DM-38599: Fix contents length checking in server-encoded HTTP responses

python/lsst/resources/http.py

@@ -992,30 +992,32 @@
                     f"Unable to download resource {self}; status: {resp.status_code} {resp.reason}"
                 )
 
-            content_length = 0
-            expected_length = int(resp.headers.get("Content-Length", "-1"))
             tmpdir, buffering = _get_temp_dir()
-
             with tempfile.NamedTemporaryFile(
                 suffix=self.getExtension(), buffering=buffering, dir=tmpdir, delete=False
             ) as tmpFile:
+                expected_length = int(resp.headers.get("Content-Length", "-1"))
                 with time_this(
                     log,
                     msg="GET %s [length=%d] to local file %s [chunk_size=%d]",
                     args=(self, expected_length, tmpFile.name, buffering),
                     mem_usage=self._config.collect_memory_usage,
                     mem_unit=u.mebibyte,
                 ):
+                    content_length = 0
                     for chunk in resp.iter_content(chunk_size=buffering):
                         tmpFile.write(chunk)
                         content_length += len(chunk)
 
-            # Check that the expected and actual content lengths match
-            if expected_length >= 0 and expected_length != content_length:
-                raise ValueError(
-                    f"Size of downloaded file does not match value in Content-Length header for {self}: "
-                    f"expecting {expected_length} and got {content_length} bytes"
-                )
+            # Check that the expected and actual content lengths match. Perform
+            # this check only when the contents of the file was not encoded by
+            # the server.
+            if "Content-Encoding" not in resp.headers:
+                if expected_length >= 0 and expected_length != content_length:
+                    raise ValueError(
+                        f"Size of downloaded file does not match value in Content-Length header for {self}: "
+                        f"expecting {expected_length} and got {content_length} bytes"
+                    )
 
             return tmpFile.name, True
 
@@ -1519,7 +1521,7 @@
         return responses
     else:
         # Could not parse the body
-        raise ValueError(f"Unable to parse response for PROPFIND request: {response}")
+        raise ValueError(f"Unable to parse response for PROPFIND request: {body}")
 
 
 class DavProperty: