Wrap http with a global canceler.

cancellable_http.js.coffee

# blatantly inspired and actually almost copied from
# https://www.exratione.com/2013/08/angularjs-wrapping-http-for-fun-and-profit/

# BEWARE: not tested in any way

# create the decorator
$cancellableHttp = ($delegate, $q) ->
  $http = $delegate
  canceler = null

  # wrap plain $http(...) calls
  wrapper = ->
    # create a canceler if needed
    canceler ||= $q.defer()

    # add the canceler as a timeout
    arguments[0] ||= {}
    arguments[0].timeout ||= canceler.promise

    # call the underlying implementation
    $http.apply($http, arguments)


  # wrap $http.get(...) and similar calls
  for verb in ["get", "post", "put", "delete", "options"]
    wrapper[verb] = ->
      canceler ||= $q.defer()
    
      # add the canceler as a timeout
      arguments[0] ||= {}
      arguments[0].timeout ||= canceler.promise
    
      $http[verb].apply($http, arguments)

  # add a cancelPending function that resolves the canceler
  wrapper.cancelPending = ->
    canceler.resolve()
    $timeout ->
      canceler = null
    return
  
  # return the wrapped $http
  wrapper

# load the decorator in a config block
angular.module(yourModule)
  .config ($provide) ->
    $provide.decorator '$http', $cancellableHttp