add oauth flow routes

pkg/apis/google/google.go

@@ -1,6 +1,17 @@
 package google
 
-import "net/url"
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"go-cal/pkg/config"
+	"go-cal/pkg/types"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"time"
+)
 
 var baseURL = "https://www.googleapis.com/"
 
@@ -22,3 +33,130 @@ func getHeaders() map[string]string {
 
 	return obj
 }
+
+// OAuthExchangeCodeToToken -
+func OAuthExchangeCodeToToken(code string) (token types.GoogleAuthToken, err error) {
+	conf := config.Get()
+	if conf == nil {
+		return token, errors.New("config not init")
+	}
+
+	u, err := url.Parse(conf.Google.TokenURL)
+	if err != nil {
+		return
+	}
+
+	qs := url.Values{}
+	qs.Set("code", code)
+	qs.Set("client_id", conf.Google.ClientID)
+	qs.Set("client_secret", conf.Google.ClientSecret)
+	qs.Set("redirect_uri", conf.Google.RedirectURL)
+	qs.Set("grant_type", "authorization_code")
+
+	reader := bytes.NewReader([]byte(qs.Encode()))
+
+	req, err := http.NewRequest("POST", fmt.Sprintf("%s", u.String()), reader)
+	if err != nil {
+		return
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return
+	}
+	defer resp.Body.Close()
+
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return
+	}
+	err = json.Unmarshal(b, &token)
+	if err != nil {
+		return
+	}
+	return
+}
+
+// OAuthRefreshToken -
+func OAuthRefreshToken(refreshToken string) (token string, expiresIn int64, err error) {
+	if len(refreshToken) == 0 {
+		return "", 0, errors.New("refresh token is empty")
+	}
+
+	conf := config.Get()
+	if conf == nil {
+		return "", 0, errors.New("config not init")
+	}
+
+	u, err := url.Parse(conf.Google.TokenURL)
+	if err != nil {
+		return
+	}
+
+	qs := url.Values{}
+	qs.Set("client_id", conf.Google.ClientID)
+	qs.Set("client_secret", conf.Google.ClientSecret)
+	qs.Set("grant_type", "refresh_token")
+
+	reader := bytes.NewReader([]byte(qs.Encode()))
+
+	req, err := http.NewRequest("POST", u.String(), reader)
+	if err != nil {
+		return
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return
+	}
+	defer resp.Body.Close()
+
+	var tokenData types.GoogleAuthToken
+	err = json.NewDecoder(resp.Body).Decode(&tokenData)
+	if err != nil {
+		return
+	}
+	tokenData.ExpiresIn += time.Now().Unix()
+
+	return tokenData.AccessToken, tokenData.ExpiresIn, nil
+}
+
+// GetTokenInfo -
+func GetTokenInfo(token string) (expire int64, err error) {
+	u, err := url.Parse("https://oauth2.googleapis.com/tokeninfo")
+	if err != nil {
+		return
+	}
+
+	body := struct {
+		Azp        string      `json:"azp"`
+		Aud        string      `json:"aud"`
+		Scope      string      `json:"scope"`
+		Exp        json.Number `json:"exp"`
+		ExpiresIn  json.Number `json:"expires_in"`
+		AccessType string      `json:"access_type"`
+	}{}
+
+	qs := url.Values{}
+	qs.Set("access_token", token)
+
+	resp, err := http.Get(fmt.Sprintf("%s?%s", u.String(), qs.Encode()))
+	if err != nil {
+		return
+	}
+	defer resp.Body.Close()
+
+	err = json.NewDecoder(resp.Body).Decode(&body)
+	if err != nil {
+		return
+	}
+
+	expTime, err := body.Exp.Int64()
+	if err != nil {
+		return
+	}
+
+	return expTime, nil
+}