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Serde Integration

Hornet provides optional serde support via a feature flag. When enabled, all AST types derive serde::Serialize and serde::Deserialize.

Enabling serde

[dependencies]
hornet = { version = "0.1", features = ["serde"] }
serde_json = "1"   # or any serde format you prefer

Serialising to JSON

use hornet_bind9::{parse_named_conf, ast::named_conf::NamedConf};

let conf: NamedConf = hornet::parse_named_conf(input)?;

// Serialize to JSON
let json = serde_json::to_string_pretty(&conf)?;
println!("{json}");

Example output (abbreviated):

{
  "statements": [
    {
      "type": "Options",
      "directory": "/var/cache/bind",
      "recursion": true,
      "allow_query": [{ "type": "Any" }]
    },
    {
      "type": "Zone",
      "name": "example.com",
      "options": {
        "zone_type": "Primary",
        "file": "/etc/bind/zones/example.com.db"
      }
    }
  ]
}

Serialising zone files

use hornet_bind9::{parse_zone_file, ast::zone_file::ZoneFile};

let zone: ZoneFile = hornet::parse_zone_file(zone_text)?;
let json = serde_json::to_string_pretty(&zone)?;
println!("{json}");

Deserialising from JSON

With serde enabled you can round-trip through JSON:

let conf: NamedConf = hornet::parse_named_conf(input)?;

// Round-trip through JSON
let json = serde_json::to_string(&conf)?;
let conf2: NamedConf = serde_json::from_str(&json)?;

Note

Deserialisation produces an AST that can be validated or written back to BIND9 config text. It does not bypass Hornet's type system — all variants must match the expected schema.

Using other serde formats

The serde feature is format-agnostic. Any serde-compatible format works:

serde_json::to_string_pretty(&conf)?

// [dependencies] toml = "0.8"
toml::to_string_pretty(&conf)?

// [dependencies] serde_yaml = "0.9"
serde_yaml::to_string(&conf)?

// [dependencies] rmp-serde = "1"
rmp_serde::to_vec(&conf)?

When to use serde

  • API responses — return parsed configs as JSON from a REST or gRPC service
  • Caching — serialise parsed ASTs to disk or a cache to avoid repeated parsing
  • Configuration diffing — use serde_json::Value to compare two configs structurally
  • Testing — golden-file tests that snapshot ASTs as JSON

Next Steps

  • Parsing — Parse configs to produce the AST you'll serialise
  • Writing & Formatting — Serialise ASTs back to BIND9 text (no serde needed)