added oauth flow to get authorization code

internal/config/config.go

@@ -6,6 +6,8 @@ import (
 	"git.haelnorr.com/h/golib/hws"
 	"git.haelnorr.com/h/golib/hwsauth"
 	"git.haelnorr.com/h/oslstats/internal/db"
+	"git.haelnorr.com/h/oslstats/internal/discord"
+	"git.haelnorr.com/h/oslstats/pkg/oauth"
 	"github.com/joho/godotenv"
 	"github.com/pkg/errors"
 )
@@ -15,6 +17,8 @@ type Config struct {
 	HWS     *hws.Config
 	HWSAuth *hwsauth.Config
 	HLOG    *hlog.Config
+	Discord *discord.Config
+	OAuth   *oauth.Config
 	Flags   *Flags
 }
 
@@ -32,6 +36,8 @@ func GetConfig(flags *Flags) (*Config, *ezconf.ConfigLoader, error) {
 		hws.NewEZConfIntegration(),
 		hwsauth.NewEZConfIntegration(),
 		db.NewEZConfIntegration(),
+		discord.NewEZConfIntegration(),
+		oauth.NewEZConfIntegration(),
 	)
 	if err := loader.ParseEnvVars(); err != nil {
 		return nil, nil, errors.Wrap(err, "loader.ParseEnvVars")
@@ -65,11 +71,23 @@ func GetConfig(flags *Flags) (*Config, *ezconf.ConfigLoader, error) {
 		return nil, nil, errors.New("DB Config not loaded")
 	}
 
+	discordcfg, ok := loader.GetConfig("discord")
+	if !ok {
+		return nil, nil, errors.New("Dicord Config not loaded")
+	}
+
+	oauthcfg, ok := loader.GetConfig("oauth")
+	if !ok {
+		return nil, nil, errors.New("OAuth Config not loaded")
+	}
+
 	config := &Config{
 		DB:      dbcfg.(*db.Config),
 		HWS:     hwscfg.(*hws.Config),
 		HWSAuth: hwsauthcfg.(*hwsauth.Config),
 		HLOG:    hlogcfg.(*hlog.Config),
+		Discord: discordcfg.(*discord.Config),
+		OAuth:   oauthcfg.(*oauth.Config),
 		Flags:   flags,
 	}
 

internal/db/ezconf.go

@@ -37,5 +37,5 @@ func (e EZConfIntegration) GroupName() string {
 
 // NewEZConfIntegration creates a new EZConf integration helper
 func NewEZConfIntegration() EZConfIntegration {
-	return EZConfIntegration{name: "db", configFunc: ConfigFromEnv}
+	return EZConfIntegration{name: "DB", configFunc: ConfigFromEnv}
 }

internal/discord/config.go

@@ -0,0 +1,50 @@
+package discord
+
+import (
+	"strings"
+
+	"git.haelnorr.com/h/golib/env"
+	"github.com/pkg/errors"
+)
+
+type Config struct {
+	ClientID     string // ENV DISCORD_CLIENT_ID: Discord application client ID (required)
+	ClientSecret string // ENV DISCORD_CLIENT_SECRET: Discord application client secret (required)
+	OAuthScopes  string // Authorisation scopes for OAuth
+	RedirectPath string // ENV DISCORD_REDIRECT_PATH: Path for the OAuth redirect handler (required)
+}
+
+func ConfigFromEnv() (any, error) {
+	cfg := &Config{
+		ClientID:     env.String("DISCORD_CLIENT_ID", ""),
+		ClientSecret: env.String("DISCORD_CLIENT_SECRET", ""),
+		OAuthScopes:  getOAuthScopes(),
+		RedirectPath: env.String("DISCORD_REDIRECT_PATH", ""),
+	}
+
+	// Check required fields
+	if cfg.ClientID == "" {
+		return nil, errors.New("Envar not set: DISCORD_CLIENT_ID")
+	}
+	if cfg.ClientSecret == "" {
+		return nil, errors.New("Envar not set: DISCORD_CLIENT_SECRET")
+	}
+	if cfg.RedirectPath == "" {
+		return nil, errors.New("Envar not set: DISCORD_REDIRECT_PATH")
+	}
+
+	return cfg, nil
+}
+
+func getOAuthScopes() string {
+	list := []string{
+		"connections",
+		"email",
+		"guilds",
+		"gdm.join",
+		"guilds.members.read",
+		"identify",
+	}
+	scopes := strings.Join(list, "+")
+	return scopes
+}

internal/discord/ezconf.go

@@ -0,0 +1,41 @@
+package discord
+
+import (
+	"runtime"
+	"strings"
+)
+
+// EZConfIntegration provides integration with ezconf for automatic configuration
+type EZConfIntegration struct {
+	configFunc func() (any, error)
+	name       string
+}
+
+// PackagePath returns the path to the config package for source parsing
+func (e EZConfIntegration) PackagePath() string {
+	_, filename, _, _ := runtime.Caller(0)
+	// Return directory of this file
+	return filename[:len(filename)-len("/ezconf.go")]
+}
+
+// ConfigFunc returns the ConfigFromEnv function for ezconf
+func (e EZConfIntegration) ConfigFunc() func() (any, error) {
+	return func() (any, error) {
+		return e.configFunc()
+	}
+}
+
+// Name returns the name to use when registering with ezconf
+func (e EZConfIntegration) Name() string {
+	return strings.ToLower(e.name)
+}
+
+// GroupName returns the display name for grouping environment variables
+func (e EZConfIntegration) GroupName() string {
+	return e.name
+}
+
+// NewEZConfIntegration creates a new EZConf integration helper
+func NewEZConfIntegration() EZConfIntegration {
+	return EZConfIntegration{name: "Discord", configFunc: ConfigFromEnv}
+}

