Struct DynamicMessage 

pub struct DynamicMessage { /* private fields */ }

A dynamically-typed protobuf message instance.

Construct one with DynamicMessage::new, populate it with DynamicMessage::set_field, and serialise with DynamicMessage::encode_to_vec. Decode bytes with DynamicMessage::decode.

Two DynamicMessages compare equal when they share the same descriptor and carry equal field values and unknown fields.

Implementations

impl DynamicMessage

pub fn new(desc: MessageDescriptor) -> Self

Create an empty message for the given descriptor.

pub fn descriptor(&self) -> MessageDescriptor

The descriptor describing this message’s schema.

pub fn unknown_fields(&self) -> &UnknownFields

Borrow the preserved unknown fields.

pub fn unknown_fields_mut(&mut self) -> &mut UnknownFields

Mutably borrow the preserved unknown fields.

pub fn has_field(&self, field: &FieldDescriptor) -> bool

Returns true if the field is explicitly set to a non-default value.

For proto3 singular scalar fields, a value equal to the type default is considered not present. For message, repeated, and map fields, presence means the entry exists and is non-empty.

pub fn get_field(&self, field: &FieldDescriptor) -> Cow<'_, Value>

Get the value of a field, returning the field’s default (as an owned value) if it is not set.

The returned Cow borrows the stored value when present and owns a freshly-constructed default otherwise.

pub fn set_field(&mut self, field: &FieldDescriptor, value: Value)

Set the value of a field.

If the field is a member of a (real, non-synthetic) oneof, all sibling arms of that oneof are cleared first, enforcing oneof exclusivity.

pub fn clear_field(&mut self, field: &FieldDescriptor)

Clear a field, removing any stored value.

pub fn get_field_by_name(&self, name: &str) -> Option<Cow<'_, Value>>

Get a field by name. Returns None if the name is not a field of this message’s descriptor.

pub fn set_field_by_name(&mut self, name: &str, value: Value) -> bool

Set a field by name. Returns false (and does nothing) if the name is not a field of this message’s descriptor.

pub fn which_oneof(&self, oneof_name: &str) -> Option<FieldDescriptor>

Returns the FieldDescriptor of whichever arm of oneof is set, if any. oneof is identified by name.

pub fn iter_fields( &self, ) -> impl Iterator<Item = (FieldDescriptor, &Value)> + '_

Iterate over the explicitly-set fields as (descriptor, value) pairs, ordered by field number.

impl DynamicMessage

pub fn to_json(&self) -> Result<Value, JsonError>

Encode this message to canonical protobuf-JSON, returning a serde_json::Value tree.

Proto3 default-valued singular scalar fields are omitted.

Errors

Returns JsonError if the message contains an unsupported feature (e.g. a group-kind field).

pub fn to_json_string(&self) -> Result<String, JsonError>

Encode this message to a canonical protobuf-JSON string.

Errors

See DynamicMessage::to_json.

pub fn from_json( desc: MessageDescriptor, json: &Value, ) -> Result<Self, JsonError>

Decode a protobuf-JSON serde_json::Value into a new DynamicMessage of the given descriptor.

Unknown JSON keys are silently skipped. null values are treated as the type default (clearing the field).

Errors

Returns JsonError if the JSON does not match the schema.

pub fn from_json_str( desc: MessageDescriptor, s: &str, ) -> Result<Self, JsonError>

Decode a protobuf-JSON string into a new DynamicMessage of the given descriptor.

Errors

Returns JsonError if the string is not valid JSON or does not match the schema.

impl DynamicMessage

pub fn to_text(&self) -> Result<String, TextError>

Encode this message to the protobuf text format.

Proto3 default-valued singular fields are omitted.

Errors

Returns TextError if encoding fails (e.g. an unsupported group field is encountered).

pub fn from_text(desc: MessageDescriptor, text: &str) -> Result<Self, TextError>

Decode a protobuf text-format string into a new DynamicMessage of the given descriptor.

Unknown fields are silently skipped. Comments (lines starting with #) are ignored.

Errors

Returns TextError if the input cannot be parsed or does not match the schema.

impl DynamicMessage

pub fn encode_to_vec(&self) -> Result<Vec<u8>, ReflectError>

Encode this message to a freshly-allocated byte vector.

Fields are written in ascending field-number order; unknown fields are appended afterwards. Proto3 singular fields equal to their type default are omitted.

Errors

Returns ReflectError::Field if the message (or a nested message) contains a group-kind field, which is unsupported.

pub fn encode(&self, buf: &mut EncodeBuffer) -> Result<(), ReflectError>

Encode this message into an existing EncodeBuffer.

Errors

See DynamicMessage::encode_to_vec.

pub fn decode( desc: MessageDescriptor, bytes: &[u8], ) -> Result<Self, ReflectError>

Decode a message of the given descriptor from bytes.

Repeated scalar fields accept both packed and unpacked encodings. Fields whose numbers are not in the descriptor are preserved as unknown fields.

Errors

Returns ReflectError::Field on malformed wire data (propagated from the wire layer) or if a group-kind field is encountered.

Trait Implementations

impl Clone for DynamicMessage

fn clone(&self) -> DynamicMessage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DynamicMessage

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

Formats the value using the given formatter.

impl PartialEq for DynamicMessage

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for DynamicMessage