I know this is stupid question, but will solve my doubts.
I am implementing a web application in ASP.NET MVC 4,in which user has to upload some document.I have a view where user has to upload file, write title,description in text boxes.I will make file upload as ajax and after its submission, user has to write titles etc.m then submit.
I want to know that this may happen that user will upload file using ajax only and then close the window.This way the file has been upload ,but has no use.
So, I want to ask that can it be possible that in such cases , file is deleted from the server as well or there can be other similar solution?
Thanks ,
I think it's better to insert a record on database at upload times, which indicates which files are useful and which have to be deleted, then you can write a service that execute for example every one hour to delete useless files.
Related
I'm developing a website in VB.Net that allows a user to submit a form that can include a video. In speaking with our server administrator, there are no write permissions for files, so I was instructed to put any videos into the MS SQL database.
I know this is inefficient, but they don't seem to care.
I think any type of file can be stored in a database by specifying the field in the DB as varbinary and then converting the file to a bitstring before uploading. But I have no idea how to actually do this, nor have I been able to find any direction from the MS site that isn't simply uploading an Image.
So what I need to know or find a resource for is:
The steps involved with accessing file chosen by the user and converting it to a useable data type to stick in the db.
The steps involved with pulling that video back from the DB and displaying it for the user in the db.
I wish I could simply tell all the users to upload it to Youtube and then just use the link, but that isn't an option either.
If I need more clarification, I can do my best.
Thanks!
Yes, I'm still using Classic ASP.
I'm about to write a script that checks a directory on the server, every 5 minutes, for newly uploaded photos, by my office, and to transfer the photos to another location. I'm using ASP and the FileSystemObject as the application and a Windows Schedule calls it.
What I would like to know is: If the user is sending 150 photos, by FTP, my application is not going to know if the user has finished uploading, or not. So then the application will go through the files one-by-one and transfer them. If my user has a slower connection than the speed of my application, the script may eventually come across the file that is currently being uploaded...
Will my application grab that file thinking it's complete or will it know that it's in the middle of upload and leave it alone? If it DOES grab it and transfers half a photo, how can I stop this from happening?
There is no good way to test for that, much depends on how the uploader is working.
Its highly unlikely that a file currently open for write access while the uploader creates it is going to allow your code to move it. An attempt to move it will result in a sharing violation or similar error. So protecting that section of code with an On Error Resume Next would do it. Have your code skip that file in the knowledge that it will be picked up again when the next poll comes round.
I have a web form that requires users to fill out some information and upload an image.
What I don't understand:
If I use uploadify to select a file doesn't it upload it right away to the server? Is there a way to defer that until the user would click on a form submit button? Or at least not save it to the file system?
Most examples use a custom HttpHandler for uploading files, but my file upload is part of a form. Should I still use a HttpHandler for that?
Well, I'll try to answer all your many questions, one by one. But before anything, open the official documentation because I will rely on it for answers.
If I use Uploadify to select a file doesn't it upload it right away to the server?
As you can see on the first demo, you can have a anchor (or a button or anything) to trigger the upload start. The Uploadify don't upload nothing until it's done (if the property auto isn't true).
Is there a way to defer that until the user would click on a form submit button?
Like described above, yes. And it's the default way (since the default value of auto is false).
Or at least not save it to the file system?
While the button doesn't trigger the .uploadifyUpload() method, nothing goes to the server. But when the Uploadify starts sending, it will be handled by the server (with the HTTP Handler). The handler is the guy that save it to the file system.
Most examples use a custom HttpHandler for uploading files, but my file upload is part of a form. Should I still use a HttpHandler for that?
As described on the script property, you can point to any server-side language that will handle the HTTP Request containing the data. The HttpHandler is the right thing because it haven't any other processing before or after the code you write. It isn't hard. The official forum shows some samples. And here on StackOverflow we have many questions about it, like these: Getting Uploadify Working in C# and Uploadify not working with ASP.NET WebForms.
The server shouldn't save the file until it is actually actioned by a handler. The Uploadify is providing the UI control for the gathering of the files and feedback. There are some settable properties available to control whether you want the "Auto" upload behavior or not.
You still need some king of server side processing for saving the data and an HTTPHandler is the usual way to do it. The HTTPHandler just operates on what file information it gets from the browser as part of a multi-part form data.
