fix: accept symbol feature flag keys (#147)

* fix: accept symbol feature flag keys

* refactor: cleanup and simplify

Author: dustinbyrne

.changeset/symbol-flag-keys.md

@@ -0,0 +1,5 @@
+---
+'posthog-ruby': patch
+---
+
+Accept symbol feature flag keys in flag APIs.

lib/posthog/client.rb

@@ -364,15 +364,15 @@ def is_feature_enabled( # rubocop:disable Naming/PredicateName
       !!response
     end
 
-    # @param [String] flag_key The unique flag key of the feature flag
+    # @param [String, Symbol] flag_key The unique flag key of the feature flag
     # @return [String] The decrypted value of the feature flag payload
     def get_remote_config_payload(flag_key)
-      @feature_flags_poller.get_remote_config_payload(flag_key)
+      @feature_flags_poller.get_remote_config_payload(flag_key.to_s)
     end
 
     # Returns whether the given feature flag is enabled for the given user or not
     #
-    # @param [String] key The key of the feature flag
+    # @param [String, Symbol] key The key of the feature flag
     # @param [String] distinct_id The distinct id of the user
     # @param [Hash] groups
     # @param [Hash] person_properties key-value pairs of properties to associate with the user.
@@ -455,7 +455,7 @@ def get_feature_flag_result(
     # @param [Hash] group_properties
     # @param [Boolean] only_evaluate_locally Skip the remote /flags call entirely
     # @param [Boolean] disable_geoip Stamped on captured access events
-    # @param [Array<String>] flag_keys When set, scopes the underlying /flags
+    # @param [Array<String, Symbol>] flag_keys When set, scopes the underlying /flags
     #   request to only these flag keys (sent as `flag_keys_to_evaluate`).
     #   Distinct from {FeatureFlagEvaluations#only}, which filters the
     #   already-fetched snapshot in memory.
@@ -598,7 +598,7 @@ def get_all_flags(
     # @deprecated Use {#get_feature_flag_result} instead, which returns both the flag value and payload
     #   and properly raises the $feature_flag_called event.
     #
-    # @param [String] key The key of the feature flag
+    # @param [String, Symbol] key The key of the feature flag
     # @param [String] distinct_id The distinct id of the user
     # @option [String or boolean] match_value The value of the feature flag to be matched
     # @option [Hash] groups
@@ -623,6 +623,7 @@ def get_feature_flag_payload(
         'instead — this consolidates flag evaluation into a single `/flags` request per ' \
         'incoming request.'
       )
+      key = key.to_s
       person_properties, group_properties = add_local_person_and_group_properties(distinct_id, groups,
                                                                                   person_properties, group_properties)
       @feature_flags_poller.get_feature_flag_payload(key, distinct_id, match_value, groups, person_properties,
@@ -725,6 +726,7 @@ def _get_feature_flag_result(
       only_evaluate_locally: false,
       send_feature_flag_events: true
     )
+      key = key.to_s
       person_properties, group_properties = add_local_person_and_group_properties(
         distinct_id, groups, person_properties, group_properties
       )

lib/posthog/feature_flags.rb

@@ -125,6 +125,7 @@ def get_feature_payloads(
 
     def get_flags(distinct_id, groups = {}, person_properties = {}, group_properties = {}, flag_keys = nil,
                   disable_geoip = nil)
+      flag_keys = flag_keys.map(&:to_s) if flag_keys.is_a?(Array)
       request_data = {
         distinct_id: distinct_id,
         groups: groups,
@@ -160,7 +161,7 @@ def get_flags(distinct_id, groups = {}, person_properties = {}, group_properties
     end
 
     def get_remote_config_payload(flag_key)
-      _request_remote_config_payload(flag_key)
+      _request_remote_config_payload(flag_key.to_s)
     end
 
     def get_feature_flag(
@@ -171,6 +172,8 @@ def get_feature_flag(
       group_properties = {},
       only_evaluate_locally = false
     )
+      key = key.to_s
+
       # make sure they're loaded on first run
       load_feature_flags
 
@@ -363,6 +366,8 @@ def get_feature_flag_payload(
       group_properties = {},
       only_evaluate_locally = false
     )
+      key = key.to_s
+
       if match_value.nil?
         match_value = get_feature_flag(
           key,
@@ -923,6 +928,7 @@ def _compute_flag_locally(flag, distinct_id, groups = {}, person_properties = {}
     def _compute_flag_payload_locally(key, match_value)
       return nil if @feature_flags_by_key.nil?
 
