Verify DomainKey-Signature Headers in Downloaded Email
See more DKIM / DomainKey Examples
Downloads email from an IMAP server and verifies the DomainKey-Signature header(s) in each email, if present.
Note: DKIM-Signatures are much more common than DomainKey-Signatures. See the other Chilkat example for verifying DKIM-Signatures (link in the code below).
Chilkat Visual FoxPro Downloads
LOCAL lnSuccess
LOCAL loImap
LOCAL loDkim
LOCAL lnBUid
LOCAL lnSeqNum
LOCAL j
LOCAL n
LOCAL loJson
LOCAL loMimeData
LOCAL lnNumSigs
lnSuccess = 0
* This example requires the Chilkat API to have been previously unlocked.
* See Global Unlock Sample for sample code.
loImap = CreateObject('Chilkat.Imap')
* Connect to an IMAP server, login, select mailbox..
* Use TLS
loImap.Ssl = 1
loImap.Port = 993
lnSuccess = loImap.Connect("imap.example.com")
IF (lnSuccess = 1) THEN
lnSuccess = loImap.Login("myLogin","myPassword")
IF (lnSuccess = 1) THEN
lnSuccess = loImap.SelectMailbox("Inbox")
ENDIF
ENDIF
IF (lnSuccess <> 1) THEN
? loImap.LastErrorText
RELEASE loImap
CANCEL
ENDIF
* Note: DKIM-Signatures are much more common than DomainKey-Signature
* See DKIM-Signature Verify Sample.
loDkim = CreateObject('Chilkat.Dkim')
* Download a max of 10 emails and verify any DomainKey-Signature headers
* that are present.
* Download emails by sequence numbers (not UIDs).
lnBUid = 0
n = loImap.NumMessages
IF (n > 50) THEN
n = 50
ENDIF
loJson = CreateObject('Chilkat.JsonObject')
loJson.EmitCompact = 0
* To verify DomainKey-Signature headers, we need the exact unmodified MIME bytes of each email.
loMimeData = CreateObject('Chilkat.BinData')
lnSeqNum = 1
DO WHILE lnSeqNum <= n
* The FetchSingleBd method was introduced in v9.5.0.76
lnSuccess = loImap.FetchSingleBd(lnSeqNum,lnBUid,loMimeData)
IF (lnSuccess <> 1) THEN
? loImap.LastErrorText
RELEASE loImap
RELEASE loDkim
RELEASE loJson
RELEASE loMimeData
CANCEL
ENDIF
* Note: DKIM-Signatures are much more common than DomainKey-Signature
* See DKIM-Signature Verify Sample.
* Get the number of DomainKey-Signature headers.
lnNumSigs = loDkim.NumDomainKeySigs(loMimeData)
* Verify each..
j = 0
DO WHILE j < lnNumSigs
? "------ DomainKey Signature " + STR(j)
lnSuccess = loDkim.DomainKeyVerify(j,loMimeData)
IF (lnSuccess <> 1) THEN
? "Not valid."
? loDkim.LastErrorText
ELSE
? "valid."
ENDIF
* Show the additional information about the signature verification
loJson.Load(loDkim.VerifyInfo)
? loJson.Emit()
* The JSON contains information such as this:
* {
* "domain": "amazonses.com",
* "selector": "7v7vs6w47njt4pimodk5mmttbegzsi6n",
* "publicKey": "MIGfMA0GCSqG...v2GvWPqGHz6uqeQIDAQAB",
* "canonicalization": "relaxed/simple",
* "algorithm": "rsa-sha256",
* "signedHeaders": "Subject:From:To:Date:Mime-Version:Content-Type:References:Message-Id:Feedback-ID",
* "verified": "yes"
* }
j = j + 1
ENDDO
lnSeqNum = lnSeqNum + 1
ENDDO
lnSuccess = loImap.Disconnect()
RELEASE loImap
RELEASE loDkim
RELEASE loJson
RELEASE loMimeData