Deserialize ObjectId from hex string?

[pianocomposer321]

I'm using mongodb for the backend api of a project I'm working on, and I want the api to return the hex string in the json, so I'm using serialize_with = "bson::serde_helpers::serialize_object_id_as_hex_string". But this causes errors when I try to deserialize from the json response, which has the id as the raw hex string, because that's how it was serialized.

The serde_helpers module has three functions for objectid's: serialize_object_id_as_hex_string, deserialize_hex_string_from_object_id, and serialize_hex_string_as_object_id.

Is there a reason that there is no fourth, something like deserialize_object_id_from_hex_string?

Thanks!

[abr-egn]

Hi! Thanks for raising this - there's no particular reason that's lacking, we should definitely add it :) I've filed https://jira.mongodb.org/browse/RUST-1681 to track this. We'd also be happy to accept a PR if you'd like to implement it!

[sunsided]

I took the liberty to give it a try in #421.

[abr-egn]

Sorry that I didn't notice this earlier - as @patrickfreed quite correctly points out, the implementation of Deserialize for ObjectId already accepts a hex string (#421 just passes through to that implementation), so this should work without an extra deserialize helper. Can you give more details about the error you're seeing?

[pianocomposer321]

Yes, so I realized this after opening the issue. The problem I was having wasn't actually related to this, I was just thinking that maybe doing this would fix it. I wanted to have the object ids represented with the ObjectId type in my code, and as a bson object id in mongodb, but as a string for the json serialization. The problem was that if I changed the serializer, it would serialize it as a string when interacting with mongodb as well, so it wouldn't store it as an ObjectId there either. I thought maybe having this feature would solve that, but now I don't think it would, because the issue is that it is serializing it the same for json and bson, when I don't want it to do that.

What I ended up doing is creating a new struct for just my json api that serializes to a hex string and keeping my main struct for interacting with mongodb the same. If there's a way to do this with a single struct by differentiating between serializing for json vs bson, I'd love to know about it. But, I think this issue can probably be closed.

[abr-egn]

Having distinct structs is probably the best way to go there, thanks for clarifying!