Allow getDefaultProvider to accept a URL as a network.

packages/providers/src.ts/index.ts

@@ -42,6 +42,25 @@ const logger = new Logger(version);
 
 function getDefaultProvider(network?: Network | string, options?: any): BaseProvider {
     if (network == null) { network = "homestead"; }
+
+    // If passed a URL, figure out the right type of provider based on the scheme
+    if (typeof(network) === "string") {
+        // @TODO: Add support for IpcProvider; maybe if it ends in ".ipc"?
+
+        // Handle http and ws (and their secure variants)
+        const match = network.match(/^(ws|http)s?:/i);
+        if (match) {
+            switch (match[1]) {
+                case "http":
+                    return new JsonRpcProvider(network);
+                case "ws":
+                    return new WebSocketProvider(network);
+                default:
+                    logger.throwArgumentError("unsupported URL scheme", "network", network);
+            }
+        }
+    }
+
     const n = getNetwork(network);
     if (!n || !n._defaultProvider) {
         logger.throwError("unsupported getDefaultProvider network", Logger.errors.NETWORK_ERROR, {