Move internal packages to an internal folder

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

internal/reader/icon/finder.go

@@ -0,0 +1,196 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package icon // import "miniflux.app/v2/internal/reader/icon"
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io"
+	"strings"
+
+	stdlib_url "net/url"
+
+	"miniflux.app/v2/internal/config"
+	"miniflux.app/v2/internal/crypto"
+	"miniflux.app/v2/internal/http/client"
+	"miniflux.app/v2/internal/logger"
+	"miniflux.app/v2/internal/model"
+	"miniflux.app/v2/internal/url"
+
+	"github.com/PuerkitoBio/goquery"
+)
+
+// FindIcon try to find the website's icon.
+func FindIcon(websiteURL, iconURL, userAgent string, fetchViaProxy, allowSelfSignedCertificates bool) (*model.Icon, error) {
+	if iconURL == "" {
+		rootURL := url.RootURL(websiteURL)
+		logger.Debug("[FindIcon] Trying to find an icon: rootURL=%q websiteURL=%q userAgent=%q", rootURL, websiteURL, userAgent)
+
+		clt := client.NewClientWithConfig(rootURL, config.Opts)
+		clt.WithUserAgent(userAgent)
+		clt.AllowSelfSignedCertificates = allowSelfSignedCertificates
+
+		if fetchViaProxy {
+			clt.WithProxy()
+		}
+
+		response, err := clt.Get()
+		if err != nil {
+			return nil, fmt.Errorf("icon: unable to download website index page: %v", err)
+		}
+
+		if response.HasServerFailure() {
+			return nil, fmt.Errorf("icon: unable to download website index page: status=%d", response.StatusCode)
+		}
+
+		iconURL, err = parseDocument(rootURL, response.Body)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if strings.HasPrefix(iconURL, "data:") {
+		return parseImageDataURL(iconURL)
+	}
+
+	logger.Debug("[FindIcon] Fetching icon => %s", iconURL)
+	icon, err := downloadIcon(iconURL, userAgent, fetchViaProxy, allowSelfSignedCertificates)
+	if err != nil {
+		return nil, err
+	}
+
+	return icon, nil
+}
+
+func parseDocument(websiteURL string, data io.Reader) (string, error) {
+	queries := []string{
+		"link[rel='shortcut icon']",
+		"link[rel='Shortcut Icon']",
+		"link[rel='icon shortcut']",
+		"link[rel='icon']",
+	}
+
+	doc, err := goquery.NewDocumentFromReader(data)
+	if err != nil {
+		return "", fmt.Errorf("icon: unable to read document: %v", err)
+	}
+
+	var iconURL string
+	for _, query := range queries {
+		doc.Find(query).Each(func(i int, s *goquery.Selection) {
+			if href, exists := s.Attr("href"); exists {
+				iconURL = strings.TrimSpace(href)
+			}
+		})
+
+		if iconURL != "" {
+			break
+		}
+	}
+
+	if iconURL == "" {
+		iconURL = url.RootURL(websiteURL) + "favicon.ico"
+	} else {
+		iconURL, _ = url.AbsoluteURL(websiteURL, iconURL)
+	}
+
+	return iconURL, nil
+}
+
+func downloadIcon(iconURL, userAgent string, fetchViaProxy, allowSelfSignedCertificates bool) (*model.Icon, error) {
+	clt := client.NewClientWithConfig(iconURL, config.Opts)
+	clt.WithUserAgent(userAgent)
+	clt.AllowSelfSignedCertificates = allowSelfSignedCertificates
+	if fetchViaProxy {
+		clt.WithProxy()
+	}
+
+	response, err := clt.Get()
+	if err != nil {
+		return nil, fmt.Errorf("icon: unable to download iconURL: %v", err)
+	}
+
+	if response.HasServerFailure() {
+		return nil, fmt.Errorf("icon: unable to download icon: status=%d", response.StatusCode)
+	}
+
+	body, err := io.ReadAll(response.Body)
+	if err != nil {
+		return nil, fmt.Errorf("icon: unable to read downloaded icon: %v", err)
+	}
+
+	if len(body) == 0 {
+		return nil, fmt.Errorf("icon: downloaded icon is empty, iconURL=%s", iconURL)
+	}
+
+	icon := &model.Icon{
+		Hash:     crypto.HashFromBytes(body),
+		MimeType: response.ContentType,
+		Content:  body,
+	}
+
+	return icon, nil
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs#syntax
+// data:[<mediatype>][;base64],<data>
+func parseImageDataURL(value string) (*model.Icon, error) {
+	var mediaType string
+	var encoding string
+
+	if !strings.HasPrefix(value, "data:") {
+		return nil, fmt.Errorf(`icon: invalid data URL (missing data:) %q`, value)
+	}
+
+	value = value[5:]
+
+	comma := strings.Index(value, ",")
+	if comma < 0 {
+		return nil, fmt.Errorf(`icon: invalid data URL (no comma) %q`, value)
+	}
+
+	data := value[comma+1:]
+	semicolon := strings.Index(value[0:comma], ";")
+
+	if semicolon > 0 {
+		mediaType = value[0:semicolon]
+		encoding = value[semicolon+1 : comma]
+	} else {
+		mediaType = value[0:comma]
+	}
+
+	if !strings.HasPrefix(mediaType, "image/") {
+		return nil, fmt.Errorf(`icon: invalid media type %q`, mediaType)
+	}
+
+	var blob []byte
+	switch encoding {
+	case "base64":
+		var err error
+		blob, err = base64.StdEncoding.DecodeString(data)
+		if err != nil {
+			return nil, fmt.Errorf(`icon: invalid data %q (%v)`, value, err)
+		}
+	case "":
+		decodedData, err := stdlib_url.QueryUnescape(data)
+		if err != nil {
+			return nil, fmt.Errorf(`icon: unable to decode data URL %q`, value)
+		}
+		blob = []byte(decodedData)
+	default:
+		return nil, fmt.Errorf(`icon: unsupported data URL encoding %q`, value)
+	}
+
+	if len(blob) == 0 {
+		return nil, fmt.Errorf(`icon: empty data URL %q`, value)
+	}
+
+	icon := &model.Icon{
+		Hash:     crypto.HashFromBytes(blob),
+		Content:  blob,
+		MimeType: mediaType,
+	}
+
+	return icon, nil
+}