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Trying to reproduce the mirror-api behaviour using Google Cloud Endpoints to enable non-glass-explorers to get an idea of what will be possible.
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endpoints-proto-datastore @ e46721a



This is an attempt to recreate the behaviour of the Mirror API (based on the official documentation) to allow developers like me who can't be 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

  • Channel API for push notifications to the browser-based emulator

  • 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 is a simple playground implementation for a Web Application that makes use of the Mirror API. handles all authentication and storing of credentials when a user signs up for the demo services. Sets up contacts and subscriptions when the user first connects. Also handles disconnection by removing all contacts and subscriptions and deleting credentials when the user wants to disconnect. handles subscription post requests coming from the Mirror API and forwards the requests to the relevant demo services.

demos/*.py are demo services that react to incoming notifications.

Getting the code - The proper way

  1. Clone (or fork and clone) this repository

    git clone
    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\

    In case you can't get the symlink to work correctly (meaning the API won't work correctly after deploying because of the missing endpoints_proto_datastore library) you can alternatively copy the folder endpoints-proto-datastore/endpoints_proto_datastore/ over to mirror_api_server manually so that you get this folder structure:

    - endpoints_proto_datastore/
      - ndb/

    You will need to repeat this copy step whenever there are changes in the endpoints_proto_datastore library.

Getting the code - The easy way

Download the latest zip file from and extract it. This includes all dependencies, but won't always be the newest available version.


  1. Create a new App Engine application at The name of the application will be referred to as yourapp for the following steps.

  2. Create a new project in the Google APIs Console

  3. Activate the Google+ API in Services, and the Places API for one of the demo services.

  4. Create a new Client ID for web applications in API Access.

    1. Click on Create an OAuth 2.0 client ID....
    2. Fill out a Product name and click Next.
    3. Keep Web application and select (more options) next to Your site or hostname.
    4. Make Authorized Redirect URIs empty.
    5. Set Authorized JavasSript Origins to and http://localhost:8080 for local testing.
    6. Click on Create client ID.
  5. Create a new Simple API Access server key.

    1. Click on Create new Server key....
    2. Keep the IP field empty if you want to accept all IP adresses, or fill in the IP subnets that you got from your ISP.
    3. Click on Create.
  6. Edit mirror_api_server/client_secrets.json and change YOUR_CLIENT_ID, YOUR_CLIENT_SECRET and YOUR_API_KEY to the information from the APIs Console. Also enter a random long string as RANDOM_SESSION_SECRET.

    If you have additional Client IDs you want to access the Mirror API with add them in additional_client_ids

    Important: Don't commit that file if you contribute to this project. One possible solution to prevent this:

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

  8. 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


To register contacts and subscriptions you will first have to sign in at the web app hosted at The functionality of this app is very limited so far but will be improved.

(Plan is to have your real web app hosted at using the same UI as the test UI, but with the difference that the real web app will use calls directly to the Mirror API while the test web app uses the self-hosted Mirror API clone.)

You can then use the API Explorer at to directly send requests to the API. You will have to turn on OAuth (in the upper right corner of the Explorer) with the scope.

You can then see the result at the Glass emulator available at 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.

Deviations from the actual Mirror API

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 filling the contentUrl in attachments directly with any URL, which also works with Data-URIs if the image isn't available online.

Not all features of the Mirror API are implemented yet. Location data is missing and not all available fields for timeline cards are used yet.


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. /

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
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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
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