Basic Authentication for spotify

gspotify/auth.go

@@ -0,0 +1,110 @@
+package gspotify
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	spotifyauth "github.com/zmb3/spotify/v2/auth"
+	"golang.org/x/oauth2"
+
+	"github.com/aditya-K2/gspot/utils"
+	"github.com/zmb3/spotify/v2"
+)
+
+const redirectURI = "http://localhost:8080/callback"
+
+var (
+	auth = spotifyauth.New(
+		spotifyauth.WithRedirectURL(redirectURI),
+		spotifyauth.WithScopes(spotifyauth.ScopeUserReadPrivate))
+	ch                           = make(chan *payload)
+	state                        = "__GSPOT_AUTH__"
+	userConfigDir, userConfigErr = os.UserConfigDir()
+	gspotDir                     = filepath.Join(userConfigDir, "/gspot")
+	tokenPath                    = filepath.Join(gspotDir, "/oauthtoken")
+)
+
+type payload struct {
+	Token *oauth2.Token
+	Err   error
+}
+
+func NewClient() (*spotify.Client, error) {
+	token := &oauth2.Token{}
+
+	// shouldn't be nil if the file doesn't exist.
+	tokenErr := errors.New("")
+
+	if utils.FileExists(tokenPath) {
+		var content []byte
+		content, tokenErr = os.ReadFile(tokenPath)
+		tokenErr = json.Unmarshal(content, token)
+	}
+
+	if tokenErr != nil {
+		http.HandleFunc("/callback", completeAuth)
+		http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+			log.Println("Got request for:", r.URL.String())
+		})
+
+		go func() {
+			err := http.ListenAndServe(":8080", nil)
+			if err != nil {
+				log.Fatal(err)
+				ch <- &payload{nil, err}
+			}
+		}()
+		url := auth.AuthURL(state)
+
+		utils.Print("BLUE", "Please log in to Spotify by visiting the following page in your browser: ")
+		utils.Print("GREEN", url)
+
+		// wait for auth to complete
+		payload := <-ch
+
+		if payload.Err != nil {
+			return nil, payload.Err
+		}
+
+		token = payload.Token
+	}
+
+	return spotify.New(auth.Client(context.Background(), token)), nil
+}
+
+func completeAuth(w http.ResponseWriter, r *http.Request) {
+	tok, err := auth.Token(r.Context(), state, r)
+	if err != nil {
+		http.Error(w, "Couldn't get token", http.StatusForbidden)
+		log.Fatal(err)
+		ch <- &payload{nil, err}
+	}
+
+	if st := r.FormValue("state"); st != state {
+		http.NotFound(w, r)
+		_s := fmt.Sprintf("State mismatch: %s != %s\n", st, state)
+		log.Fatalf(_s)
+		ch <- &payload{nil, errors.New(_s)}
+	}
+
+	if val, merr := json.Marshal(tok); merr != nil {
+		ch <- &payload{nil, merr}
+	} else {
+		if !utils.FileExists(gspotDir) {
+			if derr := os.Mkdir(gspotDir, 0777); derr != nil {
+				ch <- &payload{nil, derr}
+			}
+		}
+		if werr := os.WriteFile(tokenPath, val, 0777); werr != nil {
+			ch <- &payload{nil, werr}
+		}
+	}
+
+	ch <- &payload{tok, nil}
+}