A library to map Google Calendar events with an ORM
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A library to map Google Calendar events with an ORM.


Add this line to your application's Gemfile:

gem 'gcalmapper'

And then execute:

$ bundle

Or install it yourself as:

$ gem install gcalmapper


Authorization to connect to gcal

To have access to your google calendar go to :

Google API Console

and open a new api account :

  1. click on "Services" on the rigth top menu
  2. click on the toggle button next to "Calendar API"
  3. accept the license
  4. click on "API Access" on the rigth top menu
  5. click on the blue button "Create an Oauth2.0 Client ID ..."
  6. provide a name for the API and click next
  7. chose the type between "service account" and "installed app"
  8. click "create client id"

once you have your "installed app" access run :

$ gcal-mapper --client_id [CLIENT_ID] --client_secret [CLIENT_SECRET]

it should open a new page, click accept that the API acess your data. this gives you ~/google_auth.yaml copy it on spec/file/google_auth.yaml (you can change path with --file /path/to/the/yaml_file.yaml) (you can change scope with --scope https://www.googleapis.com/another/scope)

with the service account make sure you save well the private key. You can use service account only if you manage your domain with google. But you have to go to your google apps manager :

  1. go to "Advenced tools" -> "Manage api client acess"
  2. enter your client id(service account) in "client name"
  3. enter "http(s)://www.google.com/calendar/feeds/" in "scope"
  4. click "authorize"


when you manage to have the authorization to access your google calendar create your model

require 'active_record'

class Event < ActiveRecord::Base

  include GcalMapper::Mapper::ActiveRecord

  calendar do
    configure :file => 'path/to/your/yaml/file.yaml'

    calendar 'your_email@gmail.com'

    google_id 'gid'

    field 'name', :source => 'summary'
    field 'description', :source => 'description',
                         :match => /^category: (.*)$/, :default => 'not categorized'
    field 'status', :source => 'status'
    field 'start_at', :source => 'start.dateTime', :if_empty => 'start.date'
    field 'end_at', :source => 'end.dateTime', :if_empty => 'end.date'
    field 'created_at', :source => 'created'
    field 'updated_at', :source => 'updated'

  def self.synchronize_me


here is an example with Oauth2.0 authentification for installed app, as you can see it'is not a rails model and it work with AtiveRecord.

you can find an exemple with rails there :

GcalMapper Rails exemple


configure is used to set your crendentials. You can see above an exemple for "installed app" here is one for "service account" :

configure :file => '/path/to/the/private-key.p12',
          :client_email => 'service_account_email',
          :user_email => 'user@yourdomain.com',
          :password => 'password of your key'

:password is optional the default value is 'notasecret'


google_id must be present, and you must give it the name of an existing string field in your DB. it store the google event id and must be saved to keep your DB synchronize


if you want to synchronize more than one calendar just do someting like :

calendar 'your_email@gmail.com'
calendar 'other_accessible_calendar@gmail.com


the minimal field declatration is

field 'name_of_your_db_column', :source => 'name_of_the_source'

It is possible to be more precise with the use of :match and :default

  • :match => 'regexp' is used to parse only a part of the google data
  • :default => 'default is used to put default data in case of unmatching data

Both are optional, but if you use :match without :default, the default value will be nil

if the data you want to save is not always setted, it'is possible to use :if_empty. this will try to take data in another field if the source is empty. in the exemple you can see the usage as date.dateTime is not always present (for exemple long event that only date of start and date of end without hours).


