refactor: Move GetToken method into auth client and rename auth client from Client to Auth

api/api.go

@@ -41,7 +41,7 @@ const HelixBaseUrl = "https://api.twitch.tv/helix"
 type API struct {
 	client  *http.Client
 	baseUrl *url.URL
-	Auth    *auth.Client
+	Auth    *auth.Auth
 
 	Ads           *ads.Ads
 	Analytics     *analytics.Analytics
@@ -73,7 +73,7 @@ type API struct {
 	Whispers      *whispers.Whispers
 }
 
-func New(client *http.Client, baseUrl *url.URL, authClient *auth.Client) *API {
+func New(client *http.Client, baseUrl *url.URL, authClient *auth.Auth) *API {
 	return &API{
 		client:  client,
 		baseUrl: baseUrl,
@@ -117,7 +117,7 @@ func NewDefault(clientId, clientSecret, redirectUri string) *API {
 		},
 	}
 	baseUrl, _ := url.Parse(HelixBaseUrl)
-	authClient := auth.NewClient(clientId, clientSecret, redirectUri)
+	authClient := auth.New(clientId, clientSecret, redirectUri)
 
 	return New(client, baseUrl, authClient)
 }

auth/auth.go

@@ -0,0 +1,118 @@
+package auth
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/google/go-querystring/query"
+)
+
+type Auth struct {
+	client *http.Client
+
+	clientId     string
+	clientSecret string
+	redirectUri  string
+
+	stateStorage StateStorage
+}
+
+func New(clientId string, clientSecret string, redirectUri string) *Auth {
+	return NewWithClient(clientId, clientSecret, redirectUri, http.DefaultClient)
+}
+
+func NewWithClient(clientId string, clientSecret string, redirectUri string, client *http.Client) *Auth {
+	return &Auth{
+		client: client,
+
+		clientId:     clientId,
+		clientSecret: clientSecret,
+		redirectUri:  redirectUri,
+
+		stateStorage: NewHttpCookieStateStorage(StateStorageCookie),
+	}
+}
+
+const TokenUrl = "https://id.twitch.tv/oauth2/token"
+
+type GetTokenParams struct {
+	ClientId     string `url:"client_id"`
+	ClientSecret string `url:"client_secret"`
+	Code         string `url:"code"`
+	GrantType    string `url:"grant_type"`
+	RedirectUri  string `url:"redirect_uri"`
+}
+
+// GetToken exchanges an authorization code or refresh token for an access token.
+func (a *Auth) GetToken(ctx context.Context, params *GetTokenParams) (*Token, error) {
+	v, err := query.Values(params)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, TokenUrl, strings.NewReader(v.Encode()))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	res, err := a.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	statusOK := res.StatusCode >= 200 && res.StatusCode < 300
+	if !statusOK {
+		return nil, fmt.Errorf("failed to get token (%d)", res.StatusCode)
+	}
+
+	var token Token
+	if err := json.NewDecoder(res.Body).Decode(&token); err != nil {
+		return nil, err
+	}
+
+	token.Expiry = time.Now().Add(time.Duration(token.ExpiresIn) * time.Second)
+
+	return &token, nil
+}
+
+// GetTokenFromCode exchanges an authorization code for an access token.
+//
+// https://dev.twitch.tv/docs/authentication/getting-tokens-oidc/#oidc-authorization-code-grant-flow
+func (a *Auth) GetTokenFromCode(ctx context.Context, code string) (*Token, error) {
+	return a.GetToken(ctx, &GetTokenParams{
+		ClientId:     a.clientId,
+		ClientSecret: a.clientSecret,
+		Code:         code,
+		GrantType:    "authorization_code",
+		RedirectUri:  a.redirectUri,
+	})
+}
+
+// RefreshToken exchanges a refresh token for an access token.
+//
+// https://dev.twitch.tv/docs/authentication/refresh-tokens/
+func (a *Auth) RefreshToken(ctx context.Context, token *Token) (*Token, error) {
+	return a.GetToken(ctx, &GetTokenParams{
+		ClientId:     a.clientId,
+		ClientSecret: a.clientSecret,
+		Code:         token.RefreshToken,
+		GrantType:    "refresh_token",
+		RedirectUri:  a.redirectUri,
+	})
+}
+
+// WithStateStorage sets the instance's state storage,
+// which is used to store the state parameter between requests.
+//
+// By default, the http cookie state storage is used.
+func (a *Auth) WithStateStorage(storage StateStorage) *Auth {
+	a.stateStorage = storage
+
+	return a
+}

auth/authorize.go

@@ -51,7 +51,7 @@ type AuthorizeParams struct {
 const AuthorizeUrl = "https://id.twitch.tv/oauth2/authorize"
 
 // AuthorizeUrl returns the URL to redirect the user to for authorization.
-func (c *Client) AuthorizeUrl(params *AuthorizeParams) *url.URL {
+func (c *Auth) AuthorizeUrl(params *AuthorizeParams) *url.URL {
 	v, _ := query.Values(params)
 	v.Set("client_id", c.clientId)
 	v.Set("redirect_uri", c.redirectUri)
@@ -61,7 +61,7 @@ func (c *Client) AuthorizeUrl(params *AuthorizeParams) *url.URL {
 }
 
 type AuthorizeHandler struct {
-	client *Client
+	client *Auth
 	scopes []Scope
 }
 
