validate image existence before post or preview

backend/app/rest/api/rest_private.go

@@ -88,6 +88,20 @@ func (s *private) createCommentCtrl(w http.ResponseWriter, r *http.Request) {
 	}
 	comment = s.commentFormatter.Format(comment)
 
+	// check if images are valid
+	imgIds, err := s.imageService.ExtractPictures(comment.Text)
+	if err != nil {
+		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't extract pictures from comment text", rest.ErrCommentValidation)
+		return
+	}
+	for _, id := range imgIds {
+		_, err = s.imageService.Load(id)
+		if err != nil {
+			rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't load picture from the comment", rest.ErrImgNotFound)
+			return
+		}
+	}
+
 	// check if user blocked
 	if s.dataService.IsBlocked(comment.Locator.SiteID, comment.User.ID) {
 		rest.SendErrorJSON(w, r, http.StatusForbidden, errors.New("rejected"), "user blocked", rest.ErrUserBlocked)

backend/app/rest/api/rest_private_test.go

@@ -165,6 +165,28 @@ func TestRest_CreateRejected(t *testing.T) {
 	require.Equal(t, http.StatusForbidden, resp.StatusCode, "reject wrong aud")
 }
 
+func TestRest_CreateWithWrongImage(t *testing.T) {
+	ts, srv, teardown := startupT(t)
+	defer teardown()
+
+	// create comment
+	resp, err := post(t, ts.URL+"/api/v1/comment", fmt.Sprintf(`{"text": "![non-existent.jpg](%s/api/v1/picture/dev_user/bad_picture)", "locator":{"url": "https://radio-t.com/blah1", "site": "radio-t"}}`, srv.RemarkURL))
+	assert.NoError(t, err)
+	assert.Equal(t, http.StatusBadRequest, resp.StatusCode)
+	b, err := ioutil.ReadAll(resp.Body)
+	assert.NoError(t, err)
+	assert.NoError(t, resp.Body.Close())
+	assert.Contains(t,
+		string(b),
+		"{\"code\":20,\"details\":\"can't load picture from the comment\","+
+			"\"error\":\"can't get image file for dev_user/bad_picture: can't get image stats for dev_user/bad_picture: stat ",
+	)
+	assert.Contains(t,
+		string(b),
+		"/pics-remark42/staging/dev_user/62/bad_picture: no such file or directory\"}\n",
+	)
+}
+
 func TestRest_CreateWithLazyImage(t *testing.T) {
 	ts, _, teardown := startupT(t)
 	defer teardown()
@@ -979,6 +1001,8 @@ func TestRest_CreateWithPictures(t *testing.T) {
 	}, image.ServiceParams{
 		EditDuration: 100 * time.Millisecond,
 		MaxSize:      2000,
+		ImageAPI:     svc.RemarkURL + "/api/v1/picture/",
+		ProxyAPI:     svc.RemarkURL + "/api/v1/img",
 	})
 	defer imageService.Close(context.Background())
 
@@ -1022,7 +1046,7 @@ func TestRest_CreateWithPictures(t *testing.T) {
 		ids[i] = uploadPicture(fmt.Sprintf("pic%d.png", i))
 	}
 
-	text := fmt.Sprintf(`text 123  ![](/api/v1/picture/%s) *xxx* ![](/api/v1/picture/%s) ![](/api/v1/picture/%s)`, ids[0], ids[1], ids[2])
+	text := fmt.Sprintf(`text 123  ![](%s/api/v1/picture/%s) *xxx* ![](%s/api/v1/picture/%s) ![](%s/api/v1/picture/%s)`, svc.RemarkURL, ids[0], svc.RemarkURL, ids[1], svc.RemarkURL, ids[2])
 	body := fmt.Sprintf(`{"text": "%s", "locator":{"url": "https://radio-t.com/blah1", "site": "remark42"}}`, text)
 
 	resp, err := post(t, ts.URL+"/api/v1/comment", body)

backend/app/rest/api/rest_public.go

@@ -132,6 +132,21 @@ func (s *public) previewCommentCtrl(w http.ResponseWriter, r *http.Request) {
 
 	comment = s.commentFormatter.Format(comment)
 	comment.Sanitize()
+
+	// check if images are valid
+	imgIds, err := s.imageService.ExtractPictures(comment.Text)
+	if err != nil {
+		rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't extract pictures from comment text", rest.ErrCommentValidation)
+		return
+	}
+	for _, id := range imgIds {
+		_, err = s.imageService.Load(id)
+		if err != nil {
+			rest.SendErrorJSON(w, r, http.StatusBadRequest, err, "can't load picture from the comment", rest.ErrImgNotFound)
+			return
+		}
+	}
+
 	render.HTML(w, r, comment.Text)
 }
 

backend/app/rest/api/rest_public_test.go

@@ -45,6 +45,27 @@ func TestRest_Preview(t *testing.T) {
 	assert.Equal(t, 400, resp.StatusCode)
 }
 
