ical.go

package ical

import "time"

type Calendar struct {
  Prodid, Method string
  Events []Event
}

func (c Calendar) String() string {

  s := "BEGIN:VCALENDAR\n"

  // supported version is 2.0
  s += "VERSION:2.0\n"
  // GREGORIAN is the only available value in version 2.0 (https://tools.ietf.org/html/rfc2445#section-4.7.1)
  s += "CALSCALE:GREGORIAN\n"

  if c.Prodid != "" {
    s += "PRODID:" + c.Prodid + "\n"
  }
  if c.Method != "" {
    s += "METHOD:" + c.Method + "\n"
  }

  if c.Events != nil && len(c.Events) > 0 {
    for _, event := range c.Events {
      s += event.String()
    }
  }

  s += "END:VCALENDAR"
  return s
}

type Event struct {
  Uid, Summary, Description, Location string
  Dtstamp, Dtstart, Dtend time.Time
  Organizer Person
  Attendees []Person
}

func (e Event) String() string {

  s := "BEGIN:VEVENT\n"
  s += "UID:" + e.Uid + "\n"
  s += "ORGANIZER;" + e.Organizer.String()
  s += "DTSTAMP:" + formatTime(e.Dtstamp) + "\n"
  s += "DTSTART:" + formatTime(e.Dtstart) + "\n"
  s += "DTEND:" + formatTime(e.Dtend) + "\n"
  s += "SUMMARY:" + e.Summary + "\n"
  s += "DESCRIPTION:" + e.Description + "\n"
  s += "LOCATION:" + e.Location + "\n"
  for _, attendee := range e.Attendees {
    s += "ATTENDEE;" + attendee.String()
  }
  s += "END:VEVENT\n"

  return s
}

type Person struct {
  Cn, Mailto string
}

func (o Person) String() string {
  return "CN=" + o.Cn + ":MAILTO:" + o.Mailto + "\n"
}

func formatTime(t time.Time) string {
  return t.Format("20060102T150405Z")
}

main.go

package main

import (
  "github.com/scorredoira/email"
  "github.com/eluleci/ical"
  "net/smtp"
  "fmt"
  "bytes"
  "time"
)

func main() {

  ics := generateIcs()

  _ = ics

  to := []string{"recipient@company.com"}
  cc := []string{"cc@company.com"}
  bcc := []string{"bcc@company.com"}
  sendEventEmail(to, cc, bcc, ics)
}

func generateIcs() string {

  eventId := "uniqueEventId"
  createdAt := time.Unix(1458819901, 0)
  startDate := time.Unix(1458819901, 0)
  endDate := time.Unix(1458822600, 0)
  summary := "Event title"
  description := "Event description"
  location := "Some location"

  organizer := ical.Person{"Organizer Person", "organizer@company.com"}
  attendee1 := ical.Person{"First Attendee", "first@attendee.com"}
  attendee2 := ical.Person{"Second Attendee", "second@attendee.com"}
  event := ical.Event{eventId, summary, description, location, createdAt, startDate, endDate, organizer, []ical.Person{attendee1, attendee2}}

  ics := ical.Calendar{}
  ics.Prodid = "-//Mentornity//NONSGML v1.0//EN"
  ics.Events = []ical.Event{event}
  fmt.Println(ics)
  return ics.String()
}

func sendEventEmail(to, cc, bcc []string, ics string) {

  senderName := ""
  senderEmail := ""
  senderEmailPassword := ""
  smtpServer := "smtp.yandex.com.tr"
  smtpPort := "587"

  message := email.NewMessage("Sample event mail", "This mail should contain an event file.")
  message.From = senderEmail
  message.To = to
  message.Cc = cc
  message.Bcc = bcc

  var buf bytes.Buffer
  buf.Write([]byte(ics))

  aErr := message.AttachBuffer("meeting.ics", buf.Bytes(), false)
  if aErr != nil {
      fmt.Println(aErr)
  }

  auth := smtp.PlainAuth(senderName, senderEmail, senderEmailPassword, smtpServer)
  err := email.Send(smtpServer + ":" + smtpPort, auth, message)
  fmt.Println(err)
}