Move internal packages to an internal folder

For reference: https://go.dev/doc/go1.4#internalpackages

internal/http/client/response.go

@@ -0,0 +1,119 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package client // import "miniflux.app/v2/internal/http/client"
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+	"unicode/utf8"
+
+	"golang.org/x/net/html/charset"
+)
+
+var xmlEncodingRegex = regexp.MustCompile(`<\?xml(.*)encoding=["'](.+)["'](.*)\?>`)
+
+// Response wraps a server response.
+type Response struct {
+	Body          io.Reader
+	StatusCode    int
+	EffectiveURL  string
+	LastModified  string
+	ETag          string
+	Expires       string
+	ContentType   string
+	ContentLength int64
+}
+
+func (r *Response) String() string {
+	return fmt.Sprintf(
+		`StatusCode=%d EffectiveURL=%q LastModified=%q ETag=%s Expires=%s ContentType=%q ContentLength=%d`,
+		r.StatusCode,
+		r.EffectiveURL,
+		r.LastModified,
+		r.ETag,
+		r.Expires,
+		r.ContentType,
+		r.ContentLength,
+	)
+}
+
+// IsNotFound returns true if the resource doesn't exist anymore.
+func (r *Response) IsNotFound() bool {
+	return r.StatusCode == 404 || r.StatusCode == 410
+}
+
+// IsNotAuthorized returns true if the resource require authentication.
+func (r *Response) IsNotAuthorized() bool {
+	return r.StatusCode == 401
+}
+
+// HasServerFailure returns true if the status code represents a failure.
+func (r *Response) HasServerFailure() bool {
+	return r.StatusCode >= 400
+}
+
+// IsModified returns true if the resource has been modified.
+func (r *Response) IsModified(etag, lastModified string) bool {
+	if r.StatusCode == 304 {
+		return false
+	}
+
+	if r.ETag != "" && r.ETag == etag {
+		return false
+	}
+
+	if r.LastModified != "" && r.LastModified == lastModified {
+		return false
+	}
+
+	return true
+}
+
+// EnsureUnicodeBody makes sure the body is encoded in UTF-8.
+//
+// If a charset other than UTF-8 is detected, we convert the document to UTF-8.
+// This is used by the scraper and feed readers.
+//
+// Do not forget edge cases:
+//
+// - Feeds with encoding specified only in Content-Type header and not in XML document
+// - Feeds with encoding specified in both places
+// - 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) {
+	buffer, err := io.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 xmlEncodingRegex.Match(buffer[0:length]) {
+			return nil
+		}
+	}
+
+	r.Body, err = charset.NewReader(r.Body, r.ContentType)
+	return err
+}
+
+// BodyAsString returns the response body as string.
+func (r *Response) BodyAsString() string {
+	bytes, _ := io.ReadAll(r.Body)
+	return string(bytes)
+}