Handle FB truncating batch

Author: dmitchell

lib/koala/api/graph_batch_api.rb

@@ -45,7 +45,9 @@ def execute(http_options = {})
         return [] if batch_calls.empty?
 
         batch_results = []
-        batch_calls.each_slice(MAX_CALLS) do |batch|
+        until batch_calls.empty? do
+          batch = batch_calls.shift(MAX_CALLS)
+
           # Turn the call args collected into what facebook expects
           args = {"batch" => batch_args(batch)}
           batch.each do |call|
@@ -55,7 +57,13 @@ def execute(http_options = {})
           original_api.graph_call("/", args, "post", http_options) do |response|
             raise bad_response if response.nil?
 
-            batch_results += generate_results(response, batch)
+            # FB sometimes truncates the submission batch. dhm thinks it may be limiting create actions
+            # without erroring
+            slice_results = generate_results(response, batch)
+            batch_results += slice_results
+            if slice_results.length < batch.length
+              batch_calls.unshift(*batch[slice_results.length .. batch.length])
+            end
           end
         end
 

spec/cases/graph_api_batch_spec.rb

@@ -474,12 +474,17 @@
   end
 
   describe '#big_batches' do
+    before :all do
+      @random = Random.new
+    end
     before :each do
       payload = [{code: 200, headers: [{name: "Content-Type", value: "text/javascript; charset=UTF-8"}], body: "{\"id\":\"1234\"}"}]
       allow(Koala).to receive(:make_request) do |_request, args, _verb, _options|
         request_count = JSON.parse(args['batch']).length
         expect(request_count).to be <= 50   # check FB's limit
-        Koala::HTTPService::Response.new(200, (payload * request_count).to_json, {})
+        # simulate FB's result truncation
+        response_count = request_count > 35 ? request_count - @random.rand(15) : request_count
+        Koala::HTTPService::Response.new(200, (payload * response_count).to_json, {})
       end
     end