initialtoken.go

package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"os"
	"strings"
	"time"

	"golang.org/x/oauth2"
)

var scopes = []string{"smartRead"}

type tokenResponse struct {
	AccessToken  string `json:"access_token"`
	RefreshToken string `json:"refresh_token"`
	ExpiresIn    int    `json:"expires_in"` // nonstandard
	TokenType    string `json:"token_type"`
}

func fetchPinChallenge() (string, string, error) {
	uv := url.Values{
		"response_type": {"ecobeePin"},
		"client_id":     {*appID},
		"scope":         {strings.Join(scopes, ",")},
	}
	u := url.URL{
		Scheme:   "https",
		Host:     "api.ecobee.com",
		Path:     "authorize",
		RawQuery: uv.Encode(),
	}

	resp, err := http.Get(u.String())
	if err != nil {
		return "", "", fmt.Errorf("error retrieving response: %s", err)
	}

	defer resp.Body.Close()

	var r struct { // pinResponse
		EcobeePin string `json:"ecobeePin"`
		Code      string `json:"code"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
		return "", "", fmt.Errorf("unable to decode response: %v", r)
	}

	return r.EcobeePin, r.Code, nil
}

func fetchInitialToken(key, value string) (*oauth2.Token, error) {
	uv := url.Values{
		"grant_type": {"ecobeePin"},
		"client_id":  {*appID},
		key:          {value},
	}

	u := url.URL{
		Scheme:   "https",
		Host:     "api.ecobee.com",
		Path:     "token",
		RawQuery: uv.Encode(),
	}
	resp, err := http.PostForm(u.String(), nil)
	if err != nil {
		return nil, fmt.Errorf("error POSTing request: %s", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return nil, fmt.Errorf("invalid response: %v", resp.Status)
	}

	var tr tokenResponse
	if err := json.NewDecoder(resp.Body).Decode(&tr); err != nil {
		return nil, fmt.Errorf("error unmarshalling response: %s", err)
	}

	return &oauth2.Token{
		AccessToken:  tr.AccessToken,
		TokenType:    tr.TokenType,
		RefreshToken: tr.RefreshToken,
		Expiry:       time.Now().Add(time.Duration(tr.ExpiresIn) * time.Second),
	}, nil
}

var (
	tokenFile = flag.String("token-file", os.ExpandEnv("${HOME}/.ecobee-token"), "Where to store the OAuth tokens.")
	appID     = flag.String("app-id", "", "Ecobee App ID")
)

func main() {
	flag.Parse()

	pin, code, err := fetchPinChallenge()
	if err != nil {
		log.Fatalf("unable to get PIN challenge: %v", err)
	}

	fmt.Printf("Pin is %q\nPress <enter> after authorizing it on https://www.ecobee.com/consumerportal in the menu under 'My Apps'\n", pin)
	fmt.Scanln()

	tok, err := fetchInitialToken("code", code)
	if err != nil {
		log.Fatalf("unable to get token: %v\n", err)
	}

	f, err := os.Create(*tokenFile)
	if err != nil {
		log.Fatalf("unable to open token file: %v", err)
	}
	defer f.Close()

	if err := json.NewEncoder(f).Encode(&tok); err != nil {
		log.Fatalf("JSON encode error: %v", err)
	}
}