vld 0.6.0

Type-safe runtime validation library for Rust, inspired by Zod
Documentation 
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use serde_json::Value;

use crate::error::{IssueCode, PathSegment, VldError};
use crate::schema::VldSchema;

/// Schema for any JSON value, with optional shape checks. Built with `vld::json_value()`.
#[derive(Clone)]
pub struct ZJsonValue {
    require_object: bool,
    require_array: bool,
    required_keys: Vec<String>,
    max_depth: Option<usize>,
    custom_type_error: Option<String>,
}

impl ZJsonValue {
    /// Create the schema (the same as its `vld::` constructor function).
    pub fn new() -> Self {
        Self {
            require_object: false,
            require_array: false,
            required_keys: Vec::new(),
            max_depth: None,
            custom_type_error: None,
        }
    }

    /// Set a custom error message for type mismatch (`object()` / `array()`
    /// / `require_key` on a non-object).
    pub fn type_error(mut self, msg: impl Into<String>) -> Self {
        self.custom_type_error = Some(msg.into());
        self
    }

    /// Must be a JSON object.
    pub fn object(mut self) -> Self {
        self.require_object = true;
        self.require_array = false;
        self
    }

    /// Must be a JSON array.
    pub fn array(mut self) -> Self {
        self.require_array = true;
        self.require_object = false;
        self
    }

    /// Must be an object containing `key`.
    pub fn require_key(mut self, key: impl Into<String>) -> Self {
        self.required_keys.push(key.into());
        self
    }

    /// Nesting must not be deeper than `depth`.
    pub fn max_depth(mut self, depth: usize) -> Self {
        self.max_depth = Some(depth);
        self
    }
}

impl Default for ZJsonValue {
    fn default() -> Self {
        Self::new()
    }
}

fn depth(value: &Value) -> usize {
    match value {
        Value::Array(arr) => 1 + arr.iter().map(depth).max().unwrap_or(0),
        Value::Object(map) => 1 + map.values().map(depth).max().unwrap_or(0),
        _ => 1,
    }
}

impl VldSchema for ZJsonValue {
    type Output = Value;

    fn parse_value(&self, value: &Value) -> Result<Self::Output, VldError> {
        if self.require_object && !value.is_object() {
            return Err(crate::primitives::type_error(
                &self.custom_type_error,
                "object",
                value,
            ));
        }
        if self.require_array && !value.is_array() {
            return Err(crate::primitives::type_error(
                &self.custom_type_error,
                "array",
                value,
            ));
        }
        if !self.required_keys.is_empty() {
            let obj = value.as_object().ok_or_else(|| {
                crate::primitives::type_error(&self.custom_type_error, "object", value)
            })?;
            for k in &self.required_keys {
                if !obj.contains_key(k) {
                    return Err(VldError::from_code(IssueCode::MissingField)
                        .with_prefix(PathSegment::Field(k.clone())));
                }
            }
        }
        if let Some(max_depth) = self.max_depth {
            if depth(value) > max_depth {
                return Err(VldError::from_code_with_value(
                    IssueCode::JsonTooDeep { max_depth },
                    value,
                ));
            }
        }
        Ok(value.clone())
    }
}

#[cfg(feature = "openapi")]
impl crate::openapi::JsonSchema for ZJsonValue {
    fn json_schema(&self) -> serde_json::Value {
        let mut schema = serde_json::json!({});
        // `require_key` implies an object too.
        if self.require_object || !self.required_keys.is_empty() {
            schema["type"] = serde_json::json!("object");
            if !self.required_keys.is_empty() {
                schema["required"] = serde_json::json!(self.required_keys);
            }
        } else if self.require_array {
            schema["type"] = serde_json::json!("array");
        }
        if let Some(depth) = self.max_depth {
            schema["x-maxDepth"] = serde_json::json!(depth);
        }
        schema
    }
    /// Required only when `null` is rejected (object / array / required keys).
    fn is_required(&self) -> bool {
        self.require_object || self.require_array || !self.required_keys.is_empty()
    }
}

#[cfg(feature = "openapi")]
impl crate::openapi::CollectNestedSchemas for ZJsonValue {}