Add request retry preparation

lib/protocol/http/request.rb

@@ -153,6 +153,28 @@ def idempotent?
 				return false
 			end
 
+			# Rewind the request body so it can be sent again.
+			# @returns [Boolean] Whether the request body was rewound.
+			def rewind!
+				if body = @body
+					return body.rewind
+				end
+
+				# Requests without a body can be sent again immediately.
+				return true
+			end
+
+			# Prepare the request body to be sent again, if it is safe to retry.
+			# @returns [Boolean] Whether the request was prepared for retry.
+			def retry!
+				# Only idempotent request methods can be retried safely.
+				if @method == Methods::POST || @method == Methods::PATCH || @method == Methods::CONNECT
+					return false
+				end
+
+				return self.rewind!
+			end
+
 			# Convert the request to a hash, suitable for serialization.
 			#
 			# @returns [Hash] The request as a hash.

releases.md

@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - Add `Protocol::HTTP::Request#rewind!` and `#retry!` for preparing requests to be sent again.
+
 ## v0.63.0
 
   - Add support for the HTTP `QUERY` method.

test/protocol/http/request.rb

@@ -152,6 +152,127 @@
 			end
 		end
 
+		with "PATCH request without a body" do
+			let(:request) {subject["PATCH", "/resource"]}
+
+			it "should be idempotent" do
+				expect(request).to be(:idempotent?)
+			end
+		end
+
+		with "#rewind!" do
+			it "allows requests without a body" do
+				expect(request.rewind!).to be == true
+			end
+
+			with "request with a rewindable body" do
+				let(:request) {subject["POST", "/submit", body: "content"]}
+
+				it "rewinds the body" do
+					expect(request.body.read).to be == "content"
+
+					expect(request.rewind!).to be == true
+					expect(request.body.read).to be == "content"
+				end
+			end
+
+			with "request with a non-rewindable body" do
+				let(:body) {Protocol::HTTP::Body::Readable.new}
+				let(:request) {subject.new(nil, nil, "PUT", "/resource", nil, headers, body)}
+
+				it "does not rewind" do
+					expect(request.rewind!).to be == false
+				end
+			end
+
+			with "request with a consumed non-rewindable body" do
+				let(:body) do
+					Class.new(Protocol::HTTP::Body::Readable) do
+						def initialize
+							@chunk = "content"
+						end
+
+						def read
+							chunk = @chunk
+							@chunk = nil
+							return chunk
+						end
+
+						def empty?
+							@chunk.nil?
+						end
+					end.new
+				end
+
+				let(:request) {subject.new(nil, nil, "PUT", "/resource", nil, headers, body)}
+
+				it "does not treat empty as rewindable" do
+					expect(request.body.read).to be == "content"
+					expect(request.body).to be(:empty?)
+
+					expect(request.rewind!).to be == false
+				end
+			end
+
+			with "request with an empty non-rewindable body" do
+				let(:body) do
+					Class.new(Protocol::HTTP::Body::Readable) do
+						def empty?
+							true
+						end
+					end.new
+				end
+
+				let(:request) {subject.new(nil, nil, "PUT", "/resource", nil, headers, body)}
+
+				it "does not rewind" do
+					expect(request.rewind!).to be == false
+				end
+			end
+		end
+
+		with "#retry!" do
+			it "allows idempotent requests without a body" do
+				expect(request.retry!).to be == true
+			end
+
+			with "idempotent request with a rewindable body" do
+				let(:request) {subject["PUT", "/resource", body: "content"]}
+
+				it "allows retry and rewinds the body" do
+					expect(request.body.read).to be == "content"
+
+					expect(request.retry!).to be == true
+					expect(request.body.read).to be == "content"
+				end
+			end
+
+			with "idempotent request with a non-rewindable body" do
+				let(:body) {Protocol::HTTP::Body::Readable.new}
+				let(:request) {subject.new(nil, nil, "PUT", "/resource", nil, headers, body)}
+
+				it "does not allow retry" do
+					expect(request.retry!).to be == false
+				end
+			end
+
+			with "non-idempotent request" do
+				let(:request) {subject["POST", "/submit"]}
+
+				it "does not allow retry" do
+					expect(request.retry!).to be == false
+				end
+			end
+
+			with "PATCH request" do
+				let(:request) {subject["PATCH", "/resource"]}
+
+				it "does not allow retry" do
+					expect(request.retry!).to be == false
+				end
+			end
+		end
+
 		it "should have a string representation" do
 			expect(request.to_s).to be == "http://localhost: GET /index.html HTTP/1.0"
 		end