Server side form validation 2

internal/forms/forms.go

@@ -22,5 +22,14 @@ func New(data url.Values) *Form {
 // Has checks if form field is in post and not emtpy
 func (f *Form) Has(field string, r *http.Request) bool {
 	x := r.Form.Get(field)
-	return x != ""
+	if x == "" {
+		f.Errors.Add(field, "This field cannot be blank")
+		return false
+	}
+	return true
+}
+
+// Valid returns true if there are no errors, otherwise false
+func (f *Form) Valid() bool {
+	return len(f.Errors) == 0
 }

internal/handlers/handlers.go

@@ -76,6 +76,33 @@ func (m *Repository) MakeReservation(w http.ResponseWriter, r *http.Request) {
 
 // PostMakeReservation is the make reservation page post handler
 func (m *Repository) PostMakeReservation(w http.ResponseWriter, r *http.Request) {
+	err := r.ParseForm()
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	reservation := models.Reservation{
+		FirstName: r.Form.Get("first_name"),
+		LastName:  r.Form.Get("last_name"),
+		Email:     r.Form.Get("email"),
+		Phone:     r.Form.Get("phone"),
+	}
+
+	form := forms.New(r.PostForm)
+
+	form.Has("first_name", r)
+
+	if !form.Valid() {
+		data := make(map[string]interface{})
+		data["reservation"] = reservation
+
+		render.RenderTemplate(w, r, "make-reservation.page.tmpl", &models.TemplateData{
+			Data: data,
+			Form: form,
+		})
+		return
+	}
 }
 
 // Availability is the search for availability page handler

internal/models/models.go

@@ -0,0 +1,9 @@
+package models
+
+// Reservation holds Reservation data
+type Reservation struct {
+	FirstName string
+	LastName  string
+	Email     string
+	Phone     string
+}

templates/make-reservation.page.tmpl

@@ -8,10 +8,14 @@
             <!-- <form method="post" action="" class="needs-validation" novalidate> -->
             <form method="post" action="" class="" novalidate>
                 <input type="hidden" name="csrf_token" value="{{.CSRFToken}}">
+
                 <div class="form-group mt-5">
                     <label for="first_name">First name:</label>
-                    <input type="text" name="first_name" id="first_name" class="form-control" required
-                        autocomplete="off">
+                    {{with .Form.Errors.Get "first_name"}}
+                    <label class="text-danger">{{.}}</label>
+                    {{end}}
+                    <input type="text" name="first_name" id="first_name" class="form-control {{with .Form.Errors.Get "first_name"}} is-invalid {{end}}"
+                        required autocomplete="off">
                 </div>
                 <div class="form-group mt-5">
                     <label for="last_name">Last name:</label>