File Functions

Functions for working with files over HTTP.

Function	Description	Input → Output
Download	Fetch a text resource over HTTP/HTTPS	url, headers → file, contentType, statusCode

Download

Fetch a remote resource and return its body as text. The block is intended for text payloads — JSON, plain text, webhook content, XML.

Input	Required	Description
url	yes	Full `http://` or `https://` URL
headers	no	JSON object of request headers

Output	Type	Description
file	string	Response body decoded as UTF-8
contentType	string	`Content-Type` header from the server
statusCode	number	HTTP status code

Safety limits

To keep one flow from taking down the worker, the action enforces hard caps:

Limit	Value	What happens when exceeded
Response size	10 MiB	Block fails with `Response too large …`
Total time	30 seconds	Block fails with `Download timed out after 30000 ms`
Target host	private/reserved IPs blocked	Block fails with `… not allowed`

The size cap applies in two ways:

If the server sends a Content-Length header bigger than 10 MiB, the request is rejected immediately (no body is read).
Otherwise the body is read progressively; the read is cancelled as soon as the running total crosses the cap.

The host filter rejects any URL whose hostname resolves to a private, link-local, loopback, CGNAT/Tailscale, or cloud-metadata address. This prevents flows from probing internal infrastructure (SSRF).

Limitations

Text only. Binary files (images, PDFs, archives) come back as garbled UTF-8 and should not be used. A binary-safe upload action is on the roadmap (Upload, currently stubbed).
No retry. A transient 5xx or a timeout returns ERROR; chain the block with Branch and Retry After if your flow needs retries.

Example

Fetch a JSON webhook payload:

Input	Value
url	`https://api.example.com/webhook/abc123`
headers	`{ "Authorization": "Bearer …" }`

Outputs:

file → {"event":"...","data":{...}}
contentType → application/json
statusCode → 200

Use JSON → Parse on file to extract fields.