PragProg Customers

Real Time Phoenix Errata P47: missing {} on channel creation causes blocking error

kentbull

kentbull

Real Time Phoenix Errata P47: missing {} on channel creation causes blocking error

As of 2020-11-25 The syntax of channel.push(...) should be updated to include a second parameter.
As written the book states on page 47:

channel.push("ping")
    .receive(...)

This causes an error that precedes and prevents joining the channel in addition to preventing the reception of any messages back from the server:

image
image492×151 15.3 KB

A slight modification allows success:

channel.push("ping", {})
    .receive(...)

This error is likely due to a contract change in the Phoenix channel library.

3 comments
#errata/book-real-time-phoenix
5 964 3

Marked As Solved

sb8244

sb8244

Author of From Ruby to Elixir and Real-Time Phoenix

Hello,

Thanks for this report. You are correct. It looks like a change was introduced that assumes payload is an object, although the book uses it as undefined for that example.

I’m going to see if it’s intended that payload cannot be undefined.

Best,
Steve

2
Post #2

Also Liked

sb8244

sb8244

Author of From Ruby to Elixir and Real-Time Phoenix

Hi @kentbull. I submitted a PR to Phoenix that was accepted. This should stop being an issue when the next patch of Phoenix 1.5 is released. When I first checked this bug out, I missed that the documentation still showed channel.push("event") as valid syntax.

1
Post #3
kentbull

kentbull

That’s cool, I’m glad we caught it. Great book by the way, just finished Part 1 and am working on Part 2.

1
Post #4

Where Next?

View thread on forum
View Real Time Phoenix's book portal
Post errata for this book
Post a suggestion for this book
Post a question about this book
Post a review about this book
Home PragProg Customers
#errata/book-real-time-phoenix
5 964 3
Last post

Popular Pragmatic Bookshelf topics Top

jimmykiang
PragProg Customers

Distributed Services With Go - Agent_test.go error line 77
This test is broken right out of the box… — FAIL: TestAgent (7.82s) agent_test.go:77: Error Trace: agent_test.go:77 agent_test.go:...
#errata/book-distributed-services-with-go
4 1559 7
New
telemachus
PragProg Customers

Warnings in Python Testing With Pytest Chapter 2
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks” While running the smoke tests in Chapter 2, I get these...
#pragprog#errata/book-python-testing-with-pytest
5 2081 1
New
JohnS
PragProg Customers

Modern CSS with Tailwind: can’t setup the Rails source code
I can’t setup the Rails source code. This happens in a working directory containing multiple (postgres) Rails apps. With: ruby-3.0.0 s...
#question/book-modern-css-with-tailwind
0 1280 3
New
AndyDavis3416
PragProg Customers

Modern Front-End Development for Rails: ERROR in tsconfig.json Chapter_01/01
@noelrappin Running the webpack dev server, I receive the following warning: ERROR in tsconfig.json TS18003: No inputs were found in c...
/book-modern-front-end-development-for-rails
3 1438 3
New
fynn
PragProg Customers

Build a Weather Station with Elixir and Nerves: SGP30 vs SGP40
This is as much a suggestion as a question, as a note for others. Locally the SGP30 wasn’t available, so I ordered a SGP40. On page 53, ...
#suggestion/book-build-a-weather-station-with-elixir-and-nerves
0 1292 2
New
jskubick
PragProg Customers

Kotlin and Android Development featuring Jetpack: android:tint vs app:tint (chapter 7, p186)
I found an issue in Chapter 7 regarding android:backgroundTint vs app:backgroundTint. How to replicate: load chapter-7 from zipfile i...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 3566 3
New
tkhobbes
PragProg Customers

Modern Front-End Development for Rails - application does not start after run bin/setup (page xviii)
After some hassle, I was able to finally run bin/setup, now I have started the rails server but I get this error message right when I vis...
#errata/book-modern-front-end-development-for-rails
0 1461 5
New
andreheijstek
PragProg Customers

Modern front-end development for Rails, second edition - Struggling to get the first chapter to work
After running /bin/setup, the first error was: The foreman' command exists in these Ruby versions: That was easy to fix: gem install fore...
#errata/book-modern-front-end-development-for-rails
1 1116 3
New
gorkaio
PragProg Customers

Programming Phoenix LiveView: PentoWeb.LayoutView errata (56)
root_layout: {PentoWeb.LayoutView, :root}, This results in the following following error: no “root” html template defined for PentoWeb...
#errata/book-programming-phoenix-liveview
8 1094 4
New
dachristenson
PragProg Customers

Kotlin and Android Development featuring Jetpack: No activity_main.xml anymore
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 2172 6
New

Other popular topics Top

AstonJ
General Dev>Dev Chat

Which language or framework do you want to learn next?
Curious to know which languages and frameworks you’re all thinking about learning next :upside_down_face: Perhaps if there’s enough peop...
#community#learning
243 6639 97
New
AstonJ
General Dev>Hardware

Planck vs Preonic vs Subatomic (Keyboards)
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me. I think the Planck and the Preonic (o...
/keyboards#mechanical-keyboards#ortholinear#planck#preonic
105 17596 47
New
Exadra37
Linux>Chat

RancherOS is in end of life
Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...
#linux#rancheros
10 6358 6
New
foxtrottwist
General Dev>Dev Chat

Warp—The blazingly fast, Rust-based terminal
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
/rust#terminal
52 6785 22
New
PragmaticBookshelf
Backend>Learning Resources

Effective Haskell
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
pragprog.com
#pragprog/haskell#published-book/book-effective-haskell
15 10218 1
New
First poster: CommunityNews
AI>In The News

How to fix the eyes in AI-generated images
aidemos.info
0 4508 0
New
PragmaticBookshelf
Backend>Learning Resources

Programming Ruby 3.2 (5th Edition)
Programming Ruby is the most complete book on Ruby, covering both the language itself and the standard library as well as commonly used t...
twitter.com
#pragprog/ruby/rails#published-book/book-programming-ruby-3-2-5th-edition
28 8550 13
New
RobertRichards
Game Dev>Chat

Hair Salon Games for Girls Fun
Hair Salon Games for Girls Fun Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
#ios#android#unity#fun
2 3556 1
New
PragmaticBookshelf
Backend>Learning Resources

MySQL 9 Essentials
A concise guide to MySQL 9 database administration, covering fundamental concepts, techniques, and best practices. Neil Smyth MySQL...
pragprog.com
#pragprog#published-book/mysql/book-mysql-9-essentials
2 4162 0
New
mindriot
General Dev>Reviews

Keyboard Review: UHK60V2 vs Defy vs Voyager vs Glove80 vs Svalboard
Ok, well here are some thoughts and opinions on some of the ergonomic keyboards I have, I guess like mini review of each that I use enoug...
/keyboards#uhk60v2#defy#voyager#glove80#svalboard
5 5681 7
New
Back to top

Latest in Real-Time Phoenix

Real-Time Phoenix Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap