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package main
import (
"html/template"
"io"
"log"
"math/rand"
"net/http"
"os"
"path/filepath"
"time"
)
var templates = map[string]*template.Template{}
// TODO: Consider wrapping the data object in something that always contains
// a LoggedIn member, so that we don't need to duplicate it.
func executeTemplate(name string, w io.Writer, data interface{}) {
if err := templates[name].Execute(w, data); err != nil {
panic(err)
}
}
func wrap(inner func(http.ResponseWriter, *http.Request)) func(
http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
if err := r.ParseForm(); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if r.Method == http.MethodGet {
w.Header().Set("Cache-Control", "no-store")
}
inner(w, r)
}
}
func handleLogin(w http.ResponseWriter, r *http.Request) {
redirect := r.FormValue("redirect")
if redirect == "" {
redirect = "/"
}
session := sessionGet(w, r)
if session.LoggedIn {
http.Redirect(w, r, redirect, http.StatusSeeOther)
return
}
params := struct {
LoggedIn bool
IncorrectPassword bool
}{}
switch r.Method {
case http.MethodGet:
// We're just going to render the template.
case http.MethodPost:
if r.FormValue("password") == db.Password {
session.LoggedIn = true
http.Redirect(w, r, redirect, http.StatusSeeOther)
return
}
params.IncorrectPassword = true
default:
w.WriteHeader(http.StatusMethodNotAllowed)
return
}
executeTemplate("login.tmpl", w, ¶ms)
}
func handleLogout(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodPost {
w.WriteHeader(http.StatusMethodNotAllowed)
return
}
session := r.Context().Value(sessionContextKey{}).(*Session)
session.LoggedIn = false
http.Redirect(w, r, "/", http.StatusSeeOther)
}
func handleContainer(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodGet {
w.WriteHeader(http.StatusMethodNotAllowed)
return
}
children := []*Container{}
id := ContainerId(r.FormValue("id"))
description := ""
if id == "" {
children = db.Containers
} else if container, ok := indexContainer[id]; ok {
children = indexChildren[id]
description = container.Description
}
params := struct {
LoggedIn bool
Id ContainerId
Description string
Children []*Container
}{
LoggedIn: true,
Id: id,
Description: description,
Children: children,
}
executeTemplate("container.tmpl", w, ¶ms)
}
// TODO: Consider a wrapper function that automatically calls ParseForm
// and disables client-side caching.
func main() {
// Randomize the RNG for session