Adding new router handler

2022/01/golang_demo2/Program.go

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/gorilla/mux"
+	"net/http"
+	"os"
+)
+
+type StandardResponse struct {
+	Code    int    `json:"code"`
+	Status  string `json:"status"`
+	Handler string `json:"handler"`
+}
+
+func handleIndex(writer http.ResponseWriter, _ *http.Request) {
+	resp := StandardResponse{
+		Code:    200,
+		Status:  "OK",
+		Handler: "index",
+	}
+
+	p, err := json.Marshal(resp)
+	if err != nil {
+		writer.WriteHeader(500)
+		_, _ = writer.Write([]byte("Internal server error"))
+		_, _ = fmt.Fprintf(os.Stderr, "Internal server error while marshalling response")
+	}
+
+	writer.Header().Set("Content-Type", "application/json")
+	writer.WriteHeader(200)
+
+	_, err = writer.Write(p)
+
+	if err != nil {
+		_, _ = writer.Write([]byte("Internal server error"))
+		_, _ = fmt.Fprintf(os.Stderr, "Internal server error while sending response")
+	}
+}
+
+func handleInfo(writer http.ResponseWriter, _ *http.Request) {
+	resp := StandardResponse{
+		Code:    200,
+		Status:  "OK",
+		Handler: "info",
+	}
+
+	p, err := json.Marshal(resp)
+	if err != nil {
+		writer.WriteHeader(500)
+		_, _ = writer.Write([]byte("Internal server error"))
+		_, _ = fmt.Fprintf(os.Stderr, "Internal server error while marshalling response")
+	}
+
+	writer.Header().Set("Content-Type", "application/json")
+	writer.WriteHeader(200)
+
+	_, err = writer.Write(p)
+
+	if err != nil {
+		_, _ = writer.Write([]byte("Internal server error"))
+		_, _ = fmt.Fprintf(os.Stderr, "Internal server error while sending response")
+	}
+
+}
+
+func handleDefault(writer http.ResponseWriter, _ *http.Request) {
+	resp := StandardResponse{
+		Code:    404,
+		Status:  "Not found",
+		Handler: "default",
+	}
+
+	p, err := json.Marshal(resp)
+	if err != nil {
+		writer.WriteHeader(500)
+		_, _ = writer.Write([]byte("Internal server error"))
+		_, _ = fmt.Fprintf(os.Stderr, "Internal server error while marshalling response")
+	}
+
+	writer.Header().Set("Content-Type", "application/json")
+	writer.WriteHeader(404)
+
+	_, err = writer.Write(p)
+
+	if err != nil {
+		_, _ = writer.Write([]byte("Internal server error"))
+		_, _ = fmt.Fprintf(os.Stderr, "Internal server error while sending response")
+	}
+
+}
+
+func main() {
+	fmt.Println("Starting new server...")
+	r := mux.NewRouter()
+
+	r.HandleFunc("/", handleIndex)
+	r.HandleFunc("/info", handleInfo)
+	r.NotFoundHandler = http.HandlerFunc(handleDefault)
+
+	server := http.Server{
+		Addr:    ":8080",
+		Handler: r,
+	}
+
+	_ = server.ListenAndServe()
+}