gtsocial-umbx

token.go (10251B)

---

 // Copyright 2014 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package internal
 
 import (
 	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"math"
 	"mime"
 	"net/http"
 	"net/url"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 )
 
 // Token represents the credentials used to authorize
 // the requests to access protected resources on the OAuth 2.0
 // provider's backend.
 //
 // This type is a mirror of oauth2.Token and exists to break
 // an otherwise-circular dependency. Other internal packages
 // should convert this Token into an oauth2.Token before use.
 type Token struct {
 	// AccessToken is the token that authorizes and authenticates
 	// the requests.
 	AccessToken string
 
 	// TokenType is the type of token.
 	// The Type method returns either this or "Bearer", the default.
 	TokenType string
 
 	// RefreshToken is a token that's used by the application
 	// (as opposed to the user) to refresh the access token
 	// if it expires.
 	RefreshToken string
 
 	// Expiry is the optional expiration time of the access token.
 	//
 	// If zero, TokenSource implementations will reuse the same
 	// token forever and RefreshToken or equivalent
 	// mechanisms for that TokenSource will not be used.
 	Expiry time.Time
 
 	// Raw optionally contains extra metadata from the server
 	// when updating a token.
 	Raw interface{}
 }
 
 // tokenJSON is the struct representing the HTTP response from OAuth2
 // providers returning a token or error in JSON form.
 // https://datatracker.ietf.org/doc/html/rfc6749#section-5.1
 type tokenJSON struct {
 	AccessToken  string         `json:"access_token"`
 	TokenType    string         `json:"token_type"`
 	RefreshToken string         `json:"refresh_token"`
 	ExpiresIn    expirationTime `json:"expires_in"` // at least PayPal returns string, while most return number
 	// error fields
 	// https://datatracker.ietf.org/doc/html/rfc6749#section-5.2
 	ErrorCode        string `json:"error"`
 	ErrorDescription string `json:"error_description"`
 	ErrorURI         string `json:"error_uri"`
 }
 
 func (e *tokenJSON) expiry() (t time.Time) {
 	if v := e.ExpiresIn; v != 0 {
 		return time.Now().Add(time.Duration(v) * time.Second)
 	}
 	return
 }
 
 type expirationTime int32
 
 func (e *expirationTime) UnmarshalJSON(b []byte) error {
 	if len(b) == 0 || string(b) == "null" {
 		return nil
 	}
 	var n json.Number
 	err := json.Unmarshal(b, &n)
 	if err != nil {
 		return err
 	}
 	i, err := n.Int64()
 	if err != nil {
 		return err
 	}
 	if i > math.MaxInt32 {
 		i = math.MaxInt32
 	}
 	*e = expirationTime(i)
 	return nil
 }
 
 // RegisterBrokenAuthHeaderProvider previously did something. It is now a no-op.
 //
 // Deprecated: this function no longer does anything. Caller code that
 // wants to avoid potential extra HTTP requests made during
 // auto-probing of the provider's auth style should set
 // Endpoint.AuthStyle.
 func RegisterBrokenAuthHeaderProvider(tokenURL string) {}
 
 // AuthStyle is a copy of the golang.org/x/oauth2 package's AuthStyle type.
 type AuthStyle int
 
 const (
 	AuthStyleUnknown  AuthStyle = 0
 	AuthStyleInParams AuthStyle = 1
 	AuthStyleInHeader AuthStyle = 2
 )
 
 // authStyleCache is the set of tokenURLs we've successfully used via
 // RetrieveToken and which style auth we ended up using.
 // It's called a cache, but it doesn't (yet?) shrink. It's expected that
 // the set of OAuth2 servers a program contacts over time is fixed and
 // small.
 var authStyleCache struct {
 	sync.Mutex
 	m map[string]AuthStyle // keyed by tokenURL
 }
 
 // ResetAuthCache resets the global authentication style cache used
 // for AuthStyleUnknown token requests.
 func ResetAuthCache() {
 	authStyleCache.Lock()
 	defer authStyleCache.Unlock()
 	authStyleCache.m = nil
 }
 
