Some docs on EventMachine adapters. (#1232)

docs/adapters/em-http.md

@@ -7,20 +7,65 @@ top_name: Adapters
 top_link: ./
 ---
 
-This Adapter uses the [em-http-request][rdoc] gem to make HTTP requests.
+This Adapter uses [EventMachine](https://github.com/eventmachine/eventmachine/) and the tie in [em-http-request][src]
 
+It can be used to make parallel requests using EventMachine.
+
+The major difference between this and EMSynchrony is that it does not use fibers.
+
+**Error handling and responses have a slightly different behaviour and structure in some cases.  Please run thorough testing scenarios, including connection failures and SSL failures**
+
+You will need to add em-http-request to your Gemfile:
+
+```ruby
+# Gemfile
+gem 'em-http-request'
+```
+
+### Base request
 ```ruby
+require 'faraday'
+require 'em-http-request'
+
 conn = Faraday.new(...) do |f|
   # no custom options available
   f.adapter :em_http
 end
 ```
 
+### Parallel Requests
+
+```ruby
+require 'faraday'
+require 'em-http-request'
+
+urls = Array.new(5) { 'http://127.0.0.1:3000' }
+
+conn = Faraday::Connection.new do |builder|
+  builder.adapter :em_http
+end
+
+begin
+  conn.in_parallel do
+    puts "Parallel manager: #{conn.parallel_manager}"
+
+    @responses = urls.map do |url|
+      conn.get(url)
+    end
+  end
+end
+
+# Gather responses outside of block
+puts @responses.map(&:status).join(', ')
+puts @responses.map(&:status).compact.count
+```
+
 ## Links
 
 * [Gem RDoc][rdoc]
 * [Gem source][src]
 * [Adapter RDoc][adapter_rdoc]
+* [EM-Synchrony Adapter](./em-synchrony.md)
 
 [rdoc]: https://www.rubydoc.info/gems/em-http-request
 [src]: https://github.com/igrigorik/em-http-request#readme

docs/adapters/em-synchrony.md

@@ -7,15 +7,65 @@ top_name: Adapters
 top_link: ./
 ---
 
-This Adapter uses the [em-synchrony][rdoc] gem to make HTTP requests.
+This Adapter uses [EventMachine](https://github.com/eventmachine/eventmachine/) and the tie in [em-http-request](https://www.rubydoc.info/gems/em-http-request) in conjunction with [em-synchrony][rdoc]
+
+It can be used to make parallel requests using EventMachine.
+
+The key difference between this and EM-Http is that it uses fibers.  For more information see igrigorik's blog posts on the matter:
+
+- [fibers-cooperative-scheduling-in-ruby](https://www.igvita.com/2009/05/13/fibers-cooperative-scheduling-in-ruby/)
+- [untangling-evented-code-with-ruby-fibers](https://www.igvita.com/2010/03/22/untangling-evented-code-with-ruby-fibers)
+
+**Error handling and responses have a slightly different behaviour and structure in some cases.  Please run thorough testing scenarios, including connection failures and SSL failures**
+
+You will need to add em-http-request and em-synchrony to your Gemfile:
 
 ```ruby
+# Gemfile
+gem 'em-http-request'
+gem 'em-synchrony'
+```
+
+### Base request
+```ruby
+require 'faraday'
+require 'em-http-request'
+require 'em-synchrony'
+
 conn = Faraday.new(...) do |f|
   # no custom options available
   f.adapter :em_synchrony
 end
 ```
 
+### Parallel Requests
+
+```ruby
+require 'faraday'
+require 'em-http-request'
+require 'em-synchrony'
+
+urls = Array.new(5) { 'http://127.0.0.1:3000' }
+
+conn = Faraday::Connection.new do |builder|
+  builder.adapter :em_synchrony
+end
+
+begin
+  conn.in_parallel do
+    puts "Parallel manager: #{conn.parallel_manager}"
+
+    @responses = urls.map do |url|
+      conn.get(url)
+    end
+  end
+end
+
+# Gather responses outside of block
+puts @responses.map(&:status).join(', ')
+puts @responses.map(&:status).compact.count
+```
+
 ## Links
 
 * [Gem RDoc][rdoc]

docs/adapters/index.md

@@ -20,6 +20,7 @@ Faraday includes these adapters (but not the HTTP client libraries):
 * [Excon][excon]
 * [Patron][patron]
 * [EM-Synchrony][em-synchrony]
+* [EM-Http][em-http]
 * [HTTPClient][httpclient]
 
 While most adapters use a common Ruby HTTP client library, adapters can also
@@ -177,6 +178,7 @@ Compare to the finished example [em-synchrony](https://github.com/lostisland/far
 [excon]:        ./excon
 [patron]:       ./patron
 [em-synchrony]: ./em-synchrony
+[em-http]:      ./em-http
 [httpclient]:   ./httpclient
 [typhoeus]:     https://github.com/typhoeus/typhoeus/blob/master/lib/typhoeus/adapters/faraday.rb
 [faraday-http]: https://github.com/lostisland/faraday-http