Limit number of submissions that can be created with batch create.

app/controllers/submissions_controller.rb

@@ -80,6 +80,20 @@ def create
   end
 
   def batch_create
+    number_of_submissions = params[:_json].try(:size).to_i
+
+    if number_of_submissions > Config::MAX_SUBMISSION_BATCH_SIZE
+      render json: {
+        error: "number of submissions in batch create should be less than or equal to #{Config::MAX_SUBMISSION_BATCH_SIZE}"
+      }, status: :bad_request
+      return
+    elsif number_of_submissions == 0
+      render json: {
+        error: "there should be at least one submission in batch create"
+      }, status: :bad_request
+      return
+    end
+
     submissions = params[:_json].each.collect { |p| Submission.new(submission_params(p)) }
 
     response = []

app/helpers/config.rb

@@ -31,6 +31,7 @@ module Config
   MAX_NUMBER_OF_RUNS = (ENV['MAX_NUMBER_OF_RUNS'].presence || 20).to_i
   REDIRECT_STDERR_TO_STDOUT = ENV['REDIRECT_STDERR_TO_STDOUT'] == "true"
   MAX_EXTRACT_SIZE = (ENV['MAX_EXTRACT_SIZE'].presence || 10240).to_i
+  MAX_SUBMISSION_BATCH_SIZE = (ENV['MAX_SUBMISSION_BATCH_SIZE'].presence || 20).to_i
 
   def self.config_info
     @@default_confg ||= {
@@ -62,7 +63,8 @@ def self.config_info
       "number_of_runs": NUMBER_OF_RUNS,
       "max_number_of_runs": MAX_NUMBER_OF_RUNS,
       "redirect_stderr_to_stdout": REDIRECT_STDERR_TO_STDOUT,
-      "max_extract_size": MAX_EXTRACT_SIZE
+      "max_extract_size": MAX_EXTRACT_SIZE,
+      "max_submission_batch_size": MAX_SUBMISSION_BATCH_SIZE
     }
   end
 end

judge0-api.conf.default

@@ -266,4 +266,8 @@ REDIRECT_STDERR_TO_STDOUT=
 
 # Maximum total size (in kilobytes) of extracted files from archive.
 # Default: 10240, i.e. maximum of 10MB in total can be extracted.
-MAX_EXTRACT_SIZE=
+MAX_EXTRACT_SIZE=
+
+# Maximum number of submissions that can be created with batch create.
+# Default: 20
+MAX_SUBMISSION_BATCH_SIZE=