This is an attempt to recreate the behaviour of the Mirror API (based on public information available) to allow developers like me who aren't part of the Glass Explorer program, to test potential applications that could be feasible using Glass.

And even if the real Mirror API turns out to be completely different from what I envision it to be you can use this as a learning place for different Google technologies:

• Google Cloud Endpoints, with JavaScript and Python clients

• Google+ Sign-in, client-side flow (Glass emulator)

• Google+ Sign-in, server-side flow (Web app)

• Google App Engine for Web applications in general

• And how they all can work together

See this document for a detailed description of what this does and how it works.

mirror_api_server is meant to be hosted on Google App Engine and includes several parts.

mirror_api is an implementation of the Mirror API using Google Cloud Endpoints.

static/glass contains a browser based emulator for Glass. (can be accessed at yourapp.appspot.com/glass/)

service.py is a simple playground implementation for a Web Application that makes use of the Mirror API.

1. Clone (or fork and clone) this repository

git clone https://github.com/Scarygami/mirror-api.git
cd mirror-api

2. Fetch the endpoints_proto_datastore repository:

git submodule init
git submodule update

3. Create symlink mirror_api_server/endpoints_proto_datastore to endpoints-proto-datastore/endpoints_proto_datastore

Linux/Unix-based systems:

cd mirror_api_server
ln -s ../endpoints-proto-datastore/endpoints_proto_datastore/ endpoints_proto_datastore

Windows systems: (run cmd as Administrator)

cd mirror_api_server
mklink /D endpoints_proto_datastore ..\endpoints-proto-datastore\endpoints_proto_datastore\

Alternatively (because the appcfg.py deploy script sometimes doesn't recognize the symlink correctly) copy the folder endpoints-proto-datastore/endpoints_proto_datastore/ over to mirror_api_server so that you get this folder structure:

mirror_api_server/
- endpoints_proto_datastore/
  - ndb/

Download the latest zip file from https://www.googledrive.com/host/0B1pwzJXH7GP8Z3VRcnVudERPQ2M/ and extract it. This includes all dependencies.

Create a new App Engine application at https://appengine.google.com/ The name of the application will be referred to as yourapp for the following steps.

Create a new project in the Google APIs Console

Activate the Google+ API in Services

Create a new Client ID for web applications in API Access

Leave Redirect URIs empty but set Javascript origin to https://yourapp.appspot.com and http://localhost:8080 for local testing.

Edit mirror_api_server/client_secrets.json and change YOUR_CLIENT_ID and YOUR_CLIENT_SECRET to the information from the APIs Console.

Important: Don't commit that file if you contribute to this project. One possible solution to prevent this: http://blog.bossylobster.com/2011/10/protecting.html

Edit mirror_api_server/app.yaml to change the name of the application to yourapp.

Follow the steps in the Google App Engine Python 2.7 Getting Started to install the necessary dependencies and deploy the application. Specifically you will need the steps The Development Environment and Uploading Your Application

At the moment the only functionality of the web app hosted at https://yourapp.appspot.com/ is to send text and image cards to the Glass emulator available at https://yourapp.appspot.com/glass/ but I'm planning to add more functionality to it.

You can also use the API Explorer at https://yourapp.appspot.com/_ah/api/explorer to directly send requests to the API. You will have to turn on OAuth (in the upper right corner of the Explorer) with the https://www.googleapis.com/auth/userinfo.email scope. You can already use the Explorer to register ShareEntities and Subscriptions. The Glass emulator will display actions and shares correctly and send them to the Mirror API Server which forwards the information to the relevant subscriptions.

For simplification (and because it's easier to implement like this for Cloud endpoints) this assumes that there is only one application (i.e. one Client ID) that uses the Mirror API, so you will have access to all timeline cards of a user, whereas in the real Mirror API you would only have access to cards created by or shared with your application.

The real Mirror API supports Multipart-bodies to attach images to cards. Since this isn't possible using Google Cloud Endpoints (they only support application/json as request/response bodies), I went for a different solution with an image field inside of a card which takes any image URL. Also works with Data-URIs if the image isn't available online, which will be the case mostly when uploading images from Glass itself.

The probably unclearest part so far is how subscriptions actually work, so I make some assumptions here which might turn out to be very far from the truth:

• You can subscribe to Actions, which can be SHARE, REPLY or CUSTOM.

• I added an additional value field to actions which isn't listed in the demo, to make Actions and subscriptions work the way I think they can work.

• This value will contain the ID of the ShareEntity for SHARE actions and the ID of the registered Action for CUSTOM actions.

• REPLY will first create a new Timeline Card with the text of the reply and send the ID of this card as itemId. The card which was replied to will be listed as value.

I'm not part of the Glass Explorer program so there are no guarantees that the final Mirror API will work anything like I suppose it will in this demo implementation. The information is collected from the various public bits and pieces that have been published. Also see my document about the topic.

Copyright (c) 2013 Gerwin Sturm, FoldedSoft e.U. / www.foldedsoft.at

Licensed under the Apache License, Version 2.0 (the "License"); you may not
use this file except in compliance with the License. You may obtain a copy of
the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations under
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