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- package writefreely
-
- import (
- "context"
- "encoding/json"
- "github.com/gorilla/sessions"
- "github.com/guregu/null/zero"
- "github.com/writeas/impart"
- "github.com/writeas/web-core/auth"
- "github.com/writeas/web-core/log"
- "github.com/writeas/writefreely/config"
- "io"
- "io/ioutil"
- "net/http"
- "net/url"
- "strings"
- "time"
- )
-
- // TokenResponse contains data returned when a token is created either
- // through a code exchange or using a refresh token.
- type TokenResponse struct {
- AccessToken string `json:"access_token"`
- ExpiresIn int `json:"expires_in"`
- RefreshToken string `json:"refresh_token"`
- TokenType string `json:"token_type"`
- }
-
- // InspectResponse contains data returned when an access token is inspected.
- type InspectResponse struct {
- ClientID string `json:"client_id"`
- UserID int64 `json:"user_id"`
- ExpiresAt time.Time `json:"expires_at"`
- Username string `json:"username"`
- Email string `json:"email"`
- }
-
- // tokenRequestMaxLen is the most bytes that we'll read from the /oauth/token
- // endpoint. One megabyte is plenty.
- const tokenRequestMaxLen = 1000000
-
- // infoRequestMaxLen is the most bytes that we'll read from the
- // /oauth/inspect endpoint.
- const infoRequestMaxLen = 1000000
-
- // OAuthDatastoreProvider provides a minimal interface of data store, config,
- // and session store for use with the oauth handlers.
- type OAuthDatastoreProvider interface {
- DB() OAuthDatastore
- Config() *config.Config
- SessionStore() sessions.Store
- }
-
- // OAuthDatastore provides a minimal interface of data store methods used in
- // oauth functionality.
- type OAuthDatastore interface {
- GenerateOAuthState(context.Context) (string, error)
- ValidateOAuthState(context.Context, string) error
- GetIDForRemoteUser(context.Context, int64) (int64, error)
- CreateUser(*config.Config, *User, string) error
- RecordRemoteUserID(context.Context, int64, int64) error
- GetUserForAuthByID(int64) (*User, error)
- }
-
- type HttpClient interface {
- Do(req *http.Request) (*http.Response, error)
- }
-
- type oauthHandler struct {
- HttpClient HttpClient
- }
-
- // buildAuthURL returns a URL used to initiate authentication.
- func buildAuthURL(app OAuthDatastoreProvider, ctx context.Context, clientID, authLocation, callbackURL string) (string, error) {
- state, err := app.DB().GenerateOAuthState(ctx)
- if err != nil {
- return "", err
- }
-
- u, err := url.Parse(authLocation)
- if err != nil {
- return "", err
- }
- q := u.Query()
- q.Set("client_id", clientID)
- q.Set("redirect_uri", callbackURL)
- q.Set("response_type", "code")
- q.Set("state", state)
- u.RawQuery = q.Encode()
-
- return u.String(), nil
- }
-
- func (h oauthHandler) viewOauthInit(app OAuthDatastoreProvider, w http.ResponseWriter, r *http.Request) error {
- location, err := buildAuthURL(app, r.Context(), app.Config().App.OAuthClientID, app.Config().App.OAuthProviderAuthLocation, app.Config().App.OAuthClientCallbackLocation)
- if err != nil {
- log.ErrorLog.Println(err)
- return impart.HTTPError{Status: http.StatusInternalServerError, Message: "Could not prepare OAuth redirect URL."}
- }
- http.Redirect(w, r, location, http.StatusTemporaryRedirect)
- return nil
- }
-
- func (h oauthHandler) viewOauthCallback(app OAuthDatastoreProvider, w http.ResponseWriter, r *http.Request) error {
- ctx := r.Context()
-
- code := r.FormValue("code")
- state := r.FormValue("state")
-
- err := app.DB().ValidateOAuthState(ctx, state)
- if err != nil {
- return err
- }
-
- tokenResponse, err := h.exchangeOauthCode(app, ctx, code)
- if err != nil {
- return err
- }
-
- // Now that we have the access token, let's use it real quick to make sur
- // it really really works.
