- Electron version: 1.3.5
- Operating system: macOS/Windows

Alt-clicking a link is a default shortcut for downloading a file without a save prompt, and we make use of it in our app. But for links that end in a trailing slash, the resulting filename isn't consistent with the default file name in the save prompt.

The save prompt constructs a name from the word "download" and the extension for the mime type of the file, but the prompt-less savepath is just the domain name of the link. This leads to unusable files (e.g. with a .com file extension) being saved to the filesystem.

Here's my current workaround, but given the prompt does get a useful path, and Chrome behaves correctly, I imagine this might be straightforward to fix if you know where to look:

``` javascript
const mime = require('mime-types');
const _ = require('lodash');
const path = require('path');
const unusedFilename = require('unused-filename');

win.webContents.session.on('will-download', function (e, item, webContents) {
  if (item.getSavePath() && _.last(item.getURL()) === '/') {
      var savePath = unusedFilename.sync(path.format({
        dir: path.dirname(item.getSavePath()),
        name: 'download',
        ext: '.' + mime.extension(item.getMimeType())
      }));
      item.setSavePath(savePath);
    }
});
```

atom/browser/api/atom_api_download_item.cc
v8::Isolate* isolate, content::DownloadItem* item) {
  auto existing = TrackableObject::FromWrappedClass(isolate, item);
  if (existing)
    return mate::CreateHandle(isolate, static_cast<DownloadItem*>(existing));
  auto handle = mate::CreateHandle(isolate, new DownloadItem(isolate, item));
  
  g_download_item_objects[handle->weak_map_id()] =
      v8::Global<v8::Object>(isolate, handle.ToV8());
  return handle;
}
}  
}  
namespace {
void Initialize(v8::Local<v8::Object> exports, v8::Local<v8::Value> unused,
                v8::Local<v8::Context> context, void* priv) {
  v8::Isolate* isolate = context->GetIsolate();
  mate::Dictionary(isolate, exports)
      .Set("DownloadItem",
           atom::api::DownloadItem::GetConstructor(isolate)->GetFunction());
}
}  
NODE_MODULE_CONTEXT_AWARE_BUILTIN(atom_browser_download_item, Initialize);