I've been reading up on HTML5's sandbox attribute for <iframe>s. According to the documentation the sandbox attribute allows a developer to selectively restrict what actions can be done in an <iframe>. Is the sandbox attribute purely a security measure? Does the sandbox attribute enable web designers to implement any new functionality and if so can anyone point to any examples?
Well, it is purely a security feature, but it does allow new functionality as well. Take for example embedding third party (user) content (e.g. HTML files). Traditionally you would need to set up a separate domain from which you would serve that content, now however you can simply serve it from wherever you want to and have it treated as if it's from a separate domain.
On top of that it can prevent this third party content from doing certain things, which you could not have prevented previously like:
allow-top-navigation: Preventing it from breaking out
allow-pointer-lock: Preventing it from taking the cursor hostage
allow-popups: Preventing it from breaking out through popups
allow-scripts: Simply blocking all scripts (could also have been done through CSP)
Realistically the combination of the sandbox attribute combined with controlled CSP headers gives an incredible amount of control to run third party code in a safe environment. It's not 100% there yet, but we're getting quite close.
The sandbox can actually be pretty handy in testing. Consider the following:
tester.html
<script> document.cookie='foo=bar' </script>
<iframe src=testee.html>
testee.html
<script> console.log(document.cookie) </script>
When loading tester.html you will see on the console "foo=bar" which was dumped by testee.html.
Now add to the iframe the sandbox attribute and the cookie is gone - the sandbox created a separate runtime environment for testee.html, where it doesn't get cookie pollution from other pages that were/are open in the browser during the development process. So when you need a sterile test bed but can't or don't want to clear the browser cache, here's a quick and simple solution.
The sandbox attribute does not enable any extra functionality, it only restricts the functionality of the iframe. The only reason to use it is as a security measure.
The iframe sandbox is purely a security feature. A good resource is always the W3 HTML5 specification.
When the attribute is set, the content is treated as being from a unique origin, forms, scripts, and various potentially annoying APIs are disabled, links are prevented from targeting other browsing contexts, and plugins are secured.
I'm building a single-page Dart web app that will essentially consist of 1 Dart file (cross-compiled to JS) and 1 HTML file that has several "views" (screens, pages, etc.). in it. Depending on what "view" the user is currently located at, I will hide/enable different DOM elements defined inside this HTML file. This way the user can navigate between views without triggering multiple page loads.
I would still like to use each browser's native history-tracking mechanism, so that the user click can the back- and forward-buttons in the browser, and I'll have a Dart Historian object figure out what view to load (again just hiding/enabling DOM elements) depending on what URL the browser has in its history.
I've pretty much figured everything out, with one exception:
Say the user is currently "at" View #3, which has a URL of, say, http://myapp.example.com/#view3. Then they click a button that should take them to View #4 at, say, http://myapp.example.com/#view4. I need a way, in Dart, to tell the browser to:
Set http://myapp.example.com/#view4 in the browser URL bar
Add http://myapp.example.com/#view4 to the browser's history
If not already enabled, enable the browser's back button
I believe I can accomplish #1 above like so:
window.location.href = "http://myapp.example.com/#view3";
...but maybe not. Either way, how can I accomplish this (Dart code communicates with browser's history API)?
Check out the route library.
angular.dart also has it's own routing mechanism, but it's part of a much larger framework, so unless you plan on using the rest of it, I would recommend the stand-alone route library.
If you want to build your own solution, you can take a look at route's client.dart for inspiration.
There are two methods of history navigation supported:
The page fragment method that you've used. Reassign the window location to the new page fragment: window.location.assign(newPathWithPageFragment). Doing this will automatically add a new item to the browser history (which will then enable the back button).
The newer History API, which allows for regular URLs without fragments (e.g. http://myapp.example.com/view3. You can use window.history to control the history.The History API is only supported by newer browsers so that may be a concern (although given that dart2js also only supports newer browsers, there are probably not too many instances of a browser that dart2js supports that doesn't support the History API).
