How loop thru all files in dir on CLIENT's computer?

Question

I have an asp.net page that allows a user to select an excel file on his computer and then (1) upload it to the server, and (2) import into a SQL server table. This works fine.

Now I want to enhance the pages functionality to allow the user to select a directory on his computer and then automatically upload/import EACH file (Only of types xls, xlsx) in the clients directory. How can I do this? (Alternatively the user can select a file and then check a checkbox that says "upload all files in this directory", then it will process each file, etc.)

I found a way to loop thru the directory on the server side. But I can't figure it out for client side. Thanks!

Short answer: you can't. Long answer: try searching, there's plenty of duplicates of this question. — CodeCaster, Oct 06 '15 at 15:16
This might be an option: http://stackoverflow.com/questions/17441925/how-to-choose-multiple-files-using-file-upload-control — lintmouse, Oct 06 '15 at 15:16
Is this possible? I mean wouldn't that be a security risk if you could access all the files on a computer from a website? — Derek Van Cuyk, Oct 06 '15 at 15:16
Indeed Derek, this is why it's heavily frowned upon nowadays. You can do something with a Java applet or Flash maybe, but it's just a bad idea. — Russ Clarke, Oct 06 '15 at 15:21

score 3 · Answer 1 · answered Oct 06 '15 at 15:19

3

You can't. Or at least, you shouldn't be able to.

A properly written browser specifically prevents direct access to the file system of the computer it is running on as a security precaution. The only "correct" way to access a file on a remote machine is to use the browser's File Upload form control on the page and have the user specify the file (or files) they want to send you.

answered Oct 06 '15 at 15:19

Mike U

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it is possible to select multiple files for upload though, like imgur.com – enkryptor Oct 06 '15 at 15:29
There are ways to do that. Personally, I recommend just buying one of the existing multi-file upload packages, rather than trying to roll your own. They're generally pretty cheap (~$100) and offer a lot more functionality that you could conceivable write quickly. – Mike U Oct 07 '15 at 16:23

score 1 · Answer 2 · answered Oct 06 '15 at 15:19

Basically, no.

Many advances have been made in browser security to stop people doing this sort of thing.

The main solution is to use some kind of local plugin that gives this sort of access, but as this can be used for many nefarious deeds, it's very much frowned upon now.

You can of course let the user choose many files, there are various methods for doing this - but you can't automate it by the browser. What's to stop someone searching for 'creditscards.txt' and uploading it without the user being aware?

score 0 · Answer 3 · answered Oct 06 '15 at 15:26

One way I can think of is a Java applet. This is executed locally and has full access to the computer and the browser. They are being shut down for similar reason: it's just not safe.

I have outlined a way, but I must emphasize that this must be avoided. It's not because you can that you should.

How loop thru all files in dir on CLIENT's computer?

3 Answers3