hook_into

The hook_into configuration option determines how VCR hooks into the HTTP requests to record and replay them. There are currently 4 valid options which support many different HTTP libraries:

- :webmock can be used to hook into requests from:
  - Net::HTTP
  - HTTPClient
  - Patron
  - Curb (Curl::Easy, but not Curl::Multi)
  - EM HTTP Request
  - Typhoeus (Typhoeus::Hydra, but not Typhoeus::Easy or Typhoeus::Multi)
  - Excon
- :typhoeus can be used to hook into itself (as long as you use Typhoeus::Hydra,
  but not Typhoeus::Easy or Typhoeus::Multi).
- :excon can be used to hook into itself.
- :faraday can be used to hook into itself.

There are some addiitonal trade offs to consider when deciding which option to use:

- WebMock uses extensive monkey patching to hook into supported HTTP
  libraries.  No monkey patching is used for Typhoeus, Excon or Faraday.
- Typhoeus, Excon, Faraday can be used together, and with WebMock.

Regardless of which library you use, VCR takes care of all of the configuration for you. You should not need to interact directly with WebMock or the stubbing facilities of Typhoeus, Excon or Faraday. If/when you decide to change stubbing libraries, you can change the hook_into configuration option and it'll work with no other changes required.

Record and replay a request using each supported hook_into/http library combination

Given a file named "hook_into_http_lib_combo.rb" with:

include_http_adapter_for("<http_lib>")

require 'vcr'
VCR.configure { |c| c.ignore_localhost = true }

$server = start_sinatra_app do
  get('/') { ARGV[0] }
end

puts "The response for request 1 was: #{response_body_for(:get, "http://localhost:#{$server.port}/")}"

VCR.configure do |c|
  <configuration>
  c.cassette_library_dir = 'vcr_cassettes'
  c.ignore_localhost = false
  c.default_cassette_options = { :serialize_with => :syck }
end

VCR.use_cassette('example') do
  puts "The response for request 2 was: #{response_body_for(:get, "http://localhost:#{$server.port}/")}"
end

When I run ruby hook_into_http_lib_combo.rb 'Hello World'

Then the output should contain each of the following:

| The response for request 1 was: Hello World | | The response for request 2 was: Hello World |

And the file "vcr_cassettes/example.yml" should contain "Hello World"

When I run ruby hook_into_http_lib_combo.rb 'Goodbye World'

Then the output should contain each of the following:

| The response for request 1 was: Goodbye World | | The response for request 2 was: Hello World |

And the file "vcr_cassettes/example.yml" should contain "Hello World".

Examples

configuration	http_lib
c.hook_into :webmock	net/http
c.hook_into :webmock	httpclient
c.hook_into :webmock	curb
c.hook_into :webmock	patron
c.hook_into :webmock	em-http-request
c.hook_into :webmock	typhoeus
c.hook_into :webmock	excon
c.hook_into :typhoeus	typhoeus
c.hook_into :excon	excon
c.hook_into :faraday	faraday (w/ net_http)
c.hook_into :faraday	faraday (w/ typhoeus)

Use Typhoeus, Excon and Faraday in combination with WebMock

Given a file named "hook_into_multiple.rb" with:

require 'typhoeus'
require 'excon'
require 'faraday'
require 'vcr'
<extra_require>

VCR.configure { |c| c.ignore_localhost = true }

$server = start_sinatra_app do
  get('/:path') { "#{ARGV[0]} #{params[:path]}" }
end

def net_http_response
  Net::HTTP.get_response('localhost', '/net_http', $server.port).body
end

def typhoeus_response
  Typhoeus::Request.get("http://localhost:#{$server.port}/typhoeus").body
end

def excon_response
  Excon.get("http://localhost:#{$server.port}/excon").body
end

def faraday_response
  Faraday::Connection.new(:url => "http://localhost:#{$server.port}") do |builder|
    builder.adapter :<faraday_adapter>
  end.get('/faraday').body
end

puts "Net::HTTP 1: #{net_http_response}"
puts "Typhoeus 1: #{typhoeus_response}"
puts "Excon 1: #{excon_response}"
puts "Faraday 1: #{faraday_response}"

VCR.configure do |c|
  c.hook_into <hook_into>, :typhoeus, :excon, :faraday
  c.cassette_library_dir = 'vcr_cassettes'
  c.ignore_localhost = false
end

VCR.use_cassette('example') do
  puts "Net::HTTP 2: #{net_http_response}"
  puts "Typhoeus 2: #{typhoeus_response}"
  puts "Excon 2: #{excon_response}"
  puts "Faraday 2: #{faraday_response}"
end

When I run ruby hook_into_multiple.rb 'Hello'

Then the output should contain each of the following:

| Net::HTTP 1: Hello net_http | | Typhoeus 1: Hello typhoeus | | Excon 1: Hello excon | | Faraday 1: Hello faraday | | Net::HTTP 2: Hello net_http | | Typhoeus 2: Hello typhoeus | | Excon 2: Hello excon | | Faraday 2: Hello faraday |

And the cassette "vcr_cassettes/example.yml" should have the following response bodies:

| Hello net_http | | Hello typhoeus | | Hello excon | | Hello faraday |

When I run ruby hook_into_multiple.rb 'Goodbye'

Then the output should contain each of the following:

| Net::HTTP 1: Goodbye net_http | | Typhoeus 1: Goodbye typhoeus | | Excon 1: Goodbye excon | | Faraday 1: Goodbye faraday | | Net::HTTP 2: Hello net_http | | Typhoeus 2: Hello typhoeus | | Excon 2: Hello excon | | Faraday 2: Hello faraday |

Examples

hook_into	faraday_adapter	extra_require
:webmock	net_http
:webmock	typhoeus	require 'typhoeus/adapters/faraday'