Additional OAuth2 providers (#1010)

* add google+

* sort signin oauth2 providers based on the name so order is always the same

* update auth tip for google+

* add gitlab provider

* add bitbucket provider (and some go fmt)

* add twitter provider

* add facebook provider

* add dropbox provider

* add openid connect provider incl. new format of tips section in "Add New Source"

* lower the amount of disk storage for each session to prevent issues while building cross platform (and disk overflow)

* imports according to goimport and code style

* make it possible to set custom urls to gitlab and github provider (only these could have a different host)

* split up oauth2 into multiple files

* small typo in comment

* fix indention

* fix indentation

* fix new line before external import

* fix layout of signin part

* update "broken" dependency

vendor/github.com/markbates/goth/providers/bitbucket/bitbucket.go

@@ -0,0 +1,206 @@
+// Package bitbucket implements the OAuth2 protocol for authenticating users through Bitbucket.
+package bitbucket
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+
+	"github.com/markbates/goth"
+	"golang.org/x/oauth2"
+	"fmt"
+)
+
+const (
+	authURL         string = "https://bitbucket.org/site/oauth2/authorize"
+	tokenURL        string = "https://bitbucket.org/site/oauth2/access_token"
+	endpointProfile string = "https://api.bitbucket.org/2.0/user"
+	endpointEmail   string = "https://api.bitbucket.org/2.0/user/emails"
+)
+
+// New creates a new Bitbucket provider, and sets up important connection details.
+// You should always call `bitbucket.New` to get a new Provider. Never try to create
+// one manually.
+func New(clientKey, secret, callbackURL string, scopes ...string) *Provider {
+	p := &Provider{
+		ClientKey:           clientKey,
+		Secret:              secret,
+		CallbackURL:         callbackURL,
+		providerName:        "bitbucket",
+	}
+	p.config = newConfig(p, scopes)
+	return p
+}
+
+// Provider is the implementation of `goth.Provider` for accessing Bitbucket.
+type Provider struct {
+	ClientKey    string
+	Secret       string
+	CallbackURL  string
+	HTTPClient   *http.Client
+	config       *oauth2.Config
+	providerName string
+}
+
+// Name is the name used to retrieve this provider later.
+func (p *Provider) Name() string {
+	return p.providerName
+}
+
+// SetName is to update the name of the provider (needed in case of multiple providers of 1 type)
+func (p *Provider) SetName(name string) {
+	p.providerName = name
+}
+
+func (p *Provider) Client() *http.Client {
+	return goth.HTTPClientWithFallBack(p.HTTPClient)
+}
+
+// Debug is a no-op for the bitbucket package.
+func (p *Provider) Debug(debug bool) {}
+
+// BeginAuth asks Bitbucket for an authentication end-point.
+func (p *Provider) BeginAuth(state string) (goth.Session, error) {
+	url := p.config.AuthCodeURL(state)
+	session := &Session{
+		AuthURL: url,
+	}
+	return session, nil
+}
+
+// FetchUser will go to Bitbucket and access basic information about the user.
+func (p *Provider) FetchUser(session goth.Session) (goth.User, error) {
+	sess := session.(*Session)
+	user := goth.User{
+		AccessToken:  sess.AccessToken,
+		Provider:     p.Name(),
+		RefreshToken: sess.RefreshToken,
+		ExpiresAt:    sess.ExpiresAt,
+	}
+
+	if user.AccessToken == "" {
+		// data is not yet retrieved since accessToken is still empty
+		return user, fmt.Errorf("%s cannot get user information without accessToken", p.providerName)
+	}
+
+	response, err := goth.HTTPClientWithFallBack(p.Client()).Get(endpointProfile + "?access_token=" + url.QueryEscape(sess.AccessToken))
+	if err != nil {
+		return user, err
+	}
+	defer response.Body.Close()
+
+	if response.StatusCode != http.StatusOK {
+		return user, fmt.Errorf("%s responded with a %d trying to fetch user information", p.providerName, response.StatusCode)
+	}
+
+	bits, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		return user, err
+	}
+
+	err = json.NewDecoder(bytes.NewReader(bits)).Decode(&user.RawData)
+	if err != nil {
+		return user, err
+	}
+
+	err = userFromReader(bytes.NewReader(bits), &user)
+
+	response, err = goth.HTTPClientWithFallBack(p.Client()).Get(endpointEmail + "?access_token=" + url.QueryEscape(sess.AccessToken))
+	if err != nil {
+		return user, err
+	}
+	defer response.Body.Close()
+
+	bits, err = ioutil.ReadAll(response.Body)
+	if err != nil {
+		return user, err
+	}
+
+	err = emailFromReader(bytes.NewReader(bits), &user)
+	return user, err
+}
+
+func userFromReader(reader io.Reader, user *goth.User) error {
+	u := struct {
+		ID string `json:"uuid"`
+		Links struct {
+			Avatar struct {
+				URL string `json:"href"`
+			} `json:"avatar"`
+		} `json:"links"`
+		Email    string `json:"email"`
+		Username string `json:"username"`
+		Name     string `json:"display_name"`
+		Location string `json:"location"`
+	}{}
+
+	err := json.NewDecoder(reader).Decode(&u)
+	if err != nil {
+		return err
+	}
+
+	user.Name = u.Name
+	user.NickName = u.Username
+	user.AvatarURL = u.Links.Avatar.URL
+	user.UserID = u.ID
+	user.Location = u.Location
+
+	return err
+}
+
+func emailFromReader(reader io.Reader, user *goth.User) error {
+	e := struct {
+		Values []struct {
+			Email string `json:"email"`
+		} `json:"values"`
+	}{}
+
+	err := json.NewDecoder(reader).Decode(&e)
+	if err != nil {
+		return err
+	}
+
+	if len(e.Values) > 0 {
+		user.Email = e.Values[0].Email
+	}
+
+	return err
+}
+
+func newConfig(provider *Provider, scopes []string) *oauth2.Config {
+	c := &oauth2.Config{
+		ClientID:     provider.ClientKey,
+		ClientSecret: provider.Secret,
+		RedirectURL:  provider.CallbackURL,
+		Endpoint: oauth2.Endpoint{
+			AuthURL:  authURL,
+			TokenURL: tokenURL,
+		},
+		Scopes: []string{},
+	}
+
+	for _, scope := range scopes {
+		c.Scopes = append(c.Scopes, scope)
+	}
+
+	return c
+}
+
+//RefreshTokenAvailable refresh token is provided by auth provider or not
+func (p *Provider) RefreshTokenAvailable() bool {
+	return true
+}
+
+//RefreshToken get new access token based on the refresh token
+func (p *Provider) RefreshToken(refreshToken string) (*oauth2.Token, error) {
+	token := &oauth2.Token{RefreshToken: refreshToken}
+	ts := p.config.TokenSource(goth.ContextForClient(p.Client()), token)
+	newToken, err := ts.Token()
+	if err != nil {
+		return nil, err
+	}
+	return newToken, err
+}

