GoScrobble/internal/goscrobble/server.go

package goscrobble

import (
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"net/http"
	"os"
	"path/filepath"

	"github.com/gorilla/mux"
)

// spaHandler - Handles Single Page Applications (React)
type spaHandler struct {
	staticPath string
	indexPath  string
}

type jsonResponse struct {
	Err string `json:"error"`
}

// HandleRequests - Boot HTTP!
func HandleRequests() {
	// Create a new router
	r := mux.NewRouter().StrictSlash(true)

	v1 := r.PathPrefix("/api/v1").Subrouter()

	// Static Token for /ingress
	v1.HandleFunc("/ingress/jellyfin", tokenMiddleware(serveEndpoint))

	// JWT Auth
	v1.HandleFunc("/profile/{id}", jwtMiddleware(serveEndpoint))

	// No Auth
	v1.HandleFunc("/register", serveEndpoint).Methods("POST")
	v1.HandleFunc("/login", serveEndpoint).Methods("POST")
	v1.HandleFunc("/logout", serveEndpoint).Methods("POST")

	// This just prevents it serving frontend stuff over /api
	r.PathPrefix("/api")

	// SERVE FRONTEND - NO AUTH
	spa := spaHandler{staticPath: "web/build", indexPath: "index.html"}
	r.PathPrefix("/").Handler(spa)

	// Serve it up!
	log.Fatal(http.ListenAndServe(":42069", r))
}

// MIDDLEWARE

// tokenMiddleware - Validates token to a user
func tokenMiddleware(next http.HandlerFunc) http.HandlerFunc {
	return func(res http.ResponseWriter, req *http.Request) {
		jr := jsonResponse{
			Err: "Invalid API Token",
		}
		js, _ := json.Marshal(&jr)
		err := errors.New(string(js))
		http.Error(res, err.Error(), http.StatusUnauthorized)
		return
		// next(res, req)
	}
}

// jwtMiddleware - Validates middleware to a user
func jwtMiddleware(next http.HandlerFunc) http.HandlerFunc {
	return func(res http.ResponseWriter, req *http.Request) {
		jr := jsonResponse{
			Err: "Invalid JWT Token",
		}
		js, _ := json.Marshal(&jr)
		err := errors.New(string(js))
		http.Error(res, err.Error(), http.StatusUnauthorized)
		return
		// next(res, req)
	}
}

// ENDPOINT HANDLING

// serveEndpoint - API stuffs
func serveEndpoint(w http.ResponseWriter, r *http.Request) {
	var jsonInput map[string]interface{}
	decoder := json.NewDecoder(r.Body)
	err := decoder.Decode(&jsonInput)
	if err != nil {
		// If we can't decode. Lets tell them nicely.
		http.Error(w, "{\"error\":\"Invalid JSON\"}", http.StatusBadRequest)
		return
	}

	// Lets trick 'em for now ;) ;)
	fmt.Fprintf(w, "{}")
}

// FRONTEND HANDLING

// ServerHTTP - Frontend server
func (h spaHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// Get the absolute path to prevent directory traversal
	path, err := filepath.Abs(r.URL.Path)
	if err != nil {
		// If we failed to get the absolute path respond with a 400 bad request and return
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	// prepend the path with the path to the static directory
	path = filepath.Join(h.staticPath, path)

	// check whether a file exists at the given path
	_, err = os.Stat(path)
	if os.IsNotExist(err) {
		// file does not exist, serve index.html
		http.ServeFile(w, r, filepath.Join(h.staticPath, h.indexPath))
		return
	} else if err != nil {
		// if we got an error (that wasn't that the file doesn't exist) stating the
		// file, return a 500 internal server error and stop
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// otherwise, use http.FileServer to serve the static dir
	http.FileServer(http.Dir(h.staticPath)).ServeHTTP(w, r)
}