schneems c24c0c8834 Rack handler should use provided default host ... This issue is somewhat tricky. When Rails is booted via `rails server` there are two types of configuration options passed, ones specified directly by a user like `rails s -p 3001` will always "win". For any other config that is not explicitly passed in, puma will consider it a "default". For example when you run `rails s` (without -p) then the default port will be 3000. There is one other way to configure puma though, and that is via a config file: ``` # config/puma.rb port 3002 ``` This is the order of precedence for configuration 1) Anything the user explicitly passes to `rails s` 2) Config specified in `config/puma.rb` file 3) Default values passed in via `rails s` 4) Defaults values stored in puma This fallback mechanism works well except in the case of calling `port` in a `config/puma.rb` file. To understand look at the [old method definition](2668597ec1/lib/puma/dsl.rb (L140-L145)): ``` def port(port, host=nil) host ||= Configuration::DefaultTCPHost bind "tcp://#{host}:#{port}" end ``` When the `port` method gets called, even if the user did not specify a `host` the `Configuration::DefaultTCPHost` will be used, which is a problem for local development because it defaults to `0.0.0.0`. [SO about 0.0.0.0 versus localhost](https://stackoverflow.com/questions/20778771/what-is-the-difference-between-0-0-0-0-127-0-0-1-and-localhost). In this case, while a user did directly specify a port, they did not specify a host, so you would expect the `rails s` defaults passed in to take affect. To make Puma respect that the host coming from `rails s` has more precedence than it's own default host, we must introduce the ability to set and retrieve a default_host value. This is then used in the rack handler so when `rails s` passes in `:Host => "localhost"` then it is used instead of reverting to `0.0.0.0`. The issue with #1699 is the test was wrong, it would have failed if a config file was present with a `port` invocation.		2019-01-04 16:09:56 -06:00
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puma.rb	Rack handler should use provided default host	2019-01-04 16:09:56 -06:00