The document discusses building real-time applications with Symfony2. It begins by introducing the speaker and their company Locastic. It then defines what a real-time application is and provides examples of common use cases. The document goes on to explain various technologies that can be used to build real-time functionality, such as polling, long polling, server-sent events, websockets, and streaming. It also discusses different communication patterns and factors to consider when choosing a technology. Finally, it provides an example of a real-time dashboard that was built with Symfony2, AngularJS, and RabbitMQ and describes hosted solutions like Pusher that can be used.

1. Building Real-Time Apps With
Symfony2
Antonio Perić-Mažar, Locastic
24.10.2015 Symfony Camp Ukraine

2. @antonioperic
About me
• Antonio Perić-Mažar,
mag. ing. comp.
• CEO @ Locastic
• Software developer, Symfony2
• Sylius Contributor :)
• www.locastic.com
• antonio@locastic.com
• twitter: @antonioperic

3. @antonioperic
Who we are?
• Locastic (www.locastic.com)
• Web and mobile development
• UI/UX design
• Located in Split, Croatia

4. @antonioperic

5. @antonioperic
What is RTA?
A real-time application (RTA) is an application
program that functions within a time frame that
the user senses as immediate or current. The
latency must be less than a defined value,
usually measured in seconds. Whether or not a
given application qualifies as an RTA depends on
the worst-case execution time (WCET), the
maximum length of time a defined task or set of
tasks requires on a given hardware platform. The
use of RTAs is called real-time computing (RTC).

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Use Cases
• Videoconference applications, VoIP
• Data Visualisations, Location tracking
• Online gaming, multi-user collaboration
• Community storage solutions
• Some e-commerce transactions
• Chatting, IM (instant messaging)
• Notifications & Signalling
• Activity Streams
• …

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Use Cases
Real-Time == UX
etc.

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Understanding RTA
• History of Realtime
• LiveConnect
• Http Based solutions
• Comet

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HTTP
• A client requests a webpage from a server.
• The server calculates the response
• The server sends the response to the
client.

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Webhooks
•server only
•low update rates
•uni-directional - from publisher to consumer
(server to server)
•avg. latency
•high. efficiency (for servers)

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Polling

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Polling
• A client requests a webpage from a server
using regular HTTP (see HTTP above).
• The requested webpage executes JavaScript
which requests a file from the server at
regular intervals (e.g. 0.5 seconds).
• The server calculates each response and
sends it back, just like normal HTTP
traffic.

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Polling
• server or client
• low update rates
• batched bi-directional
• high latency
• low efficiency

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Long Polling

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Long Polling
• A client requests a webpage from a server using regular HTTP
(see HTTP above).
• The requested webpage executes JavaScript which requests a
file from the server.
• The server does not immediately respond with the requested
information but waits until there's new information
available.
• When there's new information available, the server responds
with the new information.
• The client receives the new information and immediately
sends another request to the server, re-starting the process.

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Long Polling
• server or client
• avg. update rates
• batched bi-directional
• avg. latency
• avg. efficiency

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HTML5 Server Sent Events
(SSE) / EventSource

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HTML5 Server Sent Events
(SSE) / EventSource
• A client requests a webpage from a server using regular
HTTP
• The requested webpage executes javascript which
opens a connection to the server.
• The server sends an event to the client when there's
new information available.
• Real-time traffic from server to client, mostly that's
what you'll need
• You'll want to use a server that has an event loop
• Not possible to connect with a server from another
domain

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HTML5 Server Sent Events
(SSE) / EventSource
• client (pushing)
• good update rates
• unidirectional
• good latency
• good efficiency

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WebSockets

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WebSockets
• A client requests a webpage from a server using regular http (see
HTTP above).
• The requested webpage executes JavaScript which opens a connection
with the server.
• The server and the client can now send each other messages when
new data (on either side) is available.
• Real-time traffic from the server to the client and from the client
to the server
• You'll want to use a server that has an event
• With WebSockets it is possible to connect with a server from
another domain.
• It is also possible to use a third party hosted websocket server, for
example Pusher or others. This way you'll only have to
implement the client side, which is very easy!

