Allow to forward ctx in webhook handlers (#45)

Author: litwinow

changelog.md

@@ -1,5 +1,9 @@
 # Changelog
 
+### [v2.2.0]
+
+* Fixed date filters in `ListArchives`.
+* Added `HandlerContext` and `WithActionContext` methods that pass http request's context to webhook handlers.
 
 ### [v2.1.0]
 

webhooks/handler.go

@@ -1,6 +1,7 @@
 package webhooks
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -21,7 +22,7 @@ type Configuration struct {
 
 type actionConfiguration struct {
 	secretKey string
-	handle    Handler
+	handle    HandlerContext
 }
 
 // The Handler type is used to define webhook processors.
@@ -30,6 +31,12 @@ type actionConfiguration struct {
 // pass a webhook body with a payload field decoded (ie. one of webhooks structures).
 type Handler func(*Webhook) error
 
+// The HandlerContext type is used to define webhook processors.
+//
+// It can be used with WebhookHandler, in which case WebhookHandler will
+// pass a webhook body with a payload field decoded (ie. one of webhooks structures).
+type HandlerContext func(context.Context, *Webhook) error
+
 // NewConfiguration creates basic WebhookHandler configuration that
 // processes no webhooks and uses http.Error to handle webhook processing
 // errors.
@@ -46,6 +53,19 @@ func NewConfiguration() *Configuration {
 // Otherwise, webhook's secret is strictly validated. In case of any mismatch between expected and actual secret key,
 // webhook processing is stopped and error is returned.
 func (cfg *Configuration) WithAction(action string, handler Handler, secretKey string) *Configuration {
+	cfg.actions[action] = &actionConfiguration{
+		handle:    func(ctx context.Context, wh *Webhook) error { return handler(wh) },
+		secretKey: secretKey,
+	}
+	return cfg
+}
+
+// WithActionContext allows to attach custom webhook HandlerContext for given webhook action.
+//
+// If secretKey is an empty string, then no validation of webhook's secret is performed.
+// Otherwise, webhook's secret is strictly validated. In case of any mismatch between expected and actual secret key,
+// webhook processing is stopped and error is returned.
+func (cfg *Configuration) WithActionContext(action string, handler HandlerContext, secretKey string) *Configuration {
 	cfg.actions[action] = &actionConfiguration{
 		handle:    handler,
 		secretKey: secretKey,
@@ -145,7 +165,7 @@ func NewWebhookHandler(cfg *Configuration) http.HandlerFunc {
 		}
 		wh.Payload = payload
 
-		if err = acfg.handle(&wh); err != nil {
+		if err = acfg.handle(r.Context(), &wh); err != nil {
 			cfg.handleError(w, fmt.Sprintf("webhook handler error: %v", err), http.StatusInternalServerError)
 			return
 		}

webhooks/handler_test.go

@@ -2,6 +2,7 @@ package webhooks_test
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -151,3 +152,35 @@ func TestPayloadParsingOK(t *testing.T) {
 		}
 	}
 }
+
+func TestHandlerContextForwardsRequestContext(t *testing.T) {
+	verifier := func(ctx context.Context, wh *webhooks.Webhook) error {
+		rawVal := ctx.Value("dummy-key")
+		val, ok := rawVal.(string)
+		if !ok {
+			t.Errorf("invalid type of 'dummy-key' in wh ctx: %T", rawVal)
+			return nil
+		}
+		if val != "dummy-value" {
+			t.Errorf("invalid value of 'dummy-key' in wh ctx: %v", val)
+			return nil
+		}
+		return nil
+	}
+	action := "incoming_chat"
+	cfg := webhooks.NewConfiguration().WithActionContext(action, verifier, "")
+	h := webhooks.NewWebhookHandler(cfg)
+	payload, err := ioutil.ReadFile("./testdata/" + action + ".json")
+	if err != nil {
+		t.Errorf("Missing test payload for action %v", action)
+		return
+	}
+	req := httptest.NewRequest("POST", "https://example.com", bytes.NewBuffer(payload))
+	req = req.WithContext(context.WithValue(context.Background(), "dummy-key", "dummy-value"))
+	resp := httptest.NewRecorder()
+	h(resp, req)
+	if resp.Code != http.StatusOK {
+		t.Errorf("invalid code: %v", resp.Code)
+		return
+	}
+}