chore: migrate to gitea

vendor/cloud.google.com/go/auth/credentials/internal/stsexchange/sts_exchange.go

@@ -0,0 +1,167 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stsexchange
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+
+	"cloud.google.com/go/auth"
+	"cloud.google.com/go/auth/internal"
+	"github.com/googleapis/gax-go/v2/internallog"
+)
+
+const (
+	// GrantType for a sts exchange.
+	GrantType = "urn:ietf:params:oauth:grant-type:token-exchange"
+	// TokenType for a sts exchange.
+	TokenType = "urn:ietf:params:oauth:token-type:access_token"
+
+	jwtTokenType = "urn:ietf:params:oauth:token-type:jwt"
+)
+
+// Options stores the configuration for making an sts exchange request.
+type Options struct {
+	Client         *http.Client
+	Logger         *slog.Logger
+	Endpoint       string
+	Request        *TokenRequest
+	Authentication ClientAuthentication
+	Headers        http.Header
+	// ExtraOpts are optional fields marshalled into the `options` field of the
+	// request body.
+	ExtraOpts    map[string]interface{}
+	RefreshToken string
+}
+
+// RefreshAccessToken performs the token exchange using a refresh token flow.
+func RefreshAccessToken(ctx context.Context, opts *Options) (*TokenResponse, error) {
+	data := url.Values{}
+	data.Set("grant_type", "refresh_token")
+	data.Set("refresh_token", opts.RefreshToken)
+	return doRequest(ctx, opts, data)
+}
+
+// ExchangeToken performs an oauth2 token exchange with the provided endpoint.
+func ExchangeToken(ctx context.Context, opts *Options) (*TokenResponse, error) {
+	data := url.Values{}
+	data.Set("audience", opts.Request.Audience)
+	data.Set("grant_type", GrantType)
+	data.Set("requested_token_type", TokenType)
+	data.Set("subject_token_type", opts.Request.SubjectTokenType)
+	data.Set("subject_token", opts.Request.SubjectToken)
+	data.Set("scope", strings.Join(opts.Request.Scope, " "))
+	if opts.ExtraOpts != nil {
+		opts, err := json.Marshal(opts.ExtraOpts)
+		if err != nil {
+			return nil, fmt.Errorf("credentials: failed to marshal additional options: %w", err)
+		}
+		data.Set("options", string(opts))
+	}
+	return doRequest(ctx, opts, data)
+}
+
+func doRequest(ctx context.Context, opts *Options, data url.Values) (*TokenResponse, error) {
+	opts.Authentication.InjectAuthentication(data, opts.Headers)
+	encodedData := data.Encode()
+	logger := internallog.New(opts.Logger)
+
+	req, err := http.NewRequestWithContext(ctx, "POST", opts.Endpoint, strings.NewReader(encodedData))
+	if err != nil {
+		return nil, fmt.Errorf("credentials: failed to properly build http request: %w", err)
+
+	}
+	for key, list := range opts.Headers {
+		for _, val := range list {
+			req.Header.Add(key, val)
+		}
+	}
+	req.Header.Set("Content-Length", strconv.Itoa(len(encodedData)))
+
+	logger.DebugContext(ctx, "sts token request", "request", internallog.HTTPRequest(req, []byte(encodedData)))
+	resp, body, err := internal.DoRequest(opts.Client, req)
+	if err != nil {
+		return nil, fmt.Errorf("credentials: invalid response from Secure Token Server: %w", err)
+	}
+	logger.DebugContext(ctx, "sts token response", "response", internallog.HTTPResponse(resp, body))
+	if c := resp.StatusCode; c < http.StatusOK || c > http.StatusMultipleChoices {
+		return nil, fmt.Errorf("credentials: status code %d: %s", c, body)
+	}
+	var stsResp TokenResponse
+	if err := json.Unmarshal(body, &stsResp); err != nil {
+		return nil, fmt.Errorf("credentials: failed to unmarshal response body from Secure Token Server: %w", err)
+	}
+
+	return &stsResp, nil
+}
+
+// TokenRequest contains fields necessary to make an oauth2 token
+// exchange.
+type TokenRequest struct {
+	ActingParty struct {
+		ActorToken     string
+		ActorTokenType string
+	}
+	GrantType          string
+	Resource           string
+	Audience           string
+	Scope              []string
+	RequestedTokenType string
+	SubjectToken       string
+	SubjectTokenType   string
+}
+
+// TokenResponse is used to decode the remote server response during
+// an oauth2 token exchange.
+type TokenResponse struct {
+	AccessToken     string `json:"access_token"`
+	IssuedTokenType string `json:"issued_token_type"`
+	TokenType       string `json:"token_type"`
+	ExpiresIn       int    `json:"expires_in"`
+	Scope           string `json:"scope"`
+	RefreshToken    string `json:"refresh_token"`
+}
+
+// ClientAuthentication represents an OAuth client ID and secret and the
+// mechanism for passing these credentials as stated in rfc6749#2.3.1.
+type ClientAuthentication struct {
+	AuthStyle    auth.Style
+	ClientID     string
+	ClientSecret string
+}
+
+// InjectAuthentication is used to add authentication to a Secure Token Service
+// exchange request.  It modifies either the passed url.Values or http.Header
+// depending on the desired authentication format.
+func (c *ClientAuthentication) InjectAuthentication(values url.Values, headers http.Header) {
+	if c.ClientID == "" || c.ClientSecret == "" || values == nil || headers == nil {
+		return
+	}
+	switch c.AuthStyle {
+	case auth.StyleInHeader:
+		plainHeader := c.ClientID + ":" + c.ClientSecret
+		headers.Set("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(plainHeader)))
+	default:
+		values.Set("client_id", c.ClientID)
+		values.Set("client_secret", c.ClientSecret)
+	}
+}