Add core/crypto package for WebhooksHelper.ts

Author: fern-api[bot]

src/core/crypto/createHmacOverride.ts

@@ -0,0 +1,54 @@
+export async function createHmacOverride(payload: string, key: string): Promise<string> {
+    try {
+        const crypto = require('crypto');
+        const hmac = crypto.createHmac('sha256', key);
+        hmac.update(payload, 'utf8');
+        return hmac.digest('base64');
+    }
+    catch (err) {
+        // Not in Node environmnet; use subtle crypto.
+    }
+    const subtleCrypto = getSubtleCrypto();
+    if (!subtleCrypto) {
+        throw new Error('No crypto implementation available');
+    }
+    const encoder = new TextEncoder();
+    const cryptoKey = await subtleCrypto.importKey(
+        'raw',
+        encoder.encode(key),
+        {
+            name: 'HMAC',
+            hash: { name: 'SHA-256' }
+        },
+        false,
+        ['sign']
+    );
+    const signatureBuffer = await subtleCrypto.sign(
+        'HMAC',
+        cryptoKey,
+        encoder.encode(payload)
+    );
+    return arrayBufferToBase64(signatureBuffer);
+}
+
+function getSubtleCrypto(): SubtleCrypto | undefined {
+    if (typeof window !== 'undefined' && window?.crypto?.subtle) {
+        return window.crypto.subtle;
+    }
+    return undefined;
+}
+
+function arrayBufferToBase64(buffer: ArrayBuffer): string {
+    if (typeof btoa === 'function') {
+        // Browser environment
+        const bytes = new Uint8Array(buffer);
+        let binary = '';
+        for (let i = 0; i < bytes.byteLength; i++) {
+            binary += String.fromCharCode(bytes[i]);
+        }
+        return btoa(binary);
+    } else {
+        // Node environment
+        return Buffer.from(buffer).toString('base64');
+    }
+}

src/core/crypto/index.ts

@@ -0,0 +1 @@
+export { createHmacOverride } from "./createHmacOverride";