first version

server/server.go

@@ -0,0 +1,148 @@
+package server
+
+import (
+	"embed"
+	_ "embed"
+	"errors"
+	"fmt"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+	"github.com/mileusna/useragent"
+	"html/template"
+	"log"
+	"net/http"
+	"os"
+	"retroHub/data"
+	"strings"
+)
+
+type injector struct {
+	Version string
+}
+
+type userAgentInjector struct {
+	injector
+	UserAgent useragent.UserAgent
+}
+
+type providerInjector struct {
+	injector
+	Provider data.Provider
+}
+
+type errorInjector struct {
+	injector
+	StatusCode int
+	StatusText string
+}
+
+const version string = "0.1"
+
+//go:embed templates
+var templates embed.FS
+
+var (
+	provider      data.Provider
+	indexTemplate *template.Template
+	uaTemplate    *template.Template
+	errTemplate   *template.Template
+
+	errLog *log.Logger
+)
+
+func init() {
+	indexTemplate = template.Must(template.ParseFS(templates, "templates/base.html", "templates/index.html"))
+	uaTemplate = template.Must(template.ParseFS(templates, "templates/base.html", "templates/ua.html"))
+	errTemplate = template.Must(template.ParseFS(templates, "templates/base.html", "templates/error.html"))
+
+	errLog = log.New(os.Stderr, "", log.LstdFlags)
+}
+
+func Serve(contentProvider data.Provider, port uint) error {
+	if contentProvider == nil {
+		return errors.New("content provider cannot be nil")
+	}
+	provider = contentProvider
+
+	r := chi.NewRouter()
+	r.Use(middleware.Logger)
+	r.Use(panicHandler)
+
+	r.NotFound(notFoundHandler)
+	r.Get("/", indexHandler)
+	r.Get("/ua", userAgentHandler)
+
+	log.Printf("the server is up and running on %d", port)
+	err := http.ListenAndServe(fmt.Sprintf(":%d", port), r)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func panicHandler(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		defer func() {
+			if r := recover(); r != nil {
+				errLog.Println("ERROR", r)
+				injectedData := errorInjector{
+					injector: injector{
+						Version: version,
+					},
+					StatusCode: http.StatusInternalServerError,
+					StatusText: "Internal Server Error",
+				}
+				w.WriteHeader(http.StatusInternalServerError)
+				err := errTemplate.ExecuteTemplate(w, "base", injectedData)
+				if err != nil {
+					errLog.Println("ERROR", err)
+				}
+			}
+		}()
+		next.ServeHTTP(w, r)
+	})
+}
+
+func indexHandler(w http.ResponseWriter, r *http.Request) {
+	injectedData := providerInjector{
+		injector: injector{
+			Version: version,
+		},
+		Provider: provider,
+	}
+	err := indexTemplate.ExecuteTemplate(w, "base", injectedData)
+	if err != nil {
+		errLog.Println("ERROR", err)
+	}
+}
+
+func userAgentHandler(w http.ResponseWriter, r *http.Request) {
+	injectedData := userAgentInjector{
+		injector: injector{
+			Version: version,
+		},
+	}
+	userAgent := strings.TrimSpace(r.UserAgent())
+	if len(userAgent) > 0 {
+		injectedData.UserAgent = useragent.Parse(userAgent)
+	}
+	err := uaTemplate.ExecuteTemplate(w, "base", injectedData)
+	if err != nil {
+		errLog.Println("ERROR", err)
+	}
+}
+
+func notFoundHandler(w http.ResponseWriter, _ *http.Request) {
+	injectedData := errorInjector{
+		injector: injector{
+			Version: version,
+		},
+		StatusCode: http.StatusNotFound,
+		StatusText: "Not Found",
+	}
+	w.WriteHeader(http.StatusNotFound)
+	err := errTemplate.ExecuteTemplate(w, "base", injectedData)
+	if err != nil {
+		errLog.Println("ERROR", err)
+	}
+}