Handle socket errors, sign Digest header

It turns out, signing the header about the content is pretty important.

core/httpy.py

@@ -141,18 +141,28 @@ class IpFilterWrapperTransport(httpx.BaseTransport, httpx.AsyncBaseTransport):
     #   misconfigured or malicious
 
     def handle_request(self, request: httpx.Request) -> httpx.Response:
-        self._check_addrinfo(
-            request, socket.getaddrinfo(*self._request_to_addrinfo(request))
-        )
+        try:
+            self._check_addrinfo(
+                request, socket.getaddrinfo(*self._request_to_addrinfo(request))
+            )
+        except socket.gaierror:
+            # Some kind of look up error. Gonna assume safe and let farther
+            # down the stack handle it.
+            pass
         return self.wrappee.handle_request(request)
 
     async def handle_async_request(self, request: httpx.Request) -> httpx.Response:
-        self._check_addrinfo(
-            request,
-            await asyncio.get_running_loop().getaddrinfo(
-                *self._request_to_addrinfo(request)
-            ),
-        )
+        try:
+            self._check_addrinfo(
+                request,
+                await asyncio.get_running_loop().getaddrinfo(
+                    *self._request_to_addrinfo(request)
+                ),
+            )
+        except socket.gaierror:
+            # Some kind of look up error. Gonna assume safe and let farther
+            # down the stack handle it.
+            pass
         return await self.wrappee.handle_await_request(request)
 
 

core/signatures.py

@@ -69,6 +69,16 @@ class HttpSignature:
     Allows for calculation and verification of HTTP signatures
     """
 
+    #: Headers we should consider when producing signatures
+    HEADERS_FOR_SIGNING = {
+        "date",
+        "host",
+        "(request-target)",
+        "content-type",
+        "content-length",
+        "digest",
+    }
+
     @classmethod
     def calculate_digest(cls, data, algorithm="sha-256") -> str:
         """
@@ -211,7 +221,9 @@ class HttpSignature:
 
         # Sign the headers
         signing_headers = [
-            key for key in request.headers.keys() if key.lower() != "user-agent"
+            key
+            for key in request.headers.keys()
+            if key.lower() in cls.HEADERS_FOR_SIGNING
         ]
         signed_string = "\n".join(
             f"{name.lower()}: {value}"