pub struct Settings {
pub header_table_size: u32,
pub enable_push: bool,
pub max_concurrent_streams: u32,
pub initial_window_size: u32,
pub max_frame_size: u32,
pub max_header_list_size: u32,
}Expand description
cf. https://httpwg.org/specs/rfc9113.html#SettingValues
Fields§
§header_table_size: u32This setting allows the sender to inform the remote endpoint of the maximum size of the compression table used to decode field blocks, in units of octets. The encoder can select any size equal to or less than this value by using signaling specific to the compression format inside a field block (see [COMPRESSION]). The initial value is 4,096 octets.
enable_push: boolThis setting can be used to enable or disable server push. A server MUST NOT send a PUSH_PROMISE frame if it receives this parameter set to a value of 0; see Section 8.4. A client that has both set this parameter to 0 and had it acknowledged MUST treat the receipt of a PUSH_PROMISE frame as a connection error (Section 5.4.1) of type PROTOCOL_ERROR.
The initial value of SETTINGS_ENABLE_PUSH is 1. For a client, this value indicates that it is willing to receive PUSH_PROMISE frames. For a server, this initial value has no effect, and is equivalent to the value 0. Any value other than 0 or 1 MUST be treated as a connection error (Section 5.4.1) of type PROTOCOL_ERROR.
A server MUST NOT explicitly set this value to 1. A server MAY choose to omit this setting when it sends a SETTINGS frame, but if a server does include a value, it MUST be 0. A client MUST treat receipt of a SETTINGS frame with SETTINGS_ENABLE_PUSH set to 1 as a connection error (Section 5.4.1) of type PROTOCOL_ERROR.
max_concurrent_streams: u32This setting indicates the maximum number of concurrent streams that the sender will allow. This limit is directional: it applies to the number of streams that the sender permits the receiver to create. Initially, there is no limit to this value. It is recommended that this value be no smaller than 100, so as to not unnecessarily limit parallelism.
A value of 0 for SETTINGS_MAX_CONCURRENT_STREAMS SHOULD NOT be treated as special by endpoints. A zero value does prevent the creation of new streams; however, this can also happen for any limit that is exhausted with active streams. Servers SHOULD only set a zero value for short durations; if a server does not wish to accept requests, closing the connection is more appropriate.
initial_window_size: u32This setting indicates the sender’s initial window size (in units of octets) for stream-level flow control. The initial value is 2^16-1 (65,535) octets.
This setting affects the window size of all streams (see Section 6.9.2).
Values above the maximum flow-control window size of 2^31-1 MUST be treated as a connection error (Section 5.4.1) of type FLOW_CONTROL_ERROR.
max_frame_size: u32This setting indicates the size of the largest frame payload that the sender is willing to receive, in units of octets.
The initial value is 2^14 (16,384) octets. The value advertised by an endpoint MUST be between this initial value and the maximum allowed frame size (2^24-1 or 16,777,215 octets), inclusive. Values outside this range MUST be treated as a connection error (Section 5.4.1) of type PROTOCOL_ERROR.
max_header_list_size: u32This advisory setting informs a peer of the maximum field section size that the sender is prepared to accept, in units of octets. The value is based on the uncompressed size of field lines, including the length of the name and value in units of octets plus an overhead of 32 octets for each field line.
For any given request, a lower limit than what is advertised MAY be enforced. The initial value of this setting is unlimited.