Trying to see if this is possible -
1.) User logs into our site
2.) Points to a directory
3.) The javascript code reads contents of the directory, shows thumbnails for any jpeg/gif in those directories. This all without uploading all the photos to the server. Kind of a semi desktop app.
Point 3 is something I have never done, is this possible for an online application to do ?
You can't do this...yet (unless you're using a prerelease of Chrome 9). There are some APIs coming down the pike that will make this possible in browsers that support them; there's a description of using them in this article.
But right now, no. To do this, you'll need to use a technology that allows local file access, such as a signed Java applet (normal unsigned ones obviously can't do this) or, on a severely limited number of platforms and browsers, an ActiveX control.
Update: Sorry, the new JavaScript APIs I mentioned above don't give you (user-granted) access to any old directory on their system. They do give you access to the file system, but it's a sandboxed file system. So you'd have to have the users move the files into the sandbox (which you could do via the File API and with drag-and-drop, keeping it an entirely client-side thing, no uploading required). But that isn't quite what you described.
No; this is not possible.
Javascript cannot directly interact with the user's local filesystem
No, it is not possible to access any of the clients files using JavaScript as that would be a security risk.
Related
I'd like to have a way for a webpage -which is generated dynamically by my server- to read all the files in a specific user folder, manipulate them using javascript, within the web browser, and using them to show to the user some results (specific correlations between the data, dependent on the context and sometimes some graphs, drawn using these correlations).
Communication with the server about these data is neither required nor desired. Actually, since all the manipulations needed can be done via javascript and the files can be huge, for now I absolutely don't want that their content is uploaded to the server. Therefore there are no security risks (at least none that I can see).
Server side, I'm only interested to save the name of the folder, so that the user (who is registered) doesn't need to select the files one by one or to select them again every time a new page is dynamically created.
For now, the only hopes to find a solution that I have been able to gather are about using the Chrome FileSystem API (but I'd prefer a general solution, not dependent on a specific browser) or creating an extension that the user should install to use this feature when visiting the website (which, for me, is maybe even worse than relying on a specific browser).
So I wonder if there is a way to implement this feature using only pure javascript and HTML5 and using neither extensions nor browser dependent solutions.
Due to security reasons, JavaScript running in the browser should not be used to access the filesystem directly. But definitely you can access it using Node's fs module (but that's on the server side).
Another way is, if you let the user pick files using the <input type="file"> tag then you can use the File API to fetch the contents. But I think that is not what you are looking for.
Recommended reading: https://en.wikipedia.org/wiki/JavaScript#Security
Is it possible with Javascript or jQuery to convert mp3, wav, etc. to m4r format?
Let's assume you had a library that can change the format of files.
Let's also assume you only need the application to work on current browsers that implement FileAPI or FileReference so you can have access to uploaded files (you can't have access to them without FileAPI or FileReference unless you use Flash or Java Applets or equivalent technologies).
You wouldn't be able to write the output file back to the user because JavaScript is not allowed to access the local filesystem.
Your only solution would become sending the converted file to the server and the server sending it back to you with a force download directive so that the user will be prompted to download the results.
Now back to if there were a library that can the conversion (or even native JavaScript)... I haven't heard of any. It's not impossible to build one but it is impractical and wouldn't run very fast.
Edit:
Let's not forget Node.js!
It's a backend server that uses Google Chrome's V8 JavaScript interpretor/compiler. And it runs JavaScript as a backend scripting engine.
You have access to filesystem, databases and everything if you use that (or any other backend system for that matter) and still be using JavaScript. You can use libraries too. Either written in JavaScript or libraries written in other languages that have been linked to interface with Node.js.
Edit 2:
There is a PC emulator written entirely in JavaScript. It runs binary executables if you want it to. It's called JSLinux.
If you're feeling particularly rambunctious you can grab the ffmpeg binary executable (compiled with static linking). And embed it into your application code as an uuencoded string then use JSLinux to execute the commands and grab the results.
Indeed, it is possible doing this on the client using the latest js technologies. A web-worker thread can do the work in the background. At least in Firefox and Chrome it is also possible to read ("upload in memory") and write ("download from memory") files using the new W3C File API, see here.
