first commit

common/resources/client/uploads/uploader/validate-upload.ts

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+import {UploadedFile} from '../uploaded-file';
+import {message} from '../../i18n/message';
+import {prettyBytes} from '../utils/pretty-bytes';
+import {MessageDescriptor} from '../../i18n/message-descriptor';
+import match from 'mime-match';
+
+export interface Restrictions {
+  maxFileSize?: number;
+  allowedFileTypes?: string[];
+  blockedFileTypes?: string[];
+}
+
+export function validateUpload(
+  file: UploadedFile,
+  restrictions?: Restrictions
+): MessageDescriptor | void {
+  if (!restrictions) return;
+
+  const {maxFileSize, allowedFileTypes, blockedFileTypes} = restrictions;
+
+  if (maxFileSize && file.size != null && file.size > maxFileSize) {
+    return message('`:file` exceeds maximum allowed size of :size', {
+      values: {file: file.name, size: prettyBytes(maxFileSize)},
+    });
+  }
+
+  if (allowedFileTypes?.length) {
+    if (!fileMatchesTypes(file, allowedFileTypes)) {
+      return message('This file type is not allowed');
+    }
+  }
+
+  if (blockedFileTypes?.length) {
+    if (fileMatchesTypes(file, blockedFileTypes)) {
+      return message('This file type is not allowed');
+    }
+  }
+}
+
+function fileMatchesTypes(file: UploadedFile, types: string[]): boolean {
+  return (
+    types
+      // support multiple file types in a string (video/mp4,audio/mp3,image/png)
+      .map(type => type.split(','))
+      .flat()
+      .some(type => {
+        // check if this is a mime-type
+        if (type.includes('/')) {
+          if (!file.mime) return false;
+          return match(file.mime.replace(/;.*?$/, ''), type);
+        }
+
+        // otherwise this is likely an extension
+        const extension = type.replace('.', '').toLowerCase();
+        if (extension && file.extension) {
+          return file.extension.toLowerCase() === extension;
+        }
+        return false;
+      })
+  );
+}