electron/index.js

@@ -20,6 +20,7 @@ import path from 'path';
 import { diskSpaceLinux, diskSpaceWindows, diskSpaceMac } from '../ui/util/diskspace';
 
 const { download } = require('electron-dl');
+const mime = require('mime');
 const remote = require('@electron/remote/main');
 const os = require('os');
 const sudo = require('sudo-prompt');
@@ -318,6 +319,7 @@ ipcMain.handle('get-file-from-path', (event, path) => {
       const fileName = folders[folders.length - 1];
       resolve({
         name: fileName,
+        mime: mime.getType(fileName) || undefined,
         path: path,
         buffer: data,
       });

package.json

@@ -54,6 +54,7 @@
     "humanize-duration": "^3.27.0",
     "if-env": "^1.0.4",
     "match-sorter": "^6.3.0",
+    "mime": "^3.0.0",
     "node-html-parser": "^5.1.0",
     "parse-duration": "^1.0.0",
     "proxy-polyfill": "0.1.6",

ui/component/common/file-selector.jsx

@@ -83,7 +83,16 @@ class FileSelector extends React.PureComponent<Props> {
         if (!result) {
           return;
         }
-        const file = new File([result.buffer], result.name);
+        const file = new File([result.buffer], result.name, {
+          type: result.mime,
+        });
+        // "path" is a read only property so we have to use this
+        // hack to overcome the limitation.
+        // $FlowFixMe
+        Object.defineProperty(file, 'path', {
+          value: result.path,
+          writable: false,
+        });
         this.props.onFileChosen(file);
       });
   };

ui/component/publishFile/view.jsx

@@ -233,7 +233,7 @@ function PublishFile(props: Props) {
       isTextPost = contentType[1] === 'plain' || contentType[1] === 'markdown';
       setCurrentFileType(contentType);
     } else if (file.name) {
-      // If user's machine is missign a valid content type registration
+      // If user's machine is missing a valid content type registration
       // for markdown content: text/markdown, file extension will be used instead
       const extension = file.name.split('.').pop();
       isTextPost = MARKDOWN_FILE_EXTENSIONS.includes(extension);

yarn.lock

@@ -11549,6 +11549,7 @@ __metadata:
     lodash-es: ^4.17.21
     mammoth: ^1.4.16
     match-sorter: ^6.3.0
+    mime: ^3.0.0
     moment: ^2.29.2
     node-abi: ^2.5.1
     node-fetch: ^2.6.7
@@ -12576,6 +12577,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"mime@npm:^3.0.0":
+  version: 3.0.0
+  resolution: "mime@npm:3.0.0"
+  bin:
+    mime: cli.js
+  checksum: f43f9b7bfa64534e6b05bd6062961681aeb406a5b53673b53b683f27fcc4e739989941836a355eef831f4478923651ecc739f4a5f6e20a76487b432bfd4db928
+  languageName: node
+  linkType: hard
+
 "mimic-fn@npm:^1.0.0":
   version: 1.2.0
   resolution: "mimic-fn@npm:1.2.0"