For now GcalMapper is only compatible with :

  • ActiveRecord

it can be extended quite easly

it is possible to use GcalMapper without ORM, juste include


like this :

class Event
  attr_accessor :id, :gid, :name, :description, :status, :start_at, :end_at, :created_at, :upated_at
  include GcalMapper::Mapper::Simple

  calendar do

    configure :file => 'path/to/your/yaml/file.yaml'

    calendar 'your_email@gmail.com'

    google_id 'gid'

    field 'name', :source => 'summary'
    field 'description', :source => 'description',
                         :match => /^category: (.*)$/, :default => 'not categorized'
    field 'status', :source => 'status'
    field 'start_at', :source => 'start.dateTime'
    field 'end_at', :source => 'end.dateTime'
    field 'created_at', :source => 'created'
    field 'updated_at', :source => 'updated'

  def self.synchronize_me


Source data reference

here is the reference for the source data :

  "kind": "calendar#event",
  "etag": etag,
  "id": string,
  "status": string,
  "htmlLink": string,
  "created": datetime,
  "updated": datetime,
  "summary": string,
  "description": string,
  "location": string,
  "colorId": string,
  "creator": {
    "email": string,
    "displayName": string
  "organizer": {
    "email": string,
    "displayName": string
  "start": {
    "date": date,
    "dateTime": datetime,
    "timeZone": string
  "end": {
    "date": date,
    "dateTime": datetime,
    "timeZone": string
  "recurrence": [
  "recurringEventId": string,
  "originalStartTime": {
    "date": date,
    "dateTime": datetime,
    "timeZone": string
  "transparency": string,
  "visibility": string,
  "iCalUID": string,
  "sequence": integer,
  "attendees": [
      "email": string,
      "displayName": string,
      "organizer": boolean,
      "self": boolean,
      "resource": boolean,
      "optional": boolean,
      "responseStatus": string,
      "comment": string,
      "additionalGuests": integer
  "attendeesOmitted": boolean,
  "extendedProperties": {
    "private": {
      (key): string
    "shared": {
      (key): string
  "gadget": {
    "type": string,
    "title": string,
    "link": string,
    "iconLink": string,
    "width": integer,
    "height": integer,
    "display": string,
    "preferences": {
      (key): string
  "anyoneCanAddSelf": boolean,
  "guestsCanInviteOthers": boolean,
  "guestsCanModify": boolean,
  "guestsCanSeeOtherGuests": boolean,
  "privateCopy": boolean,
  "reminders": {
    "useDefault": boolean,
    "overrides": [
        "method": string,
        "minutes": integer

for now you can access nearly all the data. you can acces all the the first and second degree key.

if you want the summary :

field 'summary', :source => 'summary'

for the creator email :

field 'creator_email', :source => 'creator.email'

if you just put creator it will give your the string dump of

"organizer": {
  "email": string,
  "displayName": string

that will look like :

"{\"email\"=>\"string\", \"displayName\"=>\"string\"}"

for things like attendees or extendedProperties, the only way of saving it is to save the string dump of that

for attendees :

field 'attendees_dump', :source 'attendees'

for extendedProperties you can do extendedProperties.private but extendedProperties.private.(field) will not work


to launch test you need to have files to do both authentification methodes

execute, with the data of the installed app

gcal-mapper --client_id [CLIENT_ID] --client_secret [CLIENT_SECRET]

copy the file ".p12" to "spec/file/privatekey.p12" copy the file "~/google_auth.yaml" to "spec/file/google_auth.yaml"

then create spec/file/config.yaml, must look like this :

p12: 'spec/file/privatekey.p12'     -> path to your p12 key
p12_2: 'spec/file/privatekey2.p12'  -> path to a second one, can be the same
client_email: '[your service account's email address]'
user_email: '[email address that your service account can impersonate]'
yaml: 'spec/file/google_auth.yaml'  -> or another path
yaml_relative: '~/google_auth.yaml' -> or another path, relative
bad_yaml: 'spec/file/bad_yaml.yaml' -> create an empty file
calendar_id: '[an accesible calendar id, possibly the same at user email]'

then run

rake spec

test's are running!


Ruby 1.8.7 does not support the vcr cassettes generate by 1.9.x, but 1.8.7 cassettes work with 1.9.x. D'ont forget to remove the cassettes before testing with 1.8.7 if you already tested with 1.9.x.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Added some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request

Copyright & License

Copyright (c) 2012 Liquid Concept. See LICENSE for details.