Flash, Silverlight, and JavaFX all look nice, but what I really want is better file upload

One of the most annoying limitations when writing web apps comes from the <input type="file"> form element, which is the standard way of uploading files.

Here are a few of the problems with <input type="file">:

• You can only select a single file per input element, and there is no way to select entire folders.
  
• Web browsers just pop-open the standard file open dialog, which is often not very good. For example, the dialog probably just shows a list of files, not thumbnails. This can make it difficult to pick the correct file if they all have names like IMG_3485.JPG, and it's therefore easy to upload the wrong file.
  
• There is no way to actually read the data locally without first sending it to the server and then having the server send it back.
  
• There is no way to do any local processing on the data, such as scaling images to make them smaller.
  

Flash apparently solves the multiple file problem (kind of), but it's my understanding that it still has all of the other problems (I'd love to be wrong about this though).

Java applets can actually do most of these things if they are signed and the user agrees to allow the applet access to their filesystem. Unfortunately, Java applets don't actually work, and after 11 years of not working, I'm not expecting that to change. Facebook has a nice image uploader applet that lets you browse your photos locally and then scales them before uploading to make the whole thing go fast. The only problem, other than the annoying "do you want to trust this applet" prompt, is that it crashed my browser the second time I tried it.

To me, the great thing about flash is that it fills in basic capabilities missing from the browser, such is video, sound, camera and microphone access, and they did it with a reasonably small and stable browser plugin that I'm not afraid to allow onto my computer. A few months ago, I accidentally upgraded one of my computers to Flash 9 -- I don't remember how exactly, I just remember that it was simple and non-eventful.

Here's my idea: I want to create a small, reliable browser plugin that does for file uploads what flash does for audio and video. It should work with all the modern browser/os combinations, and install with minimal effort and fuss (browser restarts avoided if possible). It would be free and open source, but hosted in a common location for easy install.

Popular Ajax libraries such as jQuery, YUI, and Dojo can add support in such a way that people who don't have the plugin just get the regular browser upload control (and maybe a link to install the plugin), while those who do have the plugin get a better ui. Clearly, getting people to install a new plugin isn't easy, but once any site convinces them, their experience automatically gets better on all other sites that support the plugin. There isn't a chicken&egg problem because the plugin simply provides an enhancement to the already existing (but very poor) browser functionality, so sites can easily add support without fear of losing people who don't have the plugin (unlike building a whole app in silverlight, or whatever).

I'd like to hear from anyone with experience writing browser plugins. How difficult is the technology side of this? (making it small, reliable, and stable -- crashing browsers is not ok) Also, are you interested it writing this plugin? I'm serious about this, and willing to pay quite a bit of money to make it happen.

Here are a few more details on how I imagine the plugin working:

It would not have any in-browser UI -- it would simply be an object that can be called from javascript and that would pop open a nice file browser with thumbnails and all that (similar to windows explorer, perhaps). It would also provide upload-related utility functions, such as image resizing. Since the file access is read-only and limited to what the user selects, security shouldn't be a big problem, assuming of course that the plugin implementation is secure (and it must be).

Here is some JS illustrating how I imagine using this plugin (UploadHelper is the object provided by the plugin):

// Have the user choose files or directories to upload.
// Returns undefined if user clicks Cancel. Doing this with a
// callback instead of a return value would also be ok.
var files = UploadHelper.chooseFiles(
              {filter:'*.jpg,*.gif,*.png', allowDirectories:true});
if (files) {
  var s = 'You selected: ';
  for (var f in files) {
    var file = files[f];
    s += (file.name + " (" + 
          file.imageinfo().width + "x" +
          file.imageinfo().height + ", original size = " + file.size);

    files[f] = file.scaleImage({maxwidth:100, maxheight:100, quality:5});
    s += " scaled size = " + files[f].size + ") ";

    // If I could somehow insert this image on the current web page
    // too, that would be really awsome.
  }
  alert(s);
  
  // using jquery XMLHTTP wrapper
  $.ajax({
    type: "POST",
    url: "/upload",
    data: UploadHelper.encode(files, 'multipart/form-data'),
    contentType: 'multipart/form-data'
  });
}

var files = UploadHelper.chooseFiles({filter:'*.txt'});
if (files) {
  // We can also read the content of the selected file
  // The ability to get chunks of a file also means that it's possible
  // to restart failed uploads, and to chunk large files into multiple
  // POSTs.
  for (var f in files) {
    var file = files[f];
    var d = file.getData(0, 50); // get the first 50 bytes
    if (file.size > 50) d += "...";
    alert(files[f].name + ": " + d);
  }
}

Update:

Several people have suggested that I should instead try to get this feature added to web browsers or (better yet) the web browser standards. That's a fine long-term solution, but realistically it will take years to happen. I would rather have an immediate (months, not years) fix in the form of a plugin, and then let the web browsers add it as a standard feature on their own schedule. This is somewhat similar to the path followed by XMLHTTP.

Sriram Krishnan of Microsoft makes a few good points:

• The standard file open dialog in windows already has a thumbnail view. Unfortunately, this feature is hidden under a completely unremarkable icon and despite having used windows for many years, I've never seen it before today. This is a great example of why simply adding a feature isn't good enough -- it also needs a good ui or else it may as well not even exist. Furthermore, not existing seems to be the status of the thumbnail view on OSX -- hopefully that will be fixed in 10.5.
• This feature request could be implemented in Silverlight. That's great news! MS should write and release a little Silverlight control that provides these functions to JS. I would be very hesitant to write (or rewrite) my apps in Silverlight, but if I could simply embed a little Silverlight module the same way that I would a flash mp3 player, then I'd definitely use that. This would be a very effective way for MS to get people started installing and using Silverlight (start with something small and optional).

Silverlight sounds pretty nice. Google or Adobe had better have an open alternative on the way, or else MS may be able to recapture the application platform.

Update Two:
I believe that within a few months we will have a few reasonable solutions to this problem!