vendor/github.com/markbates/goth/providers/bitbucket/session.go

@@ -0,0 +1,61 @@
+package bitbucket
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+	"time"
+
+	"github.com/markbates/goth"
+)
+
+// Session stores data during the auth process with Bitbucket.
+type Session struct {
+	AuthURL      string
+	AccessToken  string
+	RefreshToken string
+	ExpiresAt    time.Time
+}
+
+// GetAuthURL will return the URL set by calling the `BeginAuth` function on the Bitbucket provider.
+func (s Session) GetAuthURL() (string, error) {
+	if s.AuthURL == "" {
+		return "", errors.New(goth.NoAuthUrlErrorMessage)
+	}
+	return s.AuthURL, nil
+}
+
+// Authorize the session with Bitbucket and return the access token to be stored for future use.
+func (s *Session) Authorize(provider goth.Provider, params goth.Params) (string, error) {
+	p := provider.(*Provider)
+	token, err := p.config.Exchange(goth.ContextForClient(p.Client()), params.Get("code"))
+	if err != nil {
+		return "", err
+	}
+
+	if !token.Valid() {
+		return "", errors.New("Invalid token received from provider")
+	}
+
+	s.AccessToken = token.AccessToken
+	s.RefreshToken = token.RefreshToken
+	s.ExpiresAt = token.Expiry
+	return token.AccessToken, err
+}
+
+// Marshal the session into a string
+func (s Session) Marshal() string {
+	b, _ := json.Marshal(s)
+	return string(b)
+}
+
+// UnmarshalSession will unmarshal a JSON string into a session.
+func (p *Provider) UnmarshalSession(data string) (goth.Session, error) {
+	sess := &Session{}
+	err := json.NewDecoder(strings.NewReader(data)).Decode(sess)
+	return sess, err
+}
+
+func (s Session) String() string {
+	return s.Marshal()
+}