Accessing a Local Directory

stonesbg · January 12th, 2007, 01:24 PM

Right i have a website that i want to link to Directory on a local machine. It works when i use the hyperlink ie

Code:

<asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl='<%# "file:///G:/PDF_Production/" + Request.QueryString("jobno").Insert(2, "-") %>'>HyperLink</asp:HyperLink>

But i want to use some error checking on the file to make sure that there is an actual directory. The code that i am using is

Code:

Dim filename As String = "file:///G:/PDF_Production/" + Request.QueryString("jobno").Insert(2, "-")
        If (IO.Directory.Exists(filename) = True) Then
            Dim popupScript As String = "<script language='javascript'>window.open('" & filename & "');</script>"
            ClientScript.RegisterClientScriptBlock(Me.GetType(), "PopupScript", popupScript)
        Else
            Dim popupScript As String = ("<script  language='javascript'>alert(""There was nop PDF_Production Folder for this Job"");</script>")
            ClientScript.RegisterClientScriptBlock(Me.GetType(), "PopupScript", popupScript)
        End If

How come this does not work when it is exactly the same. I know it has something to do with security but if that was the case how does the hyperlink work and the javascript does not. Or is there any way that i will be able to do this on the local computer. All file directorys are fake as well!!

dparsons · January 12th, 2007, 01:36 PM

It has been my experience that the IO classes do not like UNC path's, moreover, anytime I use anything from the IO classes I have to use Server.MapPath I think that is where your error lies.

-----------------------------------------------------------
I will only tell you how to do it, not do it for you.------------
Unless, of course, you want to hire me to do work for you.---
^^Thats my signature--------------------------------------
-----------------------------------------------------------
http://www.catb.org/~esr/faqs/smart-questions.html -------
^^Took that from planoie's profile--------------------------
-----------------------------------------------------------

Aaron Edwards · January 12th, 2007, 01:39 PM

Hi,

I haven't tried your code, but I do know that you're dealing with two different user accounts in the two scenarios:

When a user clicks on a hyperlink, they are using their own account, wo if they have permissions on that directory/file, they're golden.

However, to execute code like...

Code:

If (IO.Directory.Exists(filename) = True)

ASP.NET uses the aspnet account, or I think a system account. You need to make sure that account has read/write access to the directory.

Aaron

stonesbg · January 12th, 2007, 01:44 PM

Well i don't have any accounts set up so does that mean i have to set up an account. Right now i have a database with the list of users that can access certain pages. How can i just make everyone have access to the folder. Also i can't use server.mappath as the path is not on the server it is on the local machine that i want to be able to access the local paths.

Aaron Edwards · January 12th, 2007, 03:48 PM

Oh. I get it now. Local machine means the browser's computer.

OK, well the bad news is that neither ASP.NET nor JavaScript have any access to the user's machine. ASP.NET can only access files on the web server, and JavaScript can't operate outside the browser window as a security measure.

You can, as you've discovered, create hyperlinks to local files. But that's about it.

Aaron

stonesbg · January 12th, 2007, 04:03 PM

Is there any way that i could get around this. I just want to be able to link to the directory so can i run some kind of html script to do it or does someone have any ideas on how it can be done.

Aaron Edwards · January 12th, 2007, 05:36 PM

You can write a Java Applet or ActiveX control, but I think most users would have this blocked. Actually, while I'm not a Java developer, I don't even think Java Applets can access the browser's hard drive.

Aaron

stonesbg · January 12th, 2007, 06:10 PM

Well i was just thinking is there a way that i could create HTML code on the fly that would allow me to create the necessary hyperlink. In otherwords can i keep all the processing i have done and then if there is not an option instead of showing the hyperlink then i would just not show it on the page. I know when using php i can do this but i am not sure if ASP.Net can create html code like php does. I will need to check to see if a particular directory is there and if it is there then to create the necessary hyperlink and if not there then don't display it.

On another note. How is it that the hyperlink can bypass this so called security and asp.net cannot.

Aaron Edwards · January 12th, 2007, 06:39 PM

Again,

ASP.NET, which is a server-side technology, has no access to the browser's hard drive. Period.

You can create a hyperlink to anything anywhere. It doesn't even have to exist. Here's one: http://www.someimaginarypage.com/myNonFile.doc.

If the user has access to the path that the hyperlink specifies, then they can retreive the link. If not, it is a broken link, and they'll get an error when they click the link.

JavaScript cannot access the local hard drive by design. This is a security feature, and can't be bypassed. My understanding is that Java also works in a "sandbox" mode, which protects the user's machine from malicious code. ActiveX however doesn't not have this protection, which is why most users have it turned off.

Maybe you should move the file onto the web server instead.

Good luck.