feat: generic http transport

.github/workflows/transport-http.yml

@@ -0,0 +1,30 @@
+name: Checks
+on:
+  pull_request:
+    # branches:
+    #   - main
+    paths:
+      - 'transport/http/**'
+
+jobs:
+  quality-check:
+    name: Quality Check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        # with:
+        #   fetch-depth: 0
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.21.6'
+      - name: Lint
+        uses: golangci/golangci-lint-action@v4
+        with:
+          version: v1.56.2
+          args: --out-format checkstyle:lint-report.xml,github-actions --timeout 2m --tests=false
+          working-directory: './transport/http'
+      - name: Test
+        run: go test -v -timeout 30s -count=1 ./... -coverprofile=test-report.out
+        working-directory: './transport/http'

transport/http/client.go

@@ -4,13 +4,11 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"encoding/xml"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 
-	"github.com/go-kit/kit/endpoint"
+	gkit "github.com/kikihakiem/gkit/core"
 )
 
 // HTTPClient is an interface that models *http.Client.
@@ -19,26 +17,26 @@ type HTTPClient interface {
 }
 
 // Client wraps a URL and provides a method that implements endpoint.Endpoint.
-type Client struct {
+type Client[Req, Res any] struct {
 	client         HTTPClient
-	req            CreateRequestFunc
-	dec            DecodeResponseFunc
+	req            gkit.EncodeDecodeFunc[Req, *http.Request]
+	dec            gkit.EncodeDecodeFunc[*http.Response, Res]
 	before         []RequestFunc
 	after          []ClientResponseFunc
 	finalizer      []ClientFinalizerFunc
 	bufferedStream bool
 }
 
 // NewClient constructs a usable Client for a single remote method.
-func NewClient(method string, tgt *url.URL, enc EncodeRequestFunc, dec DecodeResponseFunc, options ...ClientOption) *Client {
-	return NewExplicitClient(makeCreateRequestFunc(method, tgt, enc), dec, options...)
+func NewClient[Req, Res any](method string, tgt *url.URL, enc EncodeRequestFunc[Req], dec gkit.EncodeDecodeFunc[*http.Response, Res], options ...ClientOption[Req, Res]) *Client[Req, Res] {
+	return NewExplicitClient[Req, Res](makeCreateRequestFunc(method, tgt, enc), dec, options...)
 }
 
 // NewExplicitClient is like NewClient but uses a CreateRequestFunc instead of a
 // method, target URL, and EncodeRequestFunc, which allows for more control over
 // the outgoing HTTP request.
-func NewExplicitClient(req CreateRequestFunc, dec DecodeResponseFunc, options ...ClientOption) *Client {
-	c := &Client{
+func NewExplicitClient[Req, Res any](req gkit.EncodeDecodeFunc[Req, *http.Request], dec gkit.EncodeDecodeFunc[*http.Response, Res], options ...ClientOption[Req, Res]) *Client[Req, Res] {
+	c := &Client[Req, Res]{
 		client: http.DefaultClient,
 		req:    req,
 		dec:    dec,
@@ -50,50 +48,51 @@ func NewExplicitClient(req CreateRequestFunc, dec DecodeResponseFunc, options ..
 }
 
 // ClientOption sets an optional parameter for clients.
-type ClientOption func(*Client)
+type ClientOption[Req, Res any] gkit.Option[*Client[Req, Res]]
 
 // SetClient sets the underlying HTTP client used for requests.
 // By default, http.DefaultClient is used.
-func SetClient(client HTTPClient) ClientOption {
-	return func(c *Client) { c.client = client }
+func SetClient[Req, Res any](client HTTPClient) ClientOption[Req, Res] {
+	return func(c *Client[Req, Res]) { c.client = client }
 }
 
 // ClientBefore adds one or more RequestFuncs to be applied to the outgoing HTTP
 // request before it's invoked.
-func ClientBefore(before ...RequestFunc) ClientOption {
-	return func(c *Client) { c.before = append(c.before, before...) }
+func ClientBefore[Req, Res any](before ...RequestFunc) ClientOption[Req, Res] {
+	return func(c *Client[Req, Res]) { c.before = append(c.before, before...) }
 }
 
 // ClientAfter adds one or more ClientResponseFuncs, which are applied to the
 // incoming HTTP response prior to it being decoded. This is useful for
 // obtaining anything off of the response and adding it into the context prior
 // to decoding.
-func ClientAfter(after ...ClientResponseFunc) ClientOption {
-	return func(c *Client) { c.after = append(c.after, after...) }
+func ClientAfter[Req, Res any](after ...ClientResponseFunc) ClientOption[Req, Res] {
+	return func(c *Client[Req, Res]) { c.after = append(c.after, after...) }
 }
 
