Pancake/French Toast/Message API

User stories

As a front-end developer, I need a way to tell the native app to open a new layer containing a specific layer state.

 FrenchToast.openAppView(url)

As a front-end developer, I need a way to tell the native app to open a URL in the viewer.

 FrenchToast.openWebView(url)

I don't think we need the name parameter. I don't think we want layers to be able to talk directly to each other. Instead, I believe we can stick to a service-oriented architecture based on URLs. -Gbrander

As a front-end developer, I need the app to tell me when a layer has received focus so that I can check for updates and refresh data if necessary.

What about a DOM event?

 window.addEventListener('layerFocus', fn)

Focus isn't quite the same as active/visible. On the desktop, focus doesn't happen until an element in the window receives focus. I'm not sure how that plays out on touch devices. I think we want visibility

There is an actual API for this: PageVisibility but we would have to investigate browser support. As I understand it, our "layers" are going to be window object in UiWebViews or their equivalent, so this seems like the right place to start. I would rather polyfill this though than invent our own.

• http://davidwalsh.name/page-visibility
• https://developer.mozilla.org/en-US/docs/DOM/Using_the_Page_Visibility_API
• https://github.com/ai/visibility.js

As a front-end developer, I need a way to securely verify that the user is authenticated so that I do not expose confidential information.

 // find out if the current session is valid
 FrenchToast.getSession()
 
 // to start browserid
 FrenchToast.startBrowserId(callback)
 
 // to validate the browserid token
 FrenchToast.validateBrowserIdReceipt(receipt, callback)

Can somebody who worked on the session stuff in the past verify that these could satisfy the user story? - Gbrander

What about the way it works today are we wanting to fix? This functionality currently resides in the misnamed/misplaced lib/signin. ISTM that the modules under service/* could be FrenchToast.*. Lets talk. - Sfoster

As a front-end developer, I need access to a shared store that persists across sessions. All layers should have access to this store.

Use standard localStorage to serialize/deserialize persisted app data.

 window.localStorage
 JSON.stringify
 JSON.parse

Can we confirm that the same localStorage is available between UIWebViews - Gbrander

(From mailing list) I found this configuration option: webSettings.setSupportMultipleWindows(true); And now storage events are sent to the other web views that are open in the same app. - St3fan

Discussion

I don't think we need a general message mechanism to talk to the app. I also don't think we need to be able to send messages to specific layers from specific layers. In general, I would like to make the coupling between layers loose, and based on requesting URLs be opened. The layer itself can decide what to do with the URL. -Gbrander

Agreed that urls should be the primary messaging mechanism. We also have storage events which (browser-support willing) should allow us to signal state changes like login/logout across windows/layers. I suspect there's still a need for the native/js messaging though. - Sfoster