Sending data from popup to extension.js not working

问题

I am working on a browser extension using crossrider. I need to send some data from popup to extension.js

My code of popup

<!DOCTYPE html>
<html>
<head>
<!-- This meta tag is relevant only for IE -->
<meta http-equiv="X-UA-Compatible" content="IE=edge">

<script type="text/javascript">
/************************************************************************************
  This is your Popup Code. The crossriderMain() code block will be run
  every time the popup is opened.

  For more information, see:
  http://docs.crossrider.com/#!/api/appAPI.browserAction-method-setPopup
*************************************************************************************/

function crossriderMain($) {
  // var to store active tab's URL
  var activeTabUrl = null;

  // Message listener for response from active tab
  appAPI.message.addListener(function(msg) {
    if (msg.type === 'active-tab-url') activeTabUrl = msg.url;
  });

  // Request URL from active tab
  appAPI.message.toActiveTab({type: 'active-tab-url'});

    alert(activeTabUrl);
  // THE REST OF YOUR CODE
}
</script>

</head>
<body>

Hello World

</body>
</html>

Code of Extension.js

appAPI.ready(function($) {
  // Message listener
  appAPI.message.addListener(function(msg) {
    if (msg.type === 'active-tab-url')
      // Send active tab's URL to popup
      appAPI.message.toPopup({
        type: 'active-tab-url',
        url:encodeURIComponent(location.href)
      });
  });

  // THE REST OF YOUR CODE
});

The value of activeTabUrl is not getting updated. It gives NULL value. P.S : I am able to communicate between background.js and popup. But for some reason appAPI.message.toActiveTab function is not working for me. Where I am doing the mistake?

Background.js (Edit)

var tabUrl='';
 /* appAPI.tabs.getActive(function(tabInfo) {
        tabUrl = tabInfo.tabUrl;
        }); */
 appAPI.message.addListener(function(msg) {
        appAPI.tabs.getActive(function(tabInfo) {
        tabUrl = tabInfo.tabUrl;
        });
       var dataString = '{"url":"'+tabUrl+'","access":"'+msg.access+'","toread":"'+msg.toread+'","comment":"'+msg.comment+'"}';
     alert(dataString);
     appAPI.request.post({
        url: 'REST API URL',
        postData: dataString,
        onSuccess: function(response, additionalInfo) {
            var details = {};
            details.response = response;
            appAPI.message.toPopup({
            response:response
        });

        },
        onFailure: function(httpCode) {
        //  alert('POST:: Request failed. HTTP Code: ' + httpCode);
        }
    });
  });

Working code of Background.js

appAPI.message.addListener(function(msg) {
    appAPI.tabs.getActive(function(tabInfo) {     
       var dataString = '{"url":"'+tabInfo.tabUrl+'","access":"'+msg.access+'","toread":"'+msg.toread+'","comment":"'+msg.comment+'"}';
    // alert(dataString);
     appAPI.request.post({
        url: 'http://fostergem.com/api/bookmark',
        postData: dataString,
        onSuccess: function(response, additionalInfo) {
            var details = {};
            details.response = response;
            appAPI.message.toPopup({
            response:response
        });

        },
        onFailure: function(httpCode) {
        //  alert('POST:: Request failed. HTTP Code: ' + httpCode);
        }
    });
    });
  });

回答1:

In this code sample, the activeTabUrl variable is only set once a response is received from the extension.js file since the messaging is asynchronous by design. Hence, when calling alert(activeTabUrl); in the code, the message has not yet been received back fro the extension.js code thus the value is still null as it was initialized.

To use the activeTabUrl variable you must wait for the mesage from the extension.js file, and hence you should place the code using the variable in the callback of the message listener, preferably as a function. Also note that using an alert in the popup code causes the popup to close and should hence not be used in the popup scope.

I tested the following popup code, which does away with the variable to avoid confusion and passes the active tab URL as a parameter to the function called in the message listener, and it worked as expected:

function crossriderMain($) {
  // Message listener for response from active tab
  appAPI.message.addListener(function(msg) {
    if (msg.type === 'active-tab-url') ShowPageUrl(msg.url);
  });

  function ShowPageUrl(url) {
    $('#page-url').html('<b>Page URL</b>: ' + url);
  }

  // Request URL from active tab
  appAPI.message.toActiveTab({type: 'active-tab-url'});

    //alert(activeTabUrl);
  // THE REST OF YOUR CODE
}

[Disclaimer: I am a Crossrider employee]

来源：https://stackoverflow.com/questions/21043684/sending-data-from-popup-to-extension-js-not-working

标签

javascript

browser-extension

crossrider