Receiving a signal from and Email and generate an action #333

pberna67 · 2024-03-19T23:50:10Z

pberna67
Mar 19, 2024

Dear all,

I want to connect a surveillance camera to a siren . The camera sends an email to an Arduino board (ESP32 u-blox NINA-W102), and when it detects a person motion a siren will be activated. I can define the email message that the camera sends in term of subject and in term of message content. I want creating an Arduino program that select a specific subject (ex Subject : Camera detects a person motion) and that activates a siren asserting a port pin of the Arduino Board.
Is not clear for me how to ignore the unwanted or not fresh messages in the IMAP Email server as well how to ignore the messages (email) already used. Is anybody able to give me the trace of the code, starting from the already available example Read_Single_Email_Loop ?

Thanks !
Paolo

mobizt · 2024-03-20T01:58:05Z

mobizt
Mar 20, 2024
Maintainer

If you want to get incoming message instantly, please see this example.
https://github.com/mobizt/ESP-Mail-Client/blob/master/examples/IMAP/Mailbox_Changes_Notification/Mailbox_Changes_Notification.ino

0 replies

pberna67 · 2024-03-20T14:50:33Z

pberna67
Mar 20, 2024
Author

Dear Mibizt

Thanks for the replay but It is not exactly what I need, in the inbox can be received also other mails, not only the signalling email. So I need to create a command for siren activation on specific email Subject

Thanks

1 reply

mobizt Mar 20, 2024
Maintainer

You can search and fetch the message based on UID and sequence set number.

To apply it for your requirement you have to design your algorithm and try it yourself.

pberna67 · 2024-03-20T21:01:03Z

pberna67
Mar 20, 2024
Author

Deal mobizt

I apologize but my knowledge of how emails are handled is limited. UID seams to be associated to each email, but in this case is the Video camera that generate each mail which I can identify, when I receive it, form the sender address or from the Subject title. I can't know the UID in advance.

Can you please indicate a trace about how to write the code to fetch a specific email from a known sender address / name or from and known Subject field, to "consume" that mail, and wait for the new one.

Alternatively can you point me to a simple basic theory of the mail exchange.

Thanks for your support !

4 replies

mobizt Mar 21, 2024
Maintainer

You can search, which is what you should start from this when you don't know any message to read.

There are many keywords support to use as search criteria.

https://github.com/mobizt/ESP-Mail-Client/tree/master/src#search-criteria

No mail app knows message UID, it just belongs to mail server system. All mail apps, just using search to get all message when it first used (take time) and cache the result for next time use and searching only new message.

You can search the date, subject, sender and even message body in mailbox without to read a whole message.

mobizt Mar 21, 2024
Maintainer

For example, see this example, search it with your desired keywords.

ESP-Mail-Client/examples/IMAP/Search_And_Read/Search_And_Read.ino

Lines 195 to 198 in 5c6e231

    
           // We search the unseen messages first to get its UID and stored in msg_uid. 
        
           imap_data.search.criteria = F("SEARCH UNSEEN"); 
        
           MailClient.readMail(&imap, false /* keep session open for fetching message in opened mailbox later */);

Then we get UID of message from search and keep it to use with fetch later.

ESP-Mail-Client/examples/IMAP/Search_And_Read/Search_And_Read.ino

Lines 200 to 213 in 5c6e231

    
           // We already get the search result message, fetch it 
        
           // Fetch the messages using UID stored in msg_uid one by one 
        
           for (int i = 0; i < max_result; i++) 
        
           { 
        
               imap_data.search.criteria.clear(); 
        
               // Mark this message as read 
        
               MailClient.addFlag(&imap, msg_uid[i], F("\\Seen"), false /* Close session */, false /* Ignore response */); 
        
               // Now Fech message by UID stored in msg_uid 
        
               imap_data.fetch.uid = msg_uid[i]; 
        
               MailClient.readMail(&imap, false /* keep session open for fetching message in opened mailbox later */);

You can use operator OR and NOT for multiple keywords.

For messages that do not match the specified search key.
NOT keyword

For messages that match either search key.
OR keyword1 keyword2 keyword(n)

Here is example of search criteria that multiple keywords combined.

