Struct Configuration 

pub struct Configuration {
    pub owner_member_id: MemberId,
    pub configuration_version: u32,
    pub privacy_mode: PrivacyMode,
    pub display: RoomDisplayMetadata,
    pub max_recent_messages: usize,
    pub max_user_bans: usize,
    pub max_message_size: usize,
    pub max_nickname_size: usize,
    pub max_members: usize,
    pub max_room_name: usize,
    pub max_room_description: usize,
    pub max_direct_messages: Option<usize>,
}

Fields

owner_member_id: MemberId

configuration_version: u32

privacy_mode: PrivacyMode

display: RoomDisplayMetadata

max_recent_messages: usize

max_user_bans: usize

max_message_size: usize

max_nickname_size: usize

max_members: usize

max_room_name: usize

max_room_description: usize

max_direct_messages: Option<usize>

Owner-tunable global bound on direct_messages.messages, mirroring how max_recent_messages bounds recent_messages. None means “this configuration was signed before the field existed”; read it through Configuration::effective_max_direct_messages, which substitutes DEFAULT_MAX_DIRECT_MESSAGES, so pre-existing rooms are bounded without the owner having to re-sign anything.

Why Option + skip_serializing_if, and why that is NOT optional

AuthorizedConfigurationV1::verify_signature re-serializes this whole struct with ciborium and checks the owner’s signature over those bytes. A plain #[serde(default)] usize deserializes old bytes to 0 and then re-serializes them WITH the extra map entry, so the bytes no longer match what the owner signed: every room created before this field existed would fail verify, which also gates the #292 migration PUT — i.e. every existing room bricked, unrecoverably.

Option + skip_serializing_if makes the addition byte-neutral: an old configuration decodes to None, re-encodes without the key, and its signature still verifies. Pinned by legacy_configuration_bytes_still_verify_after_adding_the_field.

Any future field added to Configuration MUST follow this pattern AND be appended LAST — inserting an Option field mid-struct reorders the CBOR map for configurations that set it.

The pattern is one-directional, and deliberately so. It protects OLD bytes read by NEW code. The reverse — an old-struct client reading a configuration that actually SETS this field — still breaks: serde has no deny_unknown_fields here, so such a client silently drops the key, re-serializes one entry short, and the owner signature fails. That is unreachable only because the contract key is BLAKE3(wasm, params) and both the UI and riverctl include_bytes! the WASM they derive the key from: a client with the old struct also derives the OLD contract key and never sees state carrying this field. Do not weaken that coupling.

Implementations

impl Configuration

pub fn effective_max_direct_messages(&self) -> usize

The global DM cap in force for this room: the owner’s explicit Self::max_direct_messages, or DEFAULT_MAX_DIRECT_MESSAGES when unset. Every retention and horizon decision MUST read the cap through here so a legacy (None) configuration and an explicitly-defaulted one behave identically.

Trait Implementations

impl Clone for Configuration

fn clone(&self) -> Configuration

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Configuration

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

Formats the value using the given formatter.

impl Default for Configuration

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Configuration

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Configuration

fn eq(&self, other: &Configuration) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for Configuration

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Configuration