ezhttp: CURL equivalent command helper

net/http/ezhttp/ezhttp.go

@@ -1,10 +1,10 @@
 // This package aims to wrap Go HTTP Client's request-response with sane defaults:
 //
-// - You are forced to consider timeouts by having to specify Context
-// - Instead of not considering non-2xx status codes as a failure, check that by default
-//   (unless explicitly asked to)
-// - Sending and receiving JSON requires much less boilerplate, and on receiving JSON you
-//   are forced to think whether to "allowUnknownFields"
+//   - You are forced to consider timeouts by having to specify Context
+//   - Instead of not considering non-2xx status codes as a failure, check that by default
+//     (unless explicitly asked to)
+//   - Sending and receiving JSON requires much less boilerplate, and on receiving JSON you
+//     are forced to think whether to "allowUnknownFields"
 package ezhttp
 
 import (
@@ -59,29 +59,46 @@ func (e ResponseStatusError) StatusCode() int {
 	return e.statusCode
 }
 
+// returns *ResponseStatusError as error if non-2xx response (unless TolerateNon2xxResponse()).
+// error is not *ResponseStatusError for transport-level errors, content (JSON) marshaling errors etc
 func Get(ctx context.Context, url string, confPieces ...ConfigPiece) (*http.Response, error) {
 	return do(ctx, http.MethodGet, url, confPieces...)
 }
 
+// returns *ResponseStatusError as error if non-2xx response (unless TolerateNon2xxResponse()).
+// error is not *ResponseStatusError for transport-level errors, content (JSON) marshaling errors etc
 func Post(ctx context.Context, url string, confPieces ...ConfigPiece) (*http.Response, error) {
 	return do(ctx, http.MethodPost, url, confPieces...)
 }
 
+// returns *ResponseStatusError as error if non-2xx response (unless TolerateNon2xxResponse()).
+// error is not *ResponseStatusError for transport-level errors, content (JSON) marshaling errors etc
 func Put(ctx context.Context, url string, confPieces ...ConfigPiece) (*http.Response, error) {
 	return do(ctx, http.MethodPut, url, confPieces...)
 }
 
+// returns *ResponseStatusError as error if non-2xx response (unless TolerateNon2xxResponse()).
+// error is not *ResponseStatusError for transport-level errors, content (JSON) marshaling errors etc
 func Head(ctx context.Context, url string, confPieces ...ConfigPiece) (*http.Response, error) {
 	return do(ctx, http.MethodHead, url, confPieces...)
 }
 
+// returns *ResponseStatusError as error if non-2xx response (unless TolerateNon2xxResponse()).
+// error is not *ResponseStatusError for transport-level errors, content (JSON) marshaling errors etc
 func Del(ctx context.Context, url string, confPieces ...ConfigPiece) (*http.Response, error) {
 	return do(ctx, http.MethodDelete, url, confPieces...)
 }
 
-// returns *ResponseStatusError as error if non-2xx response (unless TolerateNon2xxResponse()).
-// error is not *ResponseStatusError for transport-level errors, content (JSON) marshaling errors etc
 func do(ctx context.Context, method string, url string, confPieces ...ConfigPiece) (*http.Response, error) {
+	conf, err := configure(ctx, method, url, confPieces...)
+	if err != nil {
+		return nil, err
+	}
+
+	return doRequest(conf)
+}
+
+func configure(ctx context.Context, method string, url string, confPieces ...ConfigPiece) (*Config, error) {
 	conf := &Config{
 		Client: http.DefaultClient,
 	}
@@ -129,13 +146,17 @@ func do(ctx context.Context, method string, url string, confPieces ...ConfigPiec
 		return nil, conf.Abort
 	}
 
-	resp, err := conf.Client.Do(req)
+	return conf, nil
+}
+
+func doRequest(conf *Config) (*http.Response, error) {
+	resp, err := conf.Client.Do(conf.Request)
 	if err != nil {
 		return resp, err // this is a transport-level error
 	}
 
 	// 304 is an error unless caller is expecting such response by sending caching headers
-	if resp.StatusCode == http.StatusNotModified && req.Header.Get("If-None-Match") != "" {
+	if resp.StatusCode == http.StatusNotModified && conf.Request.Header.Get("If-None-Match") != "" {
 		return resp, nil
 	}
 

net/http/ezhttp/helpers.go

@@ -1,7 +1,9 @@
 package ezhttp
 
 import (
+	"context"
 	"crypto/tls"
+	"fmt"
 	"net/http"
 )
 
@@ -26,3 +28,22 @@ func ErrorIs(err error, statusCode int) bool {
 		return false
 	}
 }
+
+// for `method` please use `net/http` "enum" (quotes because it's not declared as such)
+func CURLEquivalent(method string, url string, confPieces ...ConfigPiece) ([]string, error) {
+	conf, err := configure(context.Background(), http.MethodGet, url, confPieces...)
+	if err != nil {
+		return nil, err
+	}
+
+	cmd := []string{"curl", "--request=" + method}
+
+	for key, values := range conf.Request.Header {
+		// FIXME: doesn't take into account multiple values
+		cmd = append(cmd, fmt.Sprintf("--header=%s=%s", key, values[0]))
+	}
+
+	cmd = append(cmd, url)
+
+	return cmd, nil
+}

net/http/ezhttp/helpers_test.go

@@ -0,0 +1,16 @@
+package ezhttp
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+
+	. "github.com/function61/gokit/builtin"
+	"github.com/function61/gokit/testing/assert"
+)
+
+func TestCURLEquivalent(t *testing.T) {
+	curlCmd := Must(CURLEquivalent(http.MethodPost, "https://example.net/hello", Header("x-correlation-id", "123")))
+
+	assert.Equal(t, strings.Join(curlCmd, " "), "curl --request=POST --header=X-Correlation-Id=123 https://example.net/hello")
+}