Publish new posts to mailing list

srv/src/http/posts.go

@@ -131,11 +131,17 @@ func (a *api) renderPostHandler() http.Handler {
 
 func (a *api) renderPostsIndexHandler() http.Handler {
 
+	renderEditPostHandler := a.renderEditPostHandler()
 	tpl := a.mustParseBasedTpl("posts.html")
 	const pageCount = 20
 
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 
+		if _, ok := r.URL.Query()["edit"]; ok {
+			renderEditPostHandler.ServeHTTP(rw, r)
+			return
+		}
+
 		page, err := apiutil.StrToInt(r.FormValue("p"), 0)
 		if err != nil {
 			apiutil.BadRequest(
@@ -239,13 +245,28 @@ func (a *api) postPostHandler() http.Handler {
 			return
 		}
 
-		if err := a.params.PostStore.Set(p, time.Now()); err != nil {
+		first, err := a.params.PostStore.Set(p, time.Now())
+
+		if err != nil {
 			apiutil.InternalServerError(
 				rw, r, fmt.Errorf("storing post with id %q: %w", p.ID, err),
 			)
 			return
 		}
 
+		if first {
+
+			a.params.Logger.Info(r.Context(), "publishing blog post to mailing list")
+			urlStr := a.params.PublicURL.String() + filepath.Join("/posts", p.ID)
+
+			if err := a.params.MailingList.Publish(p.Title, urlStr); err != nil {
+				apiutil.InternalServerError(
+					rw, r, fmt.Errorf("publishing post with id %q: %w", p.ID, err),
+				)
+				return
+			}
+		}
+
 		redirectPath := fmt.Sprintf("posts/%s?edit", p.ID)
 
 		a.executeRedirectTpl(rw, r, redirectPath)

srv/src/post/post.go

@@ -48,9 +48,10 @@ type StoredPost struct {
 // Store is used for storing posts to a persistent storage.
 type Store interface {
 
-	// Set sets the Post data into the storage, keyed by the Post's ID. It
+	// Set sets the Post data into the storage, keyed by the Post's ID. If there
-	// overwrites a previous Post with the same ID, if there was one.
+	// was not a previously existing Post with the same ID then Set returns
-	Set(post Post, now time.Time) error
+	// true. It overwrites the previous Post with the same ID otherwise.
+	Set(post Post, now time.Time) (bool, error)
 
 	// Get returns count StoredPosts, sorted time descending, offset by the
 	// given page number. The returned boolean indicates if there are more pages
@@ -114,13 +115,15 @@ func (s *store) withTx(cb func(*sql.Tx) error) error {
 	return nil
 }
 
-func (s *store) Set(post Post, now time.Time) error {
+func (s *store) Set(post Post, now time.Time) (bool, error) {
 
 	if post.ID == "" {
-		return errors.New("post ID can't be empty")
+		return false, errors.New("post ID can't be empty")
 	}
 
-	return s.withTx(func(tx *sql.Tx) error {
+	var first bool
+
+	err := s.withTx(func(tx *sql.Tx) error {
 
 		nowTS := now.Unix()
 
@@ -173,8 +176,17 @@ func (s *store) Set(post Post, now time.Time) error {
 			}
 		}
 
+		err = tx.QueryRow(
+			`SELECT 1 FROM posts WHERE id=? AND last_updated_at IS NULL`,
+			post.ID,
+		).Scan(new(int))
+
+		first = !errors.Is(err, sql.ErrNoRows)
+
 		return nil
 	})
+
+	return first, err
 }
 
 func (s *store) get(

srv/src/post/post_test.go

@@ -108,7 +108,9 @@ func TestStore(t *testing.T) {
 		post := testPost(0)
 		post.Tags = []string{"foo", "bar"}
 
-		assert.NoError(t, h.store.Set(post, now))
+		first, err := h.store.Set(post, now)
+		assert.NoError(t, err)
+		assert.True(t, first)
 
 		gotPost, err := h.store.GetByID(post.ID)
 		assert.NoError(t, err)
@@ -129,7 +131,9 @@ func TestStore(t *testing.T) {
 		post.Body = "anything"
 		post.Tags = []string{"bar", "baz"}
 
-		assert.NoError(t, h.store.Set(post, newNow))
+		first, err = h.store.Set(post, newNow)
+		assert.NoError(t, err)
+		assert.False(t, first)
 
 		gotPost, err = h.store.GetByID(post.ID)
 		assert.NoError(t, err)
@@ -160,7 +164,8 @@ func TestStore(t *testing.T) {
 		}
 
 		for _, post := range posts {
-			assert.NoError(t, h.store.Set(post.Post, now))
+			_, err := h.store.Set(post.Post, now)
+			assert.NoError(t, err)
 		}
 
 		gotPosts, hasMore, err := h.store.Get(0, 2)
@@ -174,7 +179,8 @@ func TestStore(t *testing.T) {
 		assertPostsEqual(t, posts[2:4], gotPosts)
 
 		posts = append([]StoredPost{h.testStoredPost(4)}, posts...)
-		assert.NoError(t, h.store.Set(posts[0].Post, now))
+		_, err = h.store.Set(posts[0].Post, now)
+		assert.NoError(t, err)
 
 		gotPosts, hasMore, err = h.store.Get(1, 2)
 		assert.NoError(t, err)
@@ -204,7 +210,8 @@ func TestStore(t *testing.T) {
 		posts[2].Series = "bar"
 
 		for _, post := range posts {
-			assert.NoError(t, h.store.Set(post.Post, now))
+			_, err := h.store.Set(post.Post, now)
+			assert.NoError(t, err)
 		}
 
 		fooPosts, err := h.store.GetBySeries("foo")
@@ -238,7 +245,8 @@ func TestStore(t *testing.T) {
 		posts[2].Tags = []string{"bar"}
 
 		for _, post := range posts {
-			assert.NoError(t, h.store.Set(post.Post, now))
+			_, err := h.store.Set(post.Post, now)
+			assert.NoError(t, err)
 		}
 
 		fooPosts, err := h.store.GetByTag("foo")