Add mixin for aws requests

lib/paapi/aws_request.rb

@@ -0,0 +1,47 @@
+require 'http'
+require 'aws-sigv4'
+
+# https://webservices.amazon.com/paapi5/documentation/common-request-parameters.html
+module Paapi
+  module AwsRequest
+    def do_request(op:,  payload:)
+      raise ArguemntError unless Paapi::OPERATIONS.keys.include?(op)
+
+      operation = OPERATIONS[op]
+
+      headers = {
+        'X-Amz-Target' => "com.amazon.paapi5.v1.ProductAdvertisingAPIv1.#{operation.target_name}",
+        'Content-Encoding' => 'amz-1.0',
+      }
+
+      default_payload = {
+        'PartnerTag' => partner_tag,
+        'PartnerType' => partner_type,
+        'Marketplace' => marketplace.site
+      }
+
+      payload = default_payload.merge(payload)
+
+      endpoint =  "https://#{marketplace.host}/paapi5/#{operation.endpoint_suffix}"
+
+      signer = Aws::Sigv4::Signer.new(
+        service: operation.service,
+        region: marketplace.region,
+        access_key_id: access_key,
+        secret_access_key: secret_key,
+        http_method: operation.http_method,
+        endpoint: marketplace.host
+      )
+
+      signature = signer.sign_request(http_method: operation.http_method, url: endpoint, headers: headers, body: payload.to_json)
+
+      headers['Host'] = marketplace.host
+      headers['X-Amz-Date'] = signature.headers['x-amz-date']
+      headers['X-Amz-Content-Sha256']= signature.headers['x-amz-content-sha256']
+      headers['Authorization'] = signature.headers['authorization']
+      headers['Content-Type'] = 'application/json; charset=utf-8'
+
+      HTTP.headers(headers).post(endpoint, json: payload )
+    end
+  end
+end