I am having the following issue, when a user fills in a form, I make an xml file based on that information and copy a file from one folder to another. (The filename is input by the user).
If the file already exists however, there will have to be a user input on whether to overwrite this file or not. I know I can't use a messagebox and if I do whether to use javascript or jQuery, I'd be adding a page as well. Preferably, I'd like to stay in C# but thats not possible without the messageboxes.
I have looked around google and stackoverflow, and the best I can think off is creating an extra page for this, where if the file exists, the user has to pick one of two options and then go back to moving the file (or not).
I am new to ASP MVC and I was wondering if this was the best way to go about it and what the best way to go is if it isn't.
Using JQuery you could make an ajax call to a controller to see if the file exists and show the user a dialog asking if they would like to overwrite the file if it exists. I can't see that you'd need a view for this at all.
Related
I currently store a number of document preview images (jpg/tif) outside of my web root. There are 100s of them, so having this work efficiently is important.
The reason they are stored outside of the web root is that they contain data the only specific users/user groups may view (but each user can have 100s of documents they can view).
My current implementation is, when the user selects ‘view image’ an ajax call is triggered and this moves the image in question to a specific folder within the web root. The location is passed back and used to display the image to the user.
When the next image is clicked, the call deletes any existing images and copies over the requested image. At session logout / timeout the users image folder is emptied.
This has a few problems, but mainly:
Files are constantly being copied and deleted
There is the risk of images being left in the folder (issues with log off scripts)
The whole time an images is in the folder it could be viewed by another users (unlikely but possible)
Is there a better way of doing this? I looked at trying to combine the BinaryReader with the ajax call (as I hoped this would cut out the need to copy the files), but can’t see how to get the data back to be used by the JS in the calling page.
Alternatively is there a way of making selected Folders only accessible to given users based on some session criteria? (I can’t imagine there is but I thought it’s worth asking.)
So if anyone has any ideas on how this can be improved that would be great.
This is a c# ASP.NET app using Jquery.
Edit:
The image is displayed using ajax, this allows for preloading and also means the rest of the page does not need to be reloaded when they select the next/previous image.
It can almost be thought of as a javascript image swapper type situation, where the images are stored outside of the web root.
Thanks.
My current implementation is, when the user selects ‘view image’ an ajax call is triggered and this moves the image in question to a specific folder within the web root.
This is horrible idea. You realize you can just access the image data and pass it to web as stream with specific mime type, right?
Maybe try to write a method that will check user credentials by cookies, if it is not OK then load and send back some standard image that will say that user must log in to view file, if it is ok then load and show proper file from a path outside of root based on url parameter (with proper headers like content-type also often referred as mime-type ofc). Then link urls to that method with proper parameter(s).
You can easily find examples of code (like here) to display image in binary form from DB. You would need just to load them from some path outside of root, not DB.
Also you don't need to load it by AJAX - just add IMG with SRC pointing to URL of handler. Or redirect / open window if it needs to be downloaded not shown.
The issue was how to get an image to show via javascript that is not in the web root.
I created a generic handler (ashx file) that based on the session values (authentication) and submitted parameters would return an image.
That in turn is being called via AJAX.
I am working on a form on a page that uses an asp:FileUpload to allow users to upload files to a server. I'm new to ASP and am using C# for my code-behind. The plan is to have the user "attach" files one at a time, adding them to an asp:listbox. Finally when the form is submitted the files in the listbox get saved to the server.
While it seems pretty easy to save files from the FileUpload by using
myFileUpload.SaveAs("path");
I am running into some difficulty figuring out how to keep track of the files independent of the FileUpload. I can get the file names really easily using
Path.GetFileName(myFileUpload.PostedFile.FileName);
but really I need to have some way of keeping track of more than just the names. My first thought was maybe to use a temporary folder of some sort, but the files are going to potentially be pretty large so I don't want to do that because saving might take a while.
How can I keep the file around so that I can save it on the server later independent of the FileUpload?
