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Fix webhook verification without Buffer #1950

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Fix webhook verification without Buffer #1950

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8 changes: 4 additions & 4 deletions src/resources/webhooks/webhooks.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@
import { InvalidWebhookSignatureError } from '../../error';
import { APIResource } from '../../core/resource';
import { buildHeaders, HeadersLike } from '../../internal/headers';
import { fromBase64 } from '../../internal/utils/base64';
import { encodeUTF8 } from '../../internal/utils/bytes';

export class Webhooks extends APIResource {
/**
Expand Down Expand Up @@ -75,9 +77,7 @@ export class Webhooks extends APIResource {

// Decode the secret if it starts with whsec_
const decodedSecret =
secret.startsWith('whsec_') ?
Buffer.from(secret.replace('whsec_', ''), 'base64')
: Buffer.from(secret, 'utf-8');
secret.startsWith('whsec_') ? fromBase64(secret.replace('whsec_', '')) : encodeUTF8(secret);

// Create the signed payload: {webhook_id}.{timestamp}.{payload}
const signedPayload = webhookId ? `${webhookId}.${timestamp}.${payload}` : `${timestamp}.${payload}`;
Expand All @@ -94,7 +94,7 @@ export class Webhooks extends APIResource {
// Check if any signature matches using timing-safe WebCrypto verify
for (const signature of signatures) {
try {
const signatureBytes = Buffer.from(signature, 'base64');
const signatureBytes = fromBase64(signature);
const isValid = await crypto.subtle.verify(
'HMAC',
key,
Expand Down
11 changes: 11 additions & 0 deletions tests/api-resources/webhooks.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,17 @@ describe('resource webhooks', () => {
await client.webhooks.verifySignature(payload, headers, secret);
});

it('should pass for valid signature without Buffer if WebCrypto is available', async () => {
const originalBuffer = globalThis.Buffer;
try {
// @ts-expect-error Can't assign undefined to BufferConstructor
delete globalThis.Buffer;
await client.webhooks.verifySignature(payload, headers, secret);
} finally {
globalThis.Buffer = originalBuffer;
}
});

it('should throw an error for invalid secret format', async () => {
await expect(
client.webhooks.verifySignature(payload, headers, null as any),
Expand Down