UID SEARCH SINCE "01-Jan-2022" (OR FROM "mailer-daemon" FROM "postmaster") (OR SUBJECT "fail" (OR SUBJECT "undeliver" SUBJECT "returned"))

Not all IMAP servers support all keywords, you have to try it yourself first.

It can return nothing or error with search criteria you provided if server does not support.

To avoid the failure of search using multiple keywords, you can send the message with the unique subject that is easily to search from subject only e.g. contains known date/time format, timestamp or UUID number or some words that are specific.

pberna67 Mar 21, 2024
Author

Dear mobizt

Where is put the cache in ESP32, in the RAM or in some non volatile memory of the chip. Does the cache include only the read messages (searched before) or all mailbox messages with related attachment ? What happen if the ESP32 board lost its power supply ?

My application (alert a caregiver of a patient Alzheimer's disease on Video camera motion detection email alert), make sense if I can avoid to download from the server all messages.

From your description I should be able to search for a specific message, with some key-search word, read those messages and mark them as read messages, so I can avoid to used them twice. Is it correct ?

Regards
Paolo

mobizt Mar 21, 2024
Maintainer

I don't get your question clearly.
This is library (just code) not a mail app, then nothing to be cache in the library.

If you men download, here are options.

ESP-Mail-Client/examples/IMAP/Read_Single_Email/Read_Single_Email.ino

Lines 192 to 209 in 5c6e231

    
               /* Set the storage to save the downloaded files and attachments */ 
        
               imap_data.storage.saved_path = F("/email_data"); 
        
               /** The file storage type e.g. 
        
                * esp_mail_file_storage_type_none, 
        
                * esp_mail_file_storage_type_flash, and 
        
                * esp_mail_file_storage_type_sd 
        
                */ 
        
               imap_data.storage.type = esp_mail_file_storage_type_sd; 
        
               /** Set to download headers, text and html messaeges, 
        
                * attachments and inline images respectively. 
        
                */ 
        
               imap_data.download.header = true; 
        
               imap_data.download.text = true; 
        
               imap_data.download.html = true; 
        
               imap_data.download.attachment = true; 
        
               imap_data.download.inlineImg = true;

What general user can do is to follow the examples that provided enough functionality of IMAP client technology.
For advance user, library allows user to send the custom IMAP commands and giving the channel to get server response for his custom parsing.

General library user should have basic knowledge of IMAP technology where the mail app users don't need to have this knowledge.

And you are the library user which should have the basic IMAP knowledge for how library works and how to adapt it with your application.

pberna67 · 2024-03-23T20:36:14Z

pberna67
Mar 23, 2024
Author

Dear mobizt

I'm trying to test your Mailbox_Change_Notification example but if I send a test email in the INBOX of my email account I don't see any new message in the terminal windows after the app has been lunched

