Initial commit.

internal/services/core/httpserver/server.go

@@ -0,0 +1,81 @@
+package httpserver
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"go.dev.pztrn.name/vikunja-notifier/internal/services/core"
+)
+
+const httpServerAddrEnvVar = "VN_HTTP_ADDRESS"
+
+var (
+	errHTTPServerAddrInvalid = errors.New("VN_HTTP_ADDRESS environment variable contains invalid address to " +
+		"listen, should be 'host:port'")
+	errHTTPServerAddrNotFound = errors.New("VN_HTTP_ADDRESS environment variable empty")
+)
+
+func (h *httpServer) configureHTTPServer() error {
+	httpSrvAddr, found := os.LookupEnv(httpServerAddrEnvVar)
+	if !found {
+		return fmt.Errorf("configure HTTP server: get address from environment variable: %w", errHTTPServerAddrNotFound)
+	}
+
+	host, port, err := net.SplitHostPort(httpSrvAddr)
+	if err != nil {
+		return fmt.Errorf("configure HTTP server: validate HTTP server address: %w", err)
+	}
+
+	if httpSrvAddr != host+":"+port {
+		return fmt.Errorf("configure HTTP server: validate HTTP server address: %w", errHTTPServerAddrInvalid)
+	}
+
+	h.httpMux = new(http.ServeMux)
+
+	// Default catch-all handler.
+	h.RegisterHandler("", "/", h.defaultHandler)
+
+	h.httpSrv = &http.Server{
+		Addr:              httpSrvAddr,
+		Handler:           h.httpMux,
+		ReadHeaderTimeout: time.Second * 3,
+	}
+
+	return nil
+}
+
+func (h *httpServer) RegisterHandler(method, path string, handler http.HandlerFunc) {
+	h.httpMux.HandleFunc(fmt.Sprintf("%s %s", method, path), func(w http.ResponseWriter, r *http.Request) {
+		for i := len(h.middlewares) - 1; i >= 0; i-- {
+			handler = h.middlewares[i](handler)
+		}
+
+		handler(w, r)
+	})
+}
+
+func (h *httpServer) RegisterMiddleware(middleware core.HTTPMiddlewareFunc) {
+	h.middlewares = append(h.middlewares, middleware)
+}
+
+func (h *httpServer) startHTTPServer() {
+	h.logger.Info("Starting listening for HTTP requests.", "address", h.httpSrv.Addr)
+
+	if err := h.httpSrv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		h.logger.Warn("Error when listening to ", "error", err.Error())
+	}
+}
+
+func (h *httpServer) stopHTTPServer() error {
+	h.logger.Info("Stopping HTTP server...")
+
+	if err := h.httpSrv.Shutdown(h.app.ContextWithTimeout(time.Second * 3)); err != nil {
+		return fmt.Errorf("stopping HTTP server: %w", err)
+	}
+
+	return nil
+}