refactor: change directory structure

1 files changed, 509 insertions, 0 deletions

diff --git a/backend/main.go b/backend/main.go
new file mode 100644
index 0000000..018a4b2
--- /dev/null
+++ b/backend/main.go
@@ -0,0 +1,509 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"embed"
+	"fmt"
+	"html/template"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/hashicorp/go-multierror"
+	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v4/middleware"
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/mmcdole/gofeed"
+	"golang.org/x/exp/slices"
+)
+
+var (
+	basePath string
+	db       *sql.DB
+	//go:embed templates/*
+	tmplFS embed.FS
+	//go:embed static/*
+	staticFS embed.FS
+)
+
+type Template struct {
+	templates *template.Template
+}
+
+func (t *Template) Render(w io.Writer, name string, data interface{}, c echo.Context) error {
+	return t.templates.ExecuteTemplate(w, name, data)
+}
+
+func initDB(db *sql.DB) error {
+	_, err := db.Exec(`
+CREATE TABLE IF NOT EXISTS feeds (
+	id         INTEGER PRIMARY KEY AUTOINCREMENT,
+	url        TEXT NOT NULL,
+	title      TEXT NOT NULL,
+	fetched_at TEXT NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS articles (
+	id      INTEGER PRIMARY KEY AUTOINCREMENT,
+	feed_id INTEGER NOT NULL,
+	guid    TEXT NOT NULL,
+	title   TEXT NOT NULL,
+	url     TEXT NOT NULL,
+	is_read INTEGER NOT NULL
+);
+`)
+	return err
+}
+
+func getIndex(c echo.Context) error {
+	// Redirect to /feeds/unread
+	return c.Redirect(http.StatusFound, basePath+"/feeds/unread")
+}
+
+func getSettings(c echo.Context) error {
+	feedURLs := []string{}
+	rows, err := db.Query(`SELECT url FROM feeds`)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var url string
+		err := rows.Scan(&url)
+		if err != nil {
+			return c.String(http.StatusInternalServerError, err.Error())
+		}
+		feedURLs = append(feedURLs, url)
+	}
+	// Sort feedURLs in ascending order.
+	slices.Sort(feedURLs)
+
+	return c.Render(http.StatusOK, "settings.html", struct {
+		BasePath string
+		URLs     string
+	}{
+		BasePath: basePath,
+		URLs:     strings.Join(feedURLs, "\r\n"),
+	})
+}
+
+func postSettings(c echo.Context) error {
+	// Get "urls" from form parameters.
+	rawUrls := strings.Split(c.FormValue("urls"), "\r\n")
+	urls := make([]string, 0, len(rawUrls))
+	for _, rawUrl := range rawUrls {
+		url := strings.TrimSpace(rawUrl)
+		if url != "" {
+			urls = append(urls, url)
+		}
+	}
+	existingURLs := make(map[string]bool)
+	rows, err := db.Query(`SELECT url FROM feeds`)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var url string
+		err := rows.Scan(&url)
+		if err != nil {
+			return c.String(http.StatusInternalServerError, err.Error())
+		}
+		existingURLs[url] = true
+	}
+	for _, url := range urls {
+		if existingURLs[url] {
+			continue
+		}
+		_, err := db.Exec(
+			`INSERT INTO feeds (url, title, fetched_at) VALUES (?, ?, ?)`,
+			url,
+			"",
+			time.Now().AddDate(0, 0, -1).UTC().Format(time.RFC3339),
+		)
+		if err != nil {
+			return c.String(http.StatusInternalServerError, err.Error())
+		}
+	}
+	// Remove:
+	for existingURL := range existingURLs {
+		// If existingURL is not in urls, it will be removed.
+		found := false
+		for _, url := range urls {
+			if existingURL == url {
+				found = true
+				break
+			}
+		}
+		if found {
+			continue
+		}
+		// Remove feed and articles.
