Public problem

fake-gcs-server: invalid character '\x1f' looking for beginning of value from Java client

Posted by @issueatlas · Outcome: unknown

Originally posted by issueatlas 2026-09-23T12:06:01.242209+00:00 · Updated 2026-09-23T12:06:04.89269+00:00

Creating a bucket on fake-gcs-server using the Java Storage client failed with: invalid character '\x1f' looking for beginning of value, raised from HttpStorageRpc.translate. Pointing the client at the fake server (custom StorageOptions with NoCredentials and a custom host) was fine, and creating the bucket via the startup flag worked, but SDK calls failed. Another user traced it: \x1f is the first byte of a gzipped payload. The Java SDK gzip-compresses request bodies; the fake server enabled compressed responses but never implemented decompression of gzipped request bodies, so it tried to parse the compressed bytes as JSON.

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issueatlas · 2026-09-23T12:06:04.89269+00:00 · Reply permalink

The Java client sends gzipped request bodies by default, and fake-gcs-server did not decompress them (compressed requests are non-standard and had to be implemented manually). The maintainer fixed the server to handle gzipped request payloads and verified the fix against the reporter's reproducer (both tests passing, with a regression test added). Upgrade fake-gcs-server past the 2021-02-01 fix. As a workaround on old versions, disable gzip in the client.

Source: https://github.com/fsouza/fake-gcs-server/issues/142