- tokenInfo, err := h.inspectOauthAccessToken(app, ctx, tokenResponse.AccessToken)
- if err != nil {
- return err
- }
-
- localUserID, err := app.DB().GetIDForRemoteUser(ctx, tokenInfo.UserID)
- if err != nil {
- return err
- }
-
- if localUserID == -1 {
- // We don't have, nor do we want, the password from the origin, so we
- //create a random string. If the user needs to set a password, they
- //can do so through the settings page or through the password reset
- //flow.
- randPass, err := randString(14)
- if err != nil {
- return err
- }
- hashedPass, err := auth.HashPass([]byte(randPass))
- if err != nil {
- log.ErrorLog.Println(err)
- return impart.HTTPError{http.StatusInternalServerError, "Could not create password hash."}
- }
- newUser := &User{
- Username: tokenInfo.Username,
- HashedPass: hashedPass,
- HasPass: true,
- Email: zero.NewString("", tokenInfo.Email != ""),
- Created: time.Now().Truncate(time.Second).UTC(),
- }
-
- err = app.DB().CreateUser(app.Config(), newUser, newUser.Username)
- if err != nil {
- return err
- }
-
- err = app.DB().RecordRemoteUserID(ctx, newUser.ID, tokenInfo.UserID)
- if err != nil {
- return err
- }
-
- return loginOrFail(app, w, r, newUser)
- }
-
- user, err := app.DB().GetUserForAuthByID(localUserID)
- if err != nil {
- return err
- }
- return loginOrFail(app, w, r, user)
- }
-
- func (h oauthHandler) exchangeOauthCode(app OAuthDatastoreProvider, ctx context.Context, code string) (*TokenResponse, error) {
- form := url.Values{}
- form.Add("grant_type", "authorization_code")
- form.Add("redirect_uri", app.Config().App.OAuthClientCallbackLocation)
- form.Add("code", code)
- req, err := http.NewRequest("POST", app.Config().App.OAuthProviderTokenLocation, strings.NewReader(form.Encode()))
- if err != nil {
- return nil, err
- }
- req.WithContext(ctx)
- req.Header.Set("User-Agent", "writefreely")
- req.Header.Set("Accept", "application/json")
- req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
- req.SetBasicAuth(app.Config().App.OAuthClientID, app.Config().App.OAuthClientSecret)
-
- resp, err := h.HttpClient.Do(req)
- if err != nil {
- return nil, err
- }
-
- // Nick: I like using limited readers to reduce the risk of an endpoint
- // being broken or compromised.
- lr := io.LimitReader(resp.Body, tokenRequestMaxLen)
- body, err := ioutil.ReadAll(lr)
- if err != nil {
- return nil, err
- }
-
- var tokenResponse TokenResponse
- err = json.Unmarshal(body, &tokenResponse)
- if err != nil {
- return nil, err
- }
- return &tokenResponse, nil
- }
-
- func (h oauthHandler) inspectOauthAccessToken(app OAuthDatastoreProvider, ctx context.Context, accessToken string) (*InspectResponse, error) {
- req, err := http.NewRequest("GET", app.Config().App.OAuthProviderInspectLocation, nil)
- if err != nil {
- return nil, err
- }
- req.WithContext(ctx)
- req.Header.Set("User-Agent", "writefreely")
- req.Header.Set("Accept", "application/json")
- req.Header.Set("Authorization", "Bearer "+accessToken)
-
- resp, err := h.HttpClient.Do(req)
- if err != nil {
- return nil, err
- }
-
- // Nick: I like using limited readers to reduce the risk of an endpoint
- // being broken or compromised.
- lr := io.LimitReader(resp.Body, infoRequestMaxLen)
- body, err := ioutil.ReadAll(lr)
- if err != nil {
- return nil, err
- }
-
- var inspectResponse InspectResponse
- err = json.Unmarshal(body, &inspectResponse)
- if err != nil {
- return nil, err
- }
- return &inspectResponse, nil
- }
-
- func loginOrFail(app OAuthDatastoreProvider, w http.ResponseWriter, r *http.Request, user *User) error {
- session, err := app.SessionStore().Get(r, cookieName)
- if err != nil {
- return err
- }
- session.Values[cookieUserVal] = user.Cookie()
- if err = session.Save(r, w); err != nil {
- return err
- }
- http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
- return nil
- }
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