Below is an example of using Go templates for a web server:
package main
import (
"fmt"
"log"
"net/http"
"path/filepath"
"text/template"
"github.com/go-chi/chi/v5"
)
func homeHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
tplPath := filepath.Join("templates", "home.gohtml")
tpl, err := template.ParseFiles(tplPath)
if err != nil {
log.Printf("parsing template: %v", err)
http.Error(w, "There was an error parsing the template", http.StatusInternalServerError)
return
}
err = tpl.Execute(w, nil)
if err != nil {
log.Printf("executing template: %v", err)
http.Error(w, "There was an error executing the template", http.StatusInternalServerError)
return
}
}
func contactHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
tplPath := filepath.Join("templates", "contact.gohtml")
tpl, err := template.ParseFiles(tplPath)
if err != nil {
log.Printf("parsing template: %v", err)
http.Error(w, "There was an error parsing teh template", http.StatusInternalServerError)
return
}
err = tpl.Execute(w, nil)
if err != nil {
log.Printf("executing: %v", err)
http.Error(w, "There was an error executing the template", http.StatusInternalServerError)
return
}
}
func faqHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
tplPath := filepath.Join("templates", "faq.gohtml")
tpl, err := template.ParseFiles(tplPath)
if err != nil {
log.Printf("parsing template: %v", err)
http.Error(w, "There was an error parsing teh template", http.StatusInternalServerError)
return
}
err = tpl.Execute(w, nil)
if err != nil {
log.Printf("executing: %v", err)
http.Error(w, "There was an error executing the template", http.StatusInternalServerError)
return
}
}
func main() {
r := chi.NewRouter()
r.Get("/", homeHandler)
r.Get("/contact", contactHandler)
r.Get("/faq", faqHandler)
r.NotFound(func(w http.ResponseWriter, r *http.Request) {
http.Error(w, "Page Not Found", http.StatusNotFound)
})
fmt.Println("Starting the server on :3000...")
http.ListenAndServe(":3000", r)
}
Notes
- Notice how each handler is calling the specific .gohtml file:
tplPath := filepath.Join("templates", "home.gohtml")
tplPath := filepath.Join("templates", "contact.gohtml")
tplPath := filepath.Join("templates", "faq.gohtml")
- The go html files of course exist and contain the HTML code for our page. Just for reference:
├── go.mod
├── go.sum
├── main.go
└── templates
├── contact.gohtml
├── faq.gohtml
└── home.gohtml
- We can create as well a function that creates the template to avoid code repetition:
func executeTemplate(w http.ResponseWriter, filepath string) {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
tpl, err := template.ParseFiles(filepath)
if err != nil {
log.Printf("parsing template: %v", err)
http.Error(w, "There was an error parsing the template", http.StatusInternalServerError)
return
}
err = tpl.Execute(w, nil)
if err != nil {
log.Printf("executing template: %v", err)
http.Error(w, "There was an error executing the template", http.StatusInternalServerError)
return
}
}
- Then, each handler would look like this:
func homeHandler(w http.ResponseWriter, r *http.Request) {
tplPath := filepath.Join("templates", "home.gohtml")
executeTemplate(w, tplPath)
}
func contactHandler(w http.ResponseWriter, r *http.Request) {
tplPath := filepath.Join("templates", "contact.gohtml")
executeTemplate(w, tplPath)
}
func faqHandler(w http.ResponseWriter, r *http.Request) {
tplPath := filepath.Join("templates", "faq.gohtml")
executeTemplate(w, tplPath)
}
- There is no difference on regards how the web page is visualized. It looks the same. The purpose of this was to use the html template library from Go.