feat: implement base element handling in content scraper

internal/reader/processor/processor.go

@@ -61,6 +61,7 @@ func ProcessFeedEntries(store *storage.Storage, feed *model.Feed, user *model.Us
 			entry.URL = cleanedURL
 		}
 
+		pageBaseURL := ""
 		rewrittenURL := rewriteEntryURL(feed, entry)
 		entryIsNew := store.IsNewEntry(feed.ID, entry.Hash)
 		if feed.Crawler && (entryIsNew || forceRefresh) {
@@ -87,12 +88,16 @@ func ProcessFeedEntries(store *storage.Storage, feed *model.Feed, user *model.Us
 			requestBuilder.IgnoreTLSErrors(feed.AllowSelfSignedCertificates)
 			requestBuilder.DisableHTTP2(feed.DisableHTTP2)
 
-			content, scraperErr := scraper.ScrapeWebsite(
+			scrapedPageBaseURL, extractedContent, scraperErr := scraper.ScrapeWebsite(
 				requestBuilder,
 				rewrittenURL,
 				feed.ScraperRules,
 			)
 
+			if scrapedPageBaseURL != "" {
+				pageBaseURL = scrapedPageBaseURL
+			}
+
 			if config.Opts.HasMetricsCollector() {
 				status := "success"
 				if scraperErr != nil {
@@ -109,16 +114,20 @@ func ProcessFeedEntries(store *storage.Storage, feed *model.Feed, user *model.Us
 					slog.String("feed_url", feed.FeedURL),
 					slog.Any("error", scraperErr),
 				)
-			} else if content != "" {
+			} else if extractedContent != "" {
 				// We replace the entry content only if the scraper doesn't return any error.
-				entry.Content = minifyEntryContent(content)
+				entry.Content = minifyEntryContent(extractedContent)
 			}
 		}
 
 		rewrite.Rewriter(rewrittenURL, entry, feed.RewriteRules)
 
+		if pageBaseURL == "" {
+			pageBaseURL = rewrittenURL
+		}
+
 		// The sanitizer should always run at the end of the process to make sure unsafe HTML is filtered out.
-		entry.Content = sanitizer.Sanitize(rewrittenURL, entry.Content)
+		entry.Content = sanitizer.Sanitize(pageBaseURL, entry.Content)
 
 		updateEntryReadingTime(store, feed, entry, entryIsNew, user)
 		filteredEntries = append(filteredEntries, entry)
@@ -280,7 +289,7 @@ func ProcessEntryWebPage(feed *model.Feed, entry *model.Entry, user *model.User)
 	requestBuilder.IgnoreTLSErrors(feed.AllowSelfSignedCertificates)
 	requestBuilder.DisableHTTP2(feed.DisableHTTP2)
 
-	content, scraperErr := scraper.ScrapeWebsite(
+	pageBaseURL, extractedContent, scraperErr := scraper.ScrapeWebsite(
 		requestBuilder,
 		rewrittenEntryURL,
 		feed.ScraperRules,
@@ -298,15 +307,15 @@ func ProcessEntryWebPage(feed *model.Feed, entry *model.Entry, user *model.User)
 		return scraperErr
 	}
 
-	if content != "" {
+	if extractedContent != "" {
-		entry.Content = minifyEntryContent(content)
+		entry.Content = minifyEntryContent(extractedContent)
 		if user.ShowReadingTime {
 			entry.ReadingTime = readingtime.EstimateReadingTime(entry.Content, user.DefaultReadingSpeed, user.CJKReadingSpeed)
 		}
 	}
 
 	rewrite.Rewriter(rewrittenEntryURL, entry, entry.Feed.RewriteRules)
-	entry.Content = sanitizer.Sanitize(rewrittenEntryURL, entry.Content)
+	entry.Content = sanitizer.Sanitize(pageBaseURL, entry.Content)
 
 	return nil
 }

internal/reader/readability/readability.go

@@ -12,6 +12,8 @@ import (
 	"regexp"
 	"strings"
 