Rather than using a ListBox I would use actual <asp:FileUpload> controls so you can have access to all of the methods for that control - such as Save Etc.
You can put a bunch of these on your page and simply hide all but the first one. Then have a button to say "Add Another" - then with the click of this button show the next <asp:FileUpload> control - JQuery would be a nice choice to show the next <asp:FileUpload> that is currently hidden.
Then in your postback you can loop through all of your <asp:FileUpload> controls and if it HasFile - which is a property on the control - then perform your saving etc.
Save them into a temporary folder if needed - perhaps renaming the file with a GUID and store this list of GUID's in the users Session so you can grab those when needed.
Once you call SaveAs, you're saving the file. The base FileUpload control won't allow you to cache the file somewhere without actually uploading it to the server first. If you are looking to upload multiple files without uploading until the end, you may need to look into dynamically generating FileUpload controls (as many as the user wants). That way they can select the files to upload one at a time, then hit an "Upload" button at the end.
It's a little clunky to do it that way, though. I'd look for some third-party multiple upload controls. I've used PLUpload in the past.
I have a form that requires a file to be uploaded as well as additional data (name, etc...) with validation on these fields. When an error occurs, the file has to be re-uploaded. Is there a way to keep the file after a validation error occurs? This is built in C# .NET.
Tried to google this but nothing helpful came up.
Thanks in advance!
You can't genually persist the file because of Security Purpose..
If page is posted and validation error occured, check for a file using the .PostedFile property, and if one exists, save it to a temp file. In Session, store a reference to the temporary file. (use javascript)
.PostedFile is a property of the FileUpload control.
Also, during my google research, I found AJAX RadControl related to your question..
http://www.telerik.com/help/aspnet-ajax/asyncupload-persist-uploaded-files.html
I'm taking a bit of a guess at what you're doing since you really can't persist a file... are you simply using a fileupload dialog box and taking it from there? If so, it's typical to put the file/path obtained from the dialog in a txt field, then do your post (upload) with a separate button.
This scenario assumes you want to persist the path/file name, but not the actual file.
Im looking for the best way to change the URL to pages based on who is logged on, the limitation is all the pages are PRE generated so the actual html will already be generated and cannot be generated again on a pr user basis.
Posible solutions
A posible solution might be to use javascript to basicly add to the end of all URL ?=MyUserName , but im unsure if this will work with all spiders ( By all i mean the major search engines). This solution feels a bit dirty to me..
There might also be some way of of when the request comes in to then basicly say that response is from Default.aspx=?Username with doing a response.Redirect?
Its also importent to remember i will be changing the cache settings based on this, like saying if your not logged in the page can be cached.
I'm not sure if you must use .html files or another specific extension, but you could always create your own handler and process what you want to do on every request that way. Your handler would determine who is accessing the page and then do a Response.Redirect (or whatever action is necessary).
I am using asp.net mvc 1.0 and I want to return a XML file but I also want to return a strongly typed data back so I can update some fields.
Like the XML file will contain users who failed to be inserted into the database. So I want that to appear as a dialog save box what asp.net mvc return file() would do.
However I also want to return on the page like values like how many users failed to be added, how many users where added, etc.
So I want to use scafolding with the class file I want to pass it along. If this was a view I could pass it along as an object model but I don't see a parameter for that in File().
I also don't want to save the xml file onto the harddrive I want to do it through memory. So have a link that would display on the page to download the file and show the the data I want would not be desired.
I could be wrong, but I think you'll need to use JavaScript for this. What your're trying to do is a limitation of HTTP and from my understanding of HTTP, you can only return one file type per response since the protocol is a request->response.
You can have MVC return the strongly typed view in addition to the XML file name inside the ViewData. Then have a JavaScript function change the window.location property to the file's URL (or make a new window).
I'm not sure about the exact details on how to gracefully have the JavaScript spit the file out like alot of download websites have it.
Edit:
I found how to gracefully automate the download process, check this question out:
JavaScript automatic download of a file