Merge pull request #77 from blockfrost/chore/webhook-impr

chore: add common webhook fields to WebhookEvent

Author: slowbackspace

example/webhook/main.go

@@ -0,0 +1,91 @@
+// This example shows how to implement a webhook endpoint for receiving Blockfrost Webhook requests
+// https://blockfrost.dev/start-building/webhooks/
+// Run using: go run example/webhook/main.go
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+
+	"github.com/blockfrost/blockfrost-go"
+)
+
+const SECRET_AUTH_TOKEN string = "dc8f4b23-6c44-405f-8940-5d451222458e"
+
+func main() {
+	http.HandleFunc("/webhook", func(w http.ResponseWriter, req *http.Request) {
+		const MaxBodyBytes = int64(524288)
+		req.Body = http.MaxBytesReader(w, req.Body, MaxBodyBytes)
+		payload, err := io.ReadAll(req.Body)
+
+		fmt.Printf("Received webhook request.\n")
+
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error reading request body: %v\n", err)
+			w.WriteHeader(http.StatusServiceUnavailable)
+			return
+		}
+
+		event, err := blockfrost.VerifyWebhookSignature(payload, req.Header.Get("Blockfrost-Signature"), SECRET_AUTH_TOKEN)
+
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error verifying webhook signature: %v\n", err)
+			w.WriteHeader(http.StatusBadRequest)
+			return
+		}
+
+		// Unmarshal the event data into an appropriate struct depending on its Type
+		switch event.Type {
+		case "block":
+			var blockEvent blockfrost.WebhookEventBlock
+			err := json.Unmarshal(payload, &blockEvent)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error parsing webhook JSON: %v\n", err)
+				w.WriteHeader(http.StatusBadRequest)
+				return
+			}
+			fmt.Printf("Received block event: %v\n", blockEvent)
+		case "transaction":
+			var transactionEvent blockfrost.WebhookEventTransaction
+			err := json.Unmarshal(payload, &transactionEvent)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error parsing webhook JSON: %v\n", err)
+				w.WriteHeader(http.StatusBadRequest)
+				return
+			}
+			fmt.Printf("Received tx event: %v\n", transactionEvent)
+		case "epoch":
+			var epochEvent blockfrost.WebhookEventEpoch
+			err := json.Unmarshal(payload, &epochEvent)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error parsing webhook JSON: %v\n", err)
+				w.WriteHeader(http.StatusBadRequest)
+				return
+			}
+			fmt.Printf("Received epoch event: %v\n", epochEvent)
+		case "delegation":
+			var delegationEvent blockfrost.WebhookEventDelegation
+			err := json.Unmarshal(payload, &delegationEvent)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Error parsing webhook JSON: %v\n", err)
+				w.WriteHeader(http.StatusBadRequest)
+				return
+			}
+			fmt.Printf("Received delegation event: %v\n", delegationEvent)
+		default:
+			fmt.Fprintf(os.Stderr, "Unhandled webhook type: %s\n", event.Type)
+		}
+
+		w.WriteHeader(http.StatusOK)
+	})
+
+	fmt.Println("Server is starting on port 8080...")
+
+	err := http.ListenAndServe(":8080", nil)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Server failed to start: %v\n", err)
+	}
+}

webhook.go

@@ -49,33 +49,32 @@ type WebhookEventCommon struct {
 	WebhookID  string `json:"webhook_id"`
 	Created    int    `json:"created"`
 	APIVersion int    `json:"api_version,omitempty"` // omitempty because test fixtures do not include it
+	Type       string `json:"type"`                  // block, transaction, delegation, epoch
 }
 
 type WebhookEventBlock struct {
 	WebhookEventCommon
-	Type    string `json:"type"` // "block"
-	Payload Block  `json:"payload"`
+	Payload Block `json:"payload"`
 }
 
 type WebhookEventTransaction struct {
 	WebhookEventCommon
-	Type    string               `json:"type"` // "transaction"
 	Payload []TransactionPayload `json:"payload"`
 }
 
 type WebhookEventEpoch struct {
 	WebhookEventCommon
-	Type    string       `json:"type"` // "epoch"
 	Payload EpochPayload `json:"payload"`
 }
 
 type WebhookEventDelegation struct {
 	WebhookEventCommon
-	Type    string                   `json:"type"` // "delegation"
 	Payload []StakeDelegationPayload `json:"payload"`
 }
 
-type WebhookEvent interface{}
+type WebhookEvent struct {
+	WebhookEventCommon
+}
 
 const (
 	// Signatures older than this will be rejected by ConstructEvent
@@ -152,67 +151,47 @@ func parseSignatureHeader(header string) (*signedHeader, error) {
 	return sh, nil
 }
 