+	"miniflux.app/v2/internal/urllib"
+
 	"github.com/PuerkitoBio/goquery"
 	"golang.org/x/net/html"
 )
@@ -69,10 +71,17 @@ func (c candidateList) String() string {
 }
 
 // ExtractContent returns relevant content.
-func ExtractContent(page io.Reader) (string, error) {
+func ExtractContent(page io.Reader) (baseURL string, extractedContent string, err error) {
 	document, err := goquery.NewDocumentFromReader(page)
 	if err != nil {
-		return "", err
+		return "", "", err
+	}
+
+	if hrefValue, exists := document.Find("head base").First().Attr("href"); exists {
+		hrefValue = strings.TrimSpace(hrefValue)
+		if urllib.IsAbsoluteURL(hrefValue) {
+			baseURL = hrefValue
+		}
 	}
 
 	document.Find("script,style").Each(func(i int, s *goquery.Selection) {
@@ -86,12 +95,13 @@ func ExtractContent(page io.Reader) (string, error) {
 	topCandidate := getTopCandidate(document, candidates)
 
 	slog.Debug("Readability parsing",
+		slog.String("base_url", baseURL),
 		slog.Any("candidates", candidates),
 		slog.Any("topCandidate", topCandidate),
 	)
 
-	output := getArticle(topCandidate, candidates)
+	extractedContent = getArticle(topCandidate, candidates)
-	return output, nil
+	return baseURL, extractedContent, nil
 }
 
 // Now that we have the top candidate, look through its siblings for content that might also be related.

internal/reader/readability/readability_test.go

@@ -0,0 +1,102 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package readability // import "miniflux.app/v2/internal/reader/readability"
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBaseURL(t *testing.T) {
+	html := `
+		<html>
+			<head>
+				<base href="https://example.org/ ">
+			</head>
+			<body>
+				<article>
+					Some content
+				</article>
+			</body>
+		</html>`
+
+	baseURL, _, err := ExtractContent(strings.NewReader(html))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if baseURL != "https://example.org/" {
+		t.Errorf(`Unexpected base URL, got %q instead of "https://example.org/"`, baseURL)
+	}
+}
+
+func TestMultipleBaseURL(t *testing.T) {
+	html := `
+		<html>
+			<head>
+				<base href="https://example.org/ ">
+				<base href="https://example.com/ ">
+			</head>
+			<body>
+				<article>
+					Some content
+				</article>
+			</body>
+		</html>`
+
+	baseURL, _, err := ExtractContent(strings.NewReader(html))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if baseURL != "https://example.org/" {
+		t.Errorf(`Unexpected base URL, got %q instead of "https://example.org/"`, baseURL)
+	}
+}
+
+func TestRelativeBaseURL(t *testing.T) {
+	html := `
+		<html>
+			<head>
+				<base href="/test/ ">
+			</head>
+			<body>
+				<article>
+					Some content
+				</article>
+			</body>
+		</html>`
+
+	baseURL, _, err := ExtractContent(strings.NewReader(html))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if baseURL != "" {
+		t.Errorf(`Unexpected base URL, got %q`, baseURL)
+	}
+}
+
+func TestWithoutBaseURL(t *testing.T) {
+	html := `
+		<html>
+			<head>
+				<title>Test</title>
+			</head>
+			<body>
+				<article>
+					Some content
+				</article>
+			</body>
+		</html>`
+
+	baseURL, _, err := ExtractContent(strings.NewReader(html))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if baseURL != "" {
+		t.Errorf(`Unexpected base URL, got %q instead of ""`, baseURL)
+	}
+}

internal/reader/scraper/scraper.go

@@ -18,72 +18,77 @@ import (
 	"golang.org/x/net/html/charset"
 )
 
