The Facebook API docs say the parameter, "app_data," should be used to customize tabs within a Facebook Fan Page.
However, when users add our tab to their page, the "app_data" param gets lost every time, meaning the tabs aren't customized per Fan Page as they should be.
For instance, we want this page to get rendered for one client: http://www.facebook.com/apps/application.php?id=198939416792674&sk=app_198939416792674&app_data=15
After the client adds this URL as a tab to his Fan Page, though, the tab URL loses the "app_data" parameter. The page rendered no longer reflects the data specific to this client.
We need the tabs to contain a parameter specific to each Fan Page. We thought "app_data" was the right approach.
Any clues what we're doing wrong?
The best way to do what you trying to achieve is to customise the content based on the page['id'] that is passed to you via a signed request.
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hi to all and tx for your support.
until now to add a custom tab to facebook page i use this url
https://www.facebook.com/dialog/pagetab?app_id=APP-ID&redirect_uri=APP-URL
in this way i add correctly the Secure Page Tab URL to my facebook page.
my problem is that i need to add different tabs related to different urls inside the same application. i need to add for example a tab called "CONTACT" related to APP-URL/contact, another tab called "PRODUCTS" related to APP-URL/products and so on. i don't want create more than one facebook application to do this, is it possibile?
That is impossible, you can´t install an App more than one time per Page. You can only show different content depending on the Page by reading the Page ID in the signed_request parameter.
In other words: One App can be installed on several Pages, but one App can only be installed one time per Page.
Information about how to use the signed_request parameter can be found in many Stackoverflow threads, for example: how to read facebook signed_request to get user_id
It´s a simple POST parameter and you need to parse it. Just debug the result and you will see the Page ID.
I'm working on a photo contest fb app to run in a fan page tab. the user should be able to share the photo in order for others to vote for them.
supposing image link in iframe is http://example.com/image.php?id=1 for particular photo, pressing share will share this link through iframe. which leads up to the host app itself.
what I need is sharing the whole fb app tab page url with http://example.com/image.php?id=1 open in its Iframe.
is that possible in any way?
thanks for help.
So to give the “alternative” to #Lix’ answer, which focuses on canvas apps, here the analog way for page tab apps:
For some reason Facebook decided to do things differently for page tab apps – different than with canvas apps, you can not pass just any GET parameters to your app by appending them to the facebook.com address of your app, but you have to use the app_data parameter for that.
You call/link to your app in the form https://www.facebook.com/YourPage?v=app_1234567890&app_data=foo – and whatever you put as value for the parameter app_data, you will find in the signed_request parameter that Facebook POSTs to your app on initial(!) load into the iframe.
So you parse the signed_request (or let f.e. the PHP SDK do that for you), and then you find the app_data value in there. If you want to pass more than one single value, you can f.e. also put JSON-encoded data there – then you have to decode that again after you read the app_data value from the signed request.
The docs just shortly mention the app_data parameter, but the principle itself is quite simple.
Now, when it comes to sharing those links, I found that when you use an address in the above form, Facebook tends to cut the parameters from the URL, and treat the whole link as just a link to your Facebook page – it shows the page’s picture and description, and does not even pass your page tab app along, let alone the app_data parameter.
I found the most reliable way around this is not to link to your page tab on Facebook directly, but instead to a URL of your own app. When the scraper visits it, you deliver the relevant OG information. And when it’s a real user visiting, you redirect them to your page tab app, passing the data you need via the app_data parameter as described above. Redirecting can either be done server-side (info on how to detect the scraper server-side via its User-Agent header), or client-side via JavaScript (which the scraper does not “speak”).
Sure it is. All you have to do is be able to extract the information from your application canvas URL. If your canvas URL is something like this:
https://apps.facebook.com/ImadBakir
Then you could place some more info in there, like this:
https://apps.facebook.com/ImadBakir?photo_id=123
Users will share that link and now in your application, you can parse that photo_id parameter and make the needed HTML changes to display the correct image inside your iframe as the page and application loads.
With regard to parsing the the URL parameters, assuming you'll be doing it with JavaScript, you can read more about it in this post:
How can I get query string values in JavaScript?
We are creating a canvas app and would like to add directly to my fanpage.
There are 2 ways that I'm not sure about how to take the user to the app's fanpage.
First would be to create a tab and add it in the fanpage.
On this tab would have some text and a call-to-action to redirect to app canvas.
Would create a second tab and add it in the fanpage only with a redirect to take the user directly to the fanpage of the app.
Is there any documentation specific to this practice or some restriction to redirect the tab?
To see if your app was loaded inside a page tab, parse the signed_request server-side and look if there is a page-id set.
If so, answer that request with a minimal HTML document containing not much more than a piece of JavaScript code to redirect inside the top window instance, like this:
top.location.href = "https://apps.facebook.com/yourappsnamespace";
There should be no restrictions on that – Facebook is only worried about automatically redirecting users away from Facebook (to outside domains), but since you are redirecting to a canvas app, they stay on their site.
The docs clearly state:
We do not accept Canvas pages that redirect to Page Tabs, or vice
versa.
I have an iframe tab which holds php page with various links inside (like "News", "Photos" etc.). Is it possible to generate a facebook link which leads directly to certain link inside the iframe? By facebook link I mean link that will keep you on facebook, open your iframe tab and view certain page on that iframe. The thing is that all I can do now is to link only to my iframe tab which has address like http://www.facebook.com/mypage/app_someid. Then I will land on my default page tab url. But I want to land on different one. Any tips on this one?
Passing an app_data parameter to the tab URL is passed back to your application as part of the signed_request parameter in FB's post call to include your content. Use that parameter after de-signing it to then decide what to show and what not to.
Your URLs will become like:
http://www.facebook.com/mypage/app_someid?app_data=showViewX
http://www.facebook.com/mypage/app_someid?app_data=showViewY
and then in your code:
// Get Signed Request
$app_data = $signed_request['app_data'];
if($app_data === "showViewX") {
// Show one view
} else {
// show others..
}
Currently, the app_data param is not sent if the user just liked the page when he lands on it with an app_data param. The bug on FB has been filed at https://developers.facebook.com/bugs/172963266154996 and we are all hoping for an early resolution.
i have one problem with facebook landing page. i created facebook landing page through static fbml app but i have one problem with like button, user must like the page before he will navigate to another page.
i want to do same functionality in my landing page,
http://www.facebook.com/BusinessofCinema?v=app_6009294086.
anyone know about this please help me .
thanks inadvance......
At this point you'll probably want to go with iframe based Facebook page tabs instead, now that these have become available and fbml based apps are being phased out. Among other advantages, the signed_request parameter that Facebook sends to an iframe based tab app includes a flag that indicates whether the user is a fan of the page.
Now that iframes are the only way to create new Facebook apps and FBML is being phased out, you need a new way to do it.
When your app URL is loaded, it is passed a signed_request POST parameter. This parameter contains the information you need. However, it is packed and encoded so it requires some manipulation to get the right info out.
First, split the signed_request on the '.' character. The first part is the signature. The second part is the encoded_data
Decode the encoded_data into a JSON string using the URLBase64Decode function equivalent in your server-side programming language
The JSON object contains a node called "page". This contains a node called "liked".
If "liked" is true, the user liked the page and you display the "liked" version of your app. If false, show the "Please like me" version of the site.
The FBML way will continue to work the way you have it live right now, but for anyone building a new Facebook app, this is the way to do.