Simplify decorator for auth validation

This MR simplifies the decorator used to apply auth validation to URLs, mainly to remove one level of nesting that isn't really needed.

gwdatafind_server/authentication.py

@@ -42,44 +42,42 @@ def _validate_x509(request):
 
 
 def validate():
-    def decorator(f):
-        @wraps(f)
-        def validator(*args, **kwargs):
-            try:
-                # Check for SciToken in header
-                if 'Authorization' in request.headers:
-                    current_app.logger.info('View request with SciToken.')
-                    try:
-                        _validate_scitoken(request, audience=AUD, scope=SCP)
-                    except NotImplementedError as exc:
-                        msg = "SciToken authentication failed: {!r}"\
-                              .format(exc)
-                        current_app.logger.info('View request error:'
-                                                '{}'.format(msg))
-                        content = {"Error, {}.".format(msg): ""}
-                        return content, 403
-                # Else, check for X.509 certificate info in header
-                elif 'SSL_CLIENT_S_DN' and 'SSL_CLIENT_I_DN' \
-                     in request.headers:
-                    current_app.logger.info("View request with X.509 proxy "
-                                            "certificate.")
-                    try:
-                        _validate_x509(request)
-                    except RuntimeError as exc:
-                        msg = "X.509 authentication failed: {!r}".format(exc)
-                        current_app.logger.info('View request error:'
-                                                '{}'.format(msg))
-                        content = {"Error, {}.".format(msg): ""}
-                        return content, 403
-                else:
-                    raise RuntimeError("No Authentication Header or X.509 "
-                                       "cert info in header")
-                return f(*args, **kwargs)
-            except RuntimeError as exc:
-                msg = "Authentication failed: {!r}".format(exc)
-                current_app.logger.info('View request error:'
-                                        '{}'.format(msg))
-                content = {"Error, {}.".format(msg): ""}
-                return content, 403
-        return validator
-    return decorator
+    @wraps(f)
+    def validator(*args, **kwargs):
+        try:
+            # Check for SciToken in header
+            if 'Authorization' in request.headers:
+                current_app.logger.info('View request with SciToken.')
+                try:
+                    _validate_scitoken(request, audience=AUD, scope=SCP)
+                except NotImplementedError as exc:
+                    msg = "SciToken authentication failed: {!r}"\
+                          .format(exc)
+                    current_app.logger.info('View request error:'
+                                            '{}'.format(msg))
+                    content = {"Error, {}.".format(msg): ""}
+                    return content, 403
+            # Else, check for X.509 certificate info in header
+            elif 'SSL_CLIENT_S_DN' and 'SSL_CLIENT_I_DN' \
+                 in request.headers:
+                current_app.logger.info("View request with X.509 proxy "
+                                        "certificate.")
+                try:
+                    _validate_x509(request)
+                except RuntimeError as exc:
+                    msg = "X.509 authentication failed: {!r}".format(exc)
+                    current_app.logger.info('View request error:'
+                                            '{}'.format(msg))
+                    content = {"Error, {}.".format(msg): ""}
+                    return content, 403
+            else:
+                raise RuntimeError("No Authentication Header or X.509 "
+                                   "cert info in header")
+            return f(*args, **kwargs)
+        except RuntimeError as exc:
+            msg = "Authentication failed: {!r}".format(exc)
+            current_app.logger.info('View request error:'
+                                    '{}'.format(msg))
+            content = {"Error, {}.".format(msg): ""}
+            return content, 403
+    return validator