-func ScrapeWebsite(requestBuilder *fetcher.RequestBuilder, websiteURL, rules string) (string, error) {
+func ScrapeWebsite(requestBuilder *fetcher.RequestBuilder, pageURL, rules string) (baseURL string, extractedContent string, err error) {
-	responseHandler := fetcher.NewResponseHandler(requestBuilder.ExecuteRequest(websiteURL))
+	responseHandler := fetcher.NewResponseHandler(requestBuilder.ExecuteRequest(pageURL))
 	defer responseHandler.Close()
 
 	if localizedError := responseHandler.LocalizedError(); localizedError != nil {
-		slog.Warn("Unable to scrape website", slog.String("website_url", websiteURL), slog.Any("error", localizedError.Error()))
+		slog.Warn("Unable to scrape website", slog.String("website_url", pageURL), slog.Any("error", localizedError.Error()))
-		return "", localizedError.Error()
+		return "", "", localizedError.Error()
 	}
 
 	if !isAllowedContentType(responseHandler.ContentType()) {
-		return "", fmt.Errorf("scraper: this resource is not a HTML document (%s)", responseHandler.ContentType())
+		return "", "", fmt.Errorf("scraper: this resource is not a HTML document (%s)", responseHandler.ContentType())
 	}
 
 	// The entry URL could redirect somewhere else.
-	sameSite := urllib.Domain(websiteURL) == urllib.Domain(responseHandler.EffectiveURL())
+	sameSite := urllib.Domain(pageURL) == urllib.Domain(responseHandler.EffectiveURL())
-	websiteURL = responseHandler.EffectiveURL()
+	pageURL = responseHandler.EffectiveURL()
 
 	if rules == "" {
-		rules = getPredefinedScraperRules(websiteURL)
+		rules = getPredefinedScraperRules(pageURL)
 	}
 
-	var content string
-	var err error
-
 	htmlDocumentReader, err := charset.NewReader(
 		responseHandler.Body(config.Opts.HTTPClientMaxBodySize()),
 		responseHandler.ContentType(),
 	)
 	if err != nil {
-		return "", fmt.Errorf("scraper: unable to read HTML document: %v", err)
+		return "", "", fmt.Errorf("scraper: unable to read HTML document with charset reader: %v", err)
 	}
 
 	if sameSite && rules != "" {
 		slog.Debug("Extracting content with custom rules",
-			"url", websiteURL,
+			"url", pageURL,
 			"rules", rules,
 		)
-		content, err = findContentUsingCustomRules(htmlDocumentReader, rules)
+		baseURL, extractedContent, err = findContentUsingCustomRules(htmlDocumentReader, rules)
 	} else {
 		slog.Debug("Extracting content with readability",
-			"url", websiteURL,
+			"url", pageURL,
 		)
-		content, err = readability.ExtractContent(htmlDocumentReader)
+		baseURL, extractedContent, err = readability.ExtractContent(htmlDocumentReader)
 	}
 
-	if err != nil {
+	if baseURL == "" {
-		return "", err
+		baseURL = pageURL
+	} else {
+		slog.Debug("Using base URL from HTML document", "base_url", baseURL)
 	}
 
-	return content, nil
+	return baseURL, extractedContent, nil
 }
 
-func findContentUsingCustomRules(page io.Reader, rules string) (string, error) {
+func findContentUsingCustomRules(page io.Reader, rules string) (baseURL string, extractedContent string, err error) {
 	document, err := goquery.NewDocumentFromReader(page)
 	if err != nil {
-		return "", err
+		return "", "", err
+	}
+
+	if hrefValue, exists := document.Find("head base").First().Attr("href"); exists {
+		hrefValue = strings.TrimSpace(hrefValue)
+		if urllib.IsAbsoluteURL(hrefValue) {
+			baseURL = hrefValue
+		}
 	}
 
