Introduce Protocol::HTTP::Middleware.load. (#97)

Author: samuel-williams-shopify

lib/protocol/http/middleware/builder.rb

@@ -18,6 +18,22 @@ def initialize(default_app = NotFound)
 					@app = default_app
 				end
 
+				# Build the middleware application using the given block.
+				#
+				# @parameter block [Proc] The block to pass to the middleware constructor.
+				# @returns [Builder] The builder.
+				def build(&block)
+					if block_given?
+						if block.arity == 0
+							instance_exec(&block)
+						else
+							yield self
+						end
+					end
+					
+					return self
+				end
+				
 				# Use the given middleware with the given arguments and options.
 				#
 				# @parameter middleware [Class | Object] The middleware class to use.
@@ -44,19 +60,34 @@ def to_app
 			end
 
 			# Build a middleware application using the given block.
-			def self.build(&block)
-				builder = Builder.new
+			def self.build(*arguments, &block)
+				builder = Builder.new(*arguments)
+				
+				builder.build(&block)
+				
+				return builder.to_app
+			end
+			
+			# Load a middleware application from the given path.
+			#
+			# @parameter path [String] The path to the middleware application.
+			# @parameter arguments [Array] The arguments to pass to the middleware constructor.
+			# @parameter options [Hash] The options to pass to the middleware constructor.
+			# @parameter block [Proc] The block to pass to the middleware constructor.
+			def self.load(path, *arguments, &block)
+				builder = Builder.new(*arguments)
+				
+				binding = Builder::TOPLEVEL_BINDING.call(builder)
+				eval(File.read(path), binding, path)
 
 				if block_given?
-					if block.arity == 0
-						builder.instance_exec(&block)
-					else
-						yield builder
-					end
+					builder.build(&block)
 				end
 
 				return builder.to_app
 			end
 		end
 	end
 end
+
+Protocol::HTTP::Middleware::Builder::TOPLEVEL_BINDING = ->(builder){builder.instance_eval{binding}}

releases.md

@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - Introduce `Protocol::HTTP::Middleware.load` method for loading middleware applications from files.
+
 ## v0.58.1
 
   - `Protocol::HTTP::DuplicateHeaderError` now includes the existing and new values for better debugging.

test/protocol/http/middleware/builder.rb

@@ -5,6 +5,7 @@
 
 require "protocol/http/middleware"
 require "protocol/http/middleware/builder"
+require "tempfile"
 
 describe Protocol::HTTP::Middleware::Builder do
 	it "can make an app" do
@@ -41,4 +42,170 @@
 
