Struct Metadata 

pub struct Metadata { /* private fields */ }

An ordered, multi-valued map of custom gRPC metadata. Keys may repeat; insertion order is preserved through the round-trip to and from trillium::Headers.

Implementations

impl Metadata

pub fn new() -> Self

An empty metadata map.

pub fn is_empty(&self) -> bool

Whether there are zero entries.

pub fn len(&self) -> usize

The number of entries, counting repeated keys separately.

pub fn insert_ascii( &mut self, key: &str, value: impl Into<String>, ) -> Result<(), MetadataError>

Insert an ASCII metadata entry. Key must be lowercase [0-9a-z_\-.]+, must not be reserved, and must not end in -bin. Value must be printable ASCII (0x20–0x7E).

pub fn insert_binary( &mut self, key: &str, value: impl Into<Vec<u8>>, ) -> Result<(), MetadataError>

Insert a binary metadata entry. Key must end in -bin and otherwise follow the same rules as ASCII keys. Value bytes are base64-encoded at write time.

pub fn get_ascii(&self, key: &str) -> Option<&str>

Return the first ASCII value for key, if any.

pub fn get_binary(&self, key: &str) -> Option<&[u8]>

Return the first binary value for key, if any.

pub fn iter(&self) -> impl Iterator<Item = (&str, &MetadataValue)>

Iterate over (key, value) pairs in insertion order.

pub fn from_headers(headers: &Headers) -> Self

Pluck non-reserved entries out of headers. Binary -bin entries are base64-decoded; entries that fail to decode or whose ASCII values are not valid UTF-8 are skipped silently (the spec is lenient here — we’d rather drop unparseable user metadata than fail the whole RPC).

Header names are normalized to lowercase. trillium’s KnownHeaderName table presents canonical-case names (Content-Type, Retry-After, …) even though the HTTP/2 wire is lowercase-only, so we lowercase before matching against the reserved set and storing.

pub fn write_into(&self, headers: &mut Headers)

Append every entry to headers. Binary values are base64-encoded. Multiple values for the same key produce multiple appended entries, preserving wire order.

Trait Implementations

impl Clone for Metadata

fn clone(&self) -> Metadata

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Metadata

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

Formats the value using the given formatter.

impl Default for Metadata

fn default() -> Metadata

Returns the “default value” for a type.