commit 1e9293ac86dd5c1b02251acf654c53b38ebf6126
Author: Andreas Schneider <aksdb@gmx.de>
Date:   Sat Mar 31 15:20:21 2018 +0200

    Implemented folderId query

diff --git a/src/calanonsync/calanonsync.go b/src/calanonsync/calanonsync.go
new file mode 100644
index 0000000..57a66d5
--- /dev/null
+++ b/src/calanonsync/calanonsync.go
@@ -0,0 +1,125 @@
+package main
+
+import (
+	"encoding/xml"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"net/http/cookiejar"
+	"strings"
+	"time"
+)
+
+type FolderId struct {
+	Id string `xml:",attr"`
+}
+
+type CalendarItem struct {
+	Subject string
+	UID     string
+	Start   time.Time
+	End     time.Time
+}
+
+type EWSCalendar struct {
+	httpClient *http.Client
+	url        string
+	username   string
+	password   string
+	items      []CalendarItem
+}
+
+func NewEWSCalendar(url, username, password string) *EWSCalendar {
+	// Prepare a cookie jar so we don't have to provide basic auth credentials multiple times.
+	jar, err := cookiejar.New(nil)
+	if err != nil {
+		panic(err)
+	}
+	return &EWSCalendar{
+		httpClient: &http.Client{
+			Jar: jar,
+		},
+		url:      url,
+		username: username,
+		password: password,
+	}
+}
+
+func (e *EWSCalendar) prepareRequest(body io.Reader) (req *http.Request, err error) {
+	req, err = http.NewRequest(http.MethodPost, e.url, body)
+	req.Header.Set("Content-Type", "text/xml")
+	req.Header.Set("Accept", "text/xml")
+	return
+}
+
+func (e *EWSCalendar) getCalendarFolderID() (id string, err error) {
+	req, err := e.prepareRequest(strings.NewReader(folderIdRequest))
+	if err != nil {
+		return
+	}
+	// For the first request we need an authentication header
+	req.SetBasicAuth(e.username, e.password)
+
+	resp, err := e.httpClient.Do(req)
+	if err != nil {
+		return
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		err = fmt.Errorf("unexpected status when querying folderID: %d", resp.StatusCode)
+		return
+	}
+
+	d := xml.NewDecoder(resp.Body)
+	defer resp.Body.Close()
+
+	for {
+		var t xml.Token
+		t, err = d.Token()
+		if err == io.EOF {
+			err = nil
+			return
+		} else if err != nil {
+			return
+		}
+
+		switch t := t.(type) {
+		case xml.StartElement:
+			if t.Name.Local == "FolderId" {
+				fid := FolderId{}
+				err = d.DecodeElement(&fid, &t)
+				id = fid.Id
+				// The first one is enough
+				return
+			}
+		}
+	}
+}
+
+func main() {
+	e := NewEWSCalendar("https://outlook.live.com/EWS/Exchange.asmx", "", "")
+	id, err := e.getCalendarFolderID()
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	fmt.Println(id)
+}
+
+const folderIdRequest = `<?xml version="1.0" encoding="utf-8"?>
+<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
+  <soap:Header>
+    <t:RequestServerVersion Version="Exchange2013_SP1" />
+  </soap:Header>
+  <soap:Body>
+    <m:GetFolder>
+      <m:FolderShape>
+        <t:BaseShape>AllProperties</t:BaseShape>
+      </m:FolderShape>
+      <m:FolderIds>
+        <t:DistinguishedFolderId Id="calendar" />
+      </m:FolderIds>
+    </m:GetFolder>
+  </soap:Body>
+</soap:Envelope>`