Fallback to a feed's updated date when items lack a published date

Author: theandrew168

backend/feed/feed.go

@@ -49,6 +49,23 @@ func NormalizePostURL(blogURL, postURL string) string {
 	return url
 }
 
+func DeterminePublishedAt(feed *gofeed.Feed, item *gofeed.Item, now time.Time) time.Time {
+	// Default the published date to now (though it will likely get overwritten).
+	publishedAt := now
+
+	// If the feed has an updated date, use it (better than now).
+	if feed.UpdatedParsed != nil {
+		publishedAt = *feed.UpdatedParsed
+	}
+
+	// If the item has a published date, use it (better than the feed's updated date).
+	if item.PublishedParsed != nil {
+		publishedAt = *item.PublishedParsed
+	}
+
+	return publishedAt.UTC().Round(time.Microsecond)
+}
+
 func Parse(feedURL string, feedBody string) (Blog, error) {
 	fp := gofeed.NewParser()
 	feed, err := fp.ParseString(feedBody)
@@ -58,21 +75,13 @@ func Parse(feedURL string, feedBody string) (Blog, error) {
 
 	var posts []Post
 	for _, item := range feed.Items {
-		// skip items without a link or title
+		// Skip items without a link or title.
 		if item.Link == "" || item.Title == "" {
 			continue
 		}
 
 		url := NormalizePostURL(feed.Link, item.Link)
-
-		// check for a publish date, else default to now
-		publishedAt := time.Now()
-		if item.PublishedParsed != nil {
-			publishedAt = *item.PublishedParsed
-		}
-
-		// ensure publishedAt is in UTC
-		publishedAt = publishedAt.UTC().Round(time.Microsecond)
+		publishedAt := DeterminePublishedAt(feed, item, time.Now())
 
 		post := Post{
 			URL:         url,

backend/feed/feed_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/mmcdole/gofeed"
 	"github.com/theandrew168/bloggulus/backend/feed"
 	feedMock "github.com/theandrew168/bloggulus/backend/feed/mock"
 	"github.com/theandrew168/bloggulus/backend/test"
@@ -30,6 +31,59 @@ func TestNormalizePostURL(t *testing.T) {
 	}
 }
 
+func TestDeterminePublishedAt(t *testing.T) {
+	t.Parallel()
+
+	feedUpdatedParsed := time.Now().AddDate(0, 0, -1)
+	itemPublishedParsed := time.Now().AddDate(0, 0, -2)
+	now := time.Now()
+
+	tests := []struct {
+		feedUpdatedParsed   *time.Time
+		itemPublishedParsed *time.Time
+		now                 time.Time
+		want                time.Time
+	}{
+		{
+			// Without any feed or item published date, use now.
+			feedUpdatedParsed:   nil,
+			itemPublishedParsed: nil,
+			now:                 now,
+			want:                now.UTC().Round(time.Microsecond),
+		},
+		{
+			// If the feed has an updated date, use it.
+			feedUpdatedParsed:   &feedUpdatedParsed,
+			itemPublishedParsed: nil,
+			now:                 now,
+			want:                feedUpdatedParsed.UTC().Round(time.Microsecond),
+		},
+		{
+			// If the item has a published date, use it.
+			feedUpdatedParsed:   nil,
+			itemPublishedParsed: &itemPublishedParsed,
+			now:                 now,
+			want:                itemPublishedParsed.UTC().Round(time.Microsecond),
+		},
+		{
+			// If item has a published date, use it even if the feed has an updated date.
+			feedUpdatedParsed:   &feedUpdatedParsed,
+			itemPublishedParsed: &itemPublishedParsed,
+			now:                 now,
+			want:                itemPublishedParsed.UTC().Round(time.Microsecond),
+		},
+	}
+
+	for _, tt := range tests {
+		got := feed.DeterminePublishedAt(
+			&gofeed.Feed{UpdatedParsed: tt.feedUpdatedParsed},
+			&gofeed.Item{PublishedParsed: tt.itemPublishedParsed},
+			tt.now,
+		)
+		test.AssertEqual(t, got, tt.want)
+	}
+}
+
 func TestParse(t *testing.T) {
 	t.Parallel()