feat: access http response headers

src/Extism/PDK/Bindings.hs

@@ -69,6 +69,8 @@ foreign import ccall "extism_http_request" extismHTTPRequest :: MemoryOffset ->
 
 foreign import ccall "extism_http_status_code" extismHTTPStatusCode :: IO Int32
 
+foreign import ccall "extism_http_headers" extismHTTPHeaders :: IO MemoryOffset
+
 foreign import ccall "__wasm_call_ctors" wasmConstructor :: IO ()
 
 foreign import ccall "__wasm_call_dtors" wasmDestructor :: IO ()

src/Extism/PDK/HTTP.hs

@@ -26,7 +26,8 @@ data Request = Request
 -- | HTTP Response
 data Response = Response
   { statusCode :: Int,
-    responseData :: ByteString
+    responseData :: ByteString,
+    responseHeaders :: [(String, String)]
   }
 
 -- | Creates a new 'Request'
@@ -46,11 +47,11 @@ withHeaders h req =
 
 -- | Get the 'Response' body as a 'ByteString'
 responseByteString :: Response -> ByteString
-responseByteString (Response _ mem) = mem
+responseByteString (Response _ mem _) = mem
 
 -- | Get the 'Response' body as a 'String'
 responseString :: Response -> String
-responseString (Response _ mem) = fromByteString mem
+responseString (Response _ mem _) = fromByteString mem
 
 -- | Get the 'Response' body as JSON
 responseJSON :: (Text.JSON.Generic.Data a) => Response -> IO (Either String a)
@@ -67,7 +68,20 @@ responseJSON res = do
 
 -- | Get the 'Response' body and decode it
 response :: (FromBytes a) => Response -> Either String a
-response (Response _ mem) = fromBytes mem
+response (Response _ mem _) = fromBytes mem
+
+getHeaders = do
+  offs <- extismHTTPHeaders
+  if offs == 0
+    then
+      return []
+    else do
+      mem <- Extism.PDK.Memory.findMemory offs
+      h <- Extism.PDK.Memory.load mem
+      () <- Extism.PDK.Memory.free mem
+      case h of
+        Left _ -> return []
+        Right x -> return x
 
 -- | Send HTTP request with an optional request body
 sendRequestWithBody :: (ToBytes a) => Request -> a -> IO Response
@@ -83,13 +97,14 @@ sendRequestWithBody req b = do
   j <- allocString json
   res <- extismHTTPRequest (memoryOffset j) (memoryOffset body)
   code <- extismHTTPStatusCode
+  h <- getHeaders
   if res == 0
-    then return (Response (fromIntegral code) empty)
+    then return (Response (fromIntegral code) empty h)
     else do
       mem <- findMemory res
       bs <- loadByteString mem
       free mem
-      return (Response (fromIntegral code) bs)
+      return (Response (fromIntegral code) bs h)
 
 -- | Send HTTP request with an optional request body
 sendRequest :: (ToBytes a) => Request -> Maybe a -> IO Response
@@ -109,11 +124,12 @@ sendRequest req b =
             j <- allocString json
             res <- extismHTTPRequest (memoryOffset j) (memoryOffset body)
             code <- extismHTTPStatusCode
+            h <- getHeaders
             if res == 0
-              then return (Response (fromIntegral code) empty)
+              then return (Response (fromIntegral code) empty h)
               else do
                 len <- extismLengthUnsafe res
                 let mem = Memory res len
                 bs <- loadByteString mem
                 free mem
-                return (Response (fromIntegral code) bs)
+                return (Response (fromIntegral code) bs h)

src/extism-pdk.c

@@ -65,6 +65,9 @@ ExtismPointer extism_http_request(ExtismPointer req, ExtismPointer body) {
 DEFINE(http_status_code, int32_t)
 int32_t extism_http_status_code() { return _http_status_code(); }
 
+DEFINE(http_headers, int32_t)
+int32_t extism_http_headers() { return _http_headers(); }
+
 DEFINE(log_info, void, ExtismPointer)
 void extism_log_info(ExtismPointer p) { return _log_info(p); }
 DEFINE(log_debug, void, ExtismPointer)