fix: raise BadResponse when a response is not valid JSON

massive/exceptions.py

@@ -14,10 +14,11 @@ class AuthError(Exception):
 
 class BadResponse(Exception):
     """
-    Non-200 response from API
+    Non-200 response from API, or a 200 response whose body is not valid JSON
 
-    The message is the response body. ``status`` is the HTTP status code, or
-    None if not given.
+    The message is the response body; for invalid JSON it is "Invalid JSON in
+    response: " followed by the first 200 bytes of the body. ``status`` is the
+    HTTP status code, or None if not given.
     """
 
     def __init__(self, *args: object, status: Optional[int] = None):

massive/rest/base.py

@@ -111,7 +111,13 @@ def __init__(
             self.json = json
 
     def _decode(self, resp):
-        return self.json.loads(resp.data.decode("utf-8"))
+        try:
+            return self.json.loads(resp.data.decode("utf-8"))
+        except ValueError as e:
+            body = resp.data[:200].decode("utf-8", "replace")
+            raise BadResponse(
+                f"Invalid JSON in response: {body}", status=resp.status
+            ) from e
 
     def _get(
         self,
@@ -157,11 +163,7 @@ def _get(
         if raw:
             return resp
 
-        try:
-            obj = self._decode(resp)
-        except ValueError as e:
-            logger.error("Error decoding json response: %s", e)
-            return []
+        obj = self._decode(resp)
 
         if result_key:
             if result_key not in obj:
@@ -246,11 +248,7 @@ def _paginate_iter(
                 options=options,
             )
 
-            try:
-                decoded = self._decode(resp)
-            except ValueError as e:
-                logger.error("Error decoding json response: %s", e)
-                return []
+            decoded = self._decode(resp)
 
             if result_key not in decoded:
                 return []

test_rest/test_bad_response.py

@@ -1,6 +1,7 @@
 from massive.exceptions import BadResponse
 from base import BaseTest
 
+import json
 import pook  # type: ignore
 
 
@@ -24,6 +25,37 @@ def test_status_is_set(self):
                 self.assertEqual(ctx.exception.args, (body,))
                 self.assertEqual(str(ctx.exception), body)
 
+    def test_invalid_json_raises(self):
+        pook.get(self.c.BASE + "/v3/reference/tickers/BADJSON", response_body="<html>")
+        with self.assertRaises(BadResponse) as ctx:
+            self.c.get_ticker_details("BADJSON")
+        self.assertEqual(ctx.exception.status, 200)
+        self.assertEqual(str(ctx.exception), "Invalid JSON in response: <html>")
+        self.assertIsInstance(ctx.exception.__cause__, json.JSONDecodeError)
+
+    def test_invalid_json_first_page_raises(self):
+        pook.get(self.c.BASE + "/v3/trades/BADJSON", response_body="<html>")
+        with self.assertRaises(BadResponse) as ctx:
+            list(self.c.list_trades("BADJSON"))
+        self.assertEqual(ctx.exception.status, 200)
+
+    def test_invalid_json_later_page_raises(self):
+        first = {
+            "results": [{"price": 1.0}],
+            "next_url": self.c.BASE + "/v3/trades/BADJSON2?cursor=2",
+        }
+        pook.get(
+            self.c.BASE + "/v3/trades/BADJSON2?cursor=2",
+            response_body="<html>",
+        )
+        pook.get(self.c.BASE + "/v3/trades/BADJSON2", response_json=first)
+        prices = []
+        with self.assertRaises(BadResponse) as ctx:
+            for t in self.c.list_trades("BADJSON2"):
+                prices.append(t.price)
+        self.assertEqual(prices, [1.0])
+        self.assertEqual(ctx.exception.status, 200)
+
     def test_status_defaults_to_none(self):
         for args in [(), ("boom",), ("boom", 1)]:
             with self.subTest(args=args):