ASP.NET File uploading-dynamic file names - asp.net

I have a web page where i have an ASP.NET file upload control to upload files from client machine to Server.Now i want to do the uploading n number of times.Ex : I want to upload 100 files from my local pc to server.The 100 file names i can read from an excel file in my program.But is there any way to assign this file to the file upload control ?

No, as a security feature, FilUpload controls do not allow you to set what to download (imagine if you sign on to a website, and it is set to upload a passwords file or something).
Now there is probably another control, or a way to code around this, buut the FileUpload control will not allow it.
I would recommend using the jQuery Multifile Uploader which would take care of a UI (if you need one). And the actual uploads with Free ASP Uploads which takes care of the actual file transfer. Though it sounds like you are tkaing care of the programs programatically, so you can skip the multifule and just work with free asp upload.

You'll have to make your own Flash object or something to accomplish this, the basic HTML/ASP.Net controls won't let you do what you're looking for.

This will require creating some kind of an active or installable control. In order to get around the security hole of doing this, you're ultimately going to have to be able to execute code on the machine to select and upload the file.
And at that point, you're platform specific, so...
I would strongly suggest that instead of trying to have a web site automatically upload files for you, that you make a WinForms utility to accomplish this task and upload the files wherever you need, communicate with the web site over web services, etc.

This is a security restriction, you cant script the file selection of an upload box as it would allow hackers to write scripts to steal files off your computer.
You could use this silverlight upload utility which is my list of "things to use when I get the chance".
It has a nice UI and supports uploading many files at once. I originally tracked it down doing some research for a photography website that we were quoting for but that project fell through.
Anyway the project can be found here:
http://www.michielpost.nl/Silverlight/MultiFileUploader/
It also has full source code included so even if the control's developers abandon it you still have the choice to edit it yourself.

Related

How can I let user select the location for downloading an Export to Excel file in asp.net webforms?

I'm exporting an excel file that's created dynamically at run time from DataTables in aspx.cs file at server side using ClosedXML lib. I want to let user select the downloading file location at client side, which is currently moved to downloads.
You unfortantly cannot do this. This is also why you can never select a local file or location from server side.
So, the users local file system is 100% off limits.
And the reason is quite simple. If you come to my web site to look at some cute cat picture? Well, while you are doing that, do you think it would be ok if my web code also starts looking around at your files? Hum, maybe a file called banking? Maybe a filel called passwords? Hum, how about I steal all your email files? How about I look for a Excel sheet called passwords?
So, when it comes to poking around, looking at, and deciding things like file locations? You cannot on the server side GET ANY information, nor can you even find and define what file to pick for up-loading, and the SAME applies to downloading of files. If I could pick a location, then gee, why don't I start overwriting some of your system files - including some that would give me remote access to your computer, right?
So, things like what folder, what file, even the computer name etc? These things are 100% hidden, off limits and simple not allowed. Now it would be possible for someone to come out with a new web browser tht allowed local file rights and access. But then again, no one in their right minds would ever use such a browser, and the security hole would be too large. As a result, for reasons of security, such information, and even simple knowledge of the local file system is not allowed, nor even exposed to the web server.
But then again, the user might be on a iPad, or android phone, and their file systems and how their folders works is not even the same as say a windows desktop computer anyway.
However, you can see with above, that your ability or even options to mess with, or even choose local file locations is not allowed for reasons of security.
So, if you web site provides a file, or even streams down a file, it will go into the download folder as per user browser settings - you unfortantly can't change this - it works that way due to security concerns.

Upload file to server using class dll

It is fairly easy to upload a file using web form. But I need to accomplish this through DLL.
I have classic ASP page with file upload form and I need to create an object that handles the uploaded file from customer and save the file to the server. What would be the best way to approach this? I have been digging and came across Web.HttpPostedFile and HttpWebRequest. but I don't know which route to take.
Also, I am a bit confused about how to pass the uploaded file to DLL so my class can upload and manipulate the file. is there any sample code for this?
Thanks for any help or advice.
This question doesn't make much sense, as you kind of asking "I have old car's parts and I need to assemble one by using a wheel". What? That doesn't make sense.
A dll is a container for some code. You do not use a container per se to upload a file. You should search for "classic asp upload file sample", find a solution, give it a try and come back with a specific problem.
I also noticed HTTPS tag, the idea with S, is that you don't care whether it is secure or not from the programming perspective. If you are able to use HTTP, it is trivial to upload files to HTTPS - just change the URL in the UI. The server code itself wouldn't change. What will change is the server hosting configuration, you would have to add certificate details.

