learn-go/snippetbox/cmd/web/handlers.go

package main

import (
	"errors"
	"fmt"
	"net/http"
	"strconv"

	"github.com/julienschmidt/httprouter"
	"snippetbox.chaosfem.tw/internal/models"
	"snippetbox.chaosfem.tw/internal/validator"
)

// home ...
func (app *application) home(w http.ResponseWriter, r *http.Request) {
	snippets, err := app.snippets.Latest()
	if err != nil {
		app.serverError(w, r, err)
		return
	}

	data := app.newTemplateData(r)
	data.Snippets = snippets

	app.render(w, r, http.StatusOK, "home.tmpl", data)
}

// snippetView ...
func (app *application) snippetView(w http.ResponseWriter, r *http.Request) {
	params := httprouter.ParamsFromContext(r.Context())

	id, err := strconv.Atoi(params.ByName("id"))
	if err != nil || id < 1 {
		app.notFound(w)
		return
	}

	snippet, err := app.snippets.Get(id)
	if err != nil || id < 1 {
		if errors.Is(err, models.ErrNoRecord) {
			app.notFound(w)
		} else {
			app.serverError(w, r, err)
		}
		return
	}

	data := app.newTemplateData(r)
	data.Snippet = snippet

	app.render(w, r, http.StatusOK, "view.tmpl", data)
}

// (app *application) snippetCreate ...
func (app *application) snippetCreate(w http.ResponseWriter, r *http.Request) {
	data := app.newTemplateData(r)

	data.Form = snippetCreateForm{
		Expires: 365,
	}

	app.render(w, r, http.StatusOK, "create.tmpl", data)
}

type snippetCreateForm struct {
	Title       string
	Content     string
	Expires     int
	validator.Validator
}

// snippetCreatePost ...
func (app *application) snippetCreatePost(w http.ResponseWriter, r *http.Request) {
	err := r.ParseForm()
	if err != nil {
		app.clientError(w, http.StatusBadRequest)
		return
	}

	expires, err := strconv.Atoi(r.PostForm.Get("expires"))
	if err != nil {
		app.clientError(w, http.StatusBadRequest)
		return
	}

	form := snippetCreateForm{
		Title:       r.PostForm.Get("title"),
		Content:     r.PostForm.Get("content"),
		Expires:     expires,
	}

	form.CheckField(validator.NotBlank(form.Title), "title", "This field cannot be blank")
	form.CheckField(validator.MaxChars(form.Title, 100), "title", "This field cannot be more than 100 characters long")
	form.CheckField(validator.NotBlank(form.Content), "content", "This field cannot be blank")
	form.CheckField(validator.PermittedValue(form.Expires, 1, 7, 365), "expires", "This field must equal 1, 7 or 365")

	if !form.Valid() {
		data := app.newTemplateData(r)
		data.Form = form
		app.render(w, r, http.StatusUnprocessableEntity, "create.tmpl", data)
		return
	}

	id, err := app.snippets.Insert(form.Title, form.Content, form.Expires)
	if err != nil {
		app.serverError(w, r, err)
		return
	}

	http.Redirect(w, r, fmt.Sprintf("/snippet/view/%d", id), http.StatusSeeOther)
}