链接到Facebook应用程序框架的最佳方法是什么？

Question

I have a pure iframe Facebook app in PHP. By being pure I want to say it has no meaning to approach it's in-iframe URLs directly. If someone accidentaly approached (eg by opening a link from the inside of app in a new tab) URL of the app outside of iframe, my app can recognize it by JavaScript and redirects to it's version in iframe.

However, my desired behavior is to send the user to the same URL he wanted to approach, only inside Facebook platform iframe. Example:

• User goes to: http://app.myserver.com/pages/help/
• My app redirects to: https://apps.facebook.com/my-awesome-app/ , in iframe is initial page http://app.myserver.com/
• Where I'd like to redirect: https://apps.facebook.com/my-awesome-app/ , in iframe is requested page http://app.myserver.com/pages/help/

What would be the best solution in your opinion? I thought about sessions, do they have any drawbacks? I can save original location and start redirect to iframe, then find out what was the location and redirect to that page inside the iframe. How can I ensure the user who is being redirected doesn't interrupt the process and doesn't cause any unpredictible redirects later due to the saved but not resolved one? What about user having multiple tabs with my app? Tabs could steal redirects one from the another...

Answer 1

例如，将用户重定向到https://apps.facebook.com/my-awesome-app/?page=help并分析应用程序中的查询（或使用httpd重写规则）。

Answer 2

The below are my findings with respect to Page Tab apps. It may not be true at all for App on Facebook apps.

Normally, Facebook will not pass on query string parameters to the URL of your iframe, so you can't go the facebook.com/.../my_app?where=help&page=2 way.

It will however pass on the app_data paramater inside the signed request (it is the only exception to the rule AFAIK). But this leaves you with only one parameter to play with. You can counter that, by making it a url-encoded JSON object, containing in fact many variables. Example:

facebook.com/.../my_app?app_data=%7bwhere%3a+%22help%22%2c+page%3a+2%7d

Which on the server side you receive by json_decode($signedRequest['app_data']) and receiving

array(
    'where' => 'page',
    'page' => 2
)

From here on, it is up to you to perform the redirects. You won't have to use sessions, unless your user is not logged in to facebook and / or your app. Then you'd have to complicate this a little. My solution was to use sessions for the not-logged-in scenario: Facebook app - deep link for new app user