Struct Writer 

pub struct Writer { /* private fields */ }

Builds a MaxMind DB file from inserted networks.

The writer accumulates encoded data records, deduplicating equal payloads, and serializes a search tree plus metadata when Writer::write_to is called.

Example

use maxminddb::writer::{Writer, WriterOptions};

let opts = WriterOptions {
    database_type: "Test".to_string(),
    ip_version: 4,
    record_size: 24,
    ..Default::default()
};
let mut writer = Writer::new(opts).unwrap();
writer.insert("10.0.0.0/8".parse().unwrap(), "example").unwrap();

let mut buf = Vec::new();
writer.write_to(&mut buf).unwrap();
let reader = maxminddb::Reader::from_source(buf).unwrap();
assert_eq!(reader.lookup::<String>("10.0.0.1".parse().unwrap()).unwrap(), "example");

Implementations

impl Writer

pub fn new(opts: WriterOptions) -> WriterResult<Self>

Create a writer.

Errors

Returns an error if ip_version is not 4 or 6, or if record_size is not 24, 28, or 32.

pub fn insert_value( &mut self, network: IpNetwork, value: Value, ) -> WriterResult<()>

Insert a fully encoded Value for network.

Equal values are stored once in the data section and referenced by every network that uses them.

Errors

Returns an error if an IPv6 network is inserted into an IPv4 database or if the value cannot be encoded.

Overwriting

Inserting a network replaces the subtree at that prefix. Inserting a less specific network after a more specific one therefore discards the more specific entries, so insert least specific networks first.

pub fn insert<T: Serialize>( &mut self, network: IpNetwork, value: T, ) -> WriterResult<()>

Insert a Serialize value for network.

This is the same as Writer::insert_value but encodes value for you.

Errors

Returns an error if value cannot be encoded, if an IPv6 network is inserted into an IPv4 database, or if the value is out of range for the MaxMind DB format (for example a negative integer below i32::MIN).

Overwriting

See Writer::insert_value: insert least specific networks first.

pub fn write_to<W: Write>(&mut self, writer: &mut W) -> WriterResult<u64>

Serialize the database into writer, returning the number of bytes written.

This finalizes node numbering, so call it once, after all inserts.

Errors

Returns an error if a record value does not fit the configured record size, if the node count exceeds u32, or if writing to writer fails.

Trait Implementations

impl Debug for Writer

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

Formats the value using the given formatter.