+		_, err = db.Exec(`DELETE FROM articles WHERE feed_id = (SELECT id FROM feeds WHERE url = ?)`, existingURL)
+		if err != nil {
+			return c.String(http.StatusInternalServerError, err.Error())
+		}
+		_, err := db.Exec(`DELETE FROM feeds WHERE url = ?`, existingURL)
+		if err != nil {
+			return c.String(http.StatusInternalServerError, err.Error())
+		}
+	}
+	return c.Redirect(http.StatusSeeOther, basePath+"/settings")
+}
+
+func fetchOneFeed(feedID int, url string, ctx context.Context) error {
+	log.Printf("Fetching %s...\n", url)
+	fp := gofeed.NewParser()
+	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
+	defer cancel()
+	feed, err := fp.ParseURLWithContext(url, ctx)
+	if err != nil {
+		return fmt.Errorf("Failed to fetch %s: %v\n", url, err)
+	}
+	_, err = db.Exec(
+		`UPDATE feeds SET title = ?, fetched_at = ? WHERE id = ?`,
+		feed.Title,
+		time.Now().UTC().Format(time.RFC3339),
+		feedID,
+	)
+	if err != nil {
+		return err
+	}
+	rows, err := db.Query(`SELECT guid FROM articles WHERE feed_id = ?`, feedID)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+	existingArticleGUIDs := make(map[string]bool)
+	for rows.Next() {
+		var guid string
+		err := rows.Scan(&guid)
+		if err != nil {
+			return err
+		}
+		existingArticleGUIDs[guid] = true
+	}
+	for _, item := range feed.Items {
+		if existingArticleGUIDs[item.GUID] {
+			_, err := db.Exec(
+				`UPDATE articles SET title = ?, url = ? WHERE feed_id = ? AND guid = ?`,
+				item.Title,
+				item.Link,
+				feedID,
+				item.GUID,
+			)
+			if err != nil {
+				return err
+			}
+		} else {
+			_, err := db.Exec(
+				`INSERT INTO articles (feed_id, guid, title, url, is_read) VALUES (?, ?, ?, ?, ?)`,
+				feedID,
+				item.GUID,
+				item.Title,
+				item.Link,
+				0,
+			)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func listFeedsToBeFetched() (map[int]string, error) {
+	rows, err := db.Query(`SELECT id, url, fetched_at FROM feeds`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	feeds := make(map[int]string)
+	for rows.Next() {
+		var feedID int
+		var url string
+		var fetchedAt string
+		err := rows.Scan(&feedID, &url, &fetchedAt)
+		if err != nil {
+			log.Fatal(err)
+		}
+		fetchedAtTime, err := time.Parse(time.RFC3339, fetchedAt)
+		if err != nil {
+			log.Fatal(err)
+		}
+		now := time.Now().UTC()
+		if now.Sub(fetchedAtTime).Minutes() <= 10 {
+			continue
+		}
+		feeds[feedID] = url
+	}
+	return feeds, nil
+}
+
+func fetchAllFeeds(ctx context.Context) error {
+	feeds, err := listFeedsToBeFetched()
+	if err != nil {
+		return err
+	}
+
+	var result *multierror.Error
+	for feedID, url := range feeds {
+		err := fetchOneFeed(feedID, url, ctx)
+		if err != nil {
+			result = multierror.Append(result, err)
+		}
+		time.Sleep(5 * time.Second)
+	}
+	return result.ErrorOrNil()
+}
+
+func getUnreadFeeds(c echo.Context) error {
+	rows, err := db.Query(`
+SELECT a.id, a.title, f.url, f.title, f.id
+FROM articles AS a
+INNER JOIN feeds AS f ON a.feed_id = f.id
+WHERE is_read = 0
+ORDER BY a.id DESC
+LIMIT 100
+`)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	defer rows.Close()
+
+	return renderFeeds(c, "Unread feeds", "unread-feeds.html", rows)
+}
+
+func getReadFeeds(c echo.Context) error {
+	rows, err := db.Query(`
+SELECT a.id, a.title, f.url, f.title, f.id
+FROM articles AS a
+INNER JOIN feeds AS f ON a.feed_id = f.id
+WHERE is_read = 1
+ORDER BY a.id DESC
+LIMIT 100
+`)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	defer rows.Close()
+
+	return renderFeeds(c, "Read feeds", "read-feeds.html", rows)
+}
+
+func renderFeeds(c echo.Context, title string, templateName string, rows *sql.Rows) error {
+	type Article struct {
+		ID    int
+		Title string
+		URL   string
+	}
+	type Feed struct {
+		ID       int
+		URL      string
+		Title    string
+		Articles []Article
+	}
+	feeds := make(map[int]*Feed)
+	for rows.Next() {
+		var articleID int
+		var articleTitle string
+		var feedURL string
+		var feedTitle string
+		var feedID int
+		err := rows.Scan(&articleID, &articleTitle, &feedURL, &feedTitle, &feedID)
+		if err != nil {
+			return c.String(http.StatusInternalServerError, err.Error())
+		}
+		if _, ok := feeds[feedID]; !ok {
+			feeds[feedID] = &Feed{
+				ID:    feedID,
+				URL:   feedURL,
+				Title: feedTitle,
+			}
+		}
+		feed := feeds[feedID]
+		feed.Articles = append(feed.Articles, Article{
+			ID:    articleID,
+			Title: articleTitle,
+			URL:   fmt.Sprintf("%s/articles/%d", basePath, articleID),
+		})
+	}
+
+	sortedFeeds := make([]*Feed, 0, len(feeds))
+	for _, feed := range feeds {
+		sortedFeeds = append(sortedFeeds, feed)
+	}
+	slices.SortFunc(sortedFeeds, func(a, b *Feed) int {
+		// Ascending order by URL.