-	contents := ""
 	document.Find(rules).Each(func(i int, s *goquery.Selection) {
 		if content, err := goquery.OuterHtml(s); err == nil {
-			contents += content
+			extractedContent += content
 		}
 	})
 
-	return contents, nil
+	return baseURL, extractedContent, nil
 }
 
 func getPredefinedScraperRules(websiteURL string) string {

internal/reader/scraper/scraper_test.go

@@ -62,7 +62,7 @@ func TestSelectorRules(t *testing.T) {
 			t.Fatalf(`Unable to read file %q: %v`, filename, err)
 		}
 
-		actualResult, err := findContentUsingCustomRules(bytes.NewReader(html), rule)
+		_, actualResult, err := findContentUsingCustomRules(bytes.NewReader(html), rule)
 		if err != nil {
 			t.Fatalf(`Scraping error for %q - %q: %v`, filename, rule, err)
 		}
@@ -73,7 +73,67 @@ func TestSelectorRules(t *testing.T) {
 		}
 
 		if actualResult != strings.TrimSpace(string(expectedResult)) {
-			t.Errorf(`Unexpected result for %q, got "%s" instead of "%s"`, rule, actualResult, expectedResult)
+			t.Errorf(`Unexpected result for %q, got %q instead of %q`, rule, actualResult, expectedResult)
 		}
 	}
 }
+
+func TestParseBaseURLWithCustomRules(t *testing.T) {
+	html := `<html><head><base href="https://example.com/"></head><body><img src="image.jpg"></body></html>`
+	baseURL, _, err := findContentUsingCustomRules(strings.NewReader(html), "img")
+	if err != nil {
+		t.Fatalf(`Scraping error: %v`, err)
+	}
+
+	if baseURL != "https://example.com/" {
+		t.Errorf(`Unexpected base URL, got %q instead of "https://example.com/"`, baseURL)
+	}
+}
+
+func TestParseMultipleBaseURLWithCustomRules(t *testing.T) {
+	html := `<html><head><base href="https://example.com/"><base href="https://example.org/"/></head><body><img src="image.jpg"></body></html>`
+	baseURL, _, err := findContentUsingCustomRules(strings.NewReader(html), "img")
+	if err != nil {
+		t.Fatalf(`Scraping error: %v`, err)
+	}
+
+	if baseURL != "https://example.com/" {
+		t.Errorf(`Unexpected base URL, got %q instead of "https://example.com/"`, baseURL)
+	}
+}
+
+func TestParseRelativeBaseURLWithCustomRules(t *testing.T) {
+	html := `<html><head><base href="/test"></head><body><img src="image.jpg"></body></html>`
+	baseURL, _, err := findContentUsingCustomRules(strings.NewReader(html), "img")
+	if err != nil {
+		t.Fatalf(`Scraping error: %v`, err)
+	}
+
+	if baseURL != "" {
+		t.Errorf(`Unexpected base URL, got %q`, baseURL)
+	}
+}
+
+func TestParseEmptyBaseURLWithCustomRules(t *testing.T) {
+	html := `<html><head><base href=" "></head><body><img src="image.jpg"></body></html>`
+	baseURL, _, err := findContentUsingCustomRules(strings.NewReader(html), "img")
+	if err != nil {
+		t.Fatalf(`Scraping error: %v`, err)
+	}
+
+	if baseURL != "" {
+		t.Errorf(`Unexpected base URL, got %q instead of ""`, baseURL)
+	}
+}
+
+func TestParseMissingBaseURLWithCustomRules(t *testing.T) {
+	html := `<html><head></head><body><img src="image.jpg"></body></html>`
+	baseURL, _, err := findContentUsingCustomRules(strings.NewReader(html), "img")
+	if err != nil {
+		t.Fatalf(`Scraping error: %v`, err)
+	}
+
+	if baseURL != "" {
+		t.Errorf(`Unexpected base URL, got %q instead of ""`, baseURL)
+	}
+}