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File

Server Source code Package

Serves static files from a store backend. Reads the file by ingest.path, derives the Content-Type from the file extension, and responds directly. Returns false to stop the transformer chain.

Setup​

Install the package:

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Configure in your code:

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How it works​

  1. Reads ingest.path from the request context
  2. Strips the configured prefix (if set) — e.g. /static/image.png becomes image.png
  3. Looks up the remaining path in the store via store.get(key)
  4. If found, derives the Content-Type from the file extension and responds with the content
  5. Returns false to stop the chain — no further transformers or destinations run
  6. If the file is not found or the path doesn't match the prefix, the event passes through unchanged

Settings​

OptionTypeDefaultDescription
prefixstring—URL prefix to strip (e.g., /static)
headersRecord<string, string>—Default response headers (e.g., Cache-Control)
mimeTypesRecord<string, string>—Extension overrides (e.g., { ".wasm": "application/wasm" })

Environment​

KeyTypeRequiredDescription
storeStore.InstanceYesStore providing file content. Without one, the transformer warns and passes through.

Examples​

Cache + file chain​

Place the cache transformer before the file transformer. Cached files are served from memory, avoiding repeated store reads:

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Custom MIME types​

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Behavior notes​

  • Requires a store — without env.store, every request logs a warning and passes through
  • Prefix matching — if prefix is set and the path doesn't start with it, the event passes through (not an error)
  • Returns false — a served file stops the chain; no destinations receive the event
  • Content-Length — automatically set for string and Buffer content

Next steps​

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