Fix the Middleware type (#2)

README.md

@@ -107,11 +107,8 @@ logs, and headers transparently into all requests through the cHTTP clients.
 Current interface of the middleware is based on 2 types of functions:
 
 ```go
-// RoundTripper is a RoundTrip function implementation of the http.RoundTripper interface.
-type RoundTripper func(request *http.Request) (*http.Response, error)
-
 // Middleware is an extended interface to the RoundTrip function of the http.RoundTripper interface.
-type Middleware func(request *http.Request, next RoundTripper) (*http.Response, error)
+type Middleware func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error)
 ```
 
 Usage example:
@@ -134,7 +131,7 @@ func main() {
 	}
 	client := chttp.NewJSON(nil)
 	client.With(middleware.JSON(), middleware.Debug(true, nil))
-	client.With(func(request *http.Request, next chttp.RoundTripper) (*http.Response, error) {
+	client.With(func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 		fmt.Println("Before the request")
 		resp, err := next(request)
 		fmt.Println("After the request")
@@ -155,15 +152,15 @@ Adds a custom headers based on the request.
 **Example:** 
 
 ```go
-chttp.NewClient(nil).
-	With(middleware.CustomHeaders(func(request *http.Request) map[string]string {
-		if request.Method == http.MethodPost {
-			return map[string]string{
-				"Accept": "*/*",
-			}
-		}
-		return nil
-	}))
+client := chttp.NewClient(nil)
+client.With(middleware.CustomHeaders(func(request *http.Request) map[string]string {
+    if request.Method == http.MethodPost {
+        return map[string]string{
+            "Accept": "*/*",
+        }
+    }
+    return nil
+}))
 ```
 
 #### Debug
@@ -175,8 +172,8 @@ Dumps requests and responses in the logs.
 **Example:** 
 
 ```go
-chttp.NewClient(nil).
-	With(middleware.Debug(true, nil))
+client := chttp.NewClient(nil)
+client.With(middleware.Debug(true, nil))
 ```
 
 #### Headers
@@ -186,10 +183,10 @@ Adds a static headers.
 **Example:** 
 
 ```go
-chttp.NewClient(nil).
-	With(middleware.Headers(map[string]string{
-		"Accept": "*/*",
-	}))
+client := chttp.NewClient(nil)
+client.With(middleware.Headers(map[string]string{
+    "Accept": "*/*",
+}))
 ```
 
 #### JSON
@@ -199,8 +196,8 @@ Adds a `Content-Type` and `Accept` headers with the `application/json` value.
 **Example:** 
 
 ```go
-chttp.NewClient(nil).
-	With(middleware.JSON())
+client := chttp.NewClient(nil)
+client.With(middleware.JSON())
 ```
 
 #### Trace
@@ -210,8 +207,8 @@ Adds short logs on each request.
 **Example:** 
 
 ```go
-chttp.NewClient(nil).
-	With(middleware.Trace(nil))
+client := chttp.NewClient(nil)
+client.With(middleware.Trace(nil))
 ```
 
 # License

client_test.go

@@ -68,7 +68,7 @@ func TestClient_Method(t *testing.T) {
 		{
 			name: "error",
 			middlewares: []Middleware{
-				func(request *http.Request, next RoundTripper) (*http.Response, error) {
+				func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 					return nil, fmt.Errorf("test error")
 				},
 			},
@@ -134,7 +134,7 @@ func TestClient_With(t *testing.T) {
 	var index int
 	for i := 0; i < 10; i++ {
 		c.With((func(i int) Middleware {
-			return func(request *http.Request, next RoundTripper) (*http.Response, error) {
+			return func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 				if index != i {
 					t.Errorf("middleware called on wrong position: expected %d, actual %d", i, index)
 				}

json_test.go

@@ -87,7 +87,7 @@ func TestJSONClient_Method(t *testing.T) {
 		{
 			name: "error",
 			middlewares: []Middleware{
-				func(request *http.Request, next RoundTripper) (*http.Response, error) {
+				func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 					return nil, fmt.Errorf("test error")
 				},
 			},

