Book Widget

Embedding automated photo-document publication on the web and in mobile

devices

E. O’Brien-Strain, A. Hunter, J. Liu, Q. Lin, D. Tretter, J. Wang, X. Zhang, and P. Wu

Hewlett-Packard Labs

In which the author ...

explains how to design large-scale cloud platforms for document processing

Outline

Motivation

Architectural Principles

Platform Implementation

Example Application – Facebook Photo-Books

Motivation

We have a wealth of auto-publishing algorithms

Want to provide them for third parties to use

By building a cloud-based platform that Is flexible and programmable Is secure and private Is infinitely scalable Has high availability and responsiveness Reconciles WYSIWYG and style-driven use

models

Architectural Principles

REST

Capability Security Authorization

Authentication Agnostic

Scaling: Elastic, Sessionless, noSQL, Caching

Orthogonal: UI / Content Source / Artifacts

REST

“Representational State Transfer”

Architectural pattern for creating network APIs

All API calls are HTTP requests to some URL GET to retrieve data from a URL PUT to write data to a URL POST to perform some action on a URL DELETE to remove the data from the URL

Starting from response from an initial URL client code finds other URLs to operate on

Capability Security Authorization

An example of a URL from our API:

http://foo.com/document/qY9vZObN-slqsv_RWnJB4w/content/chunks.json

Has cryptographically-secure random string

If you do not know this URL there is no way to find it

Possess URL <=> Authorized to use URL “Moderate” level of security

Still vulnerable to network snoopers Can use SSL to increase security

Authentication Agnostic

No concept of a “User” Instead just store anonymous resources

Client code expected to keep track of users and authenticate them remember which resources belong to each user

Gives flexibility to client to use any authentication No need for complexity of “single-sign-on”

Allows us to avoid many security/privacy headaches avoid complexity and cost of using SSL have our data cached in Internet infrastructure

Scaling

Can use elastic infrastructure cloud rapid spin-up and spin-down of virtual servers

Sessionless Bank of web servers operating in parallel Sequence of HTTP requests sprays out

arbitrarily over multiple servers

NoSQL Highly-distributed no-master key-value store

Caching at every level

Any Permutation of

User interface for creating documents Web (HTML5 or Flash) Mobile device PC application

Where content comes from Social network Photo site / document storage site PC folder

What kind of artifacts Print at home, at retail, or at PSP View on e-Book reader, slate, or phone

Platform Implementation

Initially Targeting Photo-Oriented Documents

Unified Model for Document + Template + Content

Content Transformation

Transactional Data

Embeddable as a Widget

Monetizable

Initial Target

Platform architected to handle a wide variety of documents

Initially handles photo-oriented documents Such as photo-books

Can be extended to handle more text-heavy documents

Such as magazines

Unified “Document” Model

Document = content + “rendersheet”

A single “document” resource type for User documents (content + rendersheet) Collections of input content (just content) Templates (just rendersheet)

Any document can be used as template for new document

Any document can by used as source of content for new document

Look-and-feel of one document can be applied to another

Algorithms

Auto-organizing algorithms using Photo quality Near-duplicate detection using structural

similarity and time proximity

Auto-layout algorithms BRIC (blocked recursive image composition) START (structured layout for resizable background art)

Transactional Data

Resources are not stored indefinitely Have an expiration date

Two top-level types of resources Documents (composed of “Chunks”) Artifacts

Embeddable as a Widget

Can be embedded in Web or mobile application

Third-party developer can write their own document design user-

interface or they can use the Flash widget that we

provide

Monetizable

We include features that allow for a variety of different business models

Each client application must register with us

API key and “shared secret” token All client requests that create of modify

resources must be signed with the secret All resources are marked with the client

application that created All resources have a “time to live” before

they are deleted

Example Application

Facebook Application

Built by team of outside developers

Uses our UI widget for creating and viewing photobooks

Integrates nicely into Facebook site Leverages social connections of users To make application more viral

Summary

Introduction

Architectural Principles

Platform Implementation

Example Application – Facebook Photo-Books