 // lookupAuthStyle reports which auth style we last used with tokenURL
 // when calling RetrieveToken and whether we have ever done so.
 func lookupAuthStyle(tokenURL string) (style AuthStyle, ok bool) {
 	authStyleCache.Lock()
 	defer authStyleCache.Unlock()
 	style, ok = authStyleCache.m[tokenURL]
 	return
 }
 
 // setAuthStyle adds an entry to authStyleCache, documented above.
 func setAuthStyle(tokenURL string, v AuthStyle) {
 	authStyleCache.Lock()
 	defer authStyleCache.Unlock()
 	if authStyleCache.m == nil {
 		authStyleCache.m = make(map[string]AuthStyle)
 	}
 	authStyleCache.m[tokenURL] = v
 }
 
 // newTokenRequest returns a new *http.Request to retrieve a new token
 // from tokenURL using the provided clientID, clientSecret, and POST
 // body parameters.
 //
 // inParams is whether the clientID & clientSecret should be encoded
 // as the POST body. An 'inParams' value of true means to send it in
 // the POST body (along with any values in v); false means to send it
 // in the Authorization header.
 func newTokenRequest(tokenURL, clientID, clientSecret string, v url.Values, authStyle AuthStyle) (*http.Request, error) {
 	if authStyle == AuthStyleInParams {
 		v = cloneURLValues(v)
 		if clientID != "" {
 			v.Set("client_id", clientID)
 		}
 		if clientSecret != "" {
 			v.Set("client_secret", clientSecret)
 		}
 	}
 	req, err := http.NewRequest("POST", tokenURL, strings.NewReader(v.Encode()))
 	if err != nil {
 		return nil, err
 	}
 	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 	if authStyle == AuthStyleInHeader {
 		req.SetBasicAuth(url.QueryEscape(clientID), url.QueryEscape(clientSecret))
 	}
 	return req, nil
 }
 
 func cloneURLValues(v url.Values) url.Values {
 	v2 := make(url.Values, len(v))
 	for k, vv := range v {
 		v2[k] = append([]string(nil), vv...)
 	}
 	return v2
 }
 
 func RetrieveToken(ctx context.Context, clientID, clientSecret, tokenURL string, v url.Values, authStyle AuthStyle) (*Token, error) {
 	needsAuthStyleProbe := authStyle == 0
 	if needsAuthStyleProbe {
 		if style, ok := lookupAuthStyle(tokenURL); ok {
 			authStyle = style
 			needsAuthStyleProbe = false
 		} else {
 			authStyle = AuthStyleInHeader // the first way we'll try
 		}
 	}
 	req, err := newTokenRequest(tokenURL, clientID, clientSecret, v, authStyle)
 	if err != nil {
 		return nil, err
 	}
 	token, err := doTokenRoundTrip(ctx, req)
 	if err != nil && needsAuthStyleProbe {
 		// If we get an error, assume the server wants the
 		// clientID & clientSecret in a different form.
 		// See https://code.google.com/p/goauth2/issues/detail?id=31 for background.
 		// In summary:
 		// - Reddit only accepts client secret in the Authorization header
 		// - Dropbox accepts either it in URL param or Auth header, but not both.
 		// - Google only accepts URL param (not spec compliant?), not Auth header
 		// - Stripe only accepts client secret in Auth header with Bearer method, not Basic
 		//
 		// We used to maintain a big table in this code of all the sites and which way
 		// they went, but maintaining it didn't scale & got annoying.
 		// So just try both ways.
 		authStyle = AuthStyleInParams // the second way we'll try
 		req, _ = newTokenRequest(tokenURL, clientID, clientSecret, v, authStyle)
 		token, err = doTokenRoundTrip(ctx, req)
 	}
 	if needsAuthStyleProbe && err == nil {
 		setAuthStyle(tokenURL, authStyle)
 	}
 	// Don't overwrite `RefreshToken` with an empty value
 	// if this was a token refreshing request.
 	if token != nil && token.RefreshToken == "" {
 		token.RefreshToken = v.Get("refresh_token")
 	}
 	return token, err
 }
 
