Z2tcbze+pEc3v5W4=
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
+golang.org/x/net v0.0.0-20201029221708-28c70e62bb1d h1:dOiJ2n2cMwGLce/74I/QHMbnpk5GfY7InR8rczoMqRM=
+golang.org/x/net v0.0.0-20201029221708-28c70e62bb1d/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d h1:TzXSXBo42m9gQenoE3b9BGiEpg5IG2JkU5FkPIawgtw=
@@ -377,11 +379,14 @@ golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200615200032-f1bc736245b1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211 h1:9UQO31fZ+0aKQOFldThf7BKPMJTiBfWycGh/u3UoO88=
 golang.org/x/sys v0.0.0-20201015000850-e3ed0017c211/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/text v0.3.3 h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

http/client/response.go

@@ -87,32 +87,26 @@ func (r *Response) IsModified(etag, lastModified string) bool {
 // - Feeds with encoding specified only in XML document and not in HTTP header
 // - Feeds with wrong encoding defined and already in UTF-8
 func (r *Response) EnsureUnicodeBody() (err error) {
-	if r.ContentType != "" {
-		// JSON feeds are always in UTF-8.
-		if strings.Contains(r.ContentType, "json") {
-			return
+	buffer, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return err
+	}
+
+	r.Body = bytes.NewReader(buffer)
+	if utf8.Valid(buffer) {
+		return nil
+	}
+
+	if strings.Contains(r.ContentType, "xml") {
+		// We ignore documents with encoding specified in XML prolog.
+		// This is going to be handled by the XML parser.
+		length := 1024
+		if len(buffer) < 1024 {
+			length = len(buffer)
 		}
 
-		if strings.Contains(r.ContentType, "xml") {
-			buffer, _ := ioutil.ReadAll(r.Body)
-			r.Body = bytes.NewReader(buffer)
-
-			// We ignore documents with encoding specified in XML prolog.
-			// This is going to be handled by the XML parser.
-			length := 1024
-			if len(buffer) < 1024 {
-				length = len(buffer)
-			}
-
-			if xmlEncodingRegex.Match(buffer[0:length]) {
-				return
-			}
-
-			// If no encoding is specified in the XML prolog and
-			// the document is valid UTF-8, nothing needs to be done.
-			if utf8.Valid(buffer) {
-				return
-			}
+		if xmlEncodingRegex.Match(buffer[0:length]) {
+			return nil
 		}
 	}