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Project: Vcr 2.7.0

:once

The :once record mode will:

  • Replay previously recorded interactions.
  • Record new interactions if there is no cassette file.
  • Cause an error to be raised for new requests if there is a cassette file.

It is similar to the :new_episodes record mode, but will prevent new,
unexpected requests from being made (i.e. because the request URI changed
or whatever).

:once is the default record mode, used when you do not set one.

Background
Given
a file named "setup.rb" with:
start_sinatra_app(:port => 7777) do
  get('/') { 'Hello' }
end

require 'vcr'

VCR.configure do |c|
  c.hook_into                :webmock
  c.cassette_library_dir     = 'cassettes'
end
And
a previously recorded cassette file "cassettes/example.yml" with:
--- 
http_interactions: 
- request: 
    method: get
    uri: http://example.com/foo
    body: 
      encoding: UTF-8
      string: ""
    headers: {}
  response: 
    status: 
      code: 200
      message: OK
    headers: 
      Content-Length: 
      - "20"
    body: 
      encoding: UTF-8
      string: example.com response
    http_version: "1.1"
  recorded_at: Tue, 01 Nov 2011 04:58:44 GMT
recorded_with: VCR 2.0.0
Scenarios
Previously recorded responses are replayed
Given
a file named "replay_recorded_response.rb" with:
require 'setup'

VCR.use_cassette('example', :record => :once) do
  response = Net::HTTP.get_response('example.com', '/foo')
  puts "Response: #{response.body}"
end
When
I run ruby replay_recorded_response.rb
Then
it should pass with "Response: example.com response"
  • @exclude-jruby
New requests result in an error when the cassette file exists
Given
a file named "error_for_new_requests_when_cassette_exists.rb" with:
require 'setup'

VCR.use_cassette('example', :record => :once) do
  response = Net::HTTP.get_response('localhost', '/', 7777)
  puts "Response: #{response.body}"
end
When
I run ruby error_for_new_requests_when_cassette_exists.rb
Then
it should fail with "An HTTP request has been made that VCR does not know how to handle"
New requests get recorded when there is no cassette file
Given
a file named "record_new_requests.rb" with:
require 'setup'

VCR.use_cassette('example', :record => :once) do
  response = Net::HTTP.get_response('localhost', '/', 7777)
  puts "Response: #{response.body}"
end
When
I remove the file "cassettes/example.yml"
And
I run ruby record_new_requests.rb
Then
it should pass with "Response: Hello"
And
the file "cassettes/example.yml" should contain "Hello"

Last published over 4 years ago by myronmarston.