ch8.4

cmd/web/handlers.go

@@ -13,6 +13,13 @@ import (
 	"github.com/julienschmidt/httprouter"
 )
 
+type snippetCreateForm struct {
+	Title       string
+	Content     string
+	Expires     int
+	FieldErrors map[string]string
+}
+
 func (app *application) render(w http.ResponseWriter, status int, page string, data *templateData) {
 	ts, ok := app.templateCache[page]
 	if !ok {
@@ -74,6 +81,10 @@ func (app *application) snippetView(w http.ResponseWriter, r *http.Request) {
 func (app *application) snippetCreate(w http.ResponseWriter, r *http.Request) {
 	data := app.newTemplateData(r)
 
+	data.Form = snippetCreateForm{
+		Expires: 365,
+	}
+
 	app.render(w, http.StatusOK, "create.tmpl", data)
 }
 
@@ -83,8 +94,6 @@ func (app *application) snippetCreatePost(w http.ResponseWriter, r *http.Request
 		app.clientError(w, http.StatusBadRequest)
 		return
 	}
-	title := r.PostForm.Get("title")
-	content := r.PostForm.Get("content")
 
 	expires, err := strconv.Atoi(r.PostForm.Get("expires"))
 	if err != nil {
@@ -92,27 +101,35 @@ func (app *application) snippetCreatePost(w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	fieldErrors := make(map[string]string)
-	if strings.TrimSpace(title) == "" {
-		fieldErrors["title"] = "This field cannot be blank"
-	} else if utf8.RuneCountInString(title) > 100 {
-		fieldErrors["title"] = "This field cannot be more than 100 character long"
+	form := snippetCreateForm{
+		Title:       r.PostForm.Get("title"),
+		Content:     r.PostForm.Get("content"),
+		Expires:     expires,
+		FieldErrors: map[string]string{},
 	}
 
-	if strings.TrimSpace(content) == "" {
-		fieldErrors["content"] = "This field cannot be blank"
+	if strings.TrimSpace(form.Title) == "" {
+		form.FieldErrors["title"] = "This field cannot be blank"
+	} else if utf8.RuneCountInString(form.Title) > 100 {
+		form.FieldErrors["title"] = "This field cannot be more than 100 character long"
 	}
 
-	if expires != 1 && expires != 7 && expires != 365 {
-		fieldErrors["expires"] = "This field must equal 1, 7 and 365"
+	if strings.TrimSpace(form.Content) == "" {
+		form.FieldErrors["content"] = "This field cannot be blank"
 	}
 
-	if len(fieldErrors) > 0 {
-		fmt.Fprint(w, fieldErrors)
+	if form.Expires != 1 && form.Expires != 7 && form.Expires != 365 {
+		form.FieldErrors["expires"] = "This field must equal 1, 7 and 365"
+	}
+
+	if len(form.FieldErrors) > 0 {
+		data := app.newTemplateData(r)
+		data.Form = form
+		app.render(w, http.StatusUnprocessableEntity, "create.tmpl", data)
 		return
 	}
 
-	id, err := app.snippets.Insert(title, content, expires)
+	id, err := app.snippets.Insert(form.Title, form.Content, form.Expires)
 	if err != nil {
 		app.serverError(w, err)
 		return

cmd/web/templates.go

@@ -13,6 +13,7 @@ type templateData struct {
 	CurrentYear int
 	Snippet     *models.Snippet
 	Snippets    []*models.Snippet
+	Form        any
 }
 
 func humanDate(t time.Time) string {

ui/html/pages/create.tmpl

@@ -4,17 +4,26 @@
 <form action='/snippet/create' method='POST'>
     <div>
         <label>Title:</label>
-        <input type='text' name='title'>
+        {{with .Form.FieldErrors.title}}
+            <label class='error'>{{.}}</label>
+        {{end}}
+        <input type='text' name='title' value='{{.Form.Title}}'>
     </div>
     <div>
         <label>Content:</label>
-        <textarea name='content'></textarea>
+        {{with .Form.FieldErrors.content}}
+            <label class='error'>{{.}}</label>
+        {{end}}
+        <textarea name='content'>{{.Form.Content}}</textarea>
     </div>
     <div>
         <label>Delete in:</label>
-        <input type='radio' name='expires' value='365' checked> One Year
-        <input type='radio' name='expires' value='7'> One Week
-        <input type='radio' name='expires' value='1'> One Day
+        {{with .Form.FieldErrors.expires}}
+            <label class='error'>{{.}}</label>
+        {{end}}
+        <input type='radio' name='expires' value='365' {{if (eq .Form.Expires 365)}}checked{{end}}> One Year
+        <input type='radio' name='expires' value='7' {{if (eq .Form.Expires 7)}}checked{{end}}> One Week
+        <input type='radio' name='expires' value='1' {{if (eq .Form.Expires 1)}}checked{{end}}> One Day
     </div>
     <div>
         <input type='submit' value='Publish snippet'>