[android-components](../../../index.md) / [mozilla.components.concept.engine](../../index.md) / [EngineSession](../index.md) / [Observer](index.md) / [onExternalResource](./on-external-resource.md)

# onExternalResource

`open fun onExternalResource(url: `[`String`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`, fileName: `[`String`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`, contentLength: `[`Long`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html)`? = null, contentType: `[`String`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`? = null, cookie: `[`String`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`? = null, userAgent: `[`String`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`? = null): `[`Unit`](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) [(source)](https://github.com/mozilla-mobile/android-components/blob/master/components/concept/engine/src/main/java/mozilla/components/concept/engine/EngineSession.kt#L51)