Support for custom CORS file

index.js

@@ -242,7 +242,11 @@ class Client {
                 return Promise.resolve();
               }
               this.serverless.cli.log(`Configuring CORS for bucket...`);
-              return configure.configureCorsForBucket(this.aws, bucketName);
+              const bucketCorsFile = this.serverless.service.custom.client.bucketCorsFile;
+              const customCors =
+                bucketCorsFile && JSON.parse(fs.readFileSync(bucketCorsFile));
+
+              return configure.configureCorsForBucket(this.aws, bucketName, customCors);
             })
             .then(() => {
               this.serverless.cli.log(`Uploading client files to bucket...`);

lib/configure.js

@@ -118,10 +118,12 @@ function configurePolicyForBucket(aws, bucketName, customPolicy) {
  * @param {Object} aws - AWS class
  * @param {string} bucketName - Name of bucket to be configured
  */
-function configureCorsForBucket(aws, bucketName) {
+function configureCorsForBucket(aws, bucketName, customCors) {
+  const cors = customCors || require('./resources/CORSPolicy')
+
   const params = {
     Bucket: bucketName,
-    CORSConfiguration: require('./resources/CORSPolicy')
+    CORSConfiguration: cors
   };
 
   return aws.request('S3', 'putBucketCors', params);

lib/validate.js

@@ -58,6 +58,17 @@ function validateClient(serverless, options) {
       );
     }
   }
+
+  // check that custom bucket CORS is valid json
+  if (options.bucketCorsFile) {
+    try {
+      JSON.parse(fs.readFileSync(options.bucketCorsFile));
+    } catch (e) {
+      validationErrors.push(
+        `Failed to read and/or parse specified CORS policy. Make sure it is valid JSON.`
+      );
+    }
+  }
 
   // check website configuration options