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Schemars

Using Serde Attributes

#[serde(...)] attributes can be overriden (or replaced) with #[schemars(...)] attributes, which behave identically. You may find this useful if you want to change the generated schema without affecting Serde's behaviour, or if you're just not using Serde.

use schemars::{schema_for, JsonSchema};
use serde::{Deserialize, Serialize};

#[derive(Deserialize, Serialize, JsonSchema)]
#[schemars(rename_all = "camelCase", deny_unknown_fields)]
pub struct MyStruct {
    #[serde(rename = "thisIsOverridden")]
    #[schemars(rename = "myNumber", range(min = 1, max = 10))]
    pub my_int: i32,
    pub my_bool: bool,
    #[schemars(default)]
    pub my_nullable_enum: Option<MyEnum>,
    #[schemars(inner(regex(pattern = "^x$")))]
    pub my_vec_str: Vec<String>,
}

#[derive(Deserialize, Serialize, JsonSchema)]
#[schemars(untagged)]
pub enum MyEnum {
    StringNewType(#[schemars(phone)] String),
    StructVariant {
        #[schemars(length(min = 1, max = 100))]
        floats: Vec<f32>,
    },
}

fn main() {
    let schema = schema_for!(MyStruct);
    println!("{}", serde_json::to_string_pretty(&schema).unwrap());
}
Click to see the output JSON schema... 
{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "MyStruct",
  "type": "object",
  "required": [
    "myBool",
    "myNumber",
    "myVecStr"
  ],
  "properties": {
    "myBool": {
      "type": "boolean"
    },
    "myNullableEnum": {
      "default": null,
      "anyOf": [
        {
          "$ref": "#/definitions/MyEnum"
        },
        {
          "type": "null"
        }
      ]
    },
    "myNumber": {
      "type": "integer",
      "format": "int32",
      "maximum": 10.0,
      "minimum": 1.0
    },
    "myVecStr": {
      "type": "array",
      "items": {
        "type": "string",
        "pattern": "^x$"
      }
    }
  },
  "additionalProperties": false,
  "definitions": {
    "MyEnum": {
      "anyOf": [
        {
          "type": "string",
          "format": "phone"
        },
        {
          "type": "object",
          "required": [
            "floats"
          ],
          "properties": {
            "floats": {
              "type": "array",
              "items": {
                "type": "number",
                "format": "float"
              },
              "maxItems": 100,
              "minItems": 1
            }
          }
        }
      ]
    }
  }
}