One issue you will have to handle if you support History API is the initial page load. When a user navigates to http://myapp.example.com/view3, the browser expects to find a resource at that location. You will have to setup your server to respond to any page request by serving your Dart application and then navigate to the correct view on the client-side. This issue will apply whether you use route, angular.dart, or build your own solution, since this is a general server-side issue and the above are all client-side libraries.
How to prevent downloading images and video files from my website? Is it possible?
What would be the best way to do this?
No, it's not possible.
If you can see it, you can get it.
Don't post them to your site.
Otherwise it is not possible.
As the browser needs to transfer the content to display it (text, images, videos), the data is already on the client's computer when the website is displayed. The previous answers give little advice on how to make it harder for non-experienced users to grab the content. Here are some directions:
General
Overlay the respecitive contents with a transparent <DIV> or a
transparent image (as described in some answers to this question)
Open the website in a frameset, so saving may miss the frame content.
Open the website via window.open() to hide the menu bar.
Disable right-clicks via JavaScript (not recommended due to all the side-effects on usability)
Load the page's HTML code from another file (which may check for a specific referer or which may be ROT13) via JavaScript, so it's harder to access the source code.
Tell the browser that all content is display:none for the printer (something like #media print { body, div, p { display: none } })
Use JavaScript to hide the content before a client makes a screenshot (see Stop User from using “Print Scrn”)
Try to disable or overwrite the clipboard (see this post)
Images
Do not use the <img> tag for images but set the image as background for a <DIV>
Wrap images into SVGs or Flash movies to make them very hard to access in a usable format.
Disable caching for images (via <meta> tag or by setting the appropriate header on server delivery), so they are not stored in the browser cache (immeaditely accessible on the client's computer).
Cut an image into parts, so it takes some extra work to reconstruct the whole image
Add onmousedown events to images, e.g., display a copyright alert.
Deliver the image via server script (e.g., PHP) and check the referer.
Videos
Stream videos to prevent simple downloading via URL.
Wrap videos into a Flash movie.
Use some nasty format that supports DRM.
Texts
Make text unselectable (see How to make HTML Text unselectable)
Additionally to overlaying, wrap the text into JavaScript (e.g., after ROT13 or loaded dynamically from a second file), so the text is not directly available in the source code.
Convert texts to images (this may decrease display quality), SVGs or Flash
Again, I repeat that none of this will stop an experienced user from grabbing the content (e.g. by making a screenshot and - optionally - run OCR on it). Sometimes it's as easy as using the browser's developer tools or using the website without JavaScript. Yet, it will give inexperiences users a hard time, so they may look for some easier source to grab from.
Also keep in mind that the above techniques will affect search engines when reading the page's content (if you're interested in blocking them, start with a robots.txt).
Thank you for any other ideas to complement the above list!
Images must be downloaded in order to be viewed by the client. Videos are a similar case, in many scenarios. You can setup proxy scripts to serve the files out, but that doesn't really solve the issue of preventing the user from getting their own copy. For a more thorough discussion of this topic, see the question How can I prevent/make it hard to download my flash video?
If you are using PHP, the best way is to control it the .htaccess, you need to put your files, images and videos under consideration in a separate folder/directory, and create a new .htaccess file in this directory with the below:
RewriteEngine On
RewriteCond %{REQUEST_URI} \.(mp4|mp3|avi)$ [NC]
RewriteCond %{HTTP_REFERER} !^http://sample.com/.*$ [NC]
RewriteRule ^.* - [F,L]
The first line %{REQUEST_URI} will prevent getting the file through the web browser or through curl.
The second line %{HTTP_REFERER} will prevent accessing the image/video using HTML tags <img> or <video> from any website except the exception ! you provide instead of http://sample.com/ which usually should be your website itself.
You can also have a look at my question and the accepted answer here for more tricks on the browser side.
I'd like to add a more philosophical comment. The whole intent of the internet, particularly the World Wide Web, is to share data. If you don't want people to download a picture/video/document, don't put it on the web. It's really that simple. Too many people think they can impose their own rules on an existing design. Those who want to post content on the web, and control its distribution, are looking to have their cake and eat it too.
