Slides for Henning's talk on Sep 21st 2017.

Understanding sync vs. async control flow

Talking to synchronous (or "blocking") API

print('script start')
html = get('/foo')
print(html)
print('s...

Starting with Rails 4.0, when you get an exception reported via the ExceptionNotification gem, you will only see a very short backtrace with all backtrace lines from gems or ruby libraries missing.

This happens, because the `ExceptionNotificati...

If your external displays not switching on or showing a weird behavior (for e.g. all displays getting the same configuration all the time) you can fix it by switching off all external displays and re-enabling only one in the first step. Afterwards...

Since version 2.6 exception notifier distinguishes between foreground and background sections. The reason is that with background jobs (e.g. methods that are called by a cron job) some variables are not available for exception notifier, e.g. `@req...

When HTTP clients make an request they can define which response formats they can process. They do it by adding a header to the HTTP request like this:

Accept: application/json

This means the client will only understand JSON respon...

You are getting when connecting via SSH or deploying with Capistrano (which uses SSH):

Too many authentication failures for username

This is caused by having too many SSH keys added to your keyring or ssh-agent. Your ssh-agent will throw all...

Occasionally, you have to talk to APIs via HTTPS that use a custom certificate or a misconfigured certificate chain (like missing an intermediate certificate).

Using RestClient will then raise RestClient::SSLCertificateNotVerified errors, or wh...

We usually rely on VCR and WebMock to prevent any real network connection when running our unit tests.

This is not entirely true: They are both limited to a set of HTTP libraries...