+		if a.URL < b.URL {
+			return -1
+		} else if a.URL > b.URL {
+			return 1
+		} else {
+			return 0
+		}
+	})
+
+	return c.Render(http.StatusOK, templateName, struct {
+		BasePath string
+		Title    string
+		Feeds    []*Feed
+	}{
+		BasePath: basePath,
+		Title:    title,
+		Feeds:    sortedFeeds,
+	})
+}
+
+func getArticle(c echo.Context) error {
+	rawArticleID := c.Param("articleID")
+	articleID, err := strconv.Atoi(rawArticleID)
+	if err != nil {
+		return c.String(http.StatusNotFound, err.Error())
+	}
+	row := db.QueryRow(`SELECT url FROM articles WHERE id = ?`, articleID)
+	if row == nil {
+		return c.String(http.StatusNotFound, "Not found")
+	}
+	var url string
+	err = row.Scan(&url)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	// Turn is_read on.
+	_, err = db.Exec(`UPDATE articles SET is_read = 1 WHERE id = ?`, articleID)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	// Redirect to the article URL.
+	return c.Redirect(http.StatusFound, url)
+}
+
+func apiPutFeedRead(c echo.Context) error {
+	return apiPutFeed(c, "read")
+}
+
+func apiPutFeedUnread(c echo.Context) error {
+	return apiPutFeed(c, "unread")
+}
+
+func apiPutFeed(c echo.Context, op string) error {
+	rawFeedID := c.Param("feedID")
+	feedID, err := strconv.Atoi(rawFeedID)
+	if err != nil {
+		return c.String(http.StatusNotFound, err.Error())
+	}
+	// Turn is_read on or off.
+	var isReadValue int
+	if op == "read" {
+		isReadValue = 1
+	} else if op == "unread" {
+		isReadValue = 0
+	}
+	_, err = db.Exec(`UPDATE articles SET is_read = ? WHERE feed_id = ?`, isReadValue, feedID)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	return c.NoContent(http.StatusOK)
+}
+
+func apiPutArticleRead(c echo.Context) error {
+	return apiPutArticle(c, "read")
+}
+
+func apiPutArticleUnread(c echo.Context) error {
+	return apiPutArticle(c, "unread")
+}
+
+func apiPutArticle(c echo.Context, op string) error {
+	rawArticleID := c.Param("articleID")
+	articleID, err := strconv.Atoi(rawArticleID)
+	if err != nil {
+		return c.String(http.StatusNotFound, err.Error())
+	}
+	// Turn is_read on or off.
+	var isReadValue int
+	if op == "read" {
+		isReadValue = 1
+	} else if op == "unread" {
+		isReadValue = 0
+	}
+	_, err = db.Exec(`UPDATE articles SET is_read = ? WHERE id = ?`, isReadValue, articleID)
+	if err != nil {
+		return c.String(http.StatusInternalServerError, err.Error())
+	}
+	return c.NoContent(http.StatusOK)
+}
+
+func scheduled(ctx context.Context, d time.Duration, fn func()) {
+	ticker := time.NewTicker(d)
+	go func() {
+		for {
+			select {
+			case <-ticker.C:
+				fn()
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+}
+
+func main() {
+	basePath = os.Getenv("FEEDAKA_BASE_PATH")
+	port := os.Getenv("FEEDAKA_PORT")
+
+	var err error
+	db, err = sql.Open("sqlite3", "feedaka.db")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	err = initDB(db)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	t := &Template{
+		templates: template.Must(template.ParseFS(tmplFS, "templates/*.html")),
+	}
+
+	e := echo.New()
+
+	e.Renderer = t
+	e.Use(middleware.Logger())
+	e.Use(middleware.Recover())
+
+	e.GET("/", getIndex)
+	e.GET("/settings", getSettings)
+	e.POST("/settings", postSettings)
+	e.GET("/feeds/unread", getUnreadFeeds)
+	e.GET("/feeds/read", getReadFeeds)
+	e.GET("/articles/:articleID", getArticle)
+
+	e.PUT("/api/feeds/:feedID/read", apiPutFeedRead)
+	e.PUT("/api/feeds/:feedID/unread", apiPutFeedUnread)
+	e.PUT("/api/articles/:articleID/read", apiPutArticleRead)
+	e.PUT("/api/articles/:articleID/unread", apiPutArticleUnread)
+
+	e.GET("/static/*", echo.WrapHandler(http.FileServer(http.FS(staticFS))))
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	scheduled(ctx, 1*time.Hour, func() {
+		err := fetchAllFeeds(ctx)
+		if err != nil {
+			log.Printf("Failed to fetch feeds: %v\n", err)
+		}
+	})
+
+	err = http.ListenAndServe(":"+port, http.StripPrefix(basePath, e))
+	log.Println(err)
+}