[jira] [Reopened] (CB-6423) (iOS) cordova.js: iOSExec() not working after upgrading from Cordova 3.0 to 3.4

["Andrew Grieve (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CB-6423?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrew Grieve reopened CB-6423:
-------------------------------

Re-opening. [~joejoerubio] - are you able to share a sample project that shows the issue?

> (iOS) cordova.js: iOSExec() not working after upgrading from Cordova 3.0 to 3.4
> -------------------------------------------------------------------------------
>
>                 Key: CB-6423
>                 URL: https://issues.apache.org/jira/browse/CB-6423
>             Project: Apache Cordova
>          Issue Type: Bug
>          Components: CordovaJS, iOS
>    Affects Versions: 3.4.0
>            Reporter: Joel Rubio
>            Assignee: Andrew Grieve
>              Labels: cordovajs, ios, upgrade
>
> Hi there,
> I recently upgraded my working PhoneGap app from 3.0 to 3.4. In iOS, the app wouldn't go past the splashscreen. It would get stuck while trying to fetch a local file (in file:/// dir) through an XHR.
> I managed to trace the problem to the iOSExec function in cordova.js. Before the upgrade, it would determine bridgeMode the following way:
> bridgeMode = navigator.userAgent.indexOf(' 4_') == -1 ? jsToNativeModes.XHR_NO_PAYLOAD : jsToNativeModes.IFRAME_NAV;
> In cordova.js 3.4 it is determined the following way:
> bridgeMode = navigator.userAgent.indexOf(' 5_') == -1 ? jsToNativeModes.IFRAME_NAV: jsToNativeModes.XHR_NO_PAYLOAD;
> Notice the switch in the expressions. 
> This led to any iOS device with a version other than 5 not working. Using the jsToNativeModes.IFRAME_NAV bridgeMode would lead to the default case in the subsequent switch statement in which it determines what to do according to the bridgeMode.
> switch (bridgeMode) {
>         case jsToNativeModes.XHR_NO_PAYLOAD:
>         case jsToNativeModes.XHR_WITH_PAYLOAD:
>         case jsToNativeModes.XHR_OPTIONAL_PAYLOAD:
>             // This prevents sending an XHR when there is already one being sent.
>             // This should happen only in rare circumstances (refer to unit tests).
>             if (execXhr && execXhr.readyState != 4) {
>                 execXhr = null;
>             }
>             // Re-using the XHR improves exec() performance by about 10%.
>             execXhr = execXhr || new XMLHttpRequest();
>             // Changing this to a GET will make the XHR reach the URIProtocol on 4.2.
>             // For some reason it still doesn't work though...
>             // Add a timestamp to the query param to prevent caching.
>             execXhr.open('HEAD', "/!gap_exec?" + (+new Date()), true);
>             if (!vcHeaderValue) {
>                 vcHeaderValue = /.*\((.*)\)/.exec(navigator.userAgent)[1];
>             }
>             execXhr.setRequestHeader('vc', vcHeaderValue);
>             execXhr.setRequestHeader('rc', ++requestCount);
>             if (shouldBundleCommandJson()) {
>                 execXhr.setRequestHeader('cmds', iOSExec.nativeFetchMessages());
>             }
>             execXhr.send(null);
>             break;
>         case jsToNativeModes.IFRAME_HASH_NO_PAYLOAD:
>         case jsToNativeModes.IFRAME_HASH_WITH_PAYLOAD:
>             execHashIframe = execHashIframe || createHashIframe();
>             // Check if they've removed it from the DOM, and put it back if so.
>             if (!execHashIframe.contentWindow) {
>                 execHashIframe = createHashIframe();
>             }
>             // The delegate method is called only when the hash changes, so toggle it back and forth.
>             hashToggle = hashToggle ^ 3;
>             var hashValue = '%0' + hashToggle;
>             if (bridgeMode === jsToNativeModes.IFRAME_HASH_WITH_PAYLOAD) {
>                 hashValue += iOSExec.nativeFetchMessages();
>             }
>             execHashIframe.contentWindow.location.hash = hashValue;
>             break;
>         default:
>             execIframe = execIframe || createExecIframe();
>             // Check if they've removed it from the DOM, and put it back if so.
>             if (!execIframe.contentWindow) {
>                 execIframe = createExecIframe();
>             }
>             execIframe.src = "gap://ready";
>         }
> The default case did nothing.
> Making it always use jsToNativeModes.XHR_NO_PAYLOAD allows my app to work again with any iOS version but I feel like I'm losing certain advantages from the upgrade. Which are they? Why were the Ternary Operator expressions switched around? Which could be a possible reason why my app, which worked just fine before the upgrade, would stop working because of this change? Is there a better solution than the one I implemented?
> Thanks,
> -JR.



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