Phlex::CSV

Co-Authored-By: Will Cosgrove <[email protected]>

lib/phlex.rb

@@ -14,6 +14,8 @@ module Phlex
 	autoload :Unbuffered, "phlex/unbuffered"
 	autoload :ConcurrentMap, "phlex/concurrent_map"
 	autoload :BlackHole, "phlex/black_hole"
+	autoload :CSV, "phlex/csv"
+	autoload :Callable, "phlex/callable"
 
 	# Included in all Phlex exceptions allowing you to match any Phlex error.
 	# @example Rescue any Phlex error:

lib/phlex/csv.rb

@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+require "csv"
+
+class Phlex::CSV
+	include Phlex::Callable
+
+	def initialize(collection)
+		@_collection = collection
+		@_headers = []
+		@_current_row = []
+		@_current_column_index = 0
+		@_view_context = nil
+		@_first = true
+	end
+
+	def call(buffer = +"", view_context: nil)
+		@_view_context = view_context
+
+		@_collection.each do |record|
+			collection_yielder(record) do |*args, **kwargs|
+				template(*args, **kwargs)
+
+				if @_first && render_headers?
+					buffer << ::CSV.generate_line(@_headers)
+				end
+
+				buffer << ::CSV.generate_line(@_current_row)
+				@_current_column_index = 0
+				@_current_row.clear
+			end
+
+			@_first = false
+		end
+
+		buffer
+	end
+
+	def filename
+		nil
+	end
+
+	private
+
+	def column(header = nil, value)
+		if @_first
+			@_headers << header
+		else
+			raise unless header == @_headers[@_current_column_index]
+		end
+
+		@_current_row << value
+		@_current_column_index += 1
+	end
+
+	def collection_yielder(record)
+		yield(record)
+	end
+
+	def template(...)
+		nil
+	end
+
+	def render_headers?
+		true
+	end
+
+	def helpers
+		@_view_context
+	end
+
+	def render(renderable)
+		renderable.call(view_context: @_view_context)
+	end
+end

test/phlex/csv.rb

@@ -0,0 +1,30 @@
+class Report < Phlex::CSV
+	def template(user)
+		user => { id:, name:, email: }
+
+		column("id", id)
+		column("name", name)
+		column("email", email)
+	end
+end
+
+User = Data.define(:id, :name, :email)
+
+it "works" do
+	users = [
+		User.new(
+			id: 1,
+			name: "John Doe",
+			email: "[email protected]"
+		),
+		User.new(
+			id: 2,
+			name: "Jane Doe",
+			email: "[email protected]"
+		)
+	]
+
+	puts Report.new(
+		users
+	).call
+end