In short, no. If someone can view an image or video in their browser then they have, by definition, downloaded it. That's how the web works - it is client server based. Whatever you can view in your browser (client) has been transfered to your computer from the remote website (server).
In standard HTML, I don't know of anyway.
You didn't really say, but I'm guessing you are having problems with people deep linking into your content. If that's the case, and you are open to server side code, I believe this might work:
Create a page that accepts a numeric
id, maps it to a server file path,
opens that file, writes the binary
directly to the response stream.
On the page request, generate a
bunch of random ids, and map them to
the actual media urls, and store that
mapping object server side somewhere
(in session?) with a limited life.
Render your pages with your media
links pointing to the new media page
with the appropriate id as a query
string argument.
Clear the mapping object and generate
all new links on every postback.
This :
won't stop people from downloading
from within your page
definitely isn't as lightweight as standard
HTML
and has it's own set of issues.
But it's a general outline of a workable process which might help you prevent users from deep linking.
As many have said, you can't stop someone from downloading content. You just can't.
But you can make it harder.
You can overlay images with a transparent div, which will prevent people from right clicking on them (or, setting the background of a div to the image will have the same effect).
If you're worried about cross-linking (ie, other people linking to your images, you can check the HTTP referrer and redirect requests which come from a domain which isn't yours to "something else".
you can reduce the possibility but not eliminate it...
It also doesn't hurt to watermark your images with Photoshop or even in Lightroom 3 now. Make sure the watermark is clear and in a conspicuous place on your image. That way if it's downloaded, at least you get the advertising!
This is how I do it in case anyone in the future is wondering.
I put this in the .htaccess file on the root server:
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain.com/ [NC]
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain.com.*$ [NC]
RewriteRule \.(mp4|avi)$ - [F]
This stops them from say going to domain.com/videos/myVid.mp4 and then saving it from there.
No it's not. You may block right-clicks and simillar stuff but if someone wants to download it, he will do so, trust me ;)
As soon as they view your page that includes the picture or video, the item is downloaded into the temporary folder of their browser. So if you don't want it downloaded, don't post it.
You can mark folders or files so that they don't have read access (any of the main web servers support this). This allows you to store them on the server without any level of access to the outside world. You may want to do this if you have a service that generates images for someone else to download later, or if you use your web account for FTP access, but don't want anyone to view the files. (i.e. upload a .bak file to the server for someone else to FTP down again).
However, as others have said, getting into copyright areas where people can view the image or video but not save them locally is not fully possibly, although there are tools to discourage illegal usage.
Put your image or video in flash format. Works great.
This is an old post, but for video you might want to consider using MPEG-DASH to obfuscate your files. Plus, it will provide a better streaming experience for your users without the need for a separate streaming server. More info in this post:
How to disable video/audio downloading in web pages?
I believe THEOplayer already provides this sort of solution as a paid service, but I'm not so sure about it.
Granted that any image the user can see will be able to be saved on the computer and there is nothing you can do about it. Now if you want to block access to other images that the user is not supposed to see, I am actually doing it that way:
Every link is to the "src" in your image tag is in fact a request
send to a controller on the server,
the server checks the access
rights of that specific user, and returns the image if the user is
supposed to have access to it,
all images are stored in a directory
that is not directly accessible from the browser.
Benefit:
The user will not have access to anything that you don't intent him/her to have access to
Drawback:
Those requests are slow.. especially is there are lots of images on the same page. I haven't found a good way to accelerate that in fact..
You can set the image to be background image and have a transparent foreground image.
I think the best way is:
STREAM THE VIDEO IN SEPARATED ENCRYPTED PARTS.
There are video hosting services such as vzaar that have this functionality.
As far as I know, that will make it really hard to download directly. At least for 95% of the people.
But of course, if the video plays on the screen people can just use a screen recorder and some simple software to record sound from the audio output (but he/she will have to play the ENTIRE thing to save it, totally inconvenient).
You can't stop image/video theft but you can make harder for normal users but you can't make it harder for the programmers like us (I mean thieves that know little web programming).
There are some tricks you can try:
1.) Using flash as YouTube and many others sites like http://www.funnenjoy.com does.