 // ClientFinalizer adds one or more ClientFinalizerFuncs to be executed at the
 // end of every HTTP request. Finalizers are executed in the order in which they
 // were added. By default, no finalizer is registered.
-func ClientFinalizer(f ...ClientFinalizerFunc) ClientOption {
-	return func(s *Client) { s.finalizer = append(s.finalizer, f...) }
+func ClientFinalizer[Req, Res any](f ...ClientFinalizerFunc) ClientOption[Req, Res] {
+	return func(s *Client[Req, Res]) { s.finalizer = append(s.finalizer, f...) }
 }
 
 // BufferedStream sets whether the HTTP response body is left open, allowing it
 // to be read from later. Useful for transporting a file as a buffered stream.
 // That body has to be drained and closed to properly end the request.
-func BufferedStream(buffered bool) ClientOption {
-	return func(c *Client) { c.bufferedStream = buffered }
+func BufferedStream[Req, Res any](buffered bool) ClientOption[Req, Res] {
+	return func(c *Client[Req, Res]) { c.bufferedStream = buffered }
 }
 
 // Endpoint returns a usable Go kit endpoint that calls the remote HTTP endpoint.
-func (c Client) Endpoint() endpoint.Endpoint {
-	return func(ctx context.Context, request interface{}) (interface{}, error) {
+func (c Client[Req, Res]) Endpoint() gkit.Endpoint[Req, Res] {
+	return func(ctx context.Context, request Req) (Res, error) {
 		ctx, cancel := context.WithCancel(ctx)
 
 		var (
-			resp *http.Response
-			err  error
+			resp     *http.Response
+			response Res
+			err      error
 		)
 		if c.finalizer != nil {
 			defer func() {
@@ -110,7 +109,7 @@ func (c Client) Endpoint() endpoint.Endpoint {
 		req, err := c.req(ctx, request)
 		if err != nil {
 			cancel()
-			return nil, err
+			return response, err
 		}
 
 		for _, f := range c.before {
@@ -120,7 +119,7 @@ func (c Client) Endpoint() endpoint.Endpoint {
 		resp, err = c.client.Do(req.WithContext(ctx))
 		if err != nil {
 			cancel()
-			return nil, err
+			return response, err
 		}
 
 		// If the caller asked for a buffered stream, we don't cancel the
@@ -137,9 +136,9 @@ func (c Client) Endpoint() endpoint.Endpoint {
 			ctx = f(ctx, resp)
 		}
 
-		response, err := c.dec(ctx, resp)
+		response, err = c.dec(ctx, resp)
 		if err != nil {
-			return nil, err
+			return response, err
 		}
 
 		return response, nil
@@ -170,41 +169,18 @@ type ClientFinalizerFunc func(ctx context.Context, err error)
 
 // EncodeJSONRequest is an EncodeRequestFunc that serializes the request as a
 // JSON object to the Request body. Many JSON-over-HTTP services can use it as
-// a sensible default. If the request implements Headerer, the provided headers
+// a sensible default. TODO: If the request implements Headerer, the provided headers
 // will be applied to the request.
-func EncodeJSONRequest(c context.Context, r *http.Request, request interface{}) error {
+func EncodeJSONRequest[Req any](c context.Context, r *http.Request, request Req) error {
 	r.Header.Set("Content-Type", "application/json; charset=utf-8")
-	if headerer, ok := request.(Headerer); ok {
-		for k := range headerer.Headers() {
-			r.Header.Set(k, headerer.Headers().Get(k))
-		}
-	}
-	var b bytes.Buffer
-	r.Body = ioutil.NopCloser(&b)
-	return json.NewEncoder(&b).Encode(request)
-}
 
-// EncodeXMLRequest is an EncodeRequestFunc that serializes the request as a
-// XML object to the Request body. If the request implements Headerer,
-// the provided headers will be applied to the request.
-func EncodeXMLRequest(c context.Context, r *http.Request, request interface{}) error {
-	r.Header.Set("Content-Type", "text/xml; charset=utf-8")
-	if headerer, ok := request.(Headerer); ok {
-		for k := range headerer.Headers() {
-			r.Header.Set(k, headerer.Headers().Get(k))
-		}
-	}
 	var b bytes.Buffer
-	r.Body = ioutil.NopCloser(&b)
-	return xml.NewEncoder(&b).Encode(request)
+	r.Body = io.NopCloser(&b)
+	return json.NewEncoder(&b).Encode(request)
 }
 
-//
-//
-//
-
-func makeCreateRequestFunc(method string, target *url.URL, enc EncodeRequestFunc) CreateRequestFunc {
-	return func(ctx context.Context, request interface{}) (*http.Request, error) {
+func makeCreateRequestFunc[Req any](method string, target *url.URL, enc EncodeRequestFunc[Req]) gkit.EncodeDecodeFunc[Req, *http.Request] {
+	return func(ctx context.Context, request Req) (*http.Request, error) {
 		req, err := http.NewRequest(method, target.String(), nil)
 		if err != nil {
 			return nil, err