Getting Started

Install

go get github.com/floatpane/jwz-go

Requires Go 1.26+.

Minimal example

package main

import (
    "fmt"
    "time"

    "github.com/floatpane/jwz-go"
)

func main() {
    base := time.Now()
    threads := jwz.Build([]jwz.EmailHeader{
        {ID: "<a@example>", Subject: "Release plan", Date: base, EmailID: "1", Sender: "alice"},
        {ID: "<b@example>", InReplyTo: "<a@example>",
            Subject: "Re: Release plan", Date: base.Add(time.Minute), EmailID: "2", Sender: "bob"},
        {ID: "<c@example>", References: []string{"<a@example>", "<b@example>"},
            Subject: "Re: Re: Release plan", Date: base.Add(2 * time.Minute), EmailID: "3", Sender: "carol"},
    })

    for _, t := range threads {
        fmt.Printf("%s (%d messages, last %s)\n", t.Subject, t.Count, t.LatestAt)
        walk(t.Root, 0)
    }
}

func walk(n *jwz.ThreadNode, depth int) {
    if n == nil {
        return
    }
    fmt.Printf("%s- %s (%s)\n", indent(depth), n.Sender, n.EmailID)
    for _, c := range n.Children {
        walk(c, depth+1)
    }
}

func indent(n int) string {
    s := ""
    for i := 0; i < n; i++ {
        s += "  "
    }
    return s
}

Input

You build a []jwz.EmailHeader. Most fields map 1:1 to RFC 5322:

EmailID is what you'll get back in the ThreadNode.EmailID field so you can look the message up in your own store.

Output

jwz.Build returns []jwz.Thread. Each Thread has:

• Root — top-of-tree *ThreadNode. May be a placeholder (empty EmailID) if the thread's true root was never seen and several children share a common missing parent.
• Count — number of real messages in the thread.
• LatestAt — most recent Date in the thread.
• Subject — canonicalized subject (lowercased, prefixes stripped).
• Senders — distinct sender list in tree order, deduped.