+      key = key.to_s
       response = nil
       if [true, false].include? match_value
         response = @feature_flags_by_key.dig(key, :filters, :payloads, match_value.to_s.to_sym)

spec/posthog/feature_flag_evaluations_spec.rb

@@ -104,6 +104,16 @@ def capture_stderr
         expect(unknown[:properties]['$feature_flag_error']).to eq('flag_missing')
       end
 
+      it 'accepts symbol flag keys when reading a snapshot' do
+        stub_flags(flags_response)
+        snapshot = client.evaluate_flags('user-1')
+
+        expect(snapshot.enabled?(:'boolean-flag')).to be(true)
+        expect(snapshot.get_flag(:'variant-flag')).to eq('variant-value')
+        expect(snapshot.get_flag_payload(:'variant-flag')).to eq('key' => 'value')
+        expect(snapshot.only(:'boolean-flag').keys).to eq(['boolean-flag'])
+      end
+
       it 'enabled? returns false for unknown flags' do
         stub_flags(flags_response)
         snapshot = client.evaluate_flags('user-1')
@@ -156,6 +166,14 @@ def capture_stderr
         )
       end
 
+      it 'accepts symbol keys in the flag_keys filter array' do
+        stub_flags(flags_response)
+        client.evaluate_flags('user-1', flag_keys: [:'boolean-flag'])
+        expect(WebMock).to have_requested(:post, FLAGS_ENDPOINT).with(
+          body: hash_including(flag_keys_to_evaluate: %w[boolean-flag])
+        )
+      end
+
       it 'returns a usable empty snapshot for empty distinct_id and does not call /flags' do
         stub_flags(flags_response)
         snapshot = client.evaluate_flags('')

spec/posthog/feature_flag_spec.rb

@@ -57,6 +57,42 @@ module PostHog
                                 person_properties: { 'region' => 'Canada' })).to eq(false)
     end
 
+    it 'accepts symbol flag keys when evaluating locally' do
+      api_feature_flag_res = {
+        'flags' => [
+          {
+            'id' => 1,
+            'name' => 'Symbol Flag',
+            'key' => 'symbol-flag',
+            'is_simple_flag' => true,
+            'active' => true,
+            'filters' => {
+              'groups' => [{ 'rollout_percentage' => 100 }],
+              'payloads' => { 'true' => '{"source":"local"}' }
+            }
+          }
+        ]
+      }
+      stub_request(
+        :get,
+        'https://us.i.posthog.com/flags/definitions?token=testsecret&send_cohorts=true'
+      ).to_return(status: 200, body: api_feature_flag_res.to_json)
+      stub_request(:post, flags_endpoint).to_return(status: 400)
+
+      c = Client.new(api_key: API_KEY, personal_api_key: API_KEY, test_mode: true)
+
+      expect(c.get_feature_flag(:'symbol-flag', 'some-distinct-id',
+                                send_feature_flag_events: false)).to eq(true)
+      expect(c.is_feature_enabled(:'symbol-flag', 'some-distinct-id',
+                                  send_feature_flag_events: false)).to eq(true)
+
+      result = c.get_feature_flag_result(:'symbol-flag', 'some-distinct-id', send_feature_flag_events: false)
+      expect(result.key).to eq('symbol-flag')
+      expect(result.value).to eq(true)
+      expect(c.get_feature_flag_payload(:'symbol-flag', 'some-distinct-id')).to eq('{"source":"local"}')
+      assert_not_requested :post, flags_endpoint
+    end
+
     it 'evaluates group properties' do
       api_feature_flag_res = {
         'flags' => [

spec/posthog/flags_spec.rb

@@ -361,6 +361,15 @@ module PostHog
              })
         )
       end
+
+      it 'accepts symbol flag keys' do
+        stub_request(:post, flags_endpoint)
+          .to_return(status: 200, body: flags_v4_response.to_json)
+
+        expect(client.get_feature_flag(:'enabled-flag', 'test-distinct-id',
+                                       send_feature_flag_events: false)).to eq(true)
+        expect(client.get_feature_flag_payload(:'enabled-flag', 'test-distinct-id')).to eq('{"foo": 1}')
+      end
     end
   end
 
@@ -400,6 +409,17 @@ module PostHog
       # Verify the request was made to the correct URL with token parameter
       expect(WebMock).to have_requested(:get, remote_config_endpoint)
     end
+
+    it 'accepts a symbol flag key' do
+      remote_config_response = { test: 'payload' }
+      stub_request(:get, remote_config_endpoint)
+        .to_return(status: 200, body: remote_config_response.to_json)
+
+      result = poller.get_remote_config_payload(:'test-flag')
+
+      expect(result[:test]).to eq('payload')
+      expect(WebMock).to have_requested(:get, remote_config_endpoint)
+    end
   end
 
   describe 'Cohort evaluation' do