middleware/README.md

@@ -0,0 +1,67 @@
+# Middlewares
+
+## CustomHeaders
+
+Adds a custom headers based on the request.
+
+**Example:**
+
+```go
+client := chttp.NewClient(nil)
+client.With(middleware.CustomHeaders(func(request *http.Request) map[string]string {
+    if request.Method == http.MethodPost {
+        return map[string]string{
+            "Accept": "*/*",
+        }
+    }
+    return nil
+}))
+```
+
+## Debug
+
+**NB!** Don't use it in production!
+
+Dumps requests and responses in the logs.
+
+**Example:**
+
+```go
+client := chttp.NewClient(nil)
+client.With(middleware.Debug(true, nil))
+```
+
+## Headers
+
+Adds a static headers.
+
+**Example:**
+
+```go
+client := chttp.NewClient(nil)
+client.With(middleware.Headers(map[string]string{
+    "Accept": "*/*",
+}))
+```
+
+## JSON
+
+Adds a `Content-Type` and `Accept` headers with the `application/json` value.
+
+**Example:**
+
+```go
+client := chttp.NewClient(nil)
+client.With(middleware.JSON())
+```
+
+## Trace
+
+Adds short logs on each request.
+
+**Example:**
+
+```go
+client := chttp.NewClient(nil)
+client.With(middleware.Trace(nil))
+```

middleware/custom_header.go

@@ -8,7 +8,7 @@ import (
 
 // CustomHeaders is a chttp.Middleware constructor to add custom header based on the request to request.
 func CustomHeaders(headers func(request *http.Request) map[string]string) chttp.Middleware {
-	return func(request *http.Request, next chttp.RoundTripper) (*http.Response, error) {
+	return func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 		for name, value := range headers(request) {
 			request.Header.Set(name, value)
 		}

middleware/debug.go

@@ -9,7 +9,7 @@ import (
 
 // Debug is a constructor for Debug, that provides default transport
 func Debug(active bool, logger Logger) chttp.Middleware {
-	return func(request *http.Request, next chttp.RoundTripper) (*http.Response, error) {
+	return func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 		if !active {
 			return next(request)
 		}

middleware/header.go

@@ -8,7 +8,7 @@ import (
 
 // Headers is a chttp.Middleware constructor to add static headers to request.
 func Headers(headers map[string]string, force bool) chttp.Middleware {
-	return func(request *http.Request, next chttp.RoundTripper) (*http.Response, error) {
+	return func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 		for name, value := range headers {
 			if force || request.Header.Get(name) == "" {
 				request.Header.Set(name, value)

middleware/trace.go

@@ -9,7 +9,7 @@ import (
 
 // Trace middleware adds short logs on each request.
 func Trace(logger Logger) chttp.Middleware {
-	return func(request *http.Request, next chttp.RoundTripper) (response *http.Response, err error) {
+	return func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (response *http.Response, err error) {
 		defer func(start time.Time) {
 			var path string
 			if request.URL != nil {

transport.go

@@ -16,12 +16,12 @@ func (c *Client) transport(Default http.RoundTripper) http.RoundTripper {
 
 type transport struct {
 	Client  *Client
-	Default RoundTripper
+	Default func(request *http.Request) (*http.Response, error)
 }
 
 func (t *transport) RoundTrip(request *http.Request) (*http.Response, error) {
 	middlewares := t.Client.getMiddlewares()
-	var next RoundTripper
+	var next func(request *http.Request) (*http.Response, error)
 	next = func(request *http.Request) (*http.Response, error) {
 		var middleware Middleware
 		if len(middlewares) == 0 {
@@ -36,7 +36,7 @@ func (t *transport) RoundTrip(request *http.Request) (*http.Response, error) {
 }
 
 func (t *transport) getDefault() Middleware {
-	return func(request *http.Request, _ RoundTripper) (*http.Response, error) {
+	return func(request *http.Request, _ func(request *http.Request) (*http.Response, error)) (*http.Response, error) {
 		return t.Default(request)
 	}
 }

types.go

@@ -4,8 +4,5 @@ import (
 	"net/http"
 )
 
-// RoundTripper is a RoundTrip function implementation of the http.RoundTripper interface.
-type RoundTripper func(request *http.Request) (*http.Response, error)
-
 // Middleware is an extended interface to the RoundTrip function of the http.RoundTripper interface.
-type Middleware func(request *http.Request, next RoundTripper) (*http.Response, error)
+type Middleware func(request *http.Request, next func(request *http.Request) (*http.Response, error)) (*http.Response, error)