Example of sending a signed request to Book&Table Mobile API when POST with body data

send_signed_contact_tutor_request.rb

require 'rest-client'

user_id  = 5
secret_key = 'secret key of user with id 5'

tutor_id = 105

timestamp = Time.now.utc.httpdate # Example: "Mon, 03 Aug 2015 20:15:56 GMT"

def calculate_canonical_string(content_type, content_md5, path, timestamp)
  [ content_type,
    content_md5,
    path,
    timestamp
  ].join(",")
end

def hmac_signature(content_type, content_md5, path, timestamp, secret_key)
  canonical_string = calculate_canonical_string(content_type, content_md5, path, timestamp)
  digest = OpenSSL::Digest.new('sha1')
  hmac_digest = OpenSSL::HMAC.digest(digest, secret_key, canonical_string)
  Base64.strict_encode64(hmac_digest)
end

content_type = 'application/json'

payload = {
    "contact_tutor" => {
      "when"                => 'Immediately',
      "standard_subject_id" => 101,
      "student_grade"       => '1',
      "meeting_frequency"   => "Once or Twice a Month",
      "meeting_days"        => ["Sunday", "Saturday"],
      "meeting_times"       => ["Late afternoon (3 - 6pm)"],
      "number_of_students"  => 2,
      "state_id"            => 43,
      "zip_code"            => "19001",
      "first_name"          => 'First name',
      "last_name"           => 'Last Name',
      "mobile_phone"        => '3823828382',
      "message"             => "Can you please come back to me?"
    }
}

path_with_params = "/mobile/1.0/contact_tutor/#{tutor_id}"

calculated_md5 = Digest::MD5.base64digest(payload.to_json)

signature = hmac_signature(content_type, calculated_md5, path_with_params, timestamp, secret_key)

headers = {
    'X-BOOK-AND-TABLE-API-KEY-TYPE' => 'IOS_IPHONE',
    'X-BOOK-AND-TABLE-API-KEY'      => ENV['BOOK_AND_TABLE_API_KEY_IOS_IPHONE'],
    'Accept'                        => 'application/json',
    'Content-Type'                  => content_type,
    'Content-MD5'                   => calculated_md5,
    'Date'                          => timestamp,
    'Authorization'                 => "APIAuth #{user_id}:#{signature}"
}

request = RestClient::Request.new(url:     "http://localhost:3000#{path_with_params}",
                                  headers: headers,
                                  method:  :post,
                                  payload: payload.to_json)

response = nil
begin
  response = request.execute
rescue RestClient::UnprocessableEntity => ex
  puts ex.inspect
  exit 1
end

response_decoded = ActiveSupport::JSON.decode(response.body)
puts "The results of the request are: #{response_decoded.inspect}"