Configure routes based on post paths from DB

http.go

@@ -9,27 +9,23 @@ import (
 	"os"
 	"os/signal"
 	"strconv"
+	"sync"
 	"syscall"
 	"time"
 )
 
-func startServer() {
-	r := chi.NewRouter()
-
-	if appConfig.server.logging {
-		r.Use(middleware.RealIP)
-		r.Use(middleware.Logger)
+func startServer() error {
+	d := newDynamicHandler()
+	h, err := buildHandler()
+	if err != nil {
+		return err
 	}
-	r.Use(middleware.Recoverer)
-	r.Use(middleware.StripSlashes)
-
-	r.Get("/", hello)
-	r.Get("/*", servePost)
+	d.swapHandler(h)
 
 	address := ":" + strconv.Itoa(appConfig.server.port)
 	srv := &http.Server{
 		Addr:    address,
-		Handler: r,
+		Handler: d,
 	}
 
 	go func() {
@@ -45,10 +41,58 @@ func startServer() {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 	if err := srv.Shutdown(ctx); err != nil {
-		log.Fatal(err)
+		return err
 	}
+	return nil
+}
+
+func buildHandler() (http.Handler, error) {
+	r := chi.NewRouter()
+
+	if appConfig.server.logging {
+		r.Use(middleware.RealIP)
+		r.Use(middleware.Logger)
+	}
+	r.Use(middleware.Recoverer)
+	r.Use(middleware.StripSlashes)
+
+	r.Get("/", hello)
+
+	allPostPaths, err := allPostPaths()
+	if err != nil {
+		return nil, err
+	} else {
+		for _, path := range allPostPaths {
+			if path != "" {
+				r.Get("/"+path, servePost)
+			}
+		}
+	}
+
+	return r, nil
 }
 
 func hello(w http.ResponseWriter, _ *http.Request) {
 	_, _ = w.Write([]byte("Hello World!"))
 }
+
+type dynamicHandler struct {
+	realHandler http.Handler
+	changeMutex *sync.Mutex
+}
+
+func newDynamicHandler() *dynamicHandler {
+	return &dynamicHandler{
+		changeMutex: &sync.Mutex{},
+	}
+}
+
+func (d *dynamicHandler) swapHandler(h http.Handler) {
+	d.changeMutex.Lock()
+	d.realHandler = h
+	d.changeMutex.Unlock()
+}
+
+func (d *dynamicHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	d.realHandler.ServeHTTP(w, r)
+}

main.go

@@ -23,5 +23,8 @@ func main() {
 	}()
 	log.Println("Loaded database")
 	log.Println("Start server")
-	startServer()
+	err = startServer()
+	if err != nil {
+		log.Fatal(err)
+	}
 }

posts.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"database/sql"
 	"errors"
 	"net/http"
@@ -17,7 +18,7 @@ type post struct {
 }
 
 func servePost(w http.ResponseWriter, r *http.Request) {
-	post, err := getPost(strings.TrimSuffix(strings.TrimPrefix(r.RequestURI, "/"), "/"))
+	post, err := getPost(strings.TrimSuffix(strings.TrimPrefix(r.RequestURI, "/"), "/"), r.Context())
 	if err == postNotFound {
 		http.NotFound(w, r)
 		return
@@ -34,9 +35,9 @@ func servePost(w http.ResponseWriter, r *http.Request) {
 	_, _ = w.Write(htmlContent)
 }
 
-func getPost(path string) (*post, error) {
+func getPost(path string, context context.Context) (*post, error) {
 	queriedPost := &post{}
-	row := appDb.QueryRow("select path, COALESCE(content, ''), COALESCE(published, ''), COALESCE(updated, '') from posts where path=?", path)
+	row := appDb.QueryRowContext(context, "select path, COALESCE(content, ''), COALESCE(published, ''), COALESCE(updated, '') from posts where path=?", path)
 	err := row.Scan(&queriedPost.path, &queriedPost.content, &queriedPost.published, &queriedPost.updated)
 	if err == sql.ErrNoRows {
 		return nil, postNotFound
@@ -45,3 +46,17 @@ func getPost(path string) (*post, error) {
 	}
 	return queriedPost, nil
 }
+
+func allPostPaths() ([]string, error) {
+	var postPaths []string
+	rows, err := appDb.Query("select path from posts")
+	if err != nil {
+		return nil, err
+	}
+	for rows.Next() {
+		var path string
+		_ = rows.Scan(&path)
+		postPaths = append(postPaths, path)
+	}
+	return postPaths, nil
+}