+func TestRest_PreviewWithWrongImage(t *testing.T) {
+	ts, srv, teardown := startupT(t)
+	defer teardown()
+
+	resp, err := post(t, ts.URL+"/api/v1/preview", fmt.Sprintf(`{"text": "![non-existent.jpg](%s/api/v1/picture/dev_user/bad_picture)", "locator":{"url": "https://radio-t.com/blah1", "site": "radio-t"}}`, srv.RemarkURL))
+	assert.NoError(t, err)
+	assert.Equal(t, http.StatusBadRequest, resp.StatusCode)
+	b, err := ioutil.ReadAll(resp.Body)
+	assert.NoError(t, err)
+	assert.NoError(t, resp.Body.Close())
+	assert.Contains(t,
+		string(b),
+		"{\"code\":20,\"details\":\"can't load picture from the comment\","+
+			"\"error\":\"can't get image file for dev_user/bad_picture: can't get image stats for dev_user/bad_picture: stat ",
+	)
+	assert.Contains(t,
+		string(b),
+		"/pics-remark42/staging/dev_user/62/bad_picture: no such file or directory\"}\n",
+	)
+}
+
 func TestRest_PreviewWithMD(t *testing.T) {
 	ts, _, teardown := startupT(t)
 	defer teardown()

backend/app/rest/api/rest_test.go

@@ -402,6 +402,8 @@ func startupT(t *testing.T) (ts *httptest.Server, srv *Rest, teardown func()) {
 		RestrictedWordsMatcher: restrictedWordsMatcher,
 	}
 
+	remarkURL := "https://demo.remark42.com"
+
 	srv = &Rest{
 		DataService: dataStore,
 		Authenticator: auth.NewService(auth.Opts{
@@ -411,13 +413,15 @@ func startupT(t *testing.T) (ts *httptest.Server, srv *Rest, teardown func()) {
 		}),
 		Cache:     memCache,
 		WebRoot:   tmp,
-		RemarkURL: "https://demo.remark42.com",
+		RemarkURL: remarkURL,
 		ImageService: image.NewService(&image.FileSystem{
 			Location:   tmp + "/pics-remark42",
 			Partitions: 100,
 			Staging:    tmp + "/pics-remark42/staging",
 		}, image.ServiceParams{
 			EditDuration: 100 * time.Millisecond,
+			ImageAPI:     remarkURL + "/api/v1/picture/",
+			ProxyAPI:     remarkURL + "/api/v1/img",
 			MaxSize:      10000,
 		}),
 		ImageProxy:       &proxy.Image{},

backend/app/rest/httperrors.go

@@ -39,6 +39,7 @@ const (
 	ErrActionRejected       = 17 // general error for rejected actions
 	ErrAssetNotFound        = 18 // requested file not found
 	ErrCommentRestrictWords = 19 // restricted words in a comment
+	ErrImgNotFound          = 20 // posted image not found in the storage
 )
 
 // errTmplData store data for error message

backend/app/store/image/image.go

@@ -164,22 +164,28 @@ func (s *Service) ExtractPictures(commentHTML string) (ids []string, err error)
 				}
 			}
 			if strings.Contains(im, s.ProxyAPI) {
-				proxiedURL, err := url.Parse(im)
-				if err != nil {
+				proxiedURL, e := url.Parse(im)
+				if e != nil {
+					err = errors.Wrapf(e, "problem parsing %s", im)
 					return
 				}
-				imgURL, err := base64.URLEncoding.DecodeString(proxiedURL.Query().Get("src"))
-				if err != nil {
+				imgURL, e := base64.URLEncoding.DecodeString(proxiedURL.Query().Get("src"))
+				if e != nil {
+					err = errors.Wrapf(e, "problem decodind base64 from %s", im)
 					return
 				}
-				imgID, err := CachedImgID(string(imgURL))
-				if err != nil {
+				imgID, e := CachedImgID(string(imgURL))
+				if e != nil {
+					err = errors.Wrapf(e, "problem retrieving cached URL for %s", im)
 					return
 				}
 				ids = append(ids, imgID)
 			}
 		}
 	})
+	if err != nil {
+		return nil, err
+	}
 
 	return ids, nil
 }

backend/app/store/image/image_test.go

@@ -105,20 +105,20 @@ func TestService_ExtractPictures(t *testing.T) {
 	// bad url
 	html = `<img src=" https://remark42.radio-t.com/api/v1/img">`
 	ids, err = svc.ExtractPictures(html)
-	require.NoError(t, err)
+	require.Error(t, err)
 	require.Empty(t, ids)
 
 	// bad src
 	html = `<img src="https://remark42.radio-t.com/api/v1/img?src=bad">`
 	ids, err = svc.ExtractPictures(html)
-	require.NoError(t, err)
+	require.Error(t, err)
 	require.Empty(t, ids)
 
 	// good src with bad content
 	badURL := base64.URLEncoding.EncodeToString([]byte(" http://foo.bar"))
 	html = fmt.Sprintf(`<img src="https://remark42.radio-t.com/api/v1/img?src=%s">`, badURL)
 	ids, err = svc.ExtractPictures(html)
-	require.NoError(t, err)
+	require.Error(t, err)
 	require.Empty(t, ids)
 }