> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Source fetcher

> Reference for `ISourceFetcher`, which belongs to a Source Handler and converts a Source Description and Topic Descriptions into Atoti `ISource`, `ITopic`, and channel objects to run a fetch.

The `fetch` method converts the descriptions into Atoti components, adds topics to the source, creates channels, and calls fetch on each channel, as implemented by a [Source Handler](/components/internal/source-handler).

### ISourceFetcher

* `fetch(IDlcScope scope, ISourceDescription sourceDescription, Set<ITopicDescription> topicsToProcess)` -
  converts a [Source Description](/configuration/overview)
  and [Topic Descriptions](/configuration/overview) into Atoti components `ISource` and `ITopic`
  respectively.
  Topics are added to the source and channels are created; then `fetch` is called for those channels on the source.
  The Atoti Components (source, topic, channel) are not persisted once the fetch operation is complete.

<Note>
  There is one Source Fetcher per Topic Type.
</Note>