I need to give an option to user in jsp to choose a folder where he can save/download a file. Please help me on the same.
the text input="file" will give the file chooser but i need the directory chooser
HTTP doesn't allow you to specify (server side) where a file is downloaded to - this is not a jsp specific thing.
If you need to this then you'd need to provide an embedable application (javascript, java, flash, vbscript...) which is allowed to operate outside the browser sandbox and implements its own network client for retrieving the file. Which is far from an ideal solution.
You can force the download to use a specific name via the content disposition header.
the text input="file" will give the file chooser
..but that's for uploads - not downloads.
You can't set folder location at client machine of downloaded file using JSP/Servlet. If you want to add folder chooser feature then you have to develop an applet. You may use JFileChooser to allow user to select a folder and java.net.URL and java.net.URLConnection to download a file.
Most browsers will automatically download a file that the browser doesn't render, so it's just a link...! For example, if it's a zip file, just add it as any old "a link" in your code. When the user clicks , the download/save dialog will be launched ....
The "save/download" feature is a client issue -remember the web developers job is to provide content- it's the browser that decides how to deal with the content.
The key is the Content-Disposition header. Its value has to be set to attachment to force a Save As dialogue. You can do this job in a servlet. Just let your link URL point to a file servlet like so
download filename.ext
Then, in the file servlet, which is for the above example to be mapped on an URL pattern of /fileservlet/*, do the following:
String filename = URLDecoder.decode(request.getPathInfo().substring(1), "UTF-8");
response.setHeader("Content-Type", getServletContext().getMimeType(filename));
response.setHeader("Content-Disposition", "attachment;filename=\"" + filename + "\"");
// Now get an InputStream of the file and write it to OutputStream of response.
See also:
Simplest way to serve static data from outside the application server in a Java web application
Related
I have an asp.net web api project using token based authentication. my app uploaded and retrieve images and I keep file path in table_myfiles along with the uploaded user ID.
I would like the user to access only the files he have uploaded, which I can identify from the table.
How to protect my resources to restrict access to only to the user based on table_myfile ? And not to anyone without logging in or direct link / path ?
I have been searching for any possible solution for a week now , I think I should implement a middleware to manage access. But I couldn’t find any resources on how to implement the same.
Currently my api shows all resources just by directly accessing the file path/link.
The simple apporach is to remove the vitural folder, or that folders from the web site folders. That way, no simple URL exists for any of the files.
So, for a user to get/see/use/download a file? You present say a listview or some kind of grid (or repeater) that displays and lists out the files.
Then, when they want to download or view a file?
You use response.write and stream the file down to the client side.
Remember, on the server, code behind uses 100% clean and correct windows file paths. For any web based URL, then that folder must be in a valid path of the web site. When they type in a valid URL, it eventually gets translated to that given folder in the site (or a external folder provided when you create a mapped "virtual" folder in IIS. However, if you don't provide that virtual folder, or the folder is NOT in the web site file/folder sets, then no valid URL's exist. However, that folder can be directly used and hit with code behind - any valid server path/folder name is allowed in code behind.
Because when streaming the file, you need path name, file name, AND ALSO the "mine" type. Thankfully, .net 4.5 or later has this ability.
so, from a database (table) I display the file names like this:
But, if you click on the preview image, that is a image button.
The code behind simply gets/grabs the file name from the database.
I then download (stream) the file to the browser side like this:
if (File.Exists(strInternalFullPath))
{
string strConType = MimeMapping.GetMimeMapping(strInternalFullPath);
binFile = File.ReadAllBytes(strInternalFullPath);
Response.ContentType = strConType;
Response.AppendHeader("Content-Disposition", "attachment; filename=" + Path.GetFileName(strWebUrl));
Response.BinaryWrite(binFile);
Response.End();
}
else
MyToast2(this, btnLink.ClientID.ToString, "File Not found", "We no longer have this file avaiable.");
so, this buttion behaves 100% like a link, but there are no existing URL's or path name that points to the files folder from a web based URL.
Remember:
Web based URLs - they auto map from the web site URL to a existing folder.
You can use server.MapPath("some url to file") to "translate" this to a internal file name.
Code based files:
In your .net code (code behind) ANY file name is a standard plane, jane file name that points to a file on the server.
so, once we have that file name from the database, you can steam the file as if the user clicked on a link. But you never have to expose the actual file name, or file path. And no such valid URL's exist on the web site, since you do NOT have that files folder in the web site folder hierarchy - but placed that folder outside of the web site.
As long as that folder is outside of the web folders, and as long as you don't setup a virtual folder that points to that folder outside the web folders?
Then code behind can STILL get/grab/see/use any file on the server. that code uses a full valid windows file name, - but the web site will have no mapping to such a folder - hence no valid URL's will exist or can be typed in.