I managed to read files via drag&drop from and within the client using google's GWT which in the end is plain javascript, so it must also be possible to do it "natively".
Besides that, the conversation algorithm of course has to be implemented in a javascript web worker to avoid blocking the gui. This should be the hardest part, but not impossible, though.
You would need a backend to do this. You may want to look into the PHPExtension of FFmpeg
I'm creating a client based application in HTML Application (HTA) and I would like to know if there's a object persistent library similar to python's shevle that meets the following criteria:
Should be able to read and write on file
Cross browser: should work at least on both HTA and on Firefox (through XULRunner) so that I'll be not tied to any vendor.
Written in JavaScript form
TiddyWiki is able to save itself, regardless of the browser used, though the codes that saves and retrieves files has to be refactored to meet my need.
Well, I wasn't aware that TiddyWiki has a github repository, and they organized the files by module.
I could just take the FileSystem.js file and build a nice api on top of it to simulate shelve functionality.
Is it possible to list the files in a directory using only javascript? To clarify, I mean list the files on the server, not the files on the clients computer. For instance:
www.domain.com/files/
contains 4 images (.jpg)
Can I make an extra page (www.domain.com/files/list.html) that lists those 4 files using javascript?
No, Javascript doesn't have access to the filesystem. Server side Javascript is a whole different story but I guess you don't mean that.
Very late to this party, but my google search for this exact request led me here.
The answer is "not really", but I've found the frankenstein of hacks elsewhere: If +Indexes is (or can be) enabled in the .htaccess for the folder containing the files you want to list, then use XMLHTTPRequest with the folder name as the url (which will return an html page listing the files).
I don't know if you architecture allows it but ikf you can install and use node.js as its node API mentions, you can interact with the filesystem by requiring the fs module.
This is the environment Node.js relies on:
Node eventually wants to support all
POSIX operating systems (including
Windows with MinGW) but at the moment
it is only being tested on Linux,
Macintosh, and Solaris. The build
system requires Python 2.4 or better.
V8, on which Node is built, supports
only IA-32 and ARM processors. V8 is
included in the Node distribution. To
use TLS, OpenSSL are required. There
are no other dependencies.
You can run It side-by-side with another web app. and this will avoid blocking your web application if the interaction with the filesystem takes too long.
It is generally not a good idea to access client computer files via javascript for security reasons, however i suspect you can use the File System Object for that. I am not sure about browser-compatibility for that, it should work in IE only probably though.
You need to use server-side languages such as PHP, ASP.Net, JSP, etc
JavaScript runs inside a host environment. So if the host provides a facility to list files in this manner, then yes. But in the typical scenario where JavaScript is running in a browser with default configuration, no.
I have a javascript photo-organizer built on the YUI JS libs which can organize photos from many sites via REST api. I want to know if I can resuse any of this code to organize photos on the local filesystem.
I need a cross-browser (i.e. PC/Mac) solution to the following (in order of increasing privilege):
persistent file access to read/write local XML datafile (between sessions)
ability to manage large uploads of thumbnails to my server
FOLDER+file access to scan JPGs in a folder tree. permission granted by user via drag-drop
ability to execute local shell script to generate thumbnails
I've looked at the following and found some short-comings:
BrowserPlus - no way to save access to local FS between sessions
GoogleGears - local access to files via dialog box, only
Adobe Air - is this a possible solution??? can I reuse my javascript?
Can someone tell me if this is possible in Air, or if there are any other plugin options/strategies?
NOTE: I could live with a download and install solution like Adobe Air, as long as I don't have to write both PC/Mac versions. Does that make it NOT a security hole? Also, can I reuse my YUI/Javascript inside AdobeAir - or do I have to start from scratch?
tia, m.
Adobe Air is a standalone runtime. It will let you do what you want, but it does not run inside Browser, and will instead require users to install application to their desktop first (though it is cross browser and cross-platform).
Flash (or Flex) plugin inside Browser may be able to do some of the things you want, but I doubt it will let you free reign on the local file system for managing photos. You will be able to store some persistent data in local shared objects (kind of like Cookies), but very little amounts.