I am all too aware of the fact that even with the new FileAPI it's not possible to access the local path of a file added using a file input field or drag-and-drop. Whether or not this is good, bad or ugly is not the issue here. According to the FileAPI specs local file access is not to be implemented, and so I'm not holding my breath.
But let's just pretend I'm in a situation with the following fixed parameters:
Developing an HTML5 application only to be used internally at a company
.NET used for backend (needed due to interop with APIs)
Can specify/control exactly which browser and version should be used with the application
Need to access files that are usually located on a network share, but possibly also locally at a user's workstation
And by access I don't mean access file data, but rather be able to relay a file drag-and-drop/select event to some other API by feeding the third party the file's local path, so that the third party can pick up the file and do some sort of work on it. This can be likened to using an input[type=file] field as you would an OpenFileDialog in .NET - i.e. the point is to feed the application a file path, not an actual file.
I realise that out of the box this is probably not possible. But I also think that there must be some sort of solution to the problem.
Some ideas I've been toying with are:
Using browser specific methods for allowing "secure features"
Not sure if possible - tired using some of these features to no avail
Would limit the app to a specific version of a browser as the functionality could potentially be removed in the future
Something like a Chrome extension could possibly do the trick
Using some sort of companion application installed locally on a clients computer that takes care of all on-disk file handling, possibly communicating with the HTML5 client using websockets or the like.
A potentially pretty messy solution
Would probably confuse the users a bit at first
Submitting the selected file data to the server, storing it at specific path and sending this new path to the third party.
Would constitute a lot of sending files over the company network, some 100+ MB in size
Would not be able to do any in-place changes to a file a user has selected
... and that's about it.
Any snazzy suggestions? Wise words? Helpful links? Snarky comments?
Thanks.
Edit: For anyone curious about it, this was very simple using Silverlight as per jgauffin's suggestion below.
From the Silverlight codebehind (using elevated privileges):
private void fileBtn_Click(object sender, RoutedEventArgs e)
{
//prompt file select dialog in Silverlight:
var dlg = new OpenFileDialog();
dlg.ShowDialog();
//call JavaScript method and feed it the file path:
HtmlPage.Window.Invoke("onFileSelected", dlg.File.FullName);
}
You'll probably have to use something that runs in the browser like flash or silverlight.
Since it's an internal app I would use silverlight as everything else is in .NET. It should be enought to only make the file access part in the plugin.
Here is an article about local file access: https://www.wintellect.com/silverlight-4-s-new-local-file-system-support/
does the server hosting the site have access to the network of pc's?
you could just list all the files that way.. build a small ajax script like a file dialog that will have php or whatever sending back the structure
no plugins needed, works on all browsers... :)
Related
I'm trying to develop HTML base editor equipped with browsing local files function.
I know basically that is restricted by browser to open local files.
However I found out some method doing this activity.
using path begin from "localexplorer://" it works perfect for English path name.
But when I use Japanese folder name or file name it becomes error.
I tried to convert SJIS format that file names but this is not work.
Here is code.
[![error[![\]\[1\]][1]][1]][1]url = 'localexplorer:' + event.target.innerText;
array = str2array(url);
sjis_array = Encoding.convert(array, "SJIS", "UNICODE");
sjis= Encoding.codeToString(sjis_array);
window.open(url, '_blank');
According to browser security, javascript is only allowed to run in the sandbox, you cannot read or write arbitrary files:
JavaScript and the DOM provide the potential for malicious authors to
deliver scripts to run on a client computer via the Web. Browser
authors minimize this risk using two restrictions. First, scripts run
in a sandbox in which they can only perform Web-related actions, not
general-purpose programming tasks like creating files.
If the user selects a file via <input type="file">, you could try to read the content of the file through FileReader API, like this case: How to open a local disk file with JavaScript?
If you need to interact with files on the user's local device or a user-accessible network file system, you can try to use the File System Access API. And this must be done in a secure context, and must be called from within a user gesture. You can also read this article to learn more about it：The File System Access API: simplifying access to local files.
Thank you for your response, I solved this issue by Forefox plug in extensions, it seems like chrome did not support this functions even if there is plug in extensions.