2.) Div overlaping or background pic setting (but users with little sense can easily save all resources by opening inspect element or other developer option).
3.) You can disable right click and specific keys like CTRL + S and others possibles with JavaScript but main drawback is that if user disable JavaScript our all tricks fail down.
4.) Save image in none online directories (if you have full access to web server) and read that files with server side languages like PHP every time when image / video is required and change image id time to time or create script that can automatically change ID after every access.
5.) Use .htaccess in apache to prevent linking of your images by others sites. you can use this site to automatically generate .htacess http://www.htaccesstools.com/hotlink-protection/
Insert a transparent gif 1px x 1px just inside the <body> tag:
<body><img src="route-to-images/blim.gif" class="blimover">
Then style it with this:
.blimover {
width: 100% !important;
height: 100% !important;
z-index: 1000 !important;
position: absolute !important;
top: 0 !important;
left: 0 !important;
}
This will remove any click functionality from a page, but it sure stops people stealing any content!
You can apply the same to a <div>, <section>, <article> etc, just name accordingly and prevent your copy and/or images being ripped.
Nothing stops a screengrab though ... ...
If you want only authorised users to get the content, both the client and the server need to use encryption.
For video and audio, a good solution is Azure Media Services, which has content protection and encryption. You embed the Azure media player in your browser and it streams the video from Azure.
For documents and email, you can look at Azure Rights Management, which uses a special client. It doesn't currently work in ordinary web browsers, unfortunately, except for one-off, single-use codes.
I'm not sure exactly how secure all this is, however. As others have pointed out, from a security point of view, once those downloaded bytes are in the "attacker's" RAM, they're as good as gone. No solution is 100% secure in this case (please correct me if I'm wrong). As with most security, the goal is to make it harder, so the 99% don't bother.
I think the best way is to prevent right clicking on your webpage, because that is the most convenient way a normal user try to download the content, and you can consider it as remark if u able to do this only as you are never gonna be able to stop a computer geek or hacker people from downloading it, because once the content is on the internet, it means it is in the public domain already...
Put the content on google drive and make it download protect. This way people can only see your documents, pictures but cannot download it.
DRM solutions are available today. It makes the video viewable but not downloadable.
What is DRM?
Digital Rights Management (DRM) solutions are software programs created to help people protect and control their valuable digital content, whether it's documents, videos, images, or audio files.
Check out this. Hope it's helpful.
I have a problem where I have a frameset consisting of a parent frame loaded from one domain and a contained frame from a different domain. The contained domain also sets a cookie before the frameset is loaded. However, because of the 'same orgin' policy, enforced by most browsers, a contained frame will not pass cookies if it is not from the same domain as the parent.
Unfortunately I have no control over the parent frame (or its url) and the url for the contained frame is effectively static. So the only way to pass information to the contained site is via cookies.
The only solution I have come up with is to reload the contained domain in the parent frame but this negates some of the value of using frames in the first place.
Does anyone have a better work around for this problem?
There are a couple of methods of getting around the Same Origin Policy that is preventing your iframes from speaking to each other. If you control both servers then you can use Flash's crossdomain.xml file. If you don't control one of the servers or you would like to use JavaScript, then you are forced to use a "Cross-Domain Proxy", such as this one for java or python or php.
Cross-Site XHR is another option but it isn't supported by all browsers.
There are a lot of ways to do this. Here are two that I've used:
Have both the parent and child load
a script from a common source, using
a tag. Scripts loaded in
this way don't have same-origin
issues, and the data they return
becomes part of the document object
and can interact with other scripts
loaded by the document (this is the
way that AJAST works).
Create a reverse proxy in the parent domain, and load the frame via this proxy. To the browser, it appears that they're both served from the same domain. The downside is that this can affect caching, and bypasses any content delivery network (eg, Akamai) that you might be using.
There is also a right way of doing this in HTML 5 with postMessage.
See here: http://ajaxian.com/archives/cross-window-messaging-with-html-5-postmessage
One more thought in to this, where u can use Cross Domain Messaging API to send messages from one frame to another. here is an example! Read more on this.