fix: some idp error messages return unclear (#620)

Signed-off-by: Steve0x2a <stevesough@gmail.com>

idp/github.go

@@ -15,11 +15,13 @@
 package idp
 
 import (
-	"context"
 	"encoding/json"
+	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	"golang.org/x/oauth2"
@@ -60,9 +62,38 @@ func (idp *GithubIdProvider) getConfig() *oauth2.Config {
 	return config
 }
 
+type GithubToken struct {
+	AccessToken string `json:"access_token"`
+	TokenType   string `json:"token_type"`
+	Scope       string `json:"scope"`
+	Error       string `json:"error"`
+}
+
 func (idp *GithubIdProvider) GetToken(code string) (*oauth2.Token, error) {
-	ctx := context.WithValue(context.Background(), oauth2.HTTPClient, idp.Client)
-	return idp.Config.Exchange(ctx, code)
+	params := &struct {
+		Code         string `json:"code"`
+		ClientId     string `json:"client_id"`
+		ClientSecret string `json:"client_secret"`
+	}{code, idp.Config.ClientID, idp.Config.ClientSecret}
+	data, err := idp.postWithBody(params, idp.Config.Endpoint.TokenURL)
+	if err != nil {
+		return nil, err
+	}
+	pToken := &GithubToken{}
+	if err = json.Unmarshal(data, pToken); err != nil {
+		return nil, err
+	}
+	if pToken.Error != "" {
+		return nil, fmt.Errorf("err: %s", pToken.Error)
+	}
+
+	token := &oauth2.Token{
+		AccessToken: pToken.AccessToken,
+		TokenType:   "Bearer",
+	}
+
+	return token, nil
+
 }
 
 //{
@@ -192,3 +223,30 @@ func (idp *GithubIdProvider) GetUserInfo(token *oauth2.Token) (*UserInfo, error)
 	}
 	return &userInfo, nil
 }
+
+func (idp *GithubIdProvider) postWithBody(body interface{}, url string) ([]byte, error) {
+	bs, err := json.Marshal(body)
+	if err != nil {
+		return nil, err
+	}
+	r := strings.NewReader(string(bs))
+	req, _ := http.NewRequest("POST", url, r)
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Content-Type", "application/json")
+	resp, err := idp.Client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	data, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	defer func(Body io.ReadCloser) {
+		err := Body.Close()
+		if err != nil {
+			return
+		}
+	}(resp.Body)
+
+	return data, nil
+}