How to use ramhorns with serde_json::Value?

[thesurlydev]

I'd like to be able to use ramhorns with arbitrary data supplied via JSON. From what I can tell, serde_json::Value fits the requirement for doing this but ramhorns uses a derive trait which won't work with serde_json::Value because it's an enum.

Is there a workaround or an easier way to accomplish using arbitrary data with ramhorns that doesn't require using the ramhorns::Content trait?

[maciejhirsz]

Ramhorns supports HashMaps and BTreeMaps so you can construct arbitrary dynamic structures that way. To work with serde_json::Value directly the Content trait would need to be implemented for it, we could add it to the ramhorns crate via a feature with optional serde_json dependency.

This should be a good first issue if anyone wants to drop a PR, I might not have time to tackle this within the next week or two.

[thesurlydev]

I will try implementing Content trait for serde_json::Value

[thesurlydev]

If serde_json is to be an optional dependency, then how shall I organize the added support for serde_json::Value? I'm somewhat new to Rust, so providing as much detail as possible would be appreciated.

[maciejhirsz]

Just put the impl for serde_json::Value in a separate module, like serde.rs. In lib.rs do a conditional import:

#[cfg(feature = "json")]
mod serde;

Adding serde_json as optional feature in Cargo.toml:

[dependencies]
# ...all the other deps
serde_json = { version = "1.0", optional = true }

[features]
default = []

# Implements `Content` for `serde_json::Value`
json = ["serde_json"]

That way enabling the json feature will build Ramhorns with serde_json and the module that contains the trait impl.

[eeyun]

I think I might be hitting this as well.

But to make sure - there is no alternative means of using arbitary json (even if say, converted to some string type) with a template and ramhorns today, correct? I've been unsuccessful anyways.

If that is the case then I'm a huge 👍 on this feature request and I would be curious to know if there has been any progress on the feature!

[maciejhirsz]

@eeyun don't think there has been, happy to accept a PR.

[eeyun]

Cool I just wanted to make sure. It would be a great feature. I may try to get something together for it but a bit underwater currently. Thanks for maintaining the project either way!