Serve html from golang server via template

server.go

@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"encoding/json"
 	"fmt"
+	"html/template"
 	"log"
 	"net/http"
 
@@ -16,7 +17,8 @@ const (
 )
 
 var (
-	db *sql.DB
+	db                *sql.DB
+	indexHtmlTemplate *template.Template
 )
 
 type ChoicesPost struct {
@@ -60,6 +62,22 @@ func initDatabase() {
 	}
 }
 
+func prepareStaticContent() {
+	var err error
+	indexHtmlTemplate, err = template.ParseFiles("./static/index.html")
+	if err != nil {
+		log.Fatalf("[!] Could not parse index.html template, error: %s\n", err)
+	}
+}
+
+func handleGetRoot(w http.ResponseWriter, r *http.Request) {
+	err := indexHtmlTemplate.Execute(w, nil)
+	if err != nil {
+		log.Printf("[!] Could not execute index.html template, error: %s\n", err)
+		http.Error(w, "Error rendering template", http.StatusInternalServerError)
+	}
+}
+
 func handleGetPing(w http.ResponseWriter, r *http.Request) {
 	log.Printf("[*] Received request %v %v\n", r.Method, r.URL)
 	fmt.Fprintf(w, "PONG\n")
@@ -86,17 +104,30 @@ func handlePostSubmit(w http.ResponseWriter, r *http.Request) {
 		log.Printf("[!] Could not marshal choices, error: %s\n", err)
 	}
 
+	tx, err := db.Begin()
+	if err != nil {
+		log.Printf("[!] Could not begin database transaction, error: %s\n", err)
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
 	const query = `
 		INSERT INTO choices (pollid, username, choices)
 		VALUES (?, ?, ?);
 	`
 
-	_, err = db.Exec(query, choicesPost.PollId, choicesPost.Username, string(choicesJson))
+	_, err = tx.Exec(query, choicesPost.PollId, choicesPost.Username, string(choicesJson))
 	if err != nil {
 		log.Printf("[!] Could not insert choices into database, error: %s\n", err)
+		tx.Rollback()
+		w.WriteHeader(http.StatusBadRequest)
+		return
 	}
 
-	log.Printf("[*] Persisted choices for %s to database\n", "DUMMY USERNAME")
+	tx.Commit()
+
+	log.Printf("[*] Persisted choices for poll %d, username %s to database\n",
+		choicesPost.PollId, choicesPost.Username)
 
 	w.WriteHeader(http.StatusOK)
 }
@@ -112,11 +143,18 @@ func main() {
 	initDatabase()
 	defer db.Close()
 
+	prepareStaticContent()
+
 	http.HandleFunc(
 		"GET /api/ping",
 		handleGetPing,
 	)
 
+	http.HandleFunc(
+		"GET /",
+		handleGetRoot,
+	)
+
 	http.HandleFunc(
 		"POST /api/submit",
 		handlePostSubmit,