internal/discord/oauth.go

@@ -0,0 +1,39 @@
+package discord
+
+import (
+	"fmt"
+	"net/url"
+
+	"github.com/pkg/errors"
+)
+
+type Token struct {
+	AccessToken  string
+	TokenType    string
+	ExpiresIn    int
+	RefreshToken string
+	Scope        string
+}
+
+const oauthurl string = "https://discord.com/oauth2/authorize"
+
+func GetOAuthLink(cfg *Config, state string, trustedHost string) (string, error) {
+	if cfg == nil {
+		return "", errors.New("cfg cannot be nil")
+	}
+	if state == "" {
+		return "", errors.New("state cannot be empty")
+	}
+	if trustedHost == "" {
+		return "", errors.New("trustedHost cannot be empty")
+	}
+	values := url.Values{}
+	values.Add("response_type", "code")
+	values.Add("client_id", cfg.ClientID)
+	values.Add("scope", cfg.OAuthScopes)
+	values.Add("state", state)
+	values.Add("redirect_uri", fmt.Sprintf("%s/%s", trustedHost, cfg.RedirectPath))
+	values.Add("prompt", "none")
+
+	return fmt.Sprintf("%s?%s", oauthurl, values.Encode()), nil
+}

internal/handlers/callback.go

@@ -0,0 +1,61 @@
+package handlers
+
+import (
+	"net/http"
+
+	"git.haelnorr.com/h/golib/hws"
+	"git.haelnorr.com/h/oslstats/internal/config"
+	"git.haelnorr.com/h/oslstats/pkg/oauth"
+	"github.com/pkg/errors"
+)
+
+func Callback(server *hws.Server, cfg *config.Config) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			state := r.URL.Query().Get("state")
+			code := r.URL.Query().Get("code")
+			if state == "" && code == "" {
+				http.Redirect(w, r, "/", http.StatusBadRequest)
+				return
+			}
+			data, err := verifyState(cfg.OAuth, w, r, state)
+			if err != nil {
+				err = server.ThrowError(w, r, hws.HWSError{
+					StatusCode:      http.StatusForbidden,
+					Message:         "OAuth state verification failed",
+					Error:           err,
+					Level:           hws.ErrorLevel("debug"),
+					RenderErrorPage: true,
+				})
+				if err != nil {
+					server.ThrowFatal(w, err)
+				}
+				return
+			}
+			switch data {
+			case "login":
+				w.Write([]byte(code))
+				return
+			}
+		},
+	)
+}
+
+func verifyState(cfg *oauth.Config, w http.ResponseWriter, r *http.Request, state string) (string, error) {
+	if r == nil {
+		return "", errors.New("request cannot be nil")
+	}
+	if state == "" {
+		return "", errors.New("state param field is empty")
+	}
+	uak, err := oauth.GetStateCookie(r)
+	if err != nil {
+		return "", errors.Wrap(err, "oauth.GetStateCookie")
+	}
+	data, err := oauth.VerifyState(cfg, state, uak)
+	if err != nil {
+		return "", errors.Wrap(err, "oauth.VerifyState")
+	}
+	oauth.DeleteStateCookie(w)
+	return data, nil
+}

internal/handlers/login.go

@@ -0,0 +1,48 @@
+package handlers
+
+import (
+	"net/http"
+
+	"git.haelnorr.com/h/golib/hws"
+	"git.haelnorr.com/h/oslstats/internal/config"
+	"git.haelnorr.com/h/oslstats/internal/discord"
+	"git.haelnorr.com/h/oslstats/pkg/oauth"
+)
+
+func Login(server *hws.Server, cfg *config.Config) http.Handler {
+	return http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			state, uak, err := oauth.GenerateState(cfg.OAuth, "login")
+			if err != nil {
+				err = server.ThrowError(w, r, hws.HWSError{
+					StatusCode:      http.StatusInternalServerError,
+					Message:         "Failed to generate state token",
+					Error:           err,
+					Level:           hws.ErrorLevel("error"),
+					RenderErrorPage: true,
+				})
+				if err != nil {
+					server.ThrowFatal(w, err)
+				}
+				return
+			}
+			oauth.SetStateCookie(w, uak, cfg.HWSAuth.SSL)
+
+			link, err := discord.GetOAuthLink(cfg.Discord, state, cfg.HWSAuth.TrustedHost)
+			if err != nil {
+				err = server.ThrowError(w, r, hws.HWSError{
+					StatusCode:      http.StatusInternalServerError,
+					Message:         "An error occured trying to generate the login link",
+					Error:           err,
+					Level:           hws.ErrorLevel("error"),
+					RenderErrorPage: true,
+				})
+				if err != nil {
+					server.ThrowFatal(w, err)
+				}
+				return
+			}
+			http.Redirect(w, r, link, http.StatusSeeOther)
+		},
+	)
+}