As the title indicates i want to have a certain application get access to the local file system. To describe why i will illustrate my situation:
I am a running a IIS WebApplication with the C# MVC 4 Framework as backend module. The site solely consists of HTML, CSS markup and some JS. The page will be loaded in IE11+ (Edge) only. For the standard procedure of displaying and accessing data from as well as sending data to the server this works quite fine.
On a certain page I want the user to be able to upload a file using a simple file dialog, like the one you can initiate with a simple <input type="file"> tag. I also want to offer the posibility to download files from the server but need to know where files has been saved / will be saved to.
As described on a lot of different websites, just like this one here, the HTML5 File API does a great job but will not be able to return the full qualified filename including the local path directions, same for JS accessing the file object.
As my research confirmed HTML5, JS and also SWF (Flash) will not report detailed information because they are all sandboxed applications or restricted by RFCs. I already unterstood and appreciate the effort to secure my trips to internet.
But in this case do need the paths where a file was upload from and the file has been downloaded to.
So my question is, what is the best way to expose the full path directions for a up- as well as downloaded file to report them back to the server?
Is it possible to embed a SWF object inside HTML which will run inside an Adobe AIR sandbox or is a signed JAVA Applet still the one and only solution to accomblish this security breaking task?
A solution i would also apreciate would be the possiblity to ask the user to get access the file system, like you grant access to the web push service to receive notifications.
Also if there is a possible solution which may suite my circumstances please let me know by adding some simeple examples / revealing some factful links, thanks in advance.
We are currently looking at porting a enterprise silverlight application over to html5. The major roadblock that we have hit is the ability to open files from the user's local disk. Currently they have a document library which just links to files on their computer that they can open from within the app and view or print out. All that I read is that you can only access the local sandbox of the web app with the html5 file api's. We want to load these files from code.
Does anyone know of any workarounds to this?
Thanks
There is no way for html5 to access local file without user selection. But FSO: FileSystemObject works for IE and MAYBE could be regarded as a work around. But still there are some requirements to meet.
It is possible to use chrome's filesystem API to access files on a users local filesytem. So you'd have to be willing to make this a chrome only application.
Using java you can create a "Signed" applet which has access to the local filesystem. (if the applet is signed you can request filesystm permissions)
then there is a tutorial for accessing methods of your java code directly from javascript here: http://docs.oracle.com/javase/tutorial/deployment/applet/invokingAppletMethodsFromJavaScript.html
you should be able to perform something similar from silverlight.
There is no workaround in pure HTML5/Javascript. You need the use of plugins, such as Java or Silverlight (maybe you shouldn't port it after all). As for workarounds, HTML5 gives you an easy way drag and drop multiple files that you could transfer on the server and then display back to your users. Another workaround would be to install a custom agent (a software with only a tray icon) that would send the information about the current user "document library" to server and then again, you could display it back to the user.
Note: I've heard somewhere that browsers will eventually stop supporting plugins. http://www.howtogeek.com/179213/why-browser-plug-ins-are-going-away-and-whats-replacing-them/
Ya, I agree with Markain. However, if you were to limit your audience solely to chrome users, I daresay, you would most likely use some of your users. If Huazhihao is right, then your number of leaving customers should decrease but users who regularly use firefox won't be happy. Overall, I think that this will not work. Otherwise, there would be too many websites that trashed your hard driver (or at least wherever you have the rights to edit/delete files). I think it would be best if your product was setup to synchronize the file whenever an internet connection was detected and a change was made to the file. That way the user would not need to visit the website whenever the file was uploaded. If this is some kind of an error file, then it would be most beneficial if you were to make a link in the application that when clicked, would upload the file to the website and the website were to do whatever was necessary. If this is a purely online thing, then I don't see what business you would have looking through other peoples' files =-). Hope I helped!
I am working on project for desktop application. I am using Qt controls with visual c++.
I am loading an html file in the QWebView as,
m_pWebView->load(QUrl("../../../demo/index_Splash_Screen.html"));
Now, what i want is, say, I have some .zip files in my location "c:\demo", I want list (or array of file names) of the files present in that directory.
How can i do this through javascript ?
PS: I went through this link, but it didnt match my requirement. I have not worked with of html, javascript and jquery. Please help me.
