add config option to reject incoming deliveries with an error during the smtp transaction

useful when a catchall is configured, and messages to some address need to be
rejected.

would have been nicer if this could be part of a ruleset. but evaluating a
ruleset requires us to have the message (so we can match on headers, etc). but
we can't reject messages to individual recipients during the DATA command in
smtp. that would reject the entire delivery attempt.

for issue #156 by ally9335

webaccount/account.ts

@@ -1754,6 +1754,7 @@ const destination = async (name: string) => {
 
 	let defaultMailbox: HTMLInputElement
 	let fullName: HTMLInputElement
+	let smtpError: HTMLInputElement
 	let saveButton: HTMLButtonElement
 
 	const addresses = [name, ...Object.keys(acc.Destinations || {}).filter(a => !a.startsWith('@') && a !== name)]
@@ -1775,6 +1776,12 @@ const destination = async (name: string) => {
 			fullName=dom.input(attr.value(dest.FullName)),
 		),
 		dom.br(),
+		dom.div(
+			dom.span('Reject deliveries with SMTP Error', attr.title('If non-empty, incoming delivery attempts to this destination will be rejected during SMTP RCPT TO with this error response line. The response line must start with an error code. Currently the following error resonse codes are allowed: 421 (temporary local error), 550 (mailbox not found). If the line consists of only an error code, an appropriate error message is added. Rejecting messages with a 4xx code invites later retries by the remote, while 5xx codes should prevent further delivery attempts.')),
+			dom.br(),
+			smtpError=dom.input(attr.value(dest.SMTPError), attr.placeholder('421 or 550...')),
+		),
+		dom.br(),
 
 		dom.h2('Rulesets'),
 		dom.p('Incoming messages are checked against the rulesets. If a ruleset matches, the message is delivered to the mailbox configured for the ruleset instead of to the default mailbox.'),
@@ -1840,6 +1847,7 @@ const destination = async (name: string) => {
 						ListAllowDNSDomain: {ASCII: '', Unicode: ''},
 					}
 				}),
+				SMTPError: smtpError.value,
 			}
 			await check(saveButton, client.DestinationSave(name, dest, newDest))
 			window.location.reload() // todo: only refresh part of ui

webaccount/api.json

@@ -759,6 +759,13 @@
 						"Ruleset"
 					]
 				},
+				{
+					"Name": "SMTPError",
+					"Docs": "",
+					"Typewords": [
+						"string"
+					]
+				},
 				{
 					"Name": "FullName",
 					"Docs": "",

webaccount/api.ts

@@ -40,6 +40,7 @@ export interface IncomingWebhook {
 export interface Destination {
 	Mailbox: string
 	Rulesets?: Ruleset[] | null
+	SMTPError: string
 	FullName: string
 }
 
@@ -260,7 +261,7 @@ export const types: TypenameMap = {
 	"Account": {"Name":"Account","Docs":"","Fields":[{"Name":"OutgoingWebhook","Docs":"","Typewords":["nullable","OutgoingWebhook"]},{"Name":"IncomingWebhook","Docs":"","Typewords":["nullable","IncomingWebhook"]},{"Name":"FromIDLoginAddresses","Docs":"","Typewords":["[]","string"]},{"Name":"KeepRetiredMessagePeriod","Docs":"","Typewords":["int64"]},{"Name":"KeepRetiredWebhookPeriod","Docs":"","Typewords":["int64"]},{"Name":"Domain","Docs":"","Typewords":["string"]},{"Name":"Description","Docs":"","Typewords":["string"]},{"Name":"FullName","Docs":"","Typewords":["string"]},{"Name":"Destinations","Docs":"","Typewords":["{}","Destination"]},{"Name":"SubjectPass","Docs":"","Typewords":["SubjectPass"]},{"Name":"QuotaMessageSize","Docs":"","Typewords":["int64"]},{"Name":"RejectsMailbox","Docs":"","Typewords":["string"]},{"Name":"KeepRejects","Docs":"","Typewords":["bool"]},{"Name":"AutomaticJunkFlags","Docs":"","Typewords":["AutomaticJunkFlags"]},{"Name":"JunkFilter","Docs":"","Typewords":["nullable","JunkFilter"]},{"Name":"MaxOutgoingMessagesPerDay","Docs":"","Typewords":["int32"]},{"Name":"MaxFirstTimeRecipientsPerDay","Docs":"","Typewords":["int32"]},{"Name":"NoFirstTimeSenderDelay","Docs":"","Typewords":["bool"]},{"Name":"Routes","Docs":"","Typewords":["[]","Route"]},{"Name":"DNSDomain","Docs":"","Typewords":["Domain"]},{"Name":"Aliases","Docs":"","Typewords":["[]","AddressAlias"]}]},
 	"OutgoingWebhook": {"Name":"OutgoingWebhook","Docs":"","Fields":[{"Name":"URL","Docs":"","Typewords":["string"]},{"Name":"Authorization","Docs":"","Typewords":["string"]},{"Name":"Events","Docs":"","Typewords":["[]","string"]}]},
 	"IncomingWebhook": {"Name":"IncomingWebhook","Docs":"","Fields":[{"Name":"URL","Docs":"","Typewords":["string"]},{"Name":"Authorization","Docs":"","Typewords":["string"]}]},
-	"Destination": {"Name":"Destination","Docs":"","Fields":[{"Name":"Mailbox","Docs":"","Typewords":["string"]},{"Name":"Rulesets","Docs":"","Typewords":["[]","Ruleset"]},{"Name":"FullName","Docs":"","Typewords":["string"]}]},
+	"Destination": {"Name":"Destination","Docs":"","Fields":[{"Name":"Mailbox","Docs":"","Typewords":["string"]},{"Name":"Rulesets","Docs":"","Typewords":["[]","Ruleset"]},{"Name":"SMTPError","Docs":"","Typewords":["string"]},{"Name":"FullName","Docs":"","Typewords":["string"]}]},
 	"Ruleset": {"Name":"Ruleset","Docs":"","Fields":[{"Name":"SMTPMailFromRegexp","Docs":"","Typewords":["string"]},{"Name":"MsgFromRegexp","Docs":"","Typewords":["string"]},{"Name":"VerifiedDomain","Docs":"","Typewords":["string"]},{"Name":"HeadersRegexp","Docs":"","Typewords":["{}","string"]},{"Name":"IsForward","Docs":"","Typewords":["bool"]},{"Name":"ListAllowDomain","Docs":"","Typewords":["string"]},{"Name":"AcceptRejectsToMailbox","Docs":"","Typewords":["string"]},{"Name":"Mailbox","Docs":"","Typewords":["string"]},{"Name":"Comment","Docs":"","Typewords":["string"]},{"Name":"VerifiedDNSDomain","Docs":"","Typewords":["Domain"]},{"Name":"ListAllowDNSDomain","Docs":"","Typewords":["Domain"]}]},
 	"Domain": {"Name":"Domain","Docs":"","Fields":[{"Name":"ASCII","Docs":"","Typewords":["string"]},{"Name":"Unicode","Docs":"","Typewords":["string"]}]},
 	"SubjectPass": {"Name":"SubjectPass","Docs":"","Fields":[{"Name":"Period","Docs":"","Typewords":["int64"]}]},