Struct ParamMeta 

pub struct ParamMeta {

    pub title: Option<String>,
    pub description: Option<String>,
    pub deprecated: bool,
    pub include_in_schema: bool,
    pub example: Option<Value>,
    pub examples: HashMap<String, Example>,
    pub ge: Option<f64>,
    pub le: Option<f64>,
    pub gt: Option<f64>,
    pub lt: Option<f64>,
    pub min_length: Option<usize>,
    pub max_length: Option<usize>,
    pub pattern: Option<String>,
    pub alias: Option<String>,
    pub validation_alias: Option<String>,
    pub serialization_alias: Option<String>,
}

Parameter metadata for OpenAPI documentation.

This struct captures metadata attributes that can be specified on struct fields using #[param(...)] attributes.

Example

#[derive(FromRequest)]
struct MyQuery {
    #[param(description = "Search term", deprecated)]
    q: Option<String>,

    #[param(title = "Page Number", ge = 1)]
    page: i32,
}

Fields

title: Option<String>

Display title for the parameter.

description: Option<String>

Description of the parameter.

deprecated: bool

Whether the parameter is deprecated.

include_in_schema: bool

Whether to include in OpenAPI schema.

example: Option<Value>

Example value.

examples: HashMap<String, Example>

Named examples.

ge: Option<f64>

Minimum value constraint (for numbers).

le: Option<f64>

Maximum value constraint (for numbers).

gt: Option<f64>

Exclusive minimum (for numbers).

lt: Option<f64>

Exclusive maximum (for numbers).

min_length: Option<usize>

Minimum length (for strings).

max_length: Option<usize>

Maximum length (for strings).

pattern: Option<String>

Pattern constraint (regex).

alias: Option<String>

Alternative name used in request (query/header/form). If set and validation_alias is None, this is also used for validation. If set and serialization_alias is None, this is used for OpenAPI schema.

validation_alias: Option<String>

Name used specifically for validation (overrides alias for validation).

serialization_alias: Option<String>

Name used specifically for serialization/OpenAPI (overrides alias for serialization).

Implementations

impl ParamMeta

pub fn new() -> Self

Create a new parameter metadata with default values.

pub fn title(self, title: impl Into<String>) -> Self

Set the title.

pub fn description(self, description: impl Into<String>) -> Self

Set the description.

pub fn deprecated(self) -> Self

Mark as deprecated.

pub fn exclude_from_schema(self) -> Self

Exclude from OpenAPI schema.

pub fn example(self, example: Value) -> Self

Set an example value.

pub fn ge(self, value: f64) -> Self

Set minimum value constraint (>=).

pub fn le(self, value: f64) -> Self

Set maximum value constraint (<=).

pub fn gt(self, value: f64) -> Self

Set exclusive minimum constraint (>).

pub fn lt(self, value: f64) -> Self

Set exclusive maximum constraint (<).

pub fn min_length(self, len: usize) -> Self

Set minimum length for strings.

pub fn max_length(self, len: usize) -> Self

Set maximum length for strings.

pub fn pattern(self, pattern: impl Into<String>) -> Self

Set a regex pattern constraint.

pub fn alias(self, alias: impl Into<String>) -> Self

Set an alias for this parameter.

The alias is the alternative name used in the request (query string, header, etc.). If validation_alias is not set, this value is also used for validation. If serialization_alias is not set, this value is used in OpenAPI schema.

Example

#[param(alias = "q")]
query: String,  // Accepts ?q=value instead of ?query=value

pub fn validation_alias(self, alias: impl Into<String>) -> Self

Set a validation-specific alias.

This name is used when validating/extracting the parameter from the request. Overrides the general alias for validation purposes.

pub fn serialization_alias(self, alias: impl Into<String>) -> Self

Set a serialization-specific alias.

This name is used in the OpenAPI schema for this parameter. Overrides the general alias for serialization/OpenAPI purposes.

pub fn effective_validation_name(&self) -> Option<&str>

Get the effective name for extraction/validation.

Returns validation_alias if set, otherwise alias if set, otherwise None.

pub fn effective_serialization_name(&self) -> Option<&str>

Get the effective name for OpenAPI/serialization.

Returns serialization_alias if set, otherwise alias if set, otherwise None.

pub fn to_parameter( &self, name: impl Into<String>, location: ParameterLocation, required: bool, schema: Option<Schema>, ) -> Parameter

Convert to an OpenAPI Parameter.

If a serialization alias is configured (via serialization_alias or alias), it will be used as the parameter name in the OpenAPI schema.

Trait Implementations

impl Clone for ParamMeta

fn clone(&self) -> ParamMeta

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ParamMeta

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ParamMeta

fn default() -> ParamMeta

Returns the “default value” for a type.