 		expect(app).to be_a(Protocol::HTTP::Middleware)
 	end
+	
+	it "can initialize with custom default app" do
+		builder = Protocol::HTTP::Middleware::Builder.new(Protocol::HTTP::Middleware::Okay)
+		
+		expect(builder.to_app).to be_equal(Protocol::HTTP::Middleware::Okay)
+	end
+	
+	it "can build without block" do
+		builder = Protocol::HTTP::Middleware::Builder.new
+		result = builder.build
+		
+		expect(result).to be_equal(builder)
+		expect(builder.to_app).to be_equal(Protocol::HTTP::Middleware::NotFound)
+	end
+	
+	it "can build with zero-arity block using instance_exec" do
+		builder = Protocol::HTTP::Middleware::Builder.new
+		
+		builder.build do
+			use Protocol::HTTP::Middleware
+		end
+		
+		expect(builder.to_app).to be_a(Protocol::HTTP::Middleware)
+	end
+	
+	it "can use middleware with arguments" do
+		middleware_class = Class.new(Protocol::HTTP::Middleware) do
+			def initialize(app, argument1, argument2)
+				super(app)
+				@argument1 = argument1
+				@argument2 = argument2
+			end
+			
+			attr :argument1, :argument2
+		end
+		
+		builder = Protocol::HTTP::Middleware::Builder.new(Protocol::HTTP::Middleware::Okay)
+		builder.use(middleware_class, "test1", "test2")
+		
+		app = builder.to_app
+		expect(app).to be_a(middleware_class)
+		expect(app.argument1).to be == "test1"
+		expect(app.argument2).to be == "test2"
+	end
+	
+	it "can use middleware with options" do
+		middleware_class = Class.new(Protocol::HTTP::Middleware) do
+			def initialize(app, option1:, option2:)
+				super(app)
+				@option1 = option1
+				@option2 = option2
+			end
+			
+			attr :option1, :option2
+		end
+		
+		builder = Protocol::HTTP::Middleware::Builder.new(Protocol::HTTP::Middleware::Okay)
+		builder.use(middleware_class, option1: "value1", option2: "value2")
+		
+		app = builder.to_app
+		expect(app).to be_a(middleware_class)
+		expect(app.option1).to be == "value1"
+		expect(app.option2).to be == "value2"
+	end
+	
+	it "can use middleware with block" do
+		middleware_class = Class.new(Protocol::HTTP::Middleware) do
+			def initialize(app, &block)
+				super(app)
+				@block = block
+			end
+			
+			attr :block
+		end
+		
+		block_called = false
+		builder = Protocol::HTTP::Middleware::Builder.new(Protocol::HTTP::Middleware::Okay)
+		builder.use(middleware_class) do
+			block_called = true
+		end
+		
+		app = builder.to_app
+		expect(app).to be_a(middleware_class)
+		expect(app.block).to be_a(Proc)
+		app.block.call
+		expect(block_called).to be == true
+	end
+	
+	it "can run to set default app" do
+		builder = Protocol::HTTP::Middleware::Builder.new
+		builder.run(Protocol::HTTP::Middleware::Okay)
+		
+		expect(builder.to_app).to be_equal(Protocol::HTTP::Middleware::Okay)
+	end
+	
+	it "can chain multiple middleware" do
+		middleware1 = Class.new(Protocol::HTTP::Middleware) do
+			def initialize(app)
+				super(app)
+				@name = "middleware1"
+			end
+			
+			attr :name
+		end
+		
+		middleware2 = Class.new(Protocol::HTTP::Middleware) do
+			def initialize(app)
+				super(app)
+				@name = "middleware2"
+			end
+			
+			attr :name
+		end
+		
+		builder = Protocol::HTTP::Middleware::Builder.new(Protocol::HTTP::Middleware::Okay)
+		builder.use(middleware1)
+		builder.use(middleware2)
+		
+		app = builder.to_app
+		# Middleware are reversed, so first added becomes outermost
+		expect(app).to be_a(middleware1)
+		expect(app.delegate).to be_a(middleware2)
+		expect(app.delegate.delegate).to be_equal(Protocol::HTTP::Middleware::Okay)
+	end
+	
+	it "can convert to app directly" do
+		builder = Protocol::HTTP::Middleware::Builder.new(Protocol::HTTP::Middleware::HelloWorld)
+		
+		app = builder.to_app
+		expect(app).to be_equal(Protocol::HTTP::Middleware::HelloWorld)
+	end
+	
+	it "can load middleware from file" do
+		temp_file = Tempfile.new(["middleware", ".rb"])
+		temp_file.write(<<~RUBY)
+			use Protocol::HTTP::Middleware
+			run Protocol::HTTP::Middleware::HelloWorld
+		RUBY
+		temp_file.close
+		
+		app = Protocol::HTTP::Middleware.load(temp_file.path)
+		
+		expect(app).to be_a(Protocol::HTTP::Middleware)
+		expect(app.delegate).to be_equal(Protocol::HTTP::Middleware::HelloWorld)
+		
+	ensure
+		temp_file&.unlink
+	end
+	
+	it "can load middleware from file with block" do
+		temp_file = Tempfile.new(["middleware", ".rb"])
+		temp_file.write(<<~RUBY)
+			use Protocol::HTTP::Middleware
+		RUBY
+		temp_file.close
+		
+		app = Protocol::HTTP::Middleware.load(temp_file.path) do
+			run Protocol::HTTP::Middleware::HelloWorld
+		end
+		
+		expect(app).to be_a(Protocol::HTTP::Middleware)
+		expect(app.delegate).to be_equal(Protocol::HTTP::Middleware::HelloWorld)
+		
+	ensure
+		temp_file&.unlink
+	end
 end