Unfortunately the HTML5-File-system is no longer a part of the spec, long story short FF refused to implement because they claimed everything you could do in the File-System API was doable in the HTML5 Indexeddb (which was mostly true). Please see this blog post for more on why FF didn't implement. I do not know IE's story. (I may have exagerated why FireFox didn't implement, I'm still bummed because you cannot actually do everything in indexeddb that you can do in the noew "Chrome File-system API")
Typically if two of those three browsers implement a spec, it stays in the spec. Otherwise that spec gets orphaned. However, I'm fairly certain a large reason the file-system api didn't take off is because of the IndexedDB API (caniuse IndexedDB) really took off when both specs were introduced. If you want cross browser support, check this api out.
That all said if you are still set on the file-system api some developers wrote a nice wrapper around the IndexedDB, the File-system api wouldn't actually supply you with a stream anyway. You would have to keep appending events to a given file given a fileWriter object. you'd then have to read the entire file and send to the server via an ajax request and then downloaded from the server once successfully uploaded.
The better route would be to use the IndexedDB apiwhich as stated on developer.mozilla
- Open a database.
- Create an object store in upgrading database.
- Start a transaction and make a request to do some database operation, like adding or retrieving data.
- Wait for the operation to complete by listening to the right kind of DOM event.
- Do something
with the results (which can be found on the request object).
Here are a couple tutorials on the IndexedDB.
As for giving the user that file, as mentioned briefly before you would have to upload the file to the server and download upon the "download" request. Unfortunately you have to trick the user into giving them the data already on their machine. Anyway, hope this all helps.
