Support sending response as binary data

Author: zootalures

README.md

@@ -77,6 +77,32 @@ def handler(ctx, data: io.BytesIO=None):
 
 ```
 
+## Writing binary data from functions 
+In order to write a binary response to your function pass a `bytes` object to the response_data
+
+```python
+import io 
+from PIL import Image, ImageDraw 
+from fdk import response 
+ 
+ 
+def handler(ctx, data: io.BytesIO=None): 
+    img = Image.new('RGB', (100, 30), color='red') 
+    d = ImageDraw.Draw(img) 
+    d.text((10, 10), "hello world", fill=(255, 255, 0)) 
+    # write png image to memory  
+    output =  io.BytesIO() 
+    img.save(output, format="PNG") 
+    # get the bytes of the image  
+    imgbytes = output.getvalue() 
+ 
+    return response.Response( 
+        ctx, response_data=imgbytes, 
+        headers={"Content-Type": "image/png"} 
+    )
+```
+
+
 
 ## Unit testing your functions
 

fdk/async_http/app.py

@@ -80,7 +80,7 @@ async def handle_request(self, request, write_callback, stream_callback):
             headers = res.headers
             status = res.status
             response = HTTPResponse(
-                body=body, status=status, headers=headers,
+                body_bytes=body, status=status, headers=headers,
             )
         except CancelledError:
             response = None

fdk/event_handler.py

@@ -53,7 +53,7 @@ async def pure_handler(request):
             headers=headers,
             status=status,
             content_type=headers.get(constants.CONTENT_TYPE),
-            body_bytes=func_response.body(),
+            body_bytes=func_response.body_bytes(),
         )
 
     return pure_handler

fdk/response.py

@@ -14,14 +14,16 @@
 
 from fdk import context
 from fdk import constants
+from typing import Union
 
 
 class Response(object):
 
     def __init__(self, ctx: context.InvokeContext,
-                 response_data: str=None,
+                 response_data: Union[str, bytes]=None,
                  headers: dict=None,
-                 status_code: int=200):
+                 status_code: int=200,
+                 response_encoding: str="utf-8"):
         """
         Creates an FDK-readable response object
         :param ctx: invoke context
@@ -32,10 +34,14 @@ def __init__(self, ctx: context.InvokeContext,
         :type headers: dict
         :param status_code: response code
         :type status_code: int
+        :param response_encoding: response encoding for strings ("utf-8")
+        :type response_encoding: str
         """
         self.ctx = ctx
         self.status_code = status_code
         self.response_data = response_data if response_data else ""
+        self.response_encoding = response_encoding
+
         if headers is None:
             headers = {}
         headers.update({constants.FN_FDK_VERSION:
@@ -49,5 +55,12 @@ def status(self):
     def body(self):
         return self.response_data
 
+    def body_bytes(self):
+        if isinstance(self.response_data, bytes) or \
+                isinstance(self.response_data, bytearray):
+            return self.response_data
+        else:
+            return str(self.response_data).encode(self.response_encoding)
+
     def context(self):
         return self.ctx

fdk/tests/funcs.py

@@ -141,3 +141,7 @@ def capture_request_ctx(ctx, **kwargs):
     global captured_context
     captured_context = ctx
     return response.Response(ctx, response_data="OK")
+
+
+def binary_result(ctx, **kwargs):
+    return response.Response(ctx, response_data=bytes([1, 2, 3, 4, 5]))

fdk/tests/test_http_stream.py

@@ -249,3 +249,10 @@ async def test_encap_request_headers_gateway():
 
     assert input_ctx.HTTPHeaders() == {"my-header": "foo",
                                        "funny-header": ["baz", "bob"]}
+
+
+@pytest.mark.asyncio
+async def test_bytes_response():
+    call = await fixtures.setup_fn_call(funcs.binary_result)
+    content, status, headers = await call
+    assert content == bytes([1, 2, 3, 4, 5])