Fallback to localhost for hostname correctly and respect base64 encod…

…ed event bodies (redwoodjs#4891)

packages/graphql-server/src/functions/graphql.ts

@@ -66,6 +66,17 @@ export const formatError: FormatErrorHandler = (err: any, message: string) => {
   return err
 }
 
+// Converts base64 string to ArrayBuffer for Request body
+function base64ToArrayBuffer(base64: string): ArrayBuffer {
+  const binary_string = atob(base64)
+  const len = binary_string.length
+  const bytes = new Uint8Array(len)
+  for (let i = 0; i < len; i++) {
+    bytes[i] = binary_string.charCodeAt(i)
+  }
+  return bytes.buffer
+}
+
 /**
  * Creates an Enveloped GraphQL Server, configured with default Redwood plugins
  *
@@ -268,7 +279,7 @@ export const createGraphQLHandler = ({
 
     const requestUrl = new URL(
       event.path,
-      protocol + '://' + event.requestContext?.domainName || 'localhost'
+      protocol + '://' + (event.requestContext?.domainName || 'localhost')
     )
 
     if (event.multiValueQueryStringParameters) {
@@ -290,16 +301,23 @@ export const createGraphQLHandler = ({
       }
     }
 
-    if (event.httpMethod === 'GET' || event.httpMethod === 'HEAD') {
+    if (
+      event.httpMethod === 'GET' ||
+      event.httpMethod === 'HEAD' ||
+      event.body == null
+    ) {
       return new Request(requestUrl.toString(), {
         method: event.httpMethod,
         headers: requestHeaders,
       })
     } else {
+      const body = event.isBase64Encoded
+        ? base64ToArrayBuffer(event.body)
+        : event.body
       return new Request(requestUrl.toString(), {
         method: event.httpMethod,
         headers: requestHeaders,
-        body: event.body,
+        body,
       })
     }
   }