Add Access-Control-Allow-Origin: * to all vyper-serve requests.

bin/vyper-serve

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3.6
+#!/usr/bin/env python3
 
 import argparse
 import sys
@@ -34,12 +34,20 @@ class VyperRequestHandler(BaseHTTPRequestHandler):
         self.end_headers()
         return
 
-    def do_GET(self):
+    def send_cors_all(self):
+        self.send_header("Access-Control-Allow-Origin", "*")
+        self.send_header("Access-Control-Allow-Headers", "X-Requested-With, Content-type")
+
+    def do_OPTIONS(self):
+        self.send_cors_all()
+        self.end_headers()
 
+    def do_GET(self):
         if self.path == '/':
             self.send_response(200)
+            self.send_cors_all()
             self.end_headers()
-            self.wfile.write(b'Vyper Compiler.\n')
+            self.wfile.write('Vyper Compiler. Version: {} \n'.format(vyper.__version__).encode())
         else:
             self.send_404()
 
@@ -56,6 +64,7 @@ class VyperRequestHandler(BaseHTTPRequestHandler):
 
             self.send_response(status_code)
             self.send_header("Content-type", "application/json")
+            self.send_cors_all()
             self.end_headers()
             self.wfile.write(json.dumps(response).encode())
 

vyper/compiler.py

@@ -27,7 +27,7 @@ def gas_estimate(origcode, *args, **kwargs):
 
     # Extract the stuff inside the LLL bracket
     if code.value == 'seq':
-        if code.args[-1].value == 'return':
+        if len(code.args) > 0 and code.args[-1].value == 'return':
             code = code.args[-1].args[1].args[0]
 
     assert code.value == 'seq'