Here is an answer that provides more information about Uploadify: Getting Uploadify Working in C#
I need to add a file upload function to an ASP.NET website and would like to be able to read a small portion of the file on the server while it's still uploading. A peek or preview type function so I can determine contents and give some feedback to the user while it is still uploading (we're talking about large files here). Is there any way to do this? I'm thinking worst case of writing a custom control which uploads only a fixed number of bytes of the file once chosen and then under the covers starts another upload of the full file. Not totally sure even this is possible, but I'm looking for a more elegant solution anyway... Thanks!
It sounds like you want to avoid the "white screen of death" during large file uploads. If so, you might want to look into Telerik's RadUpload control , which provides a progress bar during upload.
If you want to roll your own, I'd decompile their trial copy for ideas. I've peeked at their source in this way, and they accomplish the progress bar through a combination of a custom HttpModule and HttpHandler along with their control. The handler routes the file in a streamed fashion while the module provides "percent complete" information--or the other way round; it's been a few years since I looked at it.
Edit:
Actually, I'm trying to do server-side processing as the file is still being uploaded. I want to import user data via HTTP, but want to present the user with preview/options of how we'll process their data while the file is still uploading (column definitions, etc.). No matter what, we'll take the file as is, so the upload doesn't need to be interrupted. Given that I actually want interaction during the upload based on reading a relatively small portion of the file as it is being uploaded, would you still recommend the same approach?
Well... it'd be very difficult to do, and it might not work cross-browser, but it could be done with this approach.
Since it's entirely possible to work with the incoming file as a stream as I mentioned, you could have your intial processing update some state as part of that stream processing. If you don't process as a stream, you have to wait for the full file upload before you can do anything with it.
The problem is this: during the file upload, you cannot have any more HTML-based interaction. The post must continue unabated or the upload will fail. The control I linked only works at all because most browsers allow javascript to continue to execute and update page DOM during the post.
So in order to make this work, you have to update some standardized state server-side during your file processing in the HttpModule, which is transmitted back to the client via XmlHttpRequest calls handled by the HttpHandler. You have to use pure javascript/DOM to update the UI for the user.
So, as I said, it's complex and likely to be buggy cross-browser, but it could theoretically be done.
There are alernatives that might be more stable, but might not necessarily be feasible: you could build an ActiveX control or a Click-Once .NET application that pre-processes the file before upload, and maybe even asynchronously transfers the file while the user continues browsing. Some users may not like that option, and I don't know the particulars of your deployment scenario, but it's an option.
There is an HTTP HEAD method but not PEEK.
HEAD will give you information and headers about the file.
Of course you can make a special request handler that does anything you want. You don't have to work with static resources, you can dynamically create any response you want.
I'm creating an ASP.NET web application to schedule tasks on our server from a remote location using a .NET Wrapper for Scheduled Tasks. However, I'm stuck.
The user needs to be able to browse the file system on the server to retrieve a "file to run" for the new task that the user's creating in this application. I need to get the filepath/filename and pass it into the .NET wrapper.
I've tried using HTMLInputFile, but I haven't found a way to make that work for me.
Any help is appreciated.
Thanks
Update:
For this project, we've decided to simply list the executables in a dropdown box that would be available to users since they don't really need total access to the file system, just for security's sake.
HTMLInputFile is used to browse the client's file system and upload a file to the server. It isn't used to browse the server's file system.
You will need something quite different. You will need some server side code to display the server side folder structure to the user via the browser.
There is an example of a basic implementation of this here.
Update:
With that sample, the path that you replace "yourfolderHere" with needs to be a virtual path, rather than an absolute path. So for example "C:\Inetpub\wwwroot\uploads" won't work, but "uploads" will work.
I hope it goes without saying that there are serious security issues to think about when implementing something like this.
The HTMLInputFile will only work on the client-side machine.
You need to write a filesystem browser in ASPX/HTML that browses on the server-side.
Shouldn't be that hard to do.
You can't use the <input type="file" tag
This brings up a client-side dialog that browses the client machine.
As far as I am aware you need to create your own 'browser'.
eg You could use the My.Computer.Filesystem classes to retrieve a list of files in a folder and show those on the webpage. The user then selects the relevant file and posts a response back to the server.
You can use System.IO.Directory to get directories and files. These can be displayed in a number of ways. A simple browser / file selection should be possible in less than 50 lines of code.
Also be aware that you may need to grant extra permissions to the user that your web app runs as so the file system is accessible.
There are also various security implications around this, so don't grant access to everything unless you really need this.