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Filters

These are a set of utility filters that come with Invirt and which you can opt for in your application.

CatchAll​

Logs all exceptions and maps exception types to HTTP response statuses. When an exception is caught that isn't mapped, a Status.INTERNAL_SERVER_ERROR is returned.

val handler = CatchAll(
    ValidationException::class to Status.BAD_REQUEST,
    AuthorisationException::class to Status.NOT_FOUND
).then(routes(/* ... */))

ErrorPages​

Automatically renders a Pebble template for specified HTTP error statuses. The HTTP status of the underlying response is preserved in the final response.

// Renders the template "error/404.peb"
val httpHandler = ErrorPages(Status.NOT_FOUND to "error/404")
    .then(routes(/* ... */))

StatusOverride​

Overrides HTTP response status codes. The example below combines StatusOverride and ErrorPages to render a "page not found" response when a user attempts to access a secured resource.

// securityFilter returns a Status.FORBIDDEN when a user
// tries to access a secure resource/page
ErrorPages(Status.NOT_FOUND to "error/404")
    .then(StatusOverride(Status.FORBIDDEN to Status.NOT_FOUND))
    .then(securityFilter)
    .then(routes)

HttpAccessLog​

Logs HTTP transactions through kotlin-logging. By default the filter logs:

  • Only HTTP transactions with error response statuses (4xx, 5xx)
  • All routes/paths
  • All headers

This can be configured to log all HTTP transactions, ignore certain URI paths or exclude headers from being logged. You can also attach extra fields by providing an extraFields lambda with an HttpTransaction argument and returning a Map<String, String>.

val handler = HttpAccessLog(
    allStatues = true,
    ignorePaths = setOf("/admin"),
    excludeHeaders = setOf("jwt-token"),
    extraFields = { httpTransaction ->
        mapOf("remoteIp" to (httpTransaction.request.header("X-Forwarded-For") ?: ""))
    }
).then(routes)

Caching​

cacheDays(days) and cacheOneYear() are thin wrappers over http4k's caching filter, primarily intended for the static assets routes.

"/static/${assetsVersion}" bind cacheDays(365).then(staticAssets(developmentMode))