use NPM module `mime` to getType(ext)

package.json

@@ -94,6 +94,7 @@
     "body-parser": "^1.18.2",
     "brolog": "^1.2.8",
     "hot-import": "^0.1.21",
+    "mime": "^2.0.3",
     "puppeteer": "^0.11.0",
     "raven": "^2.2.1",
     "request": "^2.83.0",

src/misc.ts

@@ -274,26 +274,26 @@ export class Misc {
     }
   }
 
-  public static mime(ext): string {
-    switch (ext) {
-      case 'pdf':
-        return 'application/pdf'
-      case 'bmp':
-        return 'image/bmp'
-      case 'jpeg':
-        return 'image/jpeg'
-      case 'jpg':
-        return 'image/jpeg'
-      case 'png':
-        return 'image/png'
-      case 'gif':
-        return 'image/gif'
-      case 'mp4':
-        return 'video/mp4'
-      default:
-        return 'application/octet-stream'
-    }
-  }
+  // public static mime(ext): string {
+  //   switch (ext) {
+  //     case 'pdf':
+  //       return 'application/pdf'
+  //     case 'bmp':
+  //       return 'image/bmp'
+  //     case 'jpeg':
+  //       return 'image/jpeg'
+  //     case 'jpg':
+  //       return 'image/jpeg'
+  //     case 'png':
+  //       return 'image/png'
+  //     case 'gif':
+  //       return 'image/gif'
+  //     case 'mp4':
+  //       return 'video/mp4'
+  //     default:
+  //       return 'application/octet-stream'
+  //   }
+  // }
 }
 
 export default Misc

src/puppet-web/puppet-web.ts

@@ -16,6 +16,8 @@
  *   limitations under the License.
  *
  */
+import * as mime    from 'mime'
+
 import {
   config,
   log,
@@ -326,7 +328,8 @@ export class PuppetWeb extends Puppet {
     const filename = mediaMessage.filename()
     const ext      = mediaMessage.ext()
 
-    const contentType = Misc.mime(ext)
+    // const contentType = Misc.mime(ext)
+    const contentType = mime.getType(ext)
     let mediatype: MediaType
 
     switch (ext) {