From 56548c511163b4dd22d9a96a2f5ae647f1627a7b Mon Sep 17 00:00:00 2001
From: Jeroen Wijenbergh <jeroenwijenbergh@protonmail.com>
Date: Mon, 7 Mar 2022 15:43:07 +0100
Subject: Refactor: Simplify API by using a state as context

---
 src/oauth.go | 93 ++++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 65 insertions(+), 28 deletions(-)

(limited to 'src/oauth.go')

diff --git a/src/oauth.go b/src/oauth.go
index 9eb2272..87284a2 100644
--- a/src/oauth.go
+++ b/src/oauth.go
@@ -66,33 +66,8 @@ type EduVPNOauth struct {
 	verifier      string
 }
 
-// Initializes the OAuth eduvpn class. It returns a tuple of the class and error.
-// If the error is non-nil, the class will be nil.
-func InitializeOAuth(config *oauth2.Config) (*EduVPNOauth, error) {
-	// Generate the state
-	state, stateErr := genState()
-	if stateErr != nil {
-		return nil, detailedOAuthError{errGenStateError, fmt.Sprintf("oauth failed to gen random bytes for state"), stateErr}
-	}
-
-	// Generate the verifier and challenge
-	verifier, err := genVerifier()
-	if err != nil {
-		return nil, detailedOAuthError{errGenVerifierError, fmt.Sprintf("oauth failed to verifier"), err}
-	}
-	challenge := genChallengeS256(verifier)
-
-	// Update the auth url with the challenge and state
-	codeChallengeMethod := oauth2.SetAuthURLParam("code_challenge_method", "S256")
-	codeChallenge := oauth2.SetAuthURLParam("code_challenge", challenge)
-	authURL := config.AuthCodeURL(state, codeChallengeMethod, codeChallenge)
-
-	// Return the struct with the necessary fields filled for the next call to getting the HTTP client
-	return &EduVPNOauth{AuthURL: authURL, Config: config, state: state, verifier: verifier}, nil
-}
-
 // Gets an authenticated HTTP client by obtaining refresh and access tokens
-func (eduvpn *EduVPNOauth) GetHTTPTokenClient() (*http.Client, error) {
+func (eduvpn *EduVPNOauth) getHTTPTokenClient() error {
 	eduvpn.context = context.Background()
 	mux := http.NewServeMux()
 	eduvpn.server = &http.Server{
@@ -101,9 +76,9 @@ func (eduvpn *EduVPNOauth) GetHTTPTokenClient() (*http.Client, error) {
 	}
 	mux.HandleFunc("/callback", eduvpn.oauthCallback)
 	if err := eduvpn.server.ListenAndServe(); err != http.ErrServerClosed {
-		return nil, detailedOAuthError{errCallbackServerError, fmt.Sprintf("oauth callback server error"), err}
+		return detailedOAuthError{errCallbackServerError, fmt.Sprintf("oauth callback server error"), err}
 	}
-	return eduvpn.client, eduvpn.callbackError
+	return eduvpn.callbackError
 }
 
 // Get the access and refresh tokens
@@ -169,6 +144,68 @@ func (eduvpn *EduVPNOauth) oauthCallback(w http.ResponseWriter, req *http.Reques
 	go eduvpn.server.Shutdown(eduvpn.context)
 }
 
+// Generate a config for oauth
+// It uses the state to get the server and the name
+func genConfig(vpnState *EduVPNState) (*oauth2.Config, error) {
+	config := &oauth2.Config{
+		RedirectURL: "http://127.0.0.1:8000/callback",
+		ClientID:    vpnState.Name,
+		Scopes:      []string{"config"},
+		Endpoint: oauth2.Endpoint{
+			AuthURL:  vpnState.Endpoints.API.V3.AuthorizationEndpoint,
+			TokenURL: vpnState.Endpoints.API.V3.TokenEndpoint,
+		},
+	}
+	return config, nil
+}
+
+// Initializes the OAuth for eduvpn.
+// It needs a vpn state that was gotten from `Register`
+// It returns the authurl for the browser and an error if present
+func InitializeOAuth(vpnState *EduVPNState) (string, error) {
+	if vpnState == nil {
+		panic("invalid state")
+	}
+
+	config, configErr := genConfig(vpnState)
+	if configErr != nil {
+		return "", configErr
+	}
+
+	// Generate the state
+	state, stateErr := genState()
+	if stateErr != nil {
+		return "", detailedOAuthError{errGenStateError, fmt.Sprintf("oauth failed to gen random bytes for state"), stateErr}
+	}
+
+	// Generate the verifier and challenge
+	verifier, err := genVerifier()
+	if err != nil {
+		return "", detailedOAuthError{errGenVerifierError, fmt.Sprintf("oauth failed to verifier"), err}
+	}
+	challenge := genChallengeS256(verifier)
+
+	// Update the auth url with the challenge and state
+	codeChallengeMethod := oauth2.SetAuthURLParam("code_challenge_method", "S256")
+	codeChallenge := oauth2.SetAuthURLParam("code_challenge", challenge)
+	authURL := config.AuthCodeURL(state, codeChallengeMethod, codeChallenge)
+
+	// Fill the struct with the necessary fields filled for the next call to getting the HTTP client
+	vpnState.OAuth = &EduVPNOauth{AuthURL: authURL, Config: config, state: state, verifier: verifier}
+	return authURL, nil
+}
+
+func FinishOAuth(vpnState *EduVPNState) error {
+	if vpnState == nil {
+		panic("invalid state")
+	}
+
+	if vpnState.OAuth == nil {
+		panic("invalid oauth state")
+	}
+	return vpnState.OAuth.getHTTPTokenClient()
+}
+
 // OAuthErrorCode Simplified error code for public interface.
 type OAuthErrorCode = VPNErrorCode
 type OAuthError = VPNError
-- 
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