#399

2026-07-11 21:11:36 +09:00
@@ -0,0 +1,56 @@
+require 'csv'
+
+class PostImportSourceParser
+  MAX_ROWS = 100
+  MAX_BYTES = 1.megabyte
+  MAX_CELL_BYTES = 20.kilobytes
+
+  def initialize source:, format:, has_header: false, json_path: nil
+    @source = source.to_s
+    @format = format.to_s
+    @has_header = ActiveModel::Type::Boolean.new.cast(has_header)
+    @json_path = json_path.to_s
+  end
+
+  def parse
+    raise ArgumentError, '入力が大きすぎます．' if @source.bytesize > MAX_BYTES
+
+    @format == 'json' ? parse_json : parse_delimited
+  end
+
+  private
+
+  def parse_delimited
+    separator = @format == 'csv' ? ',' : "\t"
+    table = CSV.parse(@source, col_sep: separator).map { |row| row.map { _1.to_s.strip } }
+    raise ArgumentError, '入力が空です．' if table.empty?
+
+    headers = @has_header ? table.shift : nil
+    ensure_limits!(table)
+    width = table.map(&:length).max.to_i
+    { columns: (0...width).map { |index| { key: index.to_s,
+                                          label: "#{ ('A'.ord + index).chr }：#{ headers&.[](index).presence || '列' }" } },
+      rows: table.each_with_index.map { |values, index| { source_row: index + (@has_header ? 2 : 1), values: } } }
+  rescue CSV::MalformedCSVError => e
+    raise ArgumentError, "CSV・TSV の形式が不正です: #{ e.message }"
+  end
+
+  def parse_json
+    value = JSON.parse(@source, max_nesting: 20)
+    @json_path.split('.').reject(&:blank?).each { |part| value = value.is_a?(Array) ? value[Integer(part)] : value.fetch(part) }
+    raise ArgumentError, 'JSON の投稿候補は配列にしてください．' unless value.is_a?(Array)
+
+    ensure_limits!(value)
+    keys = value.grep(Hash).flat_map(&:keys).map(&:to_s).uniq
+    { columns: keys.each_with_index.map { |key, index| { key:, label: "#{ ('A'.ord + index).chr }：#{ key }" } },
+      rows: value.each_with_index.map { |item, index| { source_row: index + 1,
+                                                         values: keys.map { item.is_a?(Hash) ? item[_1] || item[_1.to_sym] : nil } } } }
+  rescue JSON::ParserError, KeyError, ArgumentError => e
+    raise ArgumentError, "JSON の形式が不正です: #{ e.message }"
+  end
+
+  def ensure_limits! rows
+    raise ArgumentError, "取込件数は #{ MAX_ROWS } 件までです．" if rows.length > MAX_ROWS
+    raise ArgumentError, 'セルが大きすぎます．' if rows.flatten.any? { _1.to_s.bytesize > MAX_CELL_BYTES }
+  end
+end