Presented by Violeta Georgieva at Reactive Enterprise with Reactor and Spring in Toronto on June 13th, 2019.

1. Reactive Web 101:
WebFlux, WebClient, and
Reactor Netty
Violeta Georgieva
@violeta_g_g

2. Violeta Georgieva
• Pivotal
• Spring Framework contributor
• Reactor Netty committer
• Tomcat committer
2

3. Agenda
• Blocking, Non-blocking and Reactive IO
• Spring Framework 5 Reactive Web
• WebFlux
• WebClient
• Reactor Netty
• Demo
3

4. Blocking, Non-blocking and
Reactive IO

5. Synchronous Blocking IO
5
Waiting for response
Remote
Http Call
Another Remote
Http Call
Remote Http
Call Execution
Network Latency
Processing Latency

6. Synchronous Blocking IO
6
Waiting for response
Waiting for response
Waiting for response
…
Cannot Process
Anymore

7. Asynchronous Blocking IO
7
Remote
Http Call
Another Remote
Http Call
Remote Http
Call Execution
Network Latency
Processing Latency
Waiting for response

8. Asynchronous Blocking IO
8
Waiting for response
Waiting for response
…
Waiting for response
…
Cannot Process
Anymore

9. Non-blocking IO
9
Remote
Http Call
Another Remote
Http Call
Remote Http
Call Execution
Network Latency
Processing Latency

10. Non-blocking IO
10
Network Latency
Processing Latency
…
…

11. Non-blocking IO
Event Loop
Requests,
etc.
Intensive Operations
Remote CallsRegister callback
File System
Database
Remote CallOperation Complete
Trigger Callback
Computation

12. Reactive IO
12

13. Reactive IO
13

14. Spring Framework 5 Reactive
Web

15. 15
Spring WebFlux

16. 16
Functional Endpoints
Spring Framework 5.2
Spring WebFlux

17. Reactor Netty

18. Reactor Netty
• Reactive Streams API for Netty
• Hides the complexity of Netty
• Build-in Backpressure support
18

19. Reactor Netty
19
Prepares the response
Sends “Hello World”
Configures the port
Prepares the pipeline
Configures the server

20. Reactor Netty
20
Configures the port
Sends “Hello World”
Creates the server

21. Reactor Netty
• Supports UDP, TCP and HTTP
• Spring Boot 2 reactive web starter - default server runtime
• WebClient by default it is based on Reactor Netty
21

22. DEMO

23. THANKS
https://github.com/reactor/head-first-reactive-with-spring-and-reactor/tree/complete
https://github.com/reactor/head-first-reactive-with-spring-and-reactor/tree/rest-
template-example