在Web Worker中使用“Google Maps API”

Question

I'm trying to load the Google Maps API in a Javascript Web Worker, but it fails to load the maps library. The Web Worker code looks as follows:

importScripts('http://maps.googleapis.com/maps/api/js?libraries=geometry&key=MYAPIKEY&sensor=FALSE'); 

This fails with a simple

Script Error.

in Chrome when I try to load the Worker.

I assume something in the maps library tries to access the DOM. But that is just a guess. Does anyone has a solution?

EDIT: I opened the link above and tried to extract+modify it's contents. So the WebWorker.js now looks like this:

var window = {google: {}};
var google = {maps: {}};
(function() {

  function getScript(src) {
      importScripts(src);
    //document.write('<' + 'script src="' + src + '"><' + '/script>');
  }

  var modules = google.maps.modules = {};
  google.maps.__gjsload__ = function(name, text) {
    modules[name] = text;
  };

  google.maps.Load = function(apiLoad) {
    delete google.maps.Load;
    apiLoad([0.009999999776482582,[[["http://mt0.googleapis.com/vt?lyrs=m@306000000\u0026src=api\u0026hl=de-DE\u0026","http://mt1.googleapis.com/vt?lyrs=m@306000000\u0026src=api\u0026hl=de-DE\u0026"],null,null,null,null,"m@306000000",["https://mts0.google.com/vt?lyrs=m@306000000\u0026src=api\u0026hl=de-DE\u0026","https://mts1.google.com/vt?lyrs=m@306000000\u0026src=api\u0026hl=de-DE\u0026"]],[["http://khm0.googleapis.com/kh?v=174\u0026hl=de-DE\u0026","http://khm1.googleapis.com/kh?v=174\u0026hl=de-DE\u0026"],null,null,null,1,"174",["https://khms0.google.com/kh?v=174\u0026hl=de-DE\u0026","https://khms1.google.com/kh?v=174\u0026hl=de-DE\u0026"]],[["http://mt0.googleapis.com/vt?lyrs=h@306000000\u0026src=api\u0026hl=de-DE\u0026","http://mt1.googleapis.com/vt?lyrs=h@306000000\u0026src=api\u0026hl=de-DE\u0026"],null,null,null,null,"h@306000000",["https://mts0.google.com/vt?lyrs=h@306000000\u0026src=api\u0026hl=de-DE\u0026","https://mts1.google.com/vt?lyrs=h@306000000\u0026src=api\u0026hl=de-DE\u0026"]],[["http://mt0.googleapis.com/vt?lyrs=t@132,r@306000000\u0026src=api\u0026hl=de-DE\u0026","http://mt1.googleapis.com/vt?lyrs=t@132,r@306000000\u0026src=api\u0026hl=de-DE\u0026"],null,null,null,null,"t@132,r@306000000",["https://mts0.google.com/vt?lyrs=t@132,r@306000000\u0026src=api\u0026hl=de-DE\u0026","https://mts1.google.com/vt?lyrs=t@132,r@306000000\u0026src=api\u0026hl=de-DE\u0026"]],null,null,[["http://cbk0.googleapis.com/cbk?","http://cbk1.googleapis.com/cbk?"]],[["http://khm0.googleapis.com/kh?v=86\u0026hl=de-DE\u0026","http://khm1.googleapis.com/kh?v=86\u0026hl=de-DE\u0026"],null,null,null,null,"86",["https://khms0.google.com/kh?v=86\u0026hl=de-DE\u0026","https://khms1.google.com/kh?v=86\u0026hl=de-DE\u0026"]],[["http://mt0.googleapis.com/mapslt?hl=de-DE\u0026","http://mt1.googleapis.com/mapslt?hl=de-DE\u0026"]],[["http://mt0.googleapis.com/mapslt/ft?hl=de-DE\u0026","http://mt1.googleapis.com/mapslt/ft?hl=de-DE\u0026"]],[["http://mt0.googleapis.com/vt?hl=de-DE\u0026","http://mt1.googleapis.com/vt?hl=de-DE\u0026"]],[["http://mt0.googleapis.com/mapslt/loom?hl=de-DE\u0026","http://mt1.googleapis.com/mapslt/loom?hl=de-DE\u0026"]],[["https://mts0.googleapis.com/mapslt?hl=de-DE\u0026","https://mts1.googleapis.com/mapslt?hl=de-DE\u0026"]],[["https://mts0.googleapis.com/mapslt/ft?hl=de-DE\u0026","https://mts1.googleapis.com/mapslt/ft?hl=de-DE\u0026"]],[["https://mts0.googleapis.com/mapslt/loom?hl=de-DE\u0026","https://mts1.googleapis.com/mapslt/loom?hl=de-DE\u0026"]]],["de-DE","US",null,0,null,null,"http://maps.gstatic.com/mapfiles/","http://csi.gstatic.com","https://maps.googleapis.com","http://maps.googleapis.com",null,"https://maps.google.com","https://gg.google.com","http://maps.gstatic.com/maps-api-v3/api/images/","https://www.google.com/maps",0],["http://maps.gstatic.com/maps-api-v3/api/js/21/3/intl/de_ALL","3.21.3"],[141790386],1,null,null,null,null,null,"",["geometry"],null,0,"http://khm.googleapis.com/mz?v=174\u0026","AIzaSyDQi59vEjsIzBM-AFMeDbszVsOckQOb5A8","https://earthbuilder.googleapis.com","https://earthbuilder.googleapis.com",null,"http://mt.googleapis.com/vt/icon",[["http://mt0.googleapis.com/vt","http://mt1.googleapis.com/vt"],["https://mts0.googleapis.com/vt","https://mts1.googleapis.com/vt"],null,null,null,null,null,null,null,null,null,null,["https://mts0.google.com/vt","https://mts1.google.com/vt"],"/maps/vt",306000000,132],2,500,[null,"http://g0.gstatic.com/landmark/tour","http://g0.gstatic.com/landmark/config",null,"http://www.google.com/maps/preview/log204","","http://static.panoramio.com.storage.googleapis.com/photos/",["http://geo0.ggpht.com/cbk","http://geo1.ggpht.com/cbk","http://geo2.ggpht.com/cbk","http://geo3.ggpht.com/cbk"]],["https://www.google.com/maps/api/js/master?pb=!1m2!1u21!2s3!2sde-DE!3sUS!4s21/3/intl/de_ALL","https://www.google.com/maps/api/js/widget?pb=!1m2!1u21!2s3!2sde-DE"],null,0,0,"/maps/api/js/ApplicationService.GetEntityDetails",0], loadScriptTime);
  };