 func doTokenRoundTrip(ctx context.Context, req *http.Request) (*Token, error) {
 	r, err := ContextClient(ctx).Do(req.WithContext(ctx))
 	if err != nil {
 		return nil, err
 	}
 	body, err := ioutil.ReadAll(io.LimitReader(r.Body, 1<<20))
 	r.Body.Close()
 	if err != nil {
 		return nil, fmt.Errorf("oauth2: cannot fetch token: %v", err)
 	}
 
 	failureStatus := r.StatusCode < 200 || r.StatusCode > 299
 	retrieveError := &RetrieveError{
 		Response: r,
 		Body:     body,
 		// attempt to populate error detail below
 	}
 
 	var token *Token
 	content, _, _ := mime.ParseMediaType(r.Header.Get("Content-Type"))
 	switch content {
 	case "application/x-www-form-urlencoded", "text/plain":
 		// some endpoints return a query string
 		vals, err := url.ParseQuery(string(body))
 		if err != nil {
 			if failureStatus {
 				return nil, retrieveError
 			}
 			return nil, fmt.Errorf("oauth2: cannot parse response: %v", err)
 		}
 		retrieveError.ErrorCode = vals.Get("error")
 		retrieveError.ErrorDescription = vals.Get("error_description")
 		retrieveError.ErrorURI = vals.Get("error_uri")
 		token = &Token{
 			AccessToken:  vals.Get("access_token"),
 			TokenType:    vals.Get("token_type"),
 			RefreshToken: vals.Get("refresh_token"),
 			Raw:          vals,
 		}
 		e := vals.Get("expires_in")
 		expires, _ := strconv.Atoi(e)
 		if expires != 0 {
 			token.Expiry = time.Now().Add(time.Duration(expires) * time.Second)
 		}
 	default:
 		var tj tokenJSON
 		if err = json.Unmarshal(body, &tj); err != nil {
 			if failureStatus {
 				return nil, retrieveError
 			}
 			return nil, fmt.Errorf("oauth2: cannot parse json: %v", err)
 		}
 		retrieveError.ErrorCode = tj.ErrorCode
 		retrieveError.ErrorDescription = tj.ErrorDescription
 		retrieveError.ErrorURI = tj.ErrorURI
 		token = &Token{
 			AccessToken:  tj.AccessToken,
 			TokenType:    tj.TokenType,
 			RefreshToken: tj.RefreshToken,
 			Expiry:       tj.expiry(),
 			Raw:          make(map[string]interface{}),
 		}
 		json.Unmarshal(body, &token.Raw) // no error checks for optional fields
 	}
 	// according to spec, servers should respond status 400 in error case
 	// https://www.rfc-editor.org/rfc/rfc6749#section-5.2
 	// but some unorthodox servers respond 200 in error case
 	if failureStatus || retrieveError.ErrorCode != "" {
 		return nil, retrieveError
 	}
 	if token.AccessToken == "" {
 		return nil, errors.New("oauth2: server response missing access_token")
 	}
 	return token, nil
 }
 
 // mirrors oauth2.RetrieveError
 type RetrieveError struct {
 	Response         *http.Response
 	Body             []byte
 	ErrorCode        string
 	ErrorDescription string
 	ErrorURI         string
 }
 
 func (r *RetrieveError) Error() string {
 	if r.ErrorCode != "" {
 		s := fmt.Sprintf("oauth2: %q", r.ErrorCode)
 		if r.ErrorDescription != "" {
 			s += fmt.Sprintf(" %q", r.ErrorDescription)
 		}
 		if r.ErrorURI != "" {
 			s += fmt.Sprintf(" %q", r.ErrorURI)
 		}
 		return s
 	}
 	return fmt.Sprintf("oauth2: cannot fetch token: %v\nResponse: %s", r.Response.Status, r.Body)
 }