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|
package client
import (
"context"
"encoding/json"
"fmt"
"net/http"
"net/url"
"strings"
"time"
"code.crute.us/mcrute/ssh-proxy/app/models"
"github.com/google/go-querystring/query"
)
// Oauth2PKCEDeviceClient is not safe for concurrent use and should be
// created anew for each request.
type Oauth2PKCEDeviceClient struct {
Host string
ClientId string
Scope string
pkce *models.PKCEChallenge
interval time.Duration
}
func (c *Oauth2PKCEDeviceClient) discoverHost(ctx context.Context) (*models.OauthDiscoveryMetadata, error) {
u := &url.URL{
Scheme: "https",
Host: c.Host,
Path: models.Oauth2MetadataPath,
}
req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
if err != nil {
return nil, err
}
res, err := http.DefaultClient.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
return nil, fmt.Errorf("Oauth2 discovery request failed with code %d", res.StatusCode)
}
var resp models.OauthDiscoveryMetadata
if err := json.NewDecoder(res.Body).Decode(&resp); err != nil {
return nil, err
}
return &resp, nil
}
func (c *Oauth2PKCEDeviceClient) Authorize(ctx context.Context) (*models.DeviceAuthorizationResponse, error) {
challenge, err := models.NewPKCEChallenge()
if err != nil {
return nil, err
}
c.pkce = challenge
values, err := query.Values(models.AuthorizationRequest{
Challenge: c.pkce.Challenge(),
ChallengeMethod: models.ChallengeS256,
ClientId: c.ClientId,
Scope: c.Scope,
})
if err != nil {
return nil, err
}
md, err := c.discoverHost(ctx)
if err != nil {
return nil, err
}
req, err := http.NewRequestWithContext(ctx, http.MethodPost, md.DeviceAuthorizationEndpoint, strings.NewReader(values.Encode()))
if err != nil {
return nil, err
}
req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
res, err := http.DefaultClient.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
var resError models.Oauth2Error
if err := json.NewDecoder(res.Body).Decode(&resError); err != nil {
return nil, err
}
return nil, resError
}
var resp models.DeviceAuthorizationResponse
if err := json.NewDecoder(res.Body).Decode(&resp); err != nil {
return nil, err
}
c.interval = time.Duration(resp.Interval) * time.Second
if c.interval == 0 {
c.interval = 5 * time.Second
}
return &resp, nil
}
func (c *Oauth2PKCEDeviceClient) fetchToken(ctx context.Context, deviceCode string) (*models.AccessTokenResponse, error) {
values, err := query.Values(models.DeviceAccessTokenRequest{
GrantType: models.DEVICE_CODE_GRANT_TYPE,
DeviceCode: deviceCode,
ClientId: c.ClientId,
CodeVerifier: c.pkce.Verifier,
})
if err != nil {
return nil, err
}
md, err := c.discoverHost(ctx)
if err != nil {
return nil, err
}
req, err := http.NewRequestWithContext(ctx, http.MethodPost, md.TokenEndpoint, strings.NewReader(values.Encode()))
if err != nil {
return nil, err
}
req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
res, err := http.DefaultClient.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
var resError models.Oauth2Error
if err := json.NewDecoder(res.Body).Decode(&resError); err != nil {
return nil, err
}
if resError.Type == models.ErrSlowDown {
c.interval += 5 * time.Second
}
return nil, resError
}
var resp models.AccessTokenResponse
if err := json.NewDecoder(res.Body).Decode(&resp); err != nil {
return nil, err
}
return &resp, nil
}
func (c *Oauth2PKCEDeviceClient) AwaitToken(ctx context.Context, deviceCode string) (*models.AccessTokenResponse, error) {
t := time.NewTicker(c.interval)
defer t.Stop()
res, err := c.fetchToken(ctx, deviceCode)
if err == nil {
return res, nil
} else if e, ok := err.(models.Oauth2Error); ok {
if e.Type == models.ErrSlowDown {
t.Reset(c.interval)
} else if e.Type != models.ErrAuthorizationPending {
return nil, err
}
} else {
return nil, err
}
for {
select {
case <-t.C:
res, err := c.fetchToken(ctx, deviceCode)
if err == nil {
return res, nil
} else if e, ok := err.(models.Oauth2Error); ok {
if e.Type == models.ErrSlowDown {
t.Reset(c.interval)
} else if e.Type != models.ErrAuthorizationPending {
return nil, err
}
} else {
return nil, err
}
case <-ctx.Done():
return nil, fmt.Errorf("Context has expired")
}
}
}
|
