Liquid JSON template library

This library is a small wrapper around the Liquid templating engine that recursively processes structured JSON values for Liquid templates.

Liquid JSON templates help templatize JSON files used in configuration or RPC transmission.

Usage

use serde_json::json;
let template_json = json!({"this":"{{myval}}"});
let template_data = json!({"myval": 5});
let tmpl = liquid_json::LiquidJson::new(template_json);
let actual = tmpl.render(&template_data).unwrap();

let expected = json!({"this": 5}); // {{myval}} is replaced with 5
assert_eq!(actual, expected);

Features

The serde feature (enabled by default) exposes LiquidJsonValue. LiquidJsonValue is a wrapper around LiquidJson (and serde_json::Value) that lets you embed LiquidJson templates in your structs, e.g.

use serde_json::json;
#[derive(serde::Serialize, serde::Deserialize, Debug, PartialEq)]
struct YourStruct {
    inner_liquid: liquid_json::LiquidJsonValue,
}

let json_data = json!({"inner_liquid":"{{myval}}"});

let template_data = json!({"myval": 5});

let yours: YourStruct = serde_json::from_value(json_data).unwrap();
let actual = yours.inner_liquid.render(&template_data).unwrap();

Additional Filters

This library extends the default Liquid filters with the following:

• json: parses a JSON string into a Liquid object (recursing through arrays/objects as necessary).
• each: apply a template over every element in an array.
• output: mark a Liquid value as the output value of the template. Useful when you want to return an array or an object instead of a string.
• base64_encode: encode a value to a base64 string.
• base64_decode: decode a base64 value to a string. This will error if the result is not a string.

Example

Those filters can combine to produce complex JSON structures from simple input data. E.g.:

The input data:

{
  "to": ["john@example.com", "jane@example.com"]
}

Applied to the liquid JSON template:

{
  "recipients" : "{{ to | each: '{ \"email\": \"{{ el }}\" }' | json | output }}"
}

Produces the JSON:

{
  "recipients": [
    {
      "email": "john@example.com"
    },
    {
      "email": "jane@example.com"
    }
  ]
}