Struct ClientBuilder 

pub struct ClientBuilder<State> { /* private fields */ }

Builder for LastIDClient with type-state pattern.

Type-State Pattern

The builder enforces that configuration must be provided before building:

• ClientBuilder<NoConfig> - Initial state, no config
• ClientBuilder<HasConfig> - Config provided, can build

Example

use lastid_sdk::ClientBuilder;

// Auto-discover configuration
let client = ClientBuilder::new().with_auto_config()?.build()?;

// Or use explicit configuration
use lastid_sdk::SDKConfig;

let config = SDKConfig::builder()
    .idp_endpoint("https://human.lastid.co")
    .build()?;

let client = ClientBuilder::new().with_config(config).build()?;

Serverless Keypair Persistence

For serverless deployments, see with_keypair to restore a persisted DPoP keypair across invocations.

Implementations

impl ClientBuilder<NoConfig>

pub const fn new() -> Self

Create a new client builder.

pub fn with_auto_config(self) -> Result<ClientBuilder<HasConfig>, LastIDError>

Auto-discover configuration from filesystem and environment.

Searches for TOML files in standard locations:

1. ./lastid.toml (current directory)
2. ~/.config/lastid/config.toml (user config)
3. /etc/lastid/config.toml (system config, Unix only)

Environment variables override file-based configuration.

Errors

Returns LastIDError::Config if no configuration is found.

pub fn with_config(self, config: SDKConfig) -> ClientBuilder<HasConfig>

Use an explicit configuration.

pub fn with_toml_file( self, path: &Path, ) -> Result<ClientBuilder<HasConfig>, LastIDError>

Load configuration from a TOML file.

Note

This method is only available on native platforms (not WASM). In WASM, use with_config or store config in localStorage.

Errors

Returns LastIDError::Config if the file cannot be read or parsed.

impl ClientBuilder<HasConfig>

pub fn with_keypair(self, keypair: DPoPKeyPair) -> Self

Use a pre-generated or restored DPoP keypair.

This is useful for serverless deployments where the keypair needs to be persisted across invocations. The keypair can be serialized to JSON and stored in a secrets manager, then deserialized and passed to this method.

Security

The keypair contains the private key. Ensure it is stored encrypted at rest (e.g., AWS Secrets Manager, HashiCorp Vault, encrypted environment variables).

Example

Using a generated keypair:

use lastid_sdk::crypto::DPoPKeyPair;
use lastid_sdk::{ClientBuilder, SDKConfig};

let keypair = DPoPKeyPair::generate()?;

let config = SDKConfig::builder()
    .idp_endpoint("https://human.lastid.co")
    .client_id("my-app")
    .build()?;

let client = ClientBuilder::new()
    .with_config(config)
    .with_keypair(keypair)
    .build()?;

Serializing and restoring a keypair (requires keypair-serialization feature):

use lastid_sdk::{ClientBuilder, SDKConfig};
use lastid_sdk::crypto::DPoPKeyPair;

// Generate and serialize a keypair for initial deployment
let keypair = DPoPKeyPair::generate()?;
let serialized = serde_json::to_string(&keypair).unwrap();
// Store `serialized` in your secrets manager...

// Later, in a serverless function cold start:
let restored: DPoPKeyPair = serde_json::from_str(&serialized).unwrap();

let config = SDKConfig::builder()
    .idp_endpoint("https://human.lastid.co")
    .client_id("my-app")
    .build()?;

let client = ClientBuilder::new()
    .with_config(config)
    .with_keypair(restored)
    .build()?;

pub fn build(self) -> Result<LastIDClient, LastIDError>

Build the client.

Errors

Returns LastIDError if:

• Configuration validation fails
• HTTP client creation fails
• DPoP key initialization fails

Trait Implementations

impl Default for ClientBuilder<NoConfig>

fn default() -> Self

Returns the “default value” for a type.