Develop Reference

Generate id for files based on file content

I am using a upload mechanism for users to upload files and the user is suppose to receive 3 different file extracted from the uploaded one in an group which is identified by the uploaded file name.
I am trying to map the output files to it's parent file.
How can generate something unique that can be linked to the files so that they are easily associated to its group.
I am using C# and SQl Server Filestream to store the files in database.
The limitation that i am facing is that I cannot rename the file provided by user.
Can someone help me out here?

Fetching the username who last modified or created the file

Is it possible to get the name of the user who just pasted a file into a folder?
A brief overview of what I am trying to do:
My application keeps watch on a folder for new files every 10 minutes. If it finds any new file it will upload that file via FTP to a specified location.
I would like to know who dropped this file into the folder. Please note that this could be different from the person who created the file.
Thanks
Nishant

The identity of the user modifying a file is not stored in the NTFS Change Journal, but you could use auditing of file access as suggested in this related post.

how to create folder on server from code in c#?

Is there any way to show user popup to give the name to create folder
And with that if he does not want to create folder then he should be shown the list of folders to which he want to save the file
Is it proper way that I create a popup with javascript with the list of folders on my server and put a textbox and button to save the new and in code we will create directory in code passed with textbox?

string pathToCreate = "~/UserFolders/" + TextBox1.Text;
if(Directory.Exists(Server.MapPath(pathToCreate))
{
//In here, start looping and modify the path to create to add a number
//until you get the value needed
}
//Now you know it is ok, create it
Directory.CreateDirectory(Server.MapPath(pathToCreate));

string targetPath = Server.MapPath("FolderName"); //with complete path
if (!System.IO.Directory.Exists(targetPath))
{
System.IO.Directory.CreateDirectory(targetPath);
fileToUpload.PostedFile.SaveAs(targetPath + ImageFileName);
}
else
{
fileToUpload.PostedFile.SaveAs(targetPath + ImageFileName);
}

As I mentioned by commenting that Functionality like SaveFileDialog is only possible in Windows Forms application, you cannot do this in asp.net
The alternatives in asp.net are difficult however as an alternate there is a third party editor available on the web called CKEditor 3.x Developer's Guide.
You can use File Browser (Uploader) for the purpose you want to achieve.

to create folder :
System.IO.Directory.CreateDirectory(newPath);//newpath is your folder creating path

If you are developing web applications (I can see you have tagged your question as asp.net), you do not need to worry about the pop up window. You just send the file through the Response and the download window will be shown by the browser.

Using the Example given in How to Create a Folder or File You can create a folder, but in asp.net you can not Use open file dialog or save file dialog functionalities, this will work only in C# Windows forms application.

Web applications and the HTTP protocol do not support direct manipulation of the server-side file system. In fact, that would be a dangerous idea.
It sounds like you have a base folder somewhere on the web server where you want users to be able to upload files, with some user control over subfolders and location of the uploaded file. I would suggest dong this by presenting the file system in a tree view or a list of links (where the links let you navigate up/down the folder tree). Combine this with a file input and you've got yourself a solution. HOWEVER, be very careful to control and cleanse the specified file name for the uploaded file. There are many combinations (such as utilizing "..") that can allow the user to hack into unwanted file locations on your server.

how many times a file has been downloaded

I am creating a web browser using C#, and I need to get specific data from the web pages that are loaded in my browser.
The pages I am loading is a download scripts. The data I want to get is: the number of times the file has been downloaded.
I want to save this value in text.
What code can I use for this, or where can I start? Any help is appreciated.

Most web browsers have their own storage. Mozilla uses SQLite for some things.
Whenever your app/browser needs to retrieve a remote resource (URL of any kind), simply log it to a database table.
Perhaps use SQLite yourself for this. A decent start would be to create a history table like this:
URL --varchar(max)
LastAccessed --datetime
TotalRequests --int

If it is a file that the users will be downloading, you could add a global static int and increment it every time the file is downloaded.

IIS Virtual Folder URL encryption

We have a c# asp.net web application that, amongst other things, allows users to download previously uploaded files such as PDF's, Word docs etc. The asp.net app is served up via an IIS6 server and the file resources live on a different server.
When the user requests a file (i.e. click a button on the web form), we stream the file back to their browser, changing the ContentType appropriately.
This seemed a good way to avoid going down the IIS virtual folder route to serve up the file resources - which we had concerns about due to the potential for users to hack the URL. i.e. with a URL like https://mydomain/myresource/clientid/myreport.docx, a savvy user could have a good stab at guessing alternative cvlientid's and document names.
The trouble with streaming a Word document to the browser is that when the browser throws it at Word, Word treats it as a brand new doc, which means the original document's properties & margin info is lost.
Our users store metadata information in the Word doc properties, so this solution is not acceptable to them.
Serving up via IIS virtual folders solves that problem, but introduces the URL security problem.
So my questions are ...
Does anyone know how we can use URL encryption/decryption (or obfuscation) with IIS Virtual folders?
Or does anyone know of any open source projects that do a similar job.
Or does anyone have any sugestions on how to go about writing our own implementation of Virtual folders but with encrypted URLs?
Many thanks in advance.
ps. our web app is delivered over https

Sorry guys, in my question, I have made some incorrect assumptions.
What am I trying to do is persist the properties stored on a word document when they are delivered from server (using either Response.TransmitFile or via a virtual folder) to a client browser.
I set up a test scenario with an IIS virtual folder and dropped a docx file (that I know contains info in the title & subject properties) in my virtual folder's physical path.
I pointed my browser at the virtual folder alias and the browser popped up its message to either open or save the doc.
If I choose to save it, the saved docx still has the properties intact.
If I choose to open it fist and then save it from Word, the saved docx has lost the properties.
So I think I need to post a different question!

You may find that the ClaimsAuthorizationManager class in "Windows Identity Foundation" does what you want. You get to implement whatever logic you like to determine who can download what without using "directory security".