refactor: rework file structure (#325)

* wip: add middlewares

* refactor: use context fom middleware in handlers

* refactor: use controller approach in handlers

* refactor: move oauth providers into services (non-working)

* feat: create oauth broker service

* refactor: use a boostrap service to bootstrap the app

* refactor: split utils into smaller files

* refactor: use more clear name for frontend assets

* feat: allow customizability of resources dir

* fix: fix typo in ui middleware

* fix: validate resource file paths in ui middleware

* refactor: move resource handling to a controller

* feat: add some logging

* fix: configure middlewares before groups

* fix: use correct api path in login mutation

* fix: coderabbit suggestions

* fix: further coderabbit suggestions

internal/service/generic_oauth_service.go

@@ -0,0 +1,117 @@
+package service
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/tls"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+	"tinyauth/internal/config"
+
+	"golang.org/x/oauth2"
+)
+
+type GenericOAuthService struct {
+	Config             oauth2.Config
+	Context            context.Context
+	Token              *oauth2.Token
+	Verifier           string
+	InsecureSkipVerify bool
+	UserinfoURL        string
+}
+
+func NewGenericOAuthService(config config.OAuthServiceConfig) *GenericOAuthService {
+	return &GenericOAuthService{
+		Config: oauth2.Config{
+			ClientID:     config.ClientID,
+			ClientSecret: config.ClientSecret,
+			RedirectURL:  config.RedirectURL,
+			Scopes:       config.Scopes,
+			Endpoint: oauth2.Endpoint{
+				AuthURL:  config.AuthURL,
+				TokenURL: config.TokenURL,
+			},
+		},
+		InsecureSkipVerify: config.InsecureSkipVerify,
+		UserinfoURL:        config.UserinfoURL,
+	}
+}
+
+func (generic *GenericOAuthService) Init() error {
+	transport := &http.Transport{
+		TLSClientConfig: &tls.Config{
+			InsecureSkipVerify: generic.InsecureSkipVerify,
+			MinVersion:         tls.VersionTLS12,
+		},
+	}
+
+	httpClient := &http.Client{
+		Transport: transport,
+	}
+
+	ctx := context.Background()
+
+	ctx = context.WithValue(ctx, oauth2.HTTPClient, httpClient)
+	verifier := oauth2.GenerateVerifier()
+
+	generic.Context = ctx
+	generic.Verifier = verifier
+	return nil
+}
+
+func (generic *GenericOAuthService) GenerateState() string {
+	b := make([]byte, 128)
+	_, err := rand.Read(b)
+	if err != nil {
+		return base64.RawURLEncoding.EncodeToString(fmt.Appendf(nil, "state-%d", time.Now().UnixNano()))
+	}
+	state := base64.RawURLEncoding.EncodeToString(b)
+	return state
+}
+
+func (generic *GenericOAuthService) GetAuthURL(state string) string {
+	return generic.Config.AuthCodeURL(state, oauth2.AccessTypeOffline, oauth2.S256ChallengeOption(generic.Verifier))
+}
+
+func (generic *GenericOAuthService) VerifyCode(code string) error {
+	token, err := generic.Config.Exchange(generic.Context, code, oauth2.VerifierOption(generic.Verifier))
+
+	if err != nil {
+		return err
+	}
+
+	generic.Token = token
+	return nil
+}
+
+func (generic *GenericOAuthService) Userinfo() (config.Claims, error) {
+	var user config.Claims
+
+	client := generic.Config.Client(generic.Context, generic.Token)
+
+	res, err := client.Get(generic.UserinfoURL)
+	if err != nil {
+		return user, err
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode < 200 || res.StatusCode >= 300 {
+		return user, fmt.Errorf("request failed with status: %s", res.Status)
+	}
+
+	body, err := io.ReadAll(res.Body)
+	if err != nil {
+		return user, err
+	}
+
+	err = json.Unmarshal(body, &user)
+	if err != nil {
+		return user, err
+	}
+
+	return user, nil
+}