Searching for specific e-mail subject or containing variables

[Yoshibeatsu]

Hi guys,

I am currently working on a code for a ESP32 which is responsible for the communication of a machine as a graduation project. The esp32 is supposed to send e-mails to the employees, if the ESP32 gets any fault signals (digital signal). Employees can answer the e-mail to stop the continuous sending of the emails.

I can not find a way to search for our expected answered subject. The search script can not parse "AW: Lackierer 20230203 1300". I can also not find a way to return for example a boolean value if we would find the expected subject.

Thank you in advance

[mobizt]

For IMAP search, you can use search criteria like this

For subject search
config.search.criteria = F("SEARCH SUBJECT \"something to search\"");

Or multiple subject search
config.search.criteria = F("SEARCH (OR SUBJECT \"something to search\" SUBJECT \"what I'm looking for\")");

For body search
config.search.criteria = F("SEARCH BODY \"something to search\"");

Unfortunately, mixing search for body and subject is not work from my experimental.

For the simple search, see this example.

Better solution

Instead of using IMAP search periodically, you can use IMAP IDLE for mailbox changes notification to get incoming new message.
Please see this Reply_Text.ino example.

The Reply_Text.ino example scenario:

One client will send email with specific word in the message subject to the second client. The second client connected to the IMAP server to listen to the mailbox changes. When the message from first client received by second client, the message subject will be compared with the specific word. If it matches, the second client will reply email to the first client.

From the example, you can compare the strings of subject or text or html body of message with your desire string when message arrived by mailbox changes notification event.

imap.data().msgItems[index].subject or
imap.data().msgItems[index].text.content or
imap.data().msgItems[index].html.content

For the simple email notification, see this example.

[Yoshibeatsu]

Is the imap session closing if we are replying or during replaying?

[mobizt]

The session keeps open as required by IMAP IDLE command functional.

[Yoshibeatsu]

Is there a possebility to insert a string into the "void imapCallback(IMAP_Status status)" ? I can not get it to work when I try to write it like this "void imapCallback(IMAP_Status status, String subject) ".

Or is there a different place to search for the desired subject? I saw that you also use this place but I also dont understand how "if (strcmp(msgList.msgItems[0].subject, sendingSubject.c_str()) == 0)" is working.

sorry for so many questions

[mobizt]

You can't change the param of imapCallback but you can use global variable inside that function.

As I wrote above, you can access the message subject, html and text directly by using this

imap.data().msgItems[index].subject or
imap.data().msgItems[index].text.content or
imap.data().msgItems[index].html.content

The method imap.data() returns IMAP_MSG_List (class) object that is defined as msgList in the example

ESP-Mail-Client/examples/SMTP/Reply_Text/Reply_Text.ino

Line 372 in ac39ffe

IMAP_MSG_List msgList = imap.data();

To get the subject, html, text of new message (one message arrived at a time or per event, then the messages list (array) or imap.data.messageItems will contain only one message and we will use index 0 to access its member like this.

imap.data().msgItems[0].subject or
imap.data().msgItems[0].text.content or
imap.data().msgItems[0].html.content

Where strcmp is strings compare function in C/C++ which returns 0 when strings are equal.

You can compare the subject of new message with "any string" like this

if(strcmp(imap.data().msgItems[0].subject, "any string") == 0)
{
    Serial.println("Message subject matches");
}

[Yoshibeatsu]

Thank you so much !!