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https://issues.apache.org/jira/browse/CB-4897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14090435#comment-14090435
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alexgzhou commented on CB-4897:
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this would be very much useful if achieved!!! looking forward to ......
> Support window.postMessage for two way communication between local and remote
> content
> -------------------------------------------------------------------------------------
>
> Key: CB-4897
> URL: https://issues.apache.org/jira/browse/CB-4897
> Project: Apache Cordova
> Issue Type: New Feature
> Components: Plugin InAppBrowser
> Affects Versions: 3.0.0
> Reporter: Lachlan Hunt
>
> For developing a hybrid web app that will use the device APIs provided by
> Cordova plugins in combination with a remotely hosted web application, it is
> necessary to be able to communicate between the local and remotely hosted
> components.
> The InAppBrowser plugin currently only provides limited support for mostly
> one-way communication using executeScript to inject a new script into the
> remote document. But this is limited because it only allows a single return
> value, and doesn't directly allow for ongoing communication.
> It would be very useful if window.postMessage were supported by the plugin.
> When a message is received by the remote page (via the window.onmessage
> handler), the evt.source property can provide a WindowProxy or MessagePort to
> be used for subsequent communication from the remote page to the local page.
> Other solutions I have considered:
> * Using iframe instead of InAppBrowser, absolutely positioned and covering
> the full height and width of the screen.
> This works, because the Window objects are accessible to both, and posting a
> message to iframe.contentWinow from the local content provides a reference to
> evt.source (The local Window object). This isn't ideal because it prevents
> using InAppBrowser's executeScript feature to first inject a script to enable
> the two-way communication features. Ideally, I don't want the server to
> include it because I don't want the web app to enable the feature when the
> remote page is loaded outside of the native app.
> * Creating a new MessageChannel() object and returning one of the ports via
> the executeScript return value.
> This doesn't work because the MessageChannel() constructor is not yet
> supported by WebKit on the devices.
> * Loading a remote script directly into the local content, and having that
> script populate the DOM with content as needed. This isn't ideal because the
> base URL of the document is not a URL to the remote host, so relative paths
> don't work, and setting <base href> causes other problems.
> * Communication via SharedWorker
> This method is the best I've found so far, but is quite complex to setup and
> operate securely.
> Setup for local page:
> * Embed <iframe src="http://remote.example.com/bridge.html";></iframe>
> * Generate a secure shared secret key using window.crypto DOM API. (Don't use
> Math.random() because it could potentially allow attackers to guess the
> shared secret.)
> * use iframe.contentWindow.postMessage() to send messages to bridge.html.
> * Send initialisation message with the shared secret key to the bridge.
> * var win = window.open("http://remote.example.com/";, ...)
> * When loaded, use win.executeScript(...) to inject the same bridge.html
> iframe and the shared secret key into the remote page
> Setup for remote page (from executeScript call):
> * Embed <iframe src="http://remote.example.com/bridge.html";></iframe>
> * postMessage() initialisation to the bridge with the shared secret key
> Bridge.html
> * Creates a new SharedWorker("bridge.js")
> * Messages received by the SharedWorker are broadcast out to all other
> listeners that have initialised with the same shared secret key.
> Because bridge.html may potentially be embedded into any site and access the
> same SharedWorker, the shared secret key lets the worker know which pages are
> authorised to post messages, and reject messages received from other sources.
> The complexity of that solution would be solved by having native support for
> window.postMessage() in the InAppBrowser plugin.
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