如何查看/隐藏IMAP消息的状态

Question

I've read over the go documentation as well as the general imap documentation but can't seem to find the correct way to get the status of a particular message - to know if it is marked as read or unread.

Here's what I've got so far:

// 
//Code that set up 'c' and 'cmd' ...
//
for cmd.InProgress() {
    // Wait for the next response (no timeout)
    c.Recv(-1)

    // Process command data
    for _, rsp = range cmd.Data {
        if err != nil {
            fmt.Println(err)
        }
        header := imap.AsBytes(rsp.MessageInfo().Attrs["RFC822.HEADER"])  // Contains subject, from data
        uid := imap.AsNumber(rsp.MessageInfo().Attrs["UID"])  // Message unique id
        body := imap.AsBytes(rsp.MessageInfo().Attrs["RFC822.TEXT"])  // Message body
        //seenState := imap.AsBytes(rsp.MessageInfo().Attrs["Flags"])
        if msg, err := mail.ReadMessage(bytes.NewReader(header)); msg != nil {
            if err != nil {
                fmt.Println(err)
            }
            //START CUSTOM
            if strings.Contains(msg.Header.Get("Subject"), genUUID()){
                fmt.Println(rsp.Label)
                fmt.Println(rsp.MessageInfo().Attrs["Flags"])
                fmt.Println(c.Status("INBOX", string(uid)))
            }
            //END CUSTOM

For output I get:

FETCH
<nil>
LAOYU10 STATUS "INBOX" (Þ) <nil>

The documentation that I've cited has led me to believe that at least one of my methods should be printing if the message is marked as unseen. What am I missing?

EDIT: I am testing against an inbox (gmail) with four messages. The first two are read and second two are unread. Here is the output for all four messages.

FETCH
<nil>
SIHLB7 STATUS "INBOX" (Û) <nil>
FETCH
<nil>
SIHLB8 STATUS "INBOX" (Ü) <nil>
FETCH
<nil>
SIHLB9 STATUS "INBOX" (Ý) <nil>
FETCH
<nil>
SIHLB10 STATUS "INBOX" (Þ) <nil>

Answer 1

A Couple things to note, make sure you're actually requesting the flags field in your imap request. If you're issuing a fetch, then you'll have to pass in "FLAGS" as an argument to Fetch, additionally, the flags attribute in Attrs is case sensitive, so you'll need rsp.MessageInfo().Attrs["FLAGS"]. Below is a working example of using imap in Gmail with the go-imap library, run it with GMAIL_EMAIL=email.address GMAIL_PASSWD=mypassword go run go_file.go

package main

import (
    "code.google.com/p/go-imap/go1/imap"
    "crypto/rand"
    "crypto/tls"
    "fmt"
    "os"
    "time"
)

func main() {
    label := "INBOX"
    email := os.Getenv("GMAIL_EMAIL")
    passwd := os.Getenv("GMAIL_PASSWD")

    conf := &tls.Config{
        Rand: rand.Reader,
    }

    c, err := imap.DialTLS("imap.gmail.com:993", conf)
    if err != nil {
        panic("Failed to connect")
    }

    defer c.Logout(30 * time.Second)

    c.Data = nil

    if c.Caps["STARTTLS"] {
        c.StartTLS(nil)
    }

    // Authenticate
    if c.State() == imap.Login {
        c.Login(email, passwd)
    }

    if c.State() != imap.Auth {
        panic("Authentication error")
    }

    c.Select(label, true)

    set, _ := imap.NewSeqSet("*")

    cmd, err := c.Fetch(set, "FLAGS", "UID")
    if err != nil {
        panic("Bad fetch command")
    }
    _, err = cmd.Result(imap.OK)
    if err != nil {
        panic("Bad fetch response")
    }
    for _, rsp := range cmd.Data {
        seen := false
        for _, flag := range imap.AsList(rsp.MessageInfo().Attrs["FLAGS"]) {
            if flag == "\\Seen" {
                seen = true
            }
        }

        if seen {
            fmt.Printf("Message %d has been read!
", imap.AsNumber(rsp.MessageInfo().Attrs["UID"]))
        } else {
            fmt.Printf("Message %d has been not been read!
", imap.AsNumber(rsp.MessageInfo().Attrs["UID"]))
        }
    }
}