Question

I am trying to set up my Rails application to connect to the google calendar
api. I am following the Oauth2 documentation here:

http://code.google.com/apis/accounts/docs/OAuth2.html#SS

and the instructions for creating a single event on a user’s private
calendar here:

http://code.google.com/apis/calendar/data/2.0/developers_guide_protocol.html#CreatingSingle

I have been able to generate the Oauth2 access and refresh tokens
using the server side strategy, but whenever I query the api I get the
following error:

{“apiVersion”:”2.6″,”error”:{“code”:400,”message”:”Invalid
JSON”,”errors”:
[{“domain”:”GData”,”code”:”invalidJson”,”internalReason”:”Invalid
JSON”}]}}

(This is the same error given in this thread
http://groups.google.com/group/google-calendar-help-dataapi/browse_thread/thread/2171226629b28c3b
except I am passing GData-Version: 2 into the http post header, so the
apiVersion is different )

The json I am using is the example event data given in the protocol
document in the second reference link above. As far as I can tell this
is generally happening after the second time I query the api after
getting the 302 redirect. Would greatly appreciate it if someone would
explain what this error means and how to get around it. I’m including
the relevent code from my app below:

EventController.rb

event_hash = { :data => {
                 :title => "Tennis with Beth",
                 :details => "Meet for a quick lesson.",
                 :transparency => "opaque",
                 :status => "confirmed",
                 :location => "Rolling Lawn Courts",
                 :when => [{
                   :start => "2012-04-17T15:00:00.000Z",
                   :end => "2012-04-17T17:00:00.000Z"
                   }]
                }
              }

event_data = event_hash.to_json

auth_string = "Bearer " + google_oauth2_credential.access_token # gets access token for user
header_hash = { 'Content-Type' => 'application/json', 'Authorization' => auth_string, 'GData-Version' => '2' }

response = post_to_https('https://www.google.com/calendar/feeds/default/private/full', event_data, header_hash) # note see ApplicationController paste below to see the post_to_https method

if response.code == '302'
  uri_string = response.response['Location']
  response = post_to_https(uri_string, event_data, header_hash)
  render :text => "302 " + response.body
else
    render :text => "not 302 " + response.body)
end

ApplicationController.rb

def post_to_https(url_string, params_hash, header_hash = {})
  uri = URI.parse(url_string)
  http = Net::HTTP.new(uri.host, uri.port)
  http.use_ssl = true
  http.verify_mode = OpenSSL::SSL::VERIFY_PEER
  request = Net::HTTP::Post.new(uri.request_uri)
  request.set_form_data(params_hash)

  unless header_hash.empty?
    header_hash.each { |key, value| request[key] = value }
  end
  return http.request(request)
end

Answer 1

Most of the problems you’re discussing here should not occur if you use the latest version of the API and the Ruby client library, as documented here:

http://code.google.com/apis/calendar/v3/using.html#setup

page_token = nil
result = result = client.execute(:api_method => service.events.list,
                                 :parameters => {'calendarId' => 'primary'})
while true
  events = result.data.items
  events.each do |e|
    print e.summary + "\n"
  end
  if !(page_token = result.data.next_page_token)
    break
  end
  result = result = client.execute(:api_method => service.events.list,
                                   :parameters => {'calendarId' => 'primary', 'pageToken' => page_token})
end