Scanning

Midden can scan uploads before they are published. Scanners return one of three decisions:

• allow: publish normally.
• quarantine: store the file and scanner result, but do not serve it publicly.
• reject: reject the upload.

If multiple adapters run, Midden uses the most restrictive decision.

Enable Scanning

[scanning]
enabled = true
blocked_hashes = []
blocked_mime_types = []
default_on_error = "allow"

default_on_error controls what happens when an adapter fails. For high-trust public upload systems, consider quarantine instead of allow.

Block Lists

[scanning]
blocked_hashes = ["012345..."]
blocked_mime_types = ["application/x-msdownload"]

Blocked hashes and MIME types are checked before external adapters.

Command Adapter

[[scanning.adapters]]
kind = "command"
program = "/usr/local/bin/midden-scan"
args = ["{path}", "{filename}", "{content_type}", "{sha256}"]

Command exit codes:

• 0: allow.
• 10: quarantine.
• 20: reject.
• Any other status or execution error: use default_on_error.

Midden expands {path}, {filename}, {content_type}, {sha256}, {public_id}, and {size_bytes} in command arguments.

Webhook Adapter

[[scanning.adapters]]
kind = "webhook"
url = "https://scanner.example.test/midden"
secret = "change-me"

Midden posts JSON metadata to the webhook. When secret is set, it sends it in the x-midden-scanner-secret header.

Expected response:

{
  "decision": "allow",
  "detail": "clean"
}

ClamAV Adapter

[[scanning.adapters]]
kind = "clam_av"
socket = "127.0.0.1:3310"

The socket can be TCP (host:port) or a Unix socket path on Unix platforms.

Background Retries

Background jobs retry scanner decisions for candidate files when scanning is enabled. Configure retry batch size with:

[jobs]
scanner_retry_limit = 10