Trim nested arrays and drop metadata to save on payload size

lib/bugsnag/helpers.rb

@@ -5,9 +5,9 @@
 
 module Bugsnag
   module Helpers
-    MAX_STRING_LENGTH = 4096
+    MAX_STRING_LENGTH = 3072
     MAX_PAYLOAD_LENGTH = 128000
-    MAX_ARRAY_LENGTH = 400
+    MAX_ARRAY_LENGTH = 40
     RAW_DATA_TYPES = [Numeric, TrueClass, FalseClass]
 
     # Trim the size of value if the serialized JSON value is longer than is
@@ -17,7 +17,9 @@ def self.trim_if_needed(value)
       return sanitized_value unless payload_too_long?(sanitized_value)
       reduced_value = trim_strings_in_value(sanitized_value)
       return reduced_value unless payload_too_long?(reduced_value)
-      truncate_arrays_in_value(reduced_value)
+      reduced_value = truncate_arrays_in_value(reduced_value)
+      return reduced_value unless payload_too_long?(reduced_value)
+      remove_metadata_from_events(reduced_value)
     end
 
     def self.flatten_meta_data(overrides)
@@ -42,13 +44,11 @@ def self.is_json_raw_type?(value)
     TRUNCATION_INFO = '[TRUNCATED]'
 
     # Shorten array until it fits within the payload size limit when serialized
-    def self.truncate_arrays(array)
+    def self.truncate_array(array)
       return [] unless array.respond_to?(:slice)
-      array = array.slice(0, MAX_ARRAY_LENGTH)
-      while array.length > 0 and payload_too_long?(array)
-        array = array.slice(0, array.length - 1)
+      array.slice(0, MAX_ARRAY_LENGTH).map do |item|
+        truncate_arrays_in_value(item)
       end
-      array
     end
 
     # Trim all strings to be less than the maximum allowed string length
@@ -101,12 +101,21 @@ def self.truncate_arrays_in_value(value)
       when Hash
         truncate_arrays_in_hash(value)
       when Array, Set
-        truncate_arrays(value)
+        truncate_array(value)
       else
         value
       end
     end
 
+    # Remove `metaData` from array of `events` within object
+    def self.remove_metadata_from_events(object)
+      return {} unless object.is_a?(Hash) and object[:events].respond_to?(:map)
+      object[:events].map do |event|
+        event.delete(:metaData) if object.is_a?(Hash)
+      end
+      object
+    end
+
     def self.truncate_arrays_in_hash(hash)
       return {} unless hash.is_a?(Hash)
       hash.each_with_object({}) do |(key, value), reduced_hash|

spec/helper_spec.rb

@@ -135,16 +135,28 @@
 
       context "and trimmed strings are not enough" do
         it "truncates long arrays" do
-          value = 100.times.map {|i| SecureRandom.hex(8192) }
+          value = [100.times.map {|i| SecureRandom.hex(8192) }, "a"]
           trimmed_value = Bugsnag::Helpers.trim_if_needed(value)
-          expect(trimmed_value.length).to be > 0
-          trimmed_value.each do |str|
+          expect(trimmed_value.length).to eq 2
+          expect(trimmed_value.first.length).to eq Bugsnag::Helpers::MAX_ARRAY_LENGTH
+          trimmed_value.first.each do |str|
             expect(str.match(/\[TRUNCATED\]$/)).to_not be_nil
             expect(str.length).to eq(Bugsnag::Helpers::MAX_STRING_LENGTH)
           end
 
           expect(::JSON.dump(trimmed_value).length).to be < Bugsnag::Helpers::MAX_PAYLOAD_LENGTH
         end
+
+        it "removes metadata from events" do
+          metadata = Hash[*20000.times.map {|i| [i,i+1]}.flatten]
+          frames = 100.times.map {|i| SecureRandom.hex(4096) }
+          value = {key:"abc", events:[{metaData: metadata, frames: frames, cake: "carrot"}]}
+          trimmed_value = Bugsnag::Helpers.trim_if_needed(value)
+          expect(::JSON.dump(trimmed_value).length).to be < Bugsnag::Helpers::MAX_PAYLOAD_LENGTH
+          expect(trimmed_value[:key]).to eq value[:key]
+          expect(trimmed_value[:events].first.keys.to_set).to eq [:frames, :cake].to_set
+          expect(trimmed_value[:events].first[:metaData]).to be_nil
+        end
       end
     end
   end