emersion/go-imap - How to retrieve and list unseen messages

Question

I'm trying to use this implementation of IMAP protocol but it seems to be impossible to retrieve unseen messages from the mailbox.

Here's my code.

package main

import (
    "emailmonitor/util"
    "fmt"
)

func main() {

    serverGmail := util.NewServerGmail()

    serverGmail.Connect()
    serverGmail.Login()
    serverGmail.ListUnseenMessages()

}

//-----------------------------------------

package util

import (
    "io/ioutil"
    "log"
    "net/mail"
    "net/smtp"

    imap "github.com/emersion/go-imap"
    "github.com/emersion/go-imap/client"
)

type ServerGmail struct {
    user    string
    pass    string
    erro    string
    cliente *client.Client
}

func NewServerGmail() *ServerGmail {
    serverGmail := &ServerGmail{}
    serverGmail.user = "xxxxxx@gmail.com"
    serverGmail.pass = "xxxxx"
    serverGmail.erro = ""

    return serverGmail
}

func (serverGmail *ServerGmail) Connect() {
    // Connect to server
    cliente, erro := client.DialTLS("smtp.gmail.com:993", nil)
    if erro != nil {
        serverGmail.erro = erro.Error()
    }
    log.Println("Connected")

    serverGmail.cliente = cliente

}

func (serverGmail *ServerGmail) Login() {
    // Login
    if erro := serverGmail.cliente.Login(serverGmail.user, serverGmail.pass); erro != nil {
        serverGmail.erro = erro.Error()
    }
    log.Println("Logged")

}

func (serverGmail *ServerGmail) setLabelBox(label string) *imap.MailboxStatus {
    mailbox, erro := serverGmail.cliente.Select(label, true)
    if erro != nil {
        serverGmail.erro = erro.Error()
    }
    return mailbox
}

func (serverGmail *ServerGmail) ListUnseenMessages() {
    mailbox := serverGmail.setLabelBox("INBOX")
    log.Println(mailbox.Unseen)
}

This line log.Println(mailbox.Unseen) prints 0 (zero) messages and as described in the docs should be "The number of unread messages". I tried with UnseenSeqNum "The sequence number of the first unseen message in the mailbox" property and also prints 0 (zero).

Its just a start but I wonder from there, how could I retrieve the unseen messages.

Answer 1

I've done this before, here an extract of my code :

criteria := imap.NewSearchCriteria()
criteria.WithoutFlags = []string{"\\Seen"}
uids, err := c.Search(criteria)
if err != nil {
    log.Println(err)
}
seqset := new(imap.SeqSet)
seqset.AddNum(uids...)
section := &imap.BodySectionName{}
items := []imap.FetchItem{imap.FetchEnvelope, imap.FetchFlags, imap.FetchInternalDate, section.FetchItem()}
messages := make(chan *imap.Message)
err = c.Fetch(seqset, items, messages)