@@ -69,7 +69,7 @@ var _ http.Handler = (*AuthorizeHandler)(nil)
 
 // AuthorizeHandler returns an http.Handler that redirects the user to the
 // authorization URL.
-func (c *Client) AuthorizeHandler(scopes []Scope) http.Handler {
+func (c *Auth) AuthorizeHandler(scopes []Scope) http.Handler {
 	return &AuthorizeHandler{
 		client: c,
 		scopes: scopes,

auth/callback.go

@@ -6,7 +6,7 @@ import (
 )
 
 type CallbackHandler struct {
-	client  *Client
+	client  *Auth
 	handler TokenHandler
 }
 
@@ -14,7 +14,7 @@ var _ http.Handler = (*CallbackHandler)(nil)
 
 // CallbackHandler returns an http.Handler that handles callback responses
 // from the twitch authentication server.
-func (c *Client) CallbackHandler(h TokenHandler) http.Handler {
+func (c *Auth) CallbackHandler(h TokenHandler) http.Handler {
 	return &CallbackHandler{
 		client:  c,
 		handler: h,
@@ -56,7 +56,7 @@ func (c *CallbackHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	scope := q.Get("scope")
 	_ = scope
 
-	token, err := c.client.GetToken(r.Context(), code)
+	token, err := c.client.GetTokenFromCode(r.Context(), code)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return

auth/client.go

@@ -1,57 +0,0 @@
-package auth
-
-import "context"
-
-type Client struct {
-	clientId     string
-	clientSecret string
-	redirectUri  string
-
-	stateStorage StateStorage
-}
-
-func NewClient(clientId string, clientSecret string, redirectUri string) *Client {
-	return &Client{
-		clientId:     clientId,
-		clientSecret: clientSecret,
-		redirectUri:  redirectUri,
-
-		stateStorage: NewHttpCookieStateStorage(StateStorageCookie),
-	}
-}
-
-// GetToken exchanges an authorization code for an access token.
-//
-// https://dev.twitch.tv/docs/authentication/getting-tokens-oidc/#oidc-authorization-code-grant-flow
-func (c *Client) GetToken(ctx context.Context, code string) (*Token, error) {
-	return GetToken(ctx, &GetTokenParams{
-		ClientId:     c.clientId,
-		ClientSecret: c.clientSecret,
-		Code:         code,
-		GrantType:    "authorization_code",
-		RedirectUri:  c.redirectUri,
-	})
-}
-
-// RefreshToken exchanges a refresh token for an access token.
-//
-// https://dev.twitch.tv/docs/authentication/refresh-tokens/
-func (c *Client) RefreshToken(ctx context.Context, token *Token) (*Token, error) {
-	return GetToken(ctx, &GetTokenParams{
-		ClientId:     c.clientId,
-		ClientSecret: c.clientSecret,
-		Code:         token.RefreshToken,
-		GrantType:    "refresh_token",
-		RedirectUri:  c.redirectUri,
-	})
-}
-
-// WithStateStorage sets the instance's state storage,
-// which is used to store the state parameter between requests.
-//
-// By default, the http cookie state storage is used.
-func (c *Client) WithStateStorage(storage StateStorage) *Client {
-	c.stateStorage = storage
-
-	return c
-}

auth/token.go

@@ -1,14 +1,8 @@
 package auth
 
 import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"net/http"
-	"strings"
 	"time"
 
-	"github.com/google/go-querystring/query"
 	"golang.org/x/oauth2"
 )
 
@@ -38,49 +32,6 @@ func (t *Token) Underlying() *oauth2.Token {
 	}
 }
 
-const TokenUrl = "https://id.twitch.tv/oauth2/token"
-
-type GetTokenParams struct {
-	ClientId     string `url:"client_id"`
-	ClientSecret string `url:"client_secret"`
-	Code         string `url:"code"`
-	GrantType    string `url:"grant_type"`
-	RedirectUri  string `url:"redirect_uri"`
-}
-
-func GetToken(ctx context.Context, params *GetTokenParams) (*Token, error) {
-	v, err := query.Values(params)
-	if err != nil {
-		return nil, err
-	}
-
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, TokenUrl, strings.NewReader(v.Encode()))
-	if err != nil {
-		return nil, err
-	}
-	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
-
-	res, err := http.DefaultClient.Do(req)
-	if err != nil {
-		return nil, err
-	}
-	defer res.Body.Close()
-
-	statusOK := res.StatusCode >= 200 && res.StatusCode < 300
-	if !statusOK {
-		return nil, fmt.Errorf("failed to get token (%d)", res.StatusCode)
-	}
-
-	var token Token
-	if err := json.NewDecoder(res.Body).Decode(&token); err != nil {
-		return nil, err
-	}
-
-	token.Expiry = time.Now().Add(time.Duration(token.ExpiresIn) * time.Second)
-
-	return &token, nil
-}
-
 type TokenHandler interface {
 	Handle(state string, token string)
 }

auth/token_source.go

@@ -8,13 +8,13 @@ import (
 )
 
 type TokenSource struct {
-	client *Client
+	client *Auth
 	token  *Token
 
 	mu sync.Mutex
 }
 
-func (c *Client) TokenSource(token *Token) oauth2.TokenSource {
+func (c *Auth) TokenSource(token *Token) oauth2.TokenSource {
 	return &TokenSource{
 		client: c,
 		token:  token,