From ab6f2a6e71ae8fab8c4483844a028d266f6fc007 Mon Sep 17 00:00:00 2001
From: Piyush <piyush@codeitout.com>
Date: Thu, 21 May 2020 16:45:44 +0530
Subject: [PATCH] Start adding wsgi support

Co-authored-by: Dan Root <rootdan@gmail.com>
---
 twirp/asgi.py |  7 ++--
 twirp/wsgi.py | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+), 3 deletions(-)
 create mode 100644 twirp/wsgi.py

diff --git a/twirp/asgi.py b/twirp/asgi.py
index a4f15cb..7a213bc 100644
--- a/twirp/asgi.py
+++ b/twirp/asgi.py
@@ -9,9 +9,11 @@
     import json
 
 from . import base
-from . import exceptions
-from . import errors
 from . import ctxkeys
+from . import errors
+from . import exceptions
+
+
 
 try:
     import contextvars  # Python 3.7+ only.
@@ -57,7 +59,6 @@ async def __call__(self, scope, receive, send):
             self._hook.request_received(ctx=ctx)
 
             endpoint = self._get_endpoint(scope['path'])
-            headers = {k.decode('utf-8'): v.decode('utf-8') for (k,v) in scope['headers']}
             encoder, decoder = self._get_encoder_decoder(endpoint, headers)
             # add headers from request into context
             
diff --git a/twirp/wsgi.py b/twirp/wsgi.py
new file mode 100644
index 0000000..9cd89d7
--- /dev/null
+++ b/twirp/wsgi.py
@@ -0,0 +1,95 @@
+from google.protobuf import json_format
+from werkzeug.wrappers import Request, Response
+
+from . import base
+from . import ctxkeys
+from . import exceptions
+from . import errors
+
+
+class TwirpWSGIApp(base.TwirpBaseApp):
+
+    def __call__(self, environ, start_response):
+        ctx = self._ctx_class()
+        try:
+            return self.handle_request(ctx, environ, start_response)
+        except Exception as e:
+
+            return self.handle_error(ctx, e, environ, start_response)
+
+    def handle_request(self, ctx, environ, start_response):
+        request = Request(environ)
+        ctx["request"] = request
+        self._hook.request_received(ctx=ctx)
+
+        http_method = request.method
+        if http_method != "POST":
+            raise exceptions.TwirpServerException(
+            code=errors.Errors.BadRoute,
+            message="unsupported method " + http_method + " (only POST is allowed)",
+            meta={"twirp_invalid_route": http_method + " " + scope['path']},
+        )
+        ctx["http_method"] = "POST"
+        ctx["url"] = request.path
+        ctx["content-type"] = request.headers["Content-Type"]
+
+        endpoint, func, decode, encode = self.get_endpoint_methods(request)
+        ctx["endpoint"] = endpoint
+        request_routed.send(ctx)
+
+        input_arg = decode(request)
+        ctx["input"] = input_arg
+        result = func(input_arg, ctx=ctx)
+        ctx["output"] = result
+        response = encode(result)
+        ctx["response"] = response
+        response_prepared.send(ctx)
+
+        ctx["status_code"] = 200
+        response_sent.send(ctx)
+
+        return response(environ, start_response)
+
+    def handle_error(self, ctx, exc, environ, start_response):
+        base_err = {
+            "type": "Internal",
+            "msg": ("There was an error but it could not be "
+                    "serialized into JSON"),
+            "meta": {}
+        }
+        response = Response()
+        response.status_code = 500
+
+        try:
+            err = base_err
+            if isinstance(exc, TwirpServerException):
+                err["code"] = exc.code.value
+                err["msg"] = exc.message
+                if exc.meta:
+                    for k, v in exc.meta.items():
+                        err["meta"][k] = str(v)
+                response.status_code = Errors.get_status_code(exc.code)
+            else:
+                err["msg"] = "Internal non-Twirp Error"
+                err["code"] = 500
+                err["meta"] = {"raw_error": str(exc)}
+
+            for k, v in ctx.items():
+                err["meta"][k] = str(v)
+
+            response.set_data(json.dumps(err))
+        except Exception as e:
+            err = base_err
+            err["meta"] = {"original_error": str(exc),
+                           "handling_error": str(e)}
+            response.set_data(json.dumps(err))
+
+        # Force json for errors.
+        response.headers["Content-Type"] = "application/json"
+
+        ctx["status_code"] = response.status_code
+        ctx["response"] = response
+        ctx["exception"] = exc
+        error_occurred.send(ctx)
+
+        return response(environ, start_response)