Here's what I would like to accomplish:
I have a file stored in Windows Azure Blob Storage (or for that matter any file which is not on my web server but accessible via a URL).
I want to force download a file without actually downloading the file on my web server first i.e. browser should automatically fetch the file from this external URL and prompts the user to download it.
Possible Solutions Explored:
Here's what I have explored so far (and why they won't work):
Using something like FileContentResult as described here Returning a file to View/Download in ASP.NET MVC to download the file. This solution would require me to fetch the contents on my server and then stream from my server to the browser. For this reason this solution won't work.
Using HTML 5 download attribute: HTML 5 download attribute would have worked perfectly fine however the problem is that while it is really a very neat solution, it is not supported in all browsers.
Changing the file's content type: Another thing I could do (at least for the files that I own) to change the content type property of the file to something that the browser wouldn't understand and thus would be forced to download the file. This might work in some browsers however not in all as IE is smart enough to go beyond the content type and sees the file's content to determine the content type. Furthermore if I don't own the files, then I won't have access to changing the content type of the file.
Simply put, in my controller action I should be able to specify the URL of the file and somehow browser should force download the file.
Is this something which can be accomplished? If yes, then any ideas how I could accomplish this?
Simply put, in my controller action I should be able to specify the URL of the file and somehow browser should force download the file [without exposing the URL of the file to the client].
You can't. If the final URL is to remain hidden, your server must serve the data, so your server must download the file from the URL.
Your client can't download a file it can't get the URL to.
You can create file transfer WCF service (REST) which will stream your content from blob storage or from other sources through your file managers to client browser directly by URL.
https://{service}/FileTransfer/DownloadFile/{id, synonym, filename etc}
Blob path won't be exposed, web application will be free from file transfer issues.
I have a ASP.net page which writes a file to the local disk.
I want to present the user a Save File dialog box and allow him to set the path to the folder.
I know code like below can be used;
Response.Clear();
Response.ContentType = "text/csv";
Response.AddHeader( "Content-Disposition", "attachment;filename=\"report.csv\"" );
// write your CSV data to Response.OutputStream here
Response.End();
But it fixes filepath.
I need to capture the filepath that the user selects.
Is that possible in ASP.net?
Thanks.
it does not work like that from a web page, you have to initiate the download suggestiong a target file name then the user can override your suggested file name and select any folder or filename he likes and your content will be saved in that location.
you do nothing with a local path which only makes sense on the client machine on the server side of ASP.NET application.
I need to capture the filepath that the user selects. Is that possible
No. Your web server presents a file to the client, where the client has the option to save this file.
In what way would the path the client saves this file be interesting to the server?
Is there a way to get the select file dialog box open and putting the location of the file into a textbox without ever uploading the file?
ETA I'm using VB.NET in a web page. By using the asp:fileupload tag I can get the file location
_fudFileLocation.PostedFile.FileName_
But how do I prevent the file from being uploaded at all. We don't need it, just the file location. (The files are on a shared drive so if it's M:\documents\todayslunch.pdf for person A, it's the same for person B.)
You do not get access to the full filepath in the browser because of security.
If this was possible, one could get the full layout of the computer of anyone going to any website.
System.Web.HttpPostedFile.FileName gets the fully qualified name of the file on the client which includes the directory path.
I'm working on an ASP.NET web application for our corporate intranet users. I have a form where a user should provide a path to the file on the local network (something like "\localServer\someFolder\someFile.ext") without uploading the actual file. The issue is that users don't want to type the whole file path and want to use some kind of visual browse dialog.
The standard HTML <input type=file> element allows to browse for a file, but most of the browsers (except for IE) don't allow to access file's full path, so I think it should be done by some external component like Silverlight, Flash, Java applet etc.
I tried to do it with Silverlight, but I'm getting a SecurityException when trying to access file's full path using Silverlight's OpenFileDialog class.
This java applet http://jumploader.com/demo_images.html seems to do something similar to what I'm looking for, but it's focused on uploading files - I only need to be able to get file's full path and pass it to the server as a string.
Any suggestions would be appreciated.
Telerik ASP.NET AJAX RadFileExplorer has the functionality you're looking for:
http://www.telerik.com/products/aspnet-ajax/fileexplorer.aspx
You can use their Custom File Content Provider to hook the GUI to your server's file system.
http://demos.telerik.com/aspnet-ajax/fileexplorer/examples/server-sideapi/dbfilebrowsercontentprovider/defaultcs.aspx
This should be possible with Flash's uploading capabilities. SWFUpload has an API that you may be able to access from JavaScript to extract the selected file name without actually uploading anything. See docs here, for example getFile():
getFile is used to retrieve a File Object from the queue. The file retrieved by passing in a file id (the id property from a file object) or a file index (the index property from a file object).