Parsing Error with bannerExt in OpenRTB JSON: Expected ext Field?

Hello Soufian,

Ah, I see, I hadn't considered the possibility you were using the built-in JSON functionality in the Protobuf library with a bidding endpoint receiving JSON. There's two separate topics I'd like to provide some feedback on then:

• What is your use-case for parsing JSON requests into Protobuf? Why not use OpenRTB Protobuf format rather than JSON?
  • From my outside perspective, the usage you're describing seems like a potentially "worst of both worlds", where you lose the efficiency gains of Protobuf, but still end up implementing Google-specific logic to handle Protobuf. If you're comfortable enough to make an implementation using Protobuf-generated libraries, why not receive bid requests serialized in that form directly as opposed to spending processing power on parsing from / serializing to JSON?
• OpenRTB JSON sent in bid requests is processed to better match the OpenRTB spec
  • The error you're receiving likely stems from the fact that processing is done on our end to better conform to the OpenRTB spec, which has subtle differences from how the Protobuf serializes to / parses from JSON. Relevant to your case, the OpenRTB spec uses simplified "ext" extension keys, as opposed to the extension keys based on the message name. Other differences also exist that could hinder your parsing/serialization; e.g. the handling of booleans or int64 fields (not exhaustive). Because JSON format bid requests sent by our exchange adhere to the OpenRTB spec, the Protobuf parser is unable to recognize the extensions with their simplified names. If you were insistent on converting JSON bid requests to Protobuf and vice versa, you  could  work around that with some post/pre-processing (depending on whether you're converting to/from JSON), in order to adjust the extension names. I'm don't think I could recommend such an approach though.