21:25:04.927 -> Connecting to Wi-Fi.
21:25:05.255 -> Connected with IP: 192.168.10.49
21:25:05.255 ->
21:25:05.255 -> #### Connecting to IMAP server...
21:25:05.255 -> > C: ESP Mail Client v3.4.16
21:25:15.280 -> > C: Reading time from NTP server.........................................
21:25:27.346 -> > C: connecting to IMAP server
21:25:27.346 -> > C: Host > imapmail.libero.it
21:25:27.346 -> > C: Port > 993
21:25:27.863 ->
21:25:27.863 -> #### IMAP server connected
21:25:27.863 -> > C: IMAP server connected
21:25:27.863 ->
21:25:27.863 -> #### Checking the capability...
21:25:27.863 -> > C: check the capability
21:25:27.909 ->
21:25:27.909 -> #### Logging in...
21:25:27.909 -> > C: send IMAP command, AUTHENTICATE PLAIN
21:25:27.956 ->
21:25:27.956 -> #### Send client identification...
21:25:28.003 -> > C: send IMAP command, ID
21:25:28.050 -> Successfully logged in.
21:25:28.050 ->
21:25:28.050 -> #### Reading the list of mailboxes...
21:25:28.050 -> > C: send IMAP command, LIST
21:25:28.097 ->
21:25:28.097 -> Available folders: Posta inviata, Posta eliminata, trash, Recovery_20230614, Recovery_20230614/INBOX, Spam, Posta indesiderata, outbox, draft, INBOX
21:25:28.097 ->
21:25:28.097 -> #### Open the mailbox folder...
21:25:28.097 -> > C: selecting the INBOX folder...
21:25:28.143 ->
21:25:28.143 -> Info of the selected folder
21:25:28.143 -> Total Messages: 233
21:25:28.143 -> UID Validity: 1660141832
21:25:28.143 -> Predicted next UID: 1943
21:25:28.143 -> First Unseen Message Number: 221
21:25:28.143 -> Highest Modification Sequence: 5178
21:25:28.143 -> Flags: \Answered, \Flagged, \Deleted, \Seen, \Draft, $smartnletter, $utenze, $offerte, $ordini, $MDNSent, $Forwarded
21:25:28.191 ->
21:25:28.191 -> #### Listening to mailbox changes...
21:25:28.191 -> > C: listening to INBOX folder changes
21:25:28.191 ->
21:25:28.191 -> #### Polling established
21:25:28.191 -> > C: polling established on March 23, 2024 23:25:28
21:28:08.533 ->
21:28:08.533 -> Mailbox status changed
21:28:08.533 -> ----------------------
21:28:08.533 -> Total Messages: 234
21:28:08.533 -> New message 234, has been addedd, reading message...
21:28:08.668 ->
21:28:08.668 -> #### Mailbox listening stopped
21:28:08.668 -> > C: Mailbox listening stopped
21:28:08.715 ->
21:28:08.715 -> #### Get UID...
21:28:08.715 -> > C: get UID
21:28:08.715 ->
21:28:08.715 -> #### UID is 1943
21:28:08.715 -> > C: UID is 1943
21:28:08.715 ->
21:28:08.715 -> #### Fetch message 1, UID: 1943
21:28:08.715 -> > C: send IMAP command, FETCH
21:28:08.715 -> > C: fetch message header
21:28:08.807 ->
21:28:08.807 -> #### Get Flags...
21:28:08.807 -> > C: get Flags
21:28:08.852 ->
21:28:08.852 -> > C: fetch body part header, 1
21:28:08.899 -> > C: Free Heap: 215112
21:28:08.899 ->
21:28:08.899 -> #### Finished reading Email
21:28:08.899 -> > C: finished reading Email
21:28:08.899 ->
21:28:08.899 -> ****************************
21:28:08.899 -> Number: 234
21:28:08.899 -> UID: 1943
21:28:08.899 -> Attachment: no
21:28:08.899 -> Messsage-ID: 2951f2105fb2c346c57fc7de8bb0be71@smtp-36.iol.local
21:28:08.899 -> Flags: \Recent
21:28:08.899 -> To: mymail@libero.it
21:28:08.899 -> Date: Sat, 23 Mar 2024 21:28:07 +0100
21:28:08.899 -> Timestamp: 1711218487
21:28:08.899 -> Subject: Test e-mail
21:28:08.899 -> Return-Path: mymail@libero.it
21:28:08.899 -> Text Message Charset: utf-8
21:28:08.899 -> Text Message Transfer Encoding: base64
21:28:08.944 ->
21:28:08.944 ->
21:28:08.944 -> #### Listening to mailbox changes...
21:28:08.944 -> > C: listening to INBOX folder changes
21:28:08.944 ->
21:28:08.944 -> #### Polling established
21:28:08.944 -> > C: polling established on March 23, 2024 23:28:08

An email is sent to the INBOX folder now

Non reaction from the Arduno app. Shoud it detect an incomming message ?
I read that IMAP server is able to send push messages to the client when a new message is received. Is it correct that is not necessary to poll the server for the new messages arrival?

Thanks!

2 replies

mobizt Mar 24, 2024
Maintainer

Are you kidding?

