Project: Vcr 1.11.3

Publisher: VCR

Update content_length header

When the :update_content_length_header option is set to a truthy value,
VCR will ensure that the content-length header will have the correct
value. This is useful in several situations:

When you manually edit the cassette file and change the resonse body length. You can use this option so you don't have to manually calculate and update the body length.
When you use ERB, the response body length may vary. This will ensure it is always correct.
Syck, the default YAML engine for ruby 1.8 (and 1.9, unless you compile it to use Psych), has a bug where it sometimes will remove some whitespace strings when you serialize them. This may cause the content-length header to have the wrong value.

This is especially important when you use a client that checks the
content-length header. Mechanize, for example, will raise an EOFError
when the header value does not match the actual body length.

Background

Given

a previously recorded cassette file "cassettes/example.yml" with:

--- 
- !ruby/struct:VCR::HTTPInteraction 
  request: !ruby/struct:VCR::Request 
    method: :get
    uri: http://example.com:80/
    body: 
    headers: 
  response: !ruby/struct:VCR::Response 
    status: !ruby/struct:VCR::ResponseStatus 
      code: 200
      message: OK
    headers: 
      content-type: 
      - text/html;charset=utf-8
      content-length: 
      - "11"
    body: Hello <modified>
    http_version: "1.1"

And

a file named "common_stuff.rb" with:

require 'vcr'

VCR.config do |c|
  c.cassette_library_dir = 'cassettes'
  c.stub_with :fakeweb
end

def make_request_and_print_results
  response = Net::HTTP.get_response('example.com', '/')
  puts "Body length: #{response.body.length}"
  puts "Header value: #{response['content-length']}"
end

Scenarios

Default :update_content_length_header setting
:update_content_length_header => false
:update_content_length_header => true

Default :update_content_length_header setting

Given

a file named "default.rb" with:

require 'common_stuff'

VCR.use_cassette('example') do
  make_request_and_print_results
end

When

I run ruby default.rb

Then

the output should contain:

Body length: 16
Header value: 11

:update_content_length_header => false

Given

a file named "false.rb" with:

require 'common_stuff'

VCR.use_cassette('example', :update_content_length_header => false) do
  make_request_and_print_results
end

When

I run ruby false.rb

Then

the output should contain:

Body length: 16
Header value: 11

:update_content_length_header => true

Given

a file named "true.rb" with:

require 'common_stuff'

VCR.use_cassette('example', :update_content_length_header => true) do
  make_request_and_print_results
end

When

I run ruby true.rb

Then

the output should contain:

Body length: 16
Header value: 16

Last published about 5 years ago by myronmarston.

Update content_length header

Vcr settings