-func VerifyWebhookSignature(payload []byte, header string, secret string) (WebhookEvent, error) {
+func VerifyWebhookSignature(payload []byte, header string, secret string) (*WebhookEvent, error) {
 	return VerifyWebhookSignatureWithTolerance(payload, header, secret, DefaultTolerance)
 }
 
-func VerifyWebhookSignatureWithTolerance(payload []byte, header string, secret string, tolerance time.Duration) (WebhookEvent, error) {
+func VerifyWebhookSignatureWithTolerance(payload []byte, header string, secret string, tolerance time.Duration) (*WebhookEvent, error) {
 	return verifyWebhookSignature(payload, header, secret, tolerance, true)
 }
 
-func VerifyWebhookSignatureIgnoringTolerance(payload []byte, header string, secret string) (WebhookEvent, error) {
+func VerifyWebhookSignatureIgnoringTolerance(payload []byte, header string, secret string) (*WebhookEvent, error) {
 	return verifyWebhookSignature(payload, header, secret, 0*time.Second, false)
 }
 
-func verifyWebhookSignature(payload []byte, sigHeader string, secret string, tolerance time.Duration, enforceTolerance bool) (WebhookEvent, error) {
+func verifyWebhookSignature(payload []byte, sigHeader string, secret string, tolerance time.Duration, enforceTolerance bool) (*WebhookEvent, error) {
 	// First unmarshal into a generic map to inspect the type
 	var genericEvent map[string]interface{}
 	if err := json.Unmarshal(payload, &genericEvent); err != nil {
-		return nil, fmt.Errorf("failed to parse webhook body json: %s", err)
-	}
-
-	// Determine the specific event type
-	eventType, ok := genericEvent["type"].(string)
-	if !ok {
-		return nil, errors.New("event type not found")
+		return nil, fmt.Errorf("Failed to parse webhook body json: %s", err)
 	}
 
 	var event WebhookEvent
 
-	// Unmarshal into the specific event type based on the eventType
-	switch eventType {
-	case string(WebhookEventTypeBlock):
-		event = new(WebhookEventBlock)
-	case string(WebhookEventTypeTransaction):
-		event = new(WebhookEventTransaction)
-	case string(WebhookEventTypeEpoch):
-		event = new(WebhookEventEpoch)
-	case string(WebhookEventTypeDelegation):
-		event = new(WebhookEventDelegation)
-	default:
-		return nil, fmt.Errorf("unknown event type: %s", eventType)
-	}
-
 	if err := json.Unmarshal(payload, &event); err != nil {
-		return nil, fmt.Errorf("failed to parse specific webhook event json: %s", err)
+		return nil, fmt.Errorf("Failed to parse specific webhook event json: %s", err)
 	}
 
 	header, err := parseSignatureHeader(sigHeader)
 	if err != nil {
-		return event, err
+		return &event, err
 	}
 
 	expectedSignature := computeSignature(header.timestamp, payload, secret)
 	expiredTimestamp := time.Since(header.timestamp) > tolerance
 	if enforceTolerance && expiredTimestamp {
-		return event, ErrTooOld
+		return &event, ErrTooOld
 	}
 
 	for _, sig := range header.signatures {
 		if hmac.Equal(expectedSignature, sig) {
-			return event, nil
+			return &event, nil
 		}
 	}
 
-	return event, ErrNoValidSignature
+	return &event, ErrNoValidSignature
 }

webhook_test.go

@@ -15,13 +15,21 @@ func TestVerifyWebhookSignature(t *testing.T) {
 		"t=1650013856,v1=abc,t=1650013856,v1=f4c3bb2a8b0c8e21fa7d5fdada2ee87c9c6f6b0b159cc22e483146917e195c3e",
 		"59a1eb46-96f4-4f0b-8a03-b4d26e70593a")
 
-	_, ok := event.(*blockfrost.WebhookEventBlock)
-	if !ok {
-		jsonData, _ := json.Marshal(event)
-		t.Fatalf("Invalid webhook type %s", jsonData)
+	// Unmarshal the event data into an appropriate struct depending on its Type
+	var blockEvent blockfrost.WebhookEventBlock
+	switch event.Type {
+	case "block":
+		err := json.Unmarshal([]byte(validPayload), &blockEvent)
+
+		if err != nil {
+			t.Fatalf("Error parsing webhook JSON: %v\n", err)
+			return
+		}
+	default:
+		t.Fatalf("Invalid webhook type: %s\n", event.Type)
 	}
 
-	jsonData, err := json.Marshal(event)
+	jsonData, err := json.Marshal(blockEvent)
 	if err != nil {
 		t.Fatalf("Error marshaling to JSON: %s", err)
 	}