In which folder can I store user uploaded images

I've a classified ads system on ASP.NET/c#/MS SQL, and I'm trying to figure out where to store the images that people upload when placing an ad. The ad itself is being stored in a SQL server database.
The images are now being stored in a subfolder of my webapp. It seems to work fine, however I only recently discovered a big problem. Everytime a user deletes an ad, the attached images are to be deleted as well including the folder they reside in. This leads to a restart of the asp.net application. I searched internet and found that restarting the web-app is actually intended behaviour when a subfolder is being deleted.
Obviously, I need to fix this. But how to do that? Where can I store images in such a way that:
I can remove these images including the folders they are stored in?
I can acces them using a URL (the images need to be shown in the
webpages)
Without getting the web-app being
restarted?
Any feedback is appreciated!
Paul
See this question Deleting a directory results in application restart
An other alternative would be to store the images in the DB instead.
Another option would be to put the images in a directory completely unrelated to the web site then serve the images through a scripted page or handler. It would make all of your image urls look like mydomaincom/serveimage.aspx?imageid=323422, but unless you're counting on the name somewhere that really shouldn't matter much. Obviously it would require a modification to the page that serves the images in the first place as well, but if sub directories of this unrelated directory are deleted IIS really shouldn't care at all.
maybe you can store the images in SQL (check at the filestream feature in this case)
if not, I suppose you have somewhere in a business facade class, a service class or wherever you want, a methode "DeleteAd".
This method will have to do two things :
-delete the sql data
-delete the file image
also, you may change the image store to another folder, outside the web app. You will probably end with writing a custom handler (myhandler.ashx?fileid=XX) to serve the files, or a custom route and control if you use MVC.

Handling file uploads in Drupal

I've been messing around a bit with various solutions to what I would see as a fairly common problem, but I've not yet been able to solve it in a satisfactory way.
What I wish to achieve is some kind of functionality where a user can upload new files, or select existing files to reuse them.
What I've been using so far is a combination of the filefield, filefield_sources, imce and ckeditor modules. I guess ckeditor isn't really important for the solution, but I need to be able to embed images from the archive somehow, and this is done with IMCE . Since I do not want everything to be accessible from the filebrowser I created a subdirectory and set full access to it in the IMCE settings, lets call it default/files/site
This worked fine as long as all filehanding was done through IMCE, but when I uploaded files directly from the filefield my files ended up in the default/files root, so I set up folders for my fields, for example default/files/site/movies in a field that allowed the .flv format. This worked fine to, as long as I didn't try to access the files through IMCE. It appears the folders created by filefield are not accessible from IMCE?
I'm also in a position where I need to support large uploads (200MB+), but from my experience in other projects, allowing file uploads through FTP is usually a life-saver, but from what I understand IMCE won't support files not uploaded through Drupal in some way, since they are not present in the database (giving the message: The selected file could not be used because the file does not exist in the database.)
I'm aware that I don't really have a clear question to my problem, but somehow I need to figure this out pretty fast. How would I preferably solve this? I'm aware that I'm not the first to have this problem, but I have not yet been able to find a nice and stable solution. What am I missing?
Also check this thread (http://drupal.org/node/438940) and the reference to John Locke's work at: http://www.freelock.com/blog/john-locke/2010-02/using-file-field-imported-files-drupal-drush-rescue
Well, I'm not personally familiar with IMCE off of the top of my head, but if you need files that have been uploaded via ftp to be added to the files tables, then my impulse would be to write a small module which would then allow the user to click a button and start off a batch process. (This is me assuming that you are using Drupal 6, as the batch api doesn't exist in 5.)
Said batch process would then iterate over all of the files in the appropriate directory, which I would assume you had uploaded the files to, use file_copy() (from Drupal's file API) to copy the files to default/files/site, and then would add said files to the files table, which is actually quite simple with drupal_write_record().
It might not even need to use the batch api - it somewhat matters if you're just uploading 10-30 really big files, or 200-300 MB files.
For using the batch api, I'd look at http://drupal.org/node/180528 - this has a fairly basic example of how the batch api works, which basically consists of telling the api that you want to keep calling function_a, and then inside of function_a setting your progress in the context array until you're done, at which time the batch process finishes. Then you just have whoever uploads the files via ftp to hit a button on the website to move and register the files.

ASP.NET File upload - Validation

In our application , we are using asp.net FileUpload control to upload files.
Requirement is , user should be able to upload only ".doc, .xls , .pdf" files.
System should not allow him to upload other files. To achieve this we are validating the extension of the uploaded file. If it is not valid then throwing error message.. this works fine..
But if i change the any exe file as .doc file , then system is allowing to upload. this should not happen.
Is there any way to validate the file with its content instead of its extension ..?
Check out this question/answer on stackoverflow. I belive this is a duplicate question.
Also, look into reading a file's magic number especially if you are just trying to determine if the file is one of a few acceptable types. Magic number Wikipedia
Uploadify is a good file uploading tool that I have found which allows you to specify which extensions you allow the user to see when uploading their files. It also has alot of other cool options and it is highly customizeable. It uses a combination of jquery and flash to allow the user to upload more than one file at a time as well (if desired).

Resources