Sending Email

The 825gen2 can send emails.

The sendmail and msmtp commands are included in our Linux build.

Create the msmtp config file

nano ~/.msmtprc

Type the email account information such as:

defaults
tls on

account gmail
auth on
host smtp.gmail.com
port 587
user wilsonwareapps@gmail.com
from wilsonwareapps@gmail.com

account default : gmail

Save the configuration file.

Google no longer allows applications to use regular Google login password. To send email using a Google account create an app specific password in the google web portal.

Keep a record of the generated password

ueut jrqv eapo eaid

Create an email as a text file.

nano message.txt

Type the email such as:

From: wilsonwareapps@gmail.com
To: dwilson@cardet.com
Subject: Test email from 825

Test 825ARM Variscite

123456
abc

Send the email

msmtp -t < message.txt
password for wilsonwareapps@gmail.com at smtp.gmail.com: 

Enter the app password. Email was sent successfully.

How to store password to not require password entry every time email is sent?

Password can be added to config file such as:

nano ~/.msmtprc

Add the password line with the previously obtained app specific password from Google.

defaults
tls on

account gmail
auth on
host smtp.gmail.com
port 587
user wilsonwareapps@gmail.com
from wilsonwareapps@gmail.com
password ueut jrqv eapo eaid

account default : gmail



root@imx8mq-var-dart:~# msmtp -t < message.txt

The Email sent successfully with no prompt for password.

This could be done from app code using a system call.

How to send file attachments?

msmtp does not have support for file attachments directly. The message must be encoded into mime format.

Update message.txt to add MIME encoding

nano message.txt

From: wilsonwareapps@gmail.com
To: dwilson@cardet.com
Subject: Test email from 825
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="MyBoundaryString"


--MyBoundaryString
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

This is a message.

--MyBoundaryString
Content-Type: text/plain; file="file123.txt"
Content-Disposition: attachment; filename="file123.txt"
Content-Transfer-Encoding: base64

Create attachment file

nano attachment.txt

This is an attachment
123456
abcdefg

Use base64 to convert the attachment to base64 encoding:

base64 attachment.txt > /tmp/attachment

Now pipe both files to the msmtp command

cat message.txt /tmp/attachment | msmtp -t

This successfully sends email with attachment

We may create or find a library to generate mime encoded emails from application code.