feat(story-2.2): add feed parser with gofeed and article repository

internal/parser/parser.go

@@ -0,0 +1,136 @@
+// Package parser provides RSS/Atom feed parsing functionality.
+package parser
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/michael/flowreader/internal/domain"
+	"github.com/mmcdole/gofeed"
+)
+
+// FeedParser handles RSS/Atom feed parsing.
+type FeedParser struct {
+	client *http.Client
+	parser *gofeed.Parser
+}
+
+// NewFeedParser creates a new feed parser.
+func NewFeedParser() *FeedParser {
+	client := &http.Client{
+		Timeout: 30 * time.Second,
+	}
+
+	return &FeedParser{
+		client: client,
+		parser: gofeed.NewParser(),
+	}
+}
+
+// ParsedFeed contains the parsed feed data.
+type ParsedFeed struct {
+	Title       string
+	Description string
+	SiteURL     string
+	ImageURL    string
+	Articles    []*domain.Article
+}
+
+// Parse fetches and parses a feed URL.
+func (p *FeedParser) Parse(ctx context.Context, feedURL string, feedID uuid.UUID) (*ParsedFeed, error) {
+	// Create request with context
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, feedURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+	req.Header.Set("User-Agent", "FlowReader/1.0 (RSS Reader)")
+
+	// Fetch the feed
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("fetching feed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+	}
+
+	// Parse the feed
+	feed, err := p.parser.Parse(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("parsing feed: %w", err)
+	}
+
+	// Extract metadata
+	parsed := &ParsedFeed{
+		Title:       feed.Title,
+		Description: feed.Description,
+	}
+
+	if feed.Link != "" {
+		parsed.SiteURL = feed.Link
+	}
+
+	if feed.Image != nil && feed.Image.URL != "" {
+		parsed.ImageURL = feed.Image.URL
+	}
+
+	// Convert items to articles
+	for _, item := range feed.Items {
+		article := &domain.Article{
+			ID:     uuid.New(),
+			FeedID: feedID,
+			GUID:   getGUID(item),
+			Title:  item.Title,
+		}
+
+		if item.Link != "" {
+			article.URL = item.Link
+		}
+
+		if item.Content != "" {
+			article.Content = item.Content
+		}
+
+		if item.Description != "" {
+			article.Summary = item.Description
+		}
+
+		if item.Author != nil {
+			article.Author = item.Author.Name
+		} else if len(item.Authors) > 0 {
+			article.Author = item.Authors[0].Name
+		}
+
+		if item.Image != nil && item.Image.URL != "" {
+			article.ImageURL = item.Image.URL
+		}
+
+		if item.PublishedParsed != nil {
+			article.PublishedAt = item.PublishedParsed
+		} else if item.UpdatedParsed != nil {
+			article.PublishedAt = item.UpdatedParsed
+		}
+
+		article.CreatedAt = time.Now()
+
+		parsed.Articles = append(parsed.Articles, article)
+	}
+
+	return parsed, nil
+}
+
+// getGUID returns a unique identifier for the feed item.
+func getGUID(item *gofeed.Item) string {
+	if item.GUID != "" {
+		return item.GUID
+	}
+	if item.Link != "" {
+		return item.Link
+	}
+	return item.Title // Last resort fallback
+}