    importScripts(
    'http://maps.gstatic.com/maps-api-v3/api/js/21/3/intl/de_ALL/main.js'
    , 'http://maps.gstatic.com/maps-api-v3/api/js/21/3/intl/de_ALL/geometry.js'
    );

})();

But this still results in a 'Script error.'.

Answer 1

Google client api like map, drive etc needs dom element so you can not use map api in web worker. I also had similar problem in past after hours of research i confirmed that it can not be done atleast not at this time. Here are few thing you need to know about web wroker.

There are very few objects we can have access in web workers:

XMLHttpRequest, JSON, Worker, navigator, location,set and clear Timeout, import scripts, set and clear interval.

The window or parent ,localStorage objects are not accessible from a Web worker.

for more details you can check this link.

Answer 2

I've actually been able to create an instance of a marker by fooling the worker into thinking there was a DOM object for it to use. I stole the idea from people attempting to use jQuery commands within workers which encounter the same issue. My reference was from here:

// create a fake document for jQuery to function - DOES NOT PROVIDE ACCESS TO ACTUAL DOM ELEMENTS
// from Tomáš Zato comment on http://stackoverflow.com/questions/10491448/how-to-access-jquery-in-html-5-web-worker
var document = self.document = {parentNode: null, nodeType: 9, toString:function() {return "FakeDocument"}};
var window = self.window = self;
var fakeElement = Object.create(document);
fakeElement.nodeType = 1;
fakeElement.toString=function() {return "FakeElement"};
fakeElement.parentNode = fakeElement.firstChild = fakeElement.lastChild = fakeElement;
fakeElement.ownerDocument = document;

document.head = document.body = fakeElement;
document.ownerDocument = document.documentElement = document;
document.getElementById = document.createElement = function() {return fakeElement;};
document.createDocumentFragment = function() {return this;};
document.getElementsByTagName = document.getElementsByClassName = function() {return [fakeElement];};
document.getAttribute = document.setAttribute = document.removeChild =
  document.addEventListener = document.removeEventListener =
  function() {return null;};
document.cloneNode = document.appendChild = function() {return this;};
document.appendChild = function(child) {return child;};