excon case-insensitive header access benchmarks

bench.rb

#!/bin/env ruby
#
# Benchmark any performance degredation associated with moving to case-
# insensitive HTTP header access.

require 'benchmark'
require './lib/excon'

resp = Excon::Response.new
resp.headers = {}

headers = Excon::Headers.new
original_headers = []
permuted_headers = []
value = 'irrelevant'

File.readlines('headers.txt').each do |header|
  original_headers << header
  permuted_headers << header.tr('a-zA-Z', 'A-Za-z')

  resp.headers[header] = value
  headers[header] = value
end

puts "Loaded #{original_headers.size} headers."

ITERATIONS = 100_000

Benchmark.bm(35) do |bm|
  bm.report('hash, with original case:') do
    ITERATIONS.times do
      original_headers.each do |header|
        resp.headers[header]
      end
    end
  end

  bm.report('hash, with permuted case:') do
    ITERATIONS.times do
      permuted_headers.each do |header|
        # resp.get_header(header)
      end
    end
  end

  bm.report('Excon::Headers, with original case:') do
    ITERATIONS.times do
      original_headers.each do |header|
        headers[header]
      end
    end
  end

  bm.report('Excon::Headers, with permuted case:') do
    ITERATIONS.times do
      permuted_headers.each do |header|
        headers[header]
      end
    end
  end
end

headers.txt

x-emc-meta
Content-Type
location
Content-Length
ctime
date
range
x-emc-uid
x-amz-security-token
Authorization
X-Amzn-Authorization
x-amz-date
Host
x-amz-glacier-version
ETag
Transfer-Encoding
x-amz-archive-id
x-amz-multipart-upload-id
x-amz-job-id
Last-Modified
x-amz-redshift-version
If-Match
X-Amz-Target
x-amz-archive-description
x-amz-part-size
x-amz-copy-source
versionId
Content-MD5
x-amz-delete-marker
x-amz-version-id
If-Modified-Since
If-Unmodified-Since
Status
x-amz-acl
X-Amzn-Authorization
Accept
Cookie
User-Agent
x-dnsme-apiKey
x-dnsme-requestDate
x-dnsme-hmac
Auth-Token
Location
x-tmrk-contenthash
x-goog-copy-source
X-Storage-Url
X-Container-Object-Count
X-Container-Bytes-Used
X-Cdn-Enabled
X-Cdn-Uri
X-Cdn-Ssl-Uri
Accept-Encoding
X-Account-Bytes-Used
X-Account-Meta-Quota-Bytes
X-Image-Meta-Is_public
X-Copy-From
X-Account-Meta-Temp-Url-Key
X-Object-Manifest

results.txt

Loaded 58 headers.
                                          user     system      total        real
hash, with original case:             2.020000   0.000000   2.020000 (  2.024403)
hash, with permuted case:            43.810000   0.150000  43.960000 ( 47.884542)
Excon::Headers, with original case:   3.520000   0.010000   3.530000 (  3.587199)
Excon::Headers, with permuted case:   6.390000   0.020000   6.410000 (  6.651364)