Question

I am currently working on a small extension for Chrome. I need same websql database for the extension, but I get different databases based on where I create them.

If I create the database in the content page, I get the database created for a particular page where user is.

If I create database in the background page then I get extension’s own database. But it is invisible to content pages.

I wish I could access the EXTENSION’s database from content pages, without resorting to clunky message passing mechanism. Is there a way to do that?

Answer 1

This is not possible, same thing as with localStorage. Different scripts represent different contexts.

All extension scripts can communicate with background page though. Try creating a proxy API to the database on the background page. This should be simple enough.

I would implement it like this (content script):

chrome.extension.sendRequest({
      method: 'executeSql', 
      sql: 'SELECT title, author FROM docs WHERE id=?',
      params: [10]
   },
   function(response) {
      //do stuff
   }
); 

and on the other end (background page):

chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
    console.log(request);

    if(request.method == 'executeSql' && request.sql) {
        db.readTransaction(function (t) {
            t.executeSql(request.sql, request.params, function (t, r) {
               //send result with sendResponse
            }, function (t, e) {
               //send error with sendResponse
            });
        });
    } else if(...) { //some other method etc.
    } ...
}

Above code is not tested, it’s just a sketch.