21:28:08.533 -> Mailbox status changed
21:28:08.533 -> ----------------------
21:28:08.533 -> Total Messages: 234
21:28:08.533 -> New message 234, has been addedd, reading message...
21:28:08.668 ->
21:28:08.668 -> #### Mailbox listening stopped
21:28:08.668 -> > C: Mailbox listening stopped
21:28:08.715 ->
21:28:08.715 -> #### Get UID...
21:28:08.715 -> > C: get UID
21:28:08.715 ->
21:28:08.715 -> #### UID is 1943
21:28:08.715 -> > C: UID is 1943
21:28:08.715 ->
21:28:08.715 -> #### Fetch message 1, UID: 1943
21:28:08.715 -> > C: send IMAP command, FETCH
21:28:08.715 -> > C: fetch message header
21:28:08.807 ->
21:28:08.807 -> #### Get Flags...
21:28:08.807 -> > C: get Flags
21:28:08.852 ->
21:28:08.852 -> > C: fetch body part header, 1
21:28:08.899 -> > C: Free Heap: 215112
21:28:08.899 ->
21:28:08.899 -> #### Finished reading Email
21:28:08.899 -> > C: finished reading Email
21:28:08.899 ->
21:28:08.899 -> ****************************
21:28:08.899 -> Number: 234
21:28:08.899 -> UID: 1943
21:28:08.899 -> Attachment: no
21:28:08.899 -> Messsage-ID: 2951f2105fb2c346c57fc7de8bb0be71@smtp-36.iol.local
21:28:08.899 -> Flags: \Recent
21:28:08.899 -> To: mymail@libero.it
21:28:08.899 -> Date: Sat, 23 Mar 2024 21:28:07 +0100
21:28:08.899 -> Timestamp: 1711218487
21:28:08.899 -> Subject: Test e-mail
21:28:08.899 -> Return-Path: mymail@libero.it
21:28:08.899 -> Text Message Charset: utf-8
21:28:08.899 -> Text Message Transfer Encoding: base64

mobizt Mar 24, 2024
Maintainer

Is it correct that is not necessary to poll the server for the new messages arrival?

Who will do this for you without polling, scheduling and using timer?

Did you have experiences in MQTT, Webserver, and AsyncTCP programming in Arduino?

Did you see what is inside the loop?

pberna67 · 2024-03-26T22:28:16Z

pberna67
Mar 26, 2024
Author

Dear mobizt

Thank for highlight the row 21:28:08.533 -> Mailbox status changed ; When I sent the new message to the mailbox, I didn't recoglize that the Arduino terminal windows upated it with a very similar data.
So everithing works ! Sorry for the note

However, I woudl like to know who is "Sender" and the "From" fields that seems not be printer out , in the Arduino Terminal windows (see above)

In your code the related section shoud be:

void printMessages(std::vector<IMAP_MSG_Item> &msgItems, bool headerOnly)
....

    if (strlen(msg.from))
        MailClient.printf("From: %s\n", msg.from);
    if (strlen(msg.sender))
        MailClient.printf("Sender: %s\n", msg.sender);

....

Because these two fileds are not printed out, it means that strlen(msg.from) and if (strlen(msg.sender)) are both =0, but it shoudn't be because they are (see the email picture below : ReolinkCamera and mymail@libero.it )

Any idea to investigate more about the reason because these fields are not printed out ?

Thanks

1 reply

mobizt Mar 27, 2024
Maintainer

You can update the library to v3.4.18 for fixing the header issue.

The sender field header normally was not set by most mail client.

pberna67 · 2024-04-04T20:21:08Z

pberna67
Apr 4, 2024
Author

Dear mobizt

I've combined the SMPT and IMAP functionalities to create a demo program which is able to receive as well as send messages. I 'm in the final testing phase and I would like to automatically recover the communication failures, when some temporary disconnection of the WIfi or from the IMAP /SMPT servers happen. I've notice that the #define ESP_MAIL_WIFI_IS_AVAILABLE is able to recover from the WIFI disconnections events, however , I would like to know how to manage the server disconnections, and if possible how to emulate a server disconnection (with Wifi enabled) in the debugging phase of the application. Any suggestions?

Thanks

0 replies

mobizt · 2024-04-04T23:26:00Z

mobizt
Apr 4, 2024
Maintainer

https://github.com/mobizt/ESP-Mail-Client#using-tcp-session-keepalive-in-esp8266-and-esp32

0 replies

mobizt · 2024-04-05T02:21:28Z

mobizt
Apr 5, 2024
Maintainer

Do not use macros that are not presented in the examples, documentation and config file.

The ESP_MAIL_WIFI_IS_AVAILABLE is not for user but used internally which means it can be renamed, removed, unused or changed the definition in the future.

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Receiving a signal from and Email and generate an action #333

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