Add configurable time columns

Author: dgmora

README.md

@@ -323,7 +323,6 @@ SELECT date_trunc('week', created_at), COUNT(*) FROM users GROUP BY 1
 
 3 columns - timestamp, string, numeric - [Example](https://blazer.dokkuapp.com/queries/5-line-chart-format-2)
 
-
 ```sql
 SELECT date_trunc('week', created_at), gender, COUNT(*) FROM users GROUP BY 1, 2
 ```
@@ -950,6 +949,14 @@ Add [sqlite3](https://github.com/sparklemotion/sqlite3-ruby) to your Gemfile and
 data_sources:
   my_source:
     url: sqlite3:path/to/database.sqlite3
+  # Columns matching these regular expressions will be interpreted as date/time
+  # if they are strings.
+  # This is required for sqlite because it doesn't have a special
+  # date/time type. Without this, the wrong type of chart will be displayed
+  time_columns:
+    - '_at$'
+    - '_timestamp$'
+    - '_date$'
 ```
 
 ### SQL Server

lib/blazer/data_source.rb

@@ -35,6 +35,10 @@ def variable_defaults
       settings["variable_defaults"] || {}
     end
 
+    def time_columns
+      settings["time_columns"]&.map { |column_name_regex| Regexp.new(column_name_regex) } || []
+    end
+
     def timeout
       settings["timeout"]
     end

lib/blazer/result.rb

@@ -53,7 +53,7 @@ def column_types
             "string"
           elsif v.is_a?(Numeric)
             "numeric"
-          elsif v.is_a?(Time) || v.is_a?(Date)
+          elsif time?(k, v)
             "time"
           elsif v.nil?
             nil
@@ -66,6 +66,15 @@ def column_types
       end
     end
 
+    def time?(column_name, value)
+      return true if value.is_a?(Time) || value.is_a?(Date)
+      return false unless value.is_a?(String)
+
+      data_source.time_columns.any? do |column_name_regex|
+        column_name.match?(column_name_regex)
+      end
+    end
+
     def chart_type
       @chart_type ||= begin
         if column_types.compact.size >= 2 && column_types.compact == ["time"] + (column_types.compact.size - 1).times.map { "numeric" }

lib/generators/blazer/templates/config.yml.tt

@@ -32,6 +32,18 @@ data_sources:
     smart_columns:
       # user_id: "SELECT id, name FROM users WHERE id IN {value}"
 
+    # Columns matching these regular expressions  will be interpreted as date/time
+    # if they are strings.
+    # This is required for sqlite because it doesn't have a special
+    # date/time type. Without this, the wrong type of chart will be displayed
+    time_columns:
+    # - '^created_at$'
+    # - '^updated_at$'
+    # - '_at$'
+    # - '_timestamp$'
+    # - '_date$'
+
+
 # create audits
 audit: true