brazier/error

Types

BrazierError

Top-level error type for the Brazier framework. Each variant carries contextual information about what went wrong and where.

pub type BrazierError {
  TransportError(reason: String)
  CodecError(reason: String, raw: String)
  RuntimeError(reason: String)
  DiffError(reason: String)
  RenderError(reason: String)
  RouteError(reason: String)
  EffectError(reason: String)
  SessionError(reason: String)
  ConfigError(reason: String)
  InitRejected(error: InitError)
}

Constructors

```
TransportError(reason: String)
```
A WebSocket transport error occurred.
```
CodecError(reason: String, raw: String)
```
Failed to encode or decode a message on the wire.
```
RuntimeError(reason: String)
```
An error in the MVU runtime loop (init, update, or view).
```
DiffError(reason: String)
```
An error in the VDOM diff engine.
```
RenderError(reason: String)
```
An error during server-side rendering.
```
RouteError(reason: String)
```
A route matching or code generation error.
```
EffectError(reason: String)
```
An effect failed to execute.
```
SessionError(reason: String)
```
Session-related error (token expired, state not found, etc).
```
ConfigError(reason: String)
```
Configuration or initialization error.
```
InitRejected(error: InitError)
```
The app’s init refused to start the session (see InitError).

InitError

opaque </>

Why an app’s init refused to start a session: the HTTP status the server render answers with, and a reason for the server log.

The reason is never sent to the browser. The server render answers with an error page for the status, and the WebSocket closes with init_close_code(status).

Build one with unavailable (503) or refuse (any 4xx or 5xx status). A crash in init is not an InitError: it is answered with 500 on the server render and closes the WebSocket with 1011.

Reference: a LiveView mount that raises during the dead render is answered with 500, and Plug’s Plug.Exception carries the status of an error raised while handling a request.

pub opaque type InitError

Values

init_close_code

</>

pub fn init_close_code(error: InitError) -> Int

The WebSocket close code for an init refusal with status: init_close_code_base + status (4503, 4404, …). The browser reloads the page on 4400 to 4499 (at most 3 times per tab within 60 seconds, then it shows an error state) and reconnects with backoff on every other code, 4500 to 4599 included.

init_close_code_base

</>

pub const init_close_code_base: Int

Lowest close code of an init refusal: the socket closes with this plus the HTTP status (4503 for unavailable).

init_error_reason

</>

pub fn init_error_reason(error: InitError) -> String

The reason init gave, for the server log only.

init_error_status

</>

pub fn init_error_status(error: InitError) -> Int

The HTTP status the server render answers with.

init_error_to_string

</>

pub fn init_error_to_string(error: InitError) -> String

“: ”, for logs.

refuse

</>

pub fn refuse(status: Int, reason: String) -> InitError

Refuse the session with an HTTP error status, for example 404 for a record that does not exist or 403 for one the user may not see.

A status outside 400 to 599, or 499 (reserved_status), is a programming error and crashes init (answered as a crash: 500, or close 1011).

reserved_status

</>

pub const reserved_status: Int

The one status in 400 to 599 an init cannot refuse with: its close code, 4499, is the stale-build close (transport/ws.close_stale_build). 499 is not an HTTP status (nginx uses it in its logs for a client that went away), so no answer needs it.

to_string

</>

pub fn to_string(error: BrazierError) -> String

Convert a BrazierError to a human-readable string for logging.

unavailable

</>

pub fn unavailable(reason: String) -> InitError

Something init needs is down (a session store, a database): 503.