B4X
Using Replace Patterns in Email

Demonstrates how to use the replace patterns (mail-merge) feature in Chilkat MailMan.
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B4X
Dim success As Boolean = False

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

'  ---------------------------------------------------------------------
'  Create an email template for sending.
Dim emailTemplate As ChilkatEmail
emailTemplate.Initialize

'  We're going to replace "FIRST_NAME" with an actual name.
'  We arbitrarily chose "FIRST_NAME".  We can choose anything, such as "CUSTOMER_NAME" or "THE_RECIPIENT_NAME"...
emailTemplate.Subject = "Hello FIRST_NAME,"

emailTemplate.From = "john@example.com"
emailTemplate.AddTo("FIRST_NAME", "RECIPIENT_EMAIL")

emailTemplate.SetHtmlBody("<html><body><h2>Hello FIRST_NAME,</h2><p>Your order for PRODUCT_NAME has been shipped.</p></body></html>")

'  If the email is saved to a file, we can see what it contains:
emailTemplate.SaveEml("qa_output/emailTemplate.eml")

'  For example:

'  MIME-Version: 1.0
'  Date: Tue, 26 Apr 2022 07:10:52 -0500
'  Message-ID: <715CF231A9F07B0B9FDB073518CD94138D791866@XYZ>
'  Content-Type: text/html; charset=us-ascii
'  Content-Transfer-Encoding: 7bit
'  X-Priority: 3 (Normal)
'  Subject: Hello FIRST_NAME,
'  From: john@example.com
'  To: FIRST_NAME <RECIPIENT_EMAIL>
'  
'  <html><body><h2>Hello FIRST_NAME,</h2><p>Your order for PRODUCT_NAME has been shipped.</p></body></html>

'  ---------------------------------------------------------------------
'  Demonstrate replace patterns by setting and then rendering to MIME.

Dim mailman As ChilkatMailMan
mailman.Initialize("mailman")

emailTemplate.SetReplacePattern("FIRST_NAME", "Elon")
emailTemplate.SetReplacePattern("RECIPIENT_EMAIL", "elon.musk@example.com")
emailTemplate.SetReplacePattern("PRODUCT_NAME", "Twitter Corporation")

'  Render to MIME to see what we get.
'  Note: When the MailMan sends an email, it renders the email to MIME and then sends.
'  The rendering process is to do replacements, or possibly sign, encrypt, etc.
'  When MailMan.SendEmail is called, internally the email is rendered, and the rendered email is sent.
'  The equivalent to MailMan.Send email is to call email.RenderToMime followed by MailMan.SendMime.
Dim mime As String = mailman.RenderToMime(emailTemplate)
Log(mime)

'  This is the rendered MIME:

'  MIME-Version: 1.0
'  Date: Tue, 26 Apr 2022 07:25:49 -0500
'  Message-ID: <750582BCDC891C67B48CEE2293C08B902C3891E9@XYZ>
'  Content-Type: text/html; charset=us-ascii
'  Content-Transfer-Encoding: 7bit
'  X-Priority: 3 (Normal)
'  Subject: Hello Elon,
'  From: john@example.com
'  To: Elon <elon.musk@example.com>
'  
'  <html><body><h2>Hello Elon,</h2><p>Your order for Twitter Corporation has been shipped.</p></body></html>

'  Note: When rendering, the Date and Message-ID headers are automatically regenerated.

'  ---------------------------------------------------------------------
'  An application can see what replacement patterns it previously set by calling SetReplacePattern multiple times.
Dim count As Int = emailTemplate.NumReplacePatterns
Log("Number of replace patterns: " & count)

Dim i As Int = 0
Do While i < count
    '  Note: The GetReplaceString method was found to not be working correctly.  It was returning the same value as GetReplacePattern.
    '  It is fixed in Chilkat v9.5.0.91
    Log(emailTemplate.GetReplacePattern(i) & ": " & emailTemplate.GetReplaceString(i))
    i = i + 1
Loop

'  Or lookup a replacement pattern by name:
Dim name As String = "FIRST_NAME"
Log(name & " = " & emailTemplate.GetReplaceString2(name))

'  Sample output:

'  Number of replace patterns: 3
'  FIRST_NAME: Elon
'  RECIPIENT_EMAIL: elon.musk@example.com
'  PRODUCT_NAME: Twitter Corporation
'  FIRST_NAME = Elon

'  ---------------------------------------------------------------------
'  Finally... demonstrate sending emails using the replacement patterns.
'  

'  Set our mail server settings..
mailman.SmtpHost = "smtp.mail.us-west-2.awsapps.com"
mailman.SmtpSsl = True
mailman.SmtpPort = 465

mailman.SmtpUsername = "john@example.com"
mailman.SmtpPassword = "the_password"

'  Imagine we have data in JSON format, and we wish to send the templated email to each recipient...
'  

'  {
'  	"mail_merge" : [
'  		{
'  			"to": "mary@example.com",
'  			"name": "Mary",
'  			"product": "Widget 1" 
'  		},
'  		{
'  			"to": "robert@example.com",
'  			"name": "Robert",
'  			"product": "Widget 2"
'  		}	
'  		...
'  	]
'  }

Dim json As ChilkatJsonObject
json.Initialize
success = json.LoadFile("qa_data/json/mail_merge.json")
If success = False Then
    Log(json.LastErrorText)
    Return
End If


Dim emailAddr As String
Dim firstName As String
Dim product As String

i = 0
count = json.SizeOfArray("mail_merge")
Do While i < count
    json.I = i
    emailAddr = json.StringOf("mail_merge[i].to")
    firstName = json.StringOf("mail_merge[i].name")
    product = json.StringOf("mail_merge[i].product")

    emailTemplate.SetReplacePattern("FIRST_NAME", firstName)
    emailTemplate.SetReplacePattern("RECIPIENT_EMAIL", emailAddr)
    emailTemplate.SetReplacePattern("PRODUCT_NAME", product)


    success = mailman.SendEmail(emailTemplate)
    If success = False Then
        Log(mailman.LastErrorText)
        Return
    End If


    Log("Send email to " & emailAddr)

    i = i + 1
Loop

Log("Success.")