(Go) IMAP Read PEC Email of Aruba and Extract the Invoice XML Files

IMAP Read PEC Email of Aruba and Extract the Invoice XML Files.

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    imap := chilkat.NewImap()

    // Connect using TLS.
    imap.SetSsl(true)
    imap.SetPort(993)
    success := imap.Connect("imap.example.com")
    if success == false {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    // Authenticate
    success = imap.Login("email_account_login","email_account_password")
    if success == false {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    // Select an IMAP mailbox
    success = imap.SelectMailbox("Inbox/postacert")
    if success == false {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    // Search for messages having "POSTA CERTIFICATA: Invio File" in the subject.
    fetchUids := true
    messageSet := imap.Search("SUBJECT \"POSTA CERTIFICATA: Invio File\"",fetchUids)
    if imap.LastMethodSuccess() == false {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    if messageSet.Count() < 1 {
        fmt.Println("No messages found.")
        messageSet.DisposeMessageSet()
        imap.DisposeImap()
        return
    }

    // For our example, we'll process only the 1st email in the messageSet.
    // Download the MIME source of the email into a StringBuilder object.
    email := imap.FetchSingle(*messageSet.GetId(0),messageSet.HasUids())
    if imap.LastMethodSuccess() == false {
        fmt.Println(imap.LastErrorText())
        messageSet.DisposeMessageSet()
        imap.DisposeImap()
        return
    }

    messageSet.DisposeMessageSet()

    // The email should contain an attached email.
    // The Invoice XML is contained within the attached email.
    attachedEmail := email.GetAttachedMessage(0)
    if email.LastMethodSuccess() == false {
        fmt.Println(email.LastErrorText())
        email.DisposeEmail()
        imap.DisposeImap()
        return
    }

    email.DisposeEmail()

    // Get the MIME of the attached email..
    sbMime := chilkat.NewStringBuilder()
    success = attachedEmail.GetMimeSb(sbMime)
    attachedEmail.DisposeEmail()

    // Load it into a Chilkat MIME object.
    mime := chilkat.NewMime()
    success = mime.LoadMimeSb(sbMime)

    // Examine the structure of the MIME.
    fmt.Println(*mime.GetStructure("text"))

    // The MIME has this structure:
    // multipart/mixed
    //     application/octet-stream
    //     application/octet-stream     <-- This is where the XML is contained.   It is within an opaque signature.
    //     text/plain

    // The 2nd application/octet-stream MIME header looks like this:

    // ------=_Part_329673_-1348225228.1579889273592
    // Content-Type: application/octet-stream; name="SM99999_99aaa.xml.p7m"
    // Content-Transfer-Encoding: base64
    // Content-Disposition: attachment; filename="SM99999_99aaa.xml.p7m"

    // Let's get the binary content of the .p7m
    bdP7m := chilkat.NewBinData()
    // Get the 2nd sub-part, at index 1 because index 0 is the 1st sub-part.
    mimeP7m := mime.GetPart(1)
    if mime.LastMethodSuccess() != true {
        fmt.Println("Failed to get 2nd sub-part. Perhaps the MIME does not have a 2nd sub-part?")
        imap.DisposeImap()
        sbMime.DisposeStringBuilder()
        mime.DisposeMime()
        bdP7m.DisposeBinData()
        return
    }

    success = mimeP7m.GetBodyBd(bdP7m)
    mimeP7m.DisposeMime()

    // Verify the signature, which also extracts the content contained within the opaque signature.
    crypt := chilkat.NewCrypt2()
    success = crypt.OpaqueVerifyBd(bdP7m)
    if success == false {
        fmt.Println(crypt.LastErrorText())
        imap.DisposeImap()
        sbMime.DisposeStringBuilder()
        mime.DisposeMime()
        bdP7m.DisposeBinData()
        crypt.DisposeCrypt2()
        return
    }

    // The bdP7m now contains the Invoice XML.
    // Load it into an XML object.
    xml := chilkat.NewXml()
    success = xml.LoadBd(bdP7m,true)

    fmt.Println(*xml.GetXml())

    // We have XML such as the following:
    // 
    // <?xml version="1.0" encoding="windows-1252"?>
    // <?xml-stylesheet type="text/xsl" href="fatturapa_v1.2.xsl"?>
    // <p:FatturaElettronica versione="FPR12" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" 
    //     xmlns:p="http://ivaservizi.agenziaentrate.gov.it/docs/xsd/fatture/v1.2" 
    //     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    //     <FatturaElettronicaHeader>
    // 	...
    //     </FatturaElettronicaHeader>
    //     <FatturaElettronicaBody>
    // 	...
    //     </FatturaElettronicaBody>
    // </p:FatturaElettronica>

    // Use this online tool to generate parsing code from sample XML: 
    // Generate Parsing Code from XML

    fmt.Println("success.")

    imap.DisposeImap()
    sbMime.DisposeStringBuilder()
    mime.DisposeMime()
    bdP7m.DisposeBinData()
    crypt.DisposeCrypt2()
    xml.DisposeXml()