I have a FB app in an iframe on a Facebook fan-page. If I create a URL linking to that page, and that URL contains an app_data parameter, like this:
https://www.facebook.com/pages/My-Page/123?sk=app_456&app_data=mydata
Then post that in my FB feed, FB strips the app_data parameter, reverting to the canonical URL for the fan page:
https://www.facebook.com/pages/My-Page/123?sk=app_456
Which isn't what I want.
I would consider this a bug, as the state of the application is part of the "canonical" state of the fan page, but for now: Any way to get around this?
I have thought about making the bookmark to my own page:
https://facebook.mysite.com/pages/My-Page/123?sk=app_456&app_data=mydata
and dynamically generate a page with all the OpenGraph tags from the corresponding FB page (to make FB sharing work), and a redirect to the fan page (to get the user to the right place) - but this requires either (a) scraping FB for those OpenGraph tags or (b) accessing the graph.facebook.com api programmatically in a crawl-like fashion, and I don't know what FB thinks of that.
G'Day Leo, might be a bit of a hack but seems to work. I link my app_data onto a separately hosted URL and redirect back to Facebook with it.
So my URL I share is: https://externaldomain.com/deeplinker.aspx?data=stuff
Then response a redirect which is: https://www.facebook.com/[pageurl]?sk=[app]&app_data=[data]
With [data] = stuff
Related
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?
I am trying use open graph API to publish an action. URL that I provide as part of meta data property og:url can be accessed by authenticated users only. Facebook is trying to scrape the URL and is ending up with a sign_in page due to a 302 redirect.
Do I have to construct a page just for facebook scraping with meta tags in it? Isn't this url linked to the content published on facebook?
If you want your articles to be sharable or do any SEO, you shouldn't be using 302 redirects. Bots will only see the content from the destination of the redirect.
You want to have just one URL for each piece of content. If an unauthenticated user, the Facebook Scraper, or Googlebot visits that URL, you want it to see all your Meta tags and some teaser content.
If the user isn't authenticated, use a server-side scripting language to display a register/sign_in dialog instead of the premium content. If the user is authenticated, then you show them the full content.
This is better even from a UX perspective: Say I follow the link from Facebook and register. When I sign in, how are you going to get me back to the content I wanted to see in the first place?
I'm adding on my website the open graph meta tags and testing if it is working with the Facebook URL Linter.
The only thing that is not working how I would like it is the og:url: tag, in this meta tag I want to add the permalink url of the current page.
The permalink actually redirects to the current page. I use this because my URL of the pages looks like this : http://website.com/photos/243/hello-this-is-the-title/ and the last part of the URL can be changed be the user and if it is changed the URL will change and it will not be associated with all the "Likes" stored at Facebook.
This is why I have a permalink page that looks like this : http://website.com/permalink/243/ and this will redirect to http://website.com/photos/243/hello-this-is-the-title/, so that all the likes on Facebook are associated with the permalink instead of the other one.
When I use the Facebook URL linter it tells me that there are some critical errors that need to be fixed - Circular redirect path detected (see 'Redirect Path' section for details).
I don't know if what I want to do is possible. But I could really use a little help here.
This is why I have a permalink page that looks like this : http://website.com/permalink/243/ and this will redirect to http://website.com/photos/243/hello-this-is-the-title/, so that all the likes on Facebook are associated with the permalink instead of the other one.
When I use the Facebook URL linter it tells me that there are some critical errors that need to be fixed - Circular redirect path detected (see 'Redirect Path' section for details).
Two options:
Exclude the Facebook scraper from being redirected, by looking for it’s user agent (details).
Don’t redirect server-side, but do it client-side via JavaScript instead. (The scraper does not care about JavaScript.)
So I'm trying to generate the right URL to go in the facebook Like button. The URL is to a person's facebook page and it's generated using their facebook page's ID.
The facebook like button developers page says that I need to include this URL in the data-href="" attribute in the <div> they provide (that the iframe is generated in).
When I go to a URL like http://www.facebook.com/234h23o4ub23 it redirects to the right place. So I'm wondering if I can get away with using this shorter url as opposed to the url that it redirects to like for example: http://www.facebook.com/pages/example-venue-name/234h23o4ub23. I don't have the "example-venue-name" segment of the URL stored in my database making this method very difficult. Is that page going to register that it was liked or do I have to do the entire URL?
The URL on the like button is actually just what the user will follow back, so as long as the user can follow the link, you will be fine. The link is the unique tracker to the object so that Facebook knows distinct objects.
I'm playing with facebook links via posting them. On the frist time a access from a user agent containing "facebookexternalhit" will visit your site and look for some meta tags.
So far so good that works. But if I try to repost the link no furure calls happens. How can I trigger to let facebook read the page again?
Are there some API calls I can use to trigger an update?
in the documentation for the Like Button it says:
When does Facebook scrape my page?
Facebook needs to scrape your page to know how to display it around
the site.
Facebook scrapes your page every 24 hours to ensure the properties are
up to date. The page is also scraped when an admin for the Open Graph
page clicks the Like button and when the URL is entered into the
Facebook URL Linter. Facebook observes cache headers on your URLs - it
will look at "Expires" and "Cache-Control" in order of preference.
However, even if you specify a longer time, Facebook will scrape your
page every 24 hours.
The user agent of the scraper is: "facebookexternalhit/1.1
(+http://www.facebook.com/externalhit_uatext.php)"
The Linter is now known as the Facebook Debugger and when you use it for a url, it will clear the facebook cache for the same url and will then cache the new result.
One trick you can use is to simply append a "random" GET parameter to the URL that you're sharing. It won't have any effect on the page's content, but will cause Facebook's scraper bot to reaccess your site.
Original URLs:
http://example.com
http://example.com?param=1
New URLs that will force a "reaccess":
http://example.com?cache_buster=784932789532
http://example.com?param=1&cache_buster=784932789532