Send Emails with Templates API¶

The API for sending email for a template relies on a special entity called EmailEnvelope. This entity contains information about the email recipients. Specifically:

a list of email addresses for the "To", "Cc" and "Bcc" fields of the email message
a query, also known as a where clause, against the Users database table, which identifies the recipients of the email. The query takes precedence and overrides the email addresses for the "To" field.

The EmailEnvelope class is defined as:

namespace BackendlessAPI.Messaging
{
  public class EmailEnvelope
  {
    public List<string> Cc{ get; set; }
    public List<string> Bcc;
    public List<string> To;
    public string RecipientsQuery;
    public string UniqueEmails;

    // adds addresses specified in the method argument to the existing
    // collection of the "To" addresses
    public EmailEnvelope AddTo( IEnumerable<string> toAddresses )

    // replaces all existing "To" addresses in the envelope
    // with the ones provided in the method argument
    public EmailEnvelope SetTo( List<string> toAddresses )

    // adds addresses specified in the method argument to the existing
    // collection of the "Cc" addresses
    public EmailEnvelope AddCc( IEnumerable<string> ccAddresses )

    // replaces all existing "Cc" addresses in the envelope
    // with the ones provided in the method argument    
    public EmailEnvelope SetCc( List<string> ccAddresses )

    // adds addresses specified in the method argument to the existing
    // collection of the "Bcc" addresses
    public EmailEnvelope AddBcc( IEnumerable<string> bccAddresses )

    // replaces all existing "Bcc" addresses in the envelope
    // with the ones provided in the method argument        
    public EmailEnvelope SetBcc( List<string> bccAddresses )
  }
}

where:

Argument	Description
`To`	A collection of email addresses to deliver an email generated from the template to. These email addresses are ignored if and when the `RecipientsQuery` parameter is present.
`Cc`	A collection of email addresses to include into the CC (carbon copy) distribution list of the email message generated from the template.
`Bcc`	A collection of email addresses to include into the BCC (blind carbon copy) distribution list of the email message generated from the template.
`RecipientsQuery`	A where clause for the `Users` table which defined the condition for selecting the users who will be receiving an email message generated from the template. The resulting collection of users takes precedence of the the email addresses (if any are) provided through the `To` property.
`UniqueEmails`	A boolean value indicating whether a set of users identified by `RecipientsQuery` should exclude any duplicates based on the `email` column value. If `RecipientsQuery` returns multiple user records and some of them have the same email address, the server will send out multiple emails to the same address when `UniqueEmails` is set to `false` or only one email per user when the `UniqueEmails` value is set to `true`. Default value is `true`.

Non-Blocking API¶

public async Task<MessageStatus> Backendless.Messaging.SendEmailFromTemplateAsync( 
                                                               string templateName, 
                                                               EmailEnvelope envelope )
public async Task<MessageStatus> Backendless.Messaging.SendEmailFromTemplateAsync( 
                                                               string templateName, 
                                                               EmailEnvelope envelope, 
                                                               Dictionary<string, string> templateValues )

public void Backendless.Messaging.SendEmailFromTemplate( 
                                         string templateName, 
                                         EmailEnvelope envelope, 
                                         AsyncCallback<MessageStatus> responder )

public void Backendless.Messaging.SendEmailFromTemplate( 
                                         string templateName, 
                                         EmailEnvelope envelope, 
                                         Dictionary<string, string> templateValues, 
                                         AsyncCallback<MessageStatus> responder )

Blocking API¶

public MessageStatus Backendless.Messaging.SendEmailFromTemplate( string templateName, 
                                                                  EmailEnvelope envelope );

public MessageStatus Backendless.Messaging.SendEmailFromTemplate( string templateName, 
                                                                  EmailEnvelope envelope, 
                                                                  Dictionary<string, string> templateValues )

where:

Argument	Description
`templateName`	Name of an email template created in Backendless Console.
`envelope`	An instance of the `EmailEnvelope` class containing information about the email recipients.
`templateValues`	A dictionary object containing values which will be used for Smart and Dynamic text substitutions. The key names in the object are matched against the Smart/Dynamic text placeholder names. The corresponding values are used for substitution in the resulting email message. Values must be of any primitive type.

Example¶

The example below sends out an email based on a template called "Marketing Template" to all users registered in the app whose email address does not end with @gmail.com and the related country is USA:

EmailEnvelope envelope = new EmailEnvelope();
envelope.RecipientsQuery = @"email not like '%@gmail.com' and address.country = 'USA'";

var messageStatus = await Backendless.Messaging.SendEmailFromTemplateAsync( "Marketing Template", envelope );

The example below sends out an email based on a template called "Marketing Template" to the users specified in the "to" field of EmailEnvelope. The example demonstrates the usage of the "templateValues" field. It contains two substitution values for the "Users.address.country" and the "discount" placeholders:

List<string> addresses = new List<string>();
addresses.Add("joe@yahoo.com");
addresses.Add("bob@hotmail.com");

Dictionary<string, string> templateValues = new Dictionary<string,string>();
templateValues[ "Users.address.country" ] = "your country";
templateValues[ "discount" ] = "20% off";

EmailEnvelope envelope = new EmailEnvelope();
envelope.SetTo( addresses );

var messageStatus = await Backendless.Messaging.SendEmailFromTemplateAsync( "Marketing Template", envelope, templateValues );

Codeless Reference¶

email_api_send_email_template_1

where:

Argument	Description
`name`	Name of an email template created in Backendless Console.
`addresses`	A list of email addresses to deliver an email generated from the template to.
`query`	A where clause for the `Users` table which defined the condition for selecting the users who will be receiving an email message generated from the template. The resulting collection of users takes precedence of the the email addresses (if any are) provided through the `address` property.
`cc`	A list of email addresses to include into the CC (carbon copy) distribution list of the email message generated from the template.
`bcc`	A list of email addresses to include into the BCC (blind carbon copy) distribution list of the email message generated from the template.
`template values`	An object containing values which will be used for Smart and Dynamic text substitutions. The key names in the object are matched against the Smart/Dynamic text placeholder names. The corresponding values are used for substitution in the resulting email message. Values must be of any primitive type.
`attachments`	A list of string values representing paths to the files stored in the Backendless Cloud. Specified files are attached to the email message. The path begins from the root of the Backendless Cloud without the leading slash. For instance, if the file `agreement.txt` is located at `/documents/legal/agreement.txt`, then the path passed to the parameter must be `/documents/legal/agreement.txt`.
`unique emails`	A boolean value indicating whether a set of users identified by `query` should exclude any duplicates based on the `email` column value. If `query` returns multiple user records and some of them have the same email address, the server will send out multiple emails to the same address when `uniqueEmails` is set to `false` or only one email per user when the `uniqueEmails` value is set to `true`. Default value is `false`.
`return result`	When this box is checked, the operation returns an object containing the status of the email delivery or an error.

Returns an object containing the status of the email delivery or an error.

Consider the following records stored in the Users data table:

email_api_send_email_template_2

The example below sends an email message to the emails specified in the addresses property. Furthermore, the query property condition is set to include all users to the email delivery stored in the Users data table whose age is less than 30.

The template values property contains an object with the product_update_# property, representing the Smart Text. This property contains the value "Product Update #23" that replaces the Smart Text when the email is sent out.

Files that must be included to the email are specified in the attachments property as a list of paths leading to the corresponding files.

email_api_send_email_template_3