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WebSockets
• TCP, fully duplex single connection
• server or client (client mostly)
• bi-directional
• high update rates
• low latency
• high efficiency

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Streaming
• make connection, keep it open, as soon as we have
updates push it to client
• server or client
• high updated rates
• uni-directional
• low latency
• high efficiency
• business decisions, trading, unidirectional you can
only push it from server to client, single
persisting connection
• look as servers and event as standard

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WebRTC
• server or client (normally client2client)
• high update rates
• bi-directional
• low latency
• high efficiency
• audio or video generally peer2peer

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Communication patterns
• Simple messaging
• Pub/Sub
• RPC/RMI
• Data Sync

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Simple Messaging
• No abstraction. Just messages
• Fits well with HTTP and REST
• Many persist connections

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Pub/Sub
• Subscribe and publish on channels
• Multiplexed. Single connection.
• Clearity partitions complex data
• Dedicated Endpoint
• Required SDK

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RPC/RMI
• Call API Methods
• SDK Required
• Hides network activity from developer

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Data Sync
• Interact with, and synchronise, data
structures
• Dedicated endpoint + Protocol
• New Paradigm
• SDK Required
• Hides network activity from developer

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How to pick technology?
• First: Are the only real time solutions in
NodeJS?

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How to pick technology?
• First: Are the only real time solutions in
NodeJS?
NO!

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Solutions by language
• PHP: ReactPHP, Ratchet, dNode-php, phpDaemon
• Java: Netty, Jetty
• JavaScript (Node.JS): Faye, Socket.IO (Engine.IO),
Primus.io
• .NET (C#): SignalR, XSockets
• Python: Lots of options built on Tornado
• Ruby: em-websocket, Faye
• Language agnostic: most hosted services

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Solutions by language
j.mp/realtime-tech-guide

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PHP?
• Apache is not built for Real-Time
• PHP is not build for Real-Time
• Real-Time is not impossible with PHP

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PHP RTA
• Self hosted PHP solution
• Self hosted Side-by-Side solution
• Hosted solution

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Self hosted PHP
• tightly coupled
• two stacks:
• sync stack
• async stack

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PHP Self Hosted solutions
• React (PHP)
• Event-driven, non-blocking I/O with PHP.
• Ratchet (Built on React PHP)
• WebSockets, WAMP, PubSub samples. No HTTP
Fallback
• dnode-php (RPC/RMI)
• phpDaemon
• Lots of examples. Most docs in Russian.

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PHP Self Hosted solutions
Pros:
• PHP
• Simple integration
• Standards-based
• WAMP/Autobahn
• JS, Android, iOS &
more
Cons:
• No HTTP fallback
• Low-level abstractions
• Different programming
style
• You need to scale

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PHP + Faye Self Hosted
solutions
Pros:
• PubSub
• Connection fallback
• Redis support is build in
• Simple integration
Cons:
• Not PHP?
• You need to scale

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Other side by side solutions
• Socket.IO
• SockJS
• SignalR
• see real time tech guide for more

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PHP + Hosted solutions
Pros:
• Simple and powerful
• Instantly scalable
• Managed & Dedicated
• Direct integration into
Symfony
Cons:
• 3rd party reliance

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What we build?
• Real time dashboards ford Google Adwords
analytics
• Symfony2, AngularJS, RabbitMQ
• First version was with Polling
• Second version moving to hosted solution
- Pusher

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Other hosted solutions
• PubNub
• Realtime.co
• Firebase
• Simperium
• see real time tech guide for more

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References
• Phil @Leggetter
- Head of Developer Relations at @pusher. Realtime Web Technology Evangelist.
• Real-time Tech Guide
• React (PHP)
• Ratchet (PHP)
• Faye (Node/Ruby)
• Pusher
• LopiPusherBundle
• github.com/leggetter/realtime-symfonyexamples

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Thank you!

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QA
follow me on twitter:
@antonioperic