HBW-80 Limit on the number of choices in lookup select

.gitignore

@@ -44,6 +44,7 @@ db/*.sqlite3
 /public/assets/*
 /spec/tmp/*
 /cache
+/.cache
 /capybara*
 /capybara-*.html
 /gems
@@ -107,3 +108,4 @@ lib/capistrano/
 /public/assets/packs-test
 /node_modules
 yarn-debug.log*
+yarn-error.log*

CHANGELOG.md

@@ -3,6 +3,7 @@ v1.6.0 [unreleased]
 
 ### Features
 -   [#189](https://github.com/latera/homs/pull/189) Show alert if form with file upload field has no file list field.
+-   [#194](https://github.com/latera/homs/pull/194) Set limit on the number of choices in lookup select from sql requests.
 
 v1.5.0 [2018-10-29]
 -------------------

hbw/app/models/hbw/fields/select.rb

@@ -9,6 +9,8 @@ class Select < Ordinary
       definition_reader :variable
       definition_reader :entity_class
 
+      MAX_ROW_COUNT = 20
+
       class SourceLoader
         include HBW::Logger
 
@@ -21,8 +23,8 @@ def initialize(name, source, condition, variables)
           @variables = variables
         end
 
-        def load
-          values = source.select(condition, variables)
+        def load(limit = nil)
+          values = source.select(condition, variables, limit)
 
           logger.debug { "Retrieved values for %s\nfrom source %s\ncondition: %s\nvariables: %s.\nResult: %s" %
                            [name, source, condition, variables, values.to_s] }
@@ -110,7 +112,7 @@ def nullable?
       end
 
       def lookup_values(query)
-        choices_to_array(loader(lookup_sql, task.variables_hash.merge(value: query)).load.uniq)
+        choices_to_array(loader(lookup_sql, task.variables_hash.merge(value: query)).load(MAX_ROW_COUNT).uniq)
       end
 
       private

hbw/app/models/hbw/sources/oracle.rb

@@ -4,17 +4,16 @@ class Oracle < Base
       class ConnectionFailed < RuntimeError
       end
 
-
       def initialize(*)
         require 'oci8' unless defined?(OCI8)
 
         super
       end
 
-      def select(sql, variables)
+      def select(sql, variables, limit = nil)
         binds = parse_bind_names(sql)
 
-        execute(sql) do |cursor|
+        execute(sql, limit) do |cursor|
           binds.each do |bind|
             if variables.fetch(bind).nil?
               cursor.bind_param(bind, nil, Integer)
@@ -31,11 +30,15 @@ def parse_bind_names(sql)
         sql.scan(/:\w+/).map { |s| s[1..-1].to_sym }
       end
 
-      def execute(sql)
+      def execute(sql, limit = nil)
         2.times do
           begin
             establish_connection
-            return try_query(sql) { |c| yield(c) if block_given? }
+            if limit.nil?
+              return try_query(sql) { |c| yield(c) if block_given? }
+            else
+              return try_query(limit(sql, limit)) { |c| yield(c) if block_given? }
+            end
           rescue ConnectionFailed
             reconnect
           end
@@ -85,6 +88,10 @@ def reconnect
         @connection = nil
         establish_connection
       end
+
+      def limit(sql, max_row_count)
+        "SELECT * FROM (#{sql}) WHERE ROWNUM <= #{max_row_count}"
+      end
     end
   end
 end