Add encoder for array tag sets

lib/appoptics/metrics.rb

@@ -7,6 +7,7 @@
 require 'appoptics/metrics/collection'
 require 'appoptics/metrics/connection'
 require 'appoptics/metrics/errors'
+require 'appoptics/metrics/params_encoder'
 require 'appoptics/metrics/persistence'
 require 'appoptics/metrics/queue'
 require 'appoptics/metrics/smart_json'

lib/appoptics/metrics/connection.rb

@@ -32,7 +32,7 @@ def transport
         raise(NoClientProvided, "No client provided.") unless @client
         @transport ||= Faraday::Connection.new(
           url: api_endpoint + "/v1/",
-          request: {open_timeout: 20, timeout: 30}) do |f|
+          request: {open_timeout: 20, timeout: 30, params_encoder: AppOptics::Metrics::ParamsEncoder}) do |f|
 
           f.use AppOptics::Metrics::Middleware::RequestBody
           f.use AppOptics::Metrics::Middleware::Retry

lib/appoptics/metrics/params_encoder.rb

@@ -0,0 +1,68 @@
+module AppOptics
+  module Metrics
+    module ParamsEncoder
+      SUBKEY_REGEXP = /\[|\]/
+
+      def self.encode(params)
+        return encode_tags(params) if params["tags"]
+        Faraday::NestedParamsEncoder.encode(params)
+      end
+
+      def self.encode_tags(params)
+        query_string = ""
+        # Helper proc
+        to_query = proc do |parent, obj, key|
+          obj.keys.zip(obj.values).each do |k, v|
+            if v.is_a?(Hash)
+              to_query.call(parent, v, k)
+            elsif v.is_a?(Array) && key
+              v.each do |vv|
+                query_string << nested_key(key, k, vv)
+              end
+            else
+              if key
+                query_string << nested_key(key, k, v)
+              else
+                query_string << "#{k}=#{v}&"
+              end
+            end
+          end
+          query_string
+        end
+        result = to_query.call(query_string, params)
+        if result[-1] == "&"
+          result = result[0..-2]
+        end
+        result
+      end
+
+      def self.decode(query)
+        params = {}
+        query.split("&").each do |pair|
+          key, value = pair.split("=", 2)
+          keys = key.split(SUBKEY_REGEXP)
+          if keys.size > 1 # is subkey
+            params[keys[0]] ||= {}
+            if !params[keys[0]][keys[1]]
+              params[keys[0]][keys[1]] = value
+            else
+              old_value = params[keys[0]][keys[1]]
+              if !old_value.is_a?(Array)
+                params[keys[0]][keys[1]] = []
+                params[keys[0]][keys[1]] << old_value
+              end
+              params[keys[0]][keys[1]] << value
+            end
+          else
+            params[key] = value
+          end
+        end
+        params
+      end
+
+      def self.nested_key(key, subkey, value)
+        "#{key}[#{subkey}]=#{value}&"
+      end
+    end
+  end
+end

spec/unit/metrics/params_encoder_spec.rb

@@ -0,0 +1,50 @@
+require "spec_helper"
+
+module AppOptics
+  module Metrics
+    describe ParamsEncoder do
+      let(:single_tag) {
+        {
+          "resolution" => "3600",
+          "duration" => "60",
+          "tags" => {
+            "hostname" => "app1"
+          }
+        }
+      }
+
+      let(:multi_tag) {
+        {
+          "resolution" => "3600",
+          "duration" => "60",
+          "tags" => {
+            "hostname" => ['app1', 'app2']
+          }
+        }
+      }
+      context "encode" do
+        it "single value tag" do
+          result = described_class.encode(single_tag)
+          expect(result).to eq("resolution=3600&duration=60&tags[hostname]=app1")
+        end
+
+        it "array value tag" do
+          result = described_class.encode(multi_tag)
+          expect(result).to eq("resolution=3600&duration=60&tags[hostname]=app1&tags[hostname]=app2")
+        end
+      end
+
+      context "decode" do
+        it "single value tag" do
+          result = described_class.decode("resolution=3600&duration=60&tags[hostname]=app1")
+          expect(result).to eq(single_tag)
+        end
+
+        it "array value tag" do
+          result = described_class.decode("resolution=3600&duration=60&tags[hostname]=app1&tags[hostname]=app2")
+          expect(result).to eq(multi_tag)
+        end
+      end
+    end
+  end
+end