Daraja.CallbackURL (daraja v0.1.0)

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Validates callback URLs before they are registered with Safaricom.

Safaricom's servers call these URLs on payment events. Rejecting unsafe values at the library boundary reduces server-side callback SSRF risk when URLs come from multi-tenant input or compromised credentials.

Configuration

config :daraja,
  environment: :production,
  validate_callback_urls: true,
  allowed_callback_hosts: ["myapp.com", "api.myapp.com"]
  • :validate_callback_urls — when false, validation is skipped in :sandbox only. Production always validates.
  • :allowed_callback_hosts — when set, the URL host must match an entry exactly or be a subdomain of one. Omit to allow any public hostname.

Rules

  • Production requires https://. Sandbox also allows http://.
  • Literal private, loopback, link-local, and metadata addresses are rejected.
  • Known metadata hostnames (for example metadata.google.internal) are rejected.

Summary

Functions

validate(url, opts \\ [])
validate_all(params, fields, opts \\ [])

Functions

validate(url, opts \\ [])

@spec validate(
  String.t(),
  keyword()
) :: :ok | {:error, String.t()}

validate_all(params, fields, opts \\ [])

@spec validate_all(map(), [atom()], keyword()) ::
  :ok | {:error, [{atom(), String.t()}]}