Improves loading of Push Adapter, fix loading of S3Adapter

- Adds environment variables to configure S3Adapter

src/Adapters/AdapterLoader.js

@@ -28,13 +28,6 @@ export function loadAdapter(adapter, defaultAdapter, options) {
     return loadAdapter(adapter.class, undefined, adapter.options);
   } else if (adapter.adapter) {
     return loadAdapter(adapter.adapter, undefined, adapter.options);
-  } else {
-    // Try to load the defaultAdapter with the options
-    // The default adapter should throw if the options are
-    // incompatible
-    try {
-      return loadAdapter(defaultAdapter, undefined, adapter);
-    } catch (e) {};
   }
   // return the adapter as is as it's unusable otherwise
   return adapter;     

src/Adapters/Files/S3Adapter.js

@@ -8,32 +8,33 @@ import requiredParameter from '../../requiredParameter';
 
 const DEFAULT_S3_REGION = "us-east-1";
 
-function parseS3AdapterOptions(...options) {
-  if (options.length === 1 && typeof options[0] == "object") {
-    return options;
+function requiredOrFromEnvironment(env, name) {
+  let environmentVariable = process.env[env];
+  if (!environmentVariable) {
+    requiredParameter(`S3Adapter requires an ${name}`);
   }
-
-  const additionalOptions = options[3] || {};
-
-  return {
-    accessKey: options[0],
-    secretKey: options[1],
-    bucket: options[2],
-    region: additionalOptions.region
+  return environmentVariable;
+}
+
+function fromEnvironmentOrDefault(env, defaultValue) {
+  let environmentVariable = process.env[env];
+  if (environmentVariable) {
+    return environmentVariable;
   }
+  return defaultValue;
 }
 
 export class S3Adapter extends FilesAdapter {
   // Creates an S3 session.
   // Providing AWS access and secret keys is mandatory
   // Region and bucket will use sane defaults if omitted
   constructor(
-     accessKey = requiredParameter('S3Adapter requires an accessKey'),
-     secretKey = requiredParameter('S3Adapter requires a secretKey'),
-     bucket,
-     { region = DEFAULT_S3_REGION,
-       bucketPrefix = '',
-       directAccess = false } = {}) {
+     accessKey = requiredOrFromEnvironment('S3_ACCESS_KEY', 'accessKey'),
+     secretKey = requiredOrFromEnvironment('S3_SECRET_KEY', 'secretKey'),
+     bucket = fromEnvironmentOrDefault('S3_BUCKET', undefined),
+     { region = fromEnvironmentOrDefault('S3_REGION', DEFAULT_S3_REGION),
+       bucketPrefix = fromEnvironmentOrDefault('S3_BUCKET_PREFIX', ''),
+       directAccess =  fromEnvironmentOrDefault('S3_DIRECT_ACCESS', false) } = {}) {
     super();
 
     this._region = region;

src/index.js

@@ -133,7 +133,8 @@ function ParseServer({
   const filesControllerAdapter = loadAdapter(filesAdapter, () => {
     return new GridStoreAdapter(databaseURI);
   });
-  const pushControllerAdapter = loadAdapter(push, ParsePushAdapter);
+  // Pass the push options too as it works with the default
+  const pushControllerAdapter = loadAdapter(push && push.adapter, ParsePushAdapter, push);
   const loggerControllerAdapter = loadAdapter(loggerAdapter, FileLoggerAdapter);
   const emailControllerAdapter = loadAdapter(emailAdapter);
   // We pass the options and the base class for the adatper,