Implement 'video_duration_limit' from API

app/soapbox/actions/compose.ts

@@ -8,7 +8,7 @@ import { search as emojiSearch } from 'soapbox/features/emoji/emoji_mart_search_
 import { tagHistory } from 'soapbox/settings';
 import { isLoggedIn } from 'soapbox/utils/auth';
 import { getFeatures, parseVersion } from 'soapbox/utils/features';
-import { formatBytes } from 'soapbox/utils/media';
+import { formatBytes, getVideoDuration } from 'soapbox/utils/media';
 import resizeImage from 'soapbox/utils/resize_image';
 
 import { showAlert, showAlertForError } from './alerts';
@@ -89,6 +89,7 @@ const COMPOSE_SET_STATUS = 'COMPOSE_SET_STATUS';
 const messages = defineMessages({
   exceededImageSizeLimit: { id: 'upload_error.image_size_limit', defaultMessage: 'Image exceeds the current file size limit ({limit})' },
   exceededVideoSizeLimit: { id: 'upload_error.video_size_limit', defaultMessage: 'Video exceeds the current file size limit ({limit})' },
+  exceededVideoDurationLimit: { id: 'upload_error.video_duration_limit', defaultMessage: 'Video exceeds the current duration limit ({limit} seconds)' },
   scheduleError: { id: 'compose.invalid_schedule', defaultMessage: 'You must schedule a post at least 5 minutes out.' },
   success: { id: 'compose.submit_success', defaultMessage: 'Your post was sent' },
   uploadErrorLimit: { id: 'upload_error.limit', defaultMessage: 'File upload limit exceeded.' },
@@ -313,6 +314,7 @@ const uploadCompose = (files: FileList, intl: IntlShape) =>
     const attachmentLimit = getState().instance.configuration.getIn(['statuses', 'max_media_attachments']) as number;
     const maxImageSize = getState().instance.configuration.getIn(['media_attachments', 'image_size_limit']) as number | undefined;
     const maxVideoSize = getState().instance.configuration.getIn(['media_attachments', 'video_size_limit']) as number | undefined;
+    const maxVideoDuration = getState().instance.configuration.getIn(['media_attachments', 'video_duration_limit']) as number | undefined;
 
     const media  = getState().compose.media_attachments;
     const progress = new Array(files.length).fill(0);
@@ -325,11 +327,13 @@ const uploadCompose = (files: FileList, intl: IntlShape) =>
 
     dispatch(uploadComposeRequest());
 
-    Array.from(files).forEach((f, i) => {
+    Array.from(files).forEach(async(f, i) => {
       if (media.size + i > attachmentLimit - 1) return;
 
       const isImage = f.type.match(/image.*/);
       const isVideo = f.type.match(/video.*/);
+      const videoDurationInSeconds = (isVideo && maxVideoDuration) ? await getVideoDuration(f) : 0;
+
       if (isImage && maxImageSize && (f.size > maxImageSize)) {
         const limit = formatBytes(maxImageSize);
         const message = intl.formatMessage(messages.exceededImageSizeLimit, { limit });
@@ -342,6 +346,11 @@ const uploadCompose = (files: FileList, intl: IntlShape) =>
         dispatch(snackbar.error(message));
         dispatch(uploadComposeFail(true));
         return;
+      } else if (isVideo && maxVideoDuration && (videoDurationInSeconds > maxVideoDuration)) {
+        const message = intl.formatMessage(messages.exceededVideoDurationLimit, { limit: maxVideoDuration });
+        dispatch(snackbar.error(message));
+        dispatch(uploadComposeFail(true));
+        return;
       }
 
       // FIXME: Don't define const in loop

app/soapbox/utils/media.ts

@@ -25,4 +25,30 @@ const formatBytes = (bytes: number, decimals: number = 2) => {
   return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
 };
 
-export { formatBytes, truncateFilename };
+const getVideoDuration = (file: File): Promise<number> => {
+  const video = document.createElement('video');
+
+  const promise = new Promise<number>((resolve, reject) => {
+    video.addEventListener('loadedmetadata', () => {
+      // Chrome bug: https://bugs.chromium.org/p/chromium/issues/detail?id=642012
+      if (video.duration === Infinity) {
+        video.currentTime = Number.MAX_SAFE_INTEGER;
+        video.ontimeupdate = () => {
+          video.ontimeupdate = null;
+          resolve(video.duration);
+          video.currentTime = 0;
+        };
+      } else {
+        resolve(video.duration);
+      }
+    });
+
+    video.onerror = (event: any) => reject(event.target.error);
+  });
+
+  video.src = window.URL.createObjectURL(file);
+
+  return promise;
+};
+
+export { getVideoDuration, formatBytes, truncateFilename };