I'm afraid you cannot access local files or directories using javascript due to security issues.
Edit: I hadn't thought about the file api so thought for a moment this might not be true, but without some user input to give permission, this still cannot be done.
This question has a good response from PhilNicholas:
I'm afraid I may be the bearer of bad news for your design: The action
you are requesting expressly violates the security model as specified
in the File API spec. The client implementation of FileReader() must
make sure that "all files that are being read by FileReader objects
have first been selected by the user." (W3C File API , 13. Security
Considerations: http://www.w3.org/TR/FileAPI/#security-discussion).
It would be a huge security risk of browser scripts could just
arbitrarily open and read any file from a path without any user
interaction. No browser manufacturer would allow unfettered access to
the entire file system like that.
Thinking about it however, if it is all being run locally, you could use ajax to query a server side script that could return the directory you request.
If it is a Windows application then you could access the local filesystem by using ActiveX objects. You might have a look at this link Reading a txt file from Javascript
Note that activeX usage is possible only when using IE as browser/engine; I used to need it a while ago for developing an HTML application (.hta files).
I'm working on a Silverlight control that will allow multi-file downloading. At the moment I'm trying to get my mind around the permission model of the browser.
Let's say, on a web page, a user enters a local folder (c:\temp) in a text box. The user then clicks a button.
Is it possible in JavaScript or Silverlight, to write a collection of files (that are stored on the server) to that folder on the user's drive?
From Javascript - NO. It would be way too easy from some scumbag to install a virus on your PC if that were possible.
Silverlight I don't know about, but I would assume writing to the users hard drive would be very limited and tightly controlled.
Only if the browser has a security hole that you can exploit.
Since the capability you describe would allow any webpage to do whatever it damn well pleases to the visitor's system, there is no way anyone would implement arbitrary access to the local disk deliberately in this day and age.
The next best thing you can to is to have the user download a ZIP archive and tell him to decompress him wherever he likes.
You cannot from Silverlight. The only thing you have access to is the Isolated Storage.
http://blog.paranoidferret.com/index.php/2007/10/12/silverlight-tutorial-using-isolated-storage/
http://msdn.microsoft.com/en-us/library/bdts8hk0.aspx
Warning: most of these answers are incorrect.
You can so write to a file via Javascript in both MSIE (using ActiveX FileSystemObject) and Firefox (using nsIFileOutputStream). In both cases the user will be presented with a security dialogue, which can be allow or deny the read or write.
I have used the Scripting.FileSystemObject to do this. Only works in IE, and only with very relaxed and unsafe security settings, but it might work for intranet sites in an enterprise, at least it worked for me.
Google Gears has a method to do client-side storage.
http://gears.google.com/
That said, I doubt it will do what you are attempting. I think you would be better off having a server-side thing download files and put them into a .zip file for the client before passing it on to them.
As it was answered earlier, this would have to be done via server-side, Silverlight and JavaScript are sandboxed to disable this type of security hole. I would suggest packing the files into a zip archive on the server and then downloading the zip archive.
You can do this via an ActiveX control or Java applet. Either way you do this the project has to be signed with a code signing certificate. You can use a self-signed certificate but the warning dialogs will be louder and brighter.
You can then use Javascript to call into the signed control and save files. Be very careful about creating an applet like this. You don't want to allow any other website to use this control so the control must implement some of the following:
Only work on a certain website.
Save files only in a specific location.
Prompt the user where to save the files so that they know that this is happening and it doesn't happen silently in the background.
You can probably find a control or applet somewhere that can be controlled with Javascript.
I don't believe this is possible as it create countless security problems. The only way I can see this being secure is a mix of user permissions and some way of verifying (on the client side) the authenticity of the website and the files they want to download to my computer.
One method you could do is triggering the "FileSaveDialog" but I don't think that is what your looking for. Maybe packaging the collection of files first and then triggering is the way to achieve your goals. Silverlight only allows for 1mb of isolated storage per domain and will absolutely not give sites access to the clients hard drive.
This doesn't directly answer the question, but Adobe Flex 4 allows doing it with FileReference class.
Silverlight 4 OOB allows access to the user's document directory.