initial commit

main.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+	"strings"
+
+	"deadbeef.codes/steven/siteviewcounter/countersql"
+	"github.com/go-sql-driver/mysql"
+)
+
+var (
+	database     countersql.Configuration
+	uniqueVisits int
+)
+
+// Application Startup
+func init() {
+	envVars := make(map[string]string)
+	envVars["dbusername"] = os.Getenv("dbusername")
+	envVars["dbpassword"] = os.Getenv("dbpassword")
+	envVars["dbhostname"] = os.Getenv("dbhostname")
+	envVars["dbname"] = os.Getenv("dbname")
+	envVars["timezone"] = os.Getenv("timezone")
+
+	for key, value := range envVars {
+		if value == "" {
+			log.Fatalf("shell environment variable %s is not set", key)
+		}
+	}
+
+	// Database Config
+	dbConfig := mysql.Config{}
+	dbConfig.User = envVars["dbusername"]
+	dbConfig.Passwd = envVars["dbpassword"]
+	dbConfig.Addr = envVars["dbhostname"]
+	dbConfig.DBName = envVars["dbname"]
+	dbConfig.Net = "tcp"
+	dbConfig.ParseTime = true
+	dbConfig.AllowNativePasswords = true
+	database = countersql.Configuration{}
+	database.DSN = dbConfig.FormatDSN()
+
+	// Test database online at startup and get count of visits
+	dbConn, err := database.Connect()
+	if err != nil {
+		log.Fatalf("failed to connect to database: %v", err)
+	}
+
+	uniqueVisits, err = dbConn.GetUniqueVisits()
+	if err != nil {
+		log.Fatalf("failed to get number of unique visits from database: %v", err)
+	}
+
+	dbConn.DB.Close()
+}
+
+// HTTP Routing
+func main() {
+
+	// API Handlers
+	http.HandleFunc("/", countHandler)
+
+	log.Print("Service listening on :8080")
+	log.Fatal(http.ListenAndServe(":8080", nil))
+
+}
+
+func countHandler(w http.ResponseWriter, r *http.Request) {
+	if r.Method == "GET" {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		w.Write([]byte(strconv.Itoa(uniqueVisits)))
+		dbConn, err := database.Connect()
+		if err != nil {
+			log.Printf("failed to connect to database: %v", err)
+			w.WriteHeader(http.StatusFailedDependency)
+			return
+		}
+		defer dbConn.DB.Close()
+
+		var ipAddress string
+
+		if len(r.Header.Get("X-Forwarded-For")) > 0 {
+			ipAddress = r.Header.Get("X-Forwarded-For")
+		} else {
+			ipAddress = r.RemoteAddr
+		}
+
+		ipAddress = strings.Split(ipAddress, ":")[0]
+
+		returnVisitor, err := dbConn.HasIPVisited(ipAddress)
+		if err != nil {
+			log.Printf("failed to determine if this is a return visitor, no data is being logged: %v", err)
+			return
+		}
+
+		if returnVisitor {
+			err = dbConn.IncrementVisitor(ipAddress)
+			log.Printf("return visitor from %s", ipAddress)
+		} else {
+			err = dbConn.AddVisitor(ipAddress)
+			uniqueVisits++
+			log.Printf("new visitor from %s", ipAddress)
+		}
+		if err != nil {
+			log.Printf("failed to add/update visit record in database: %v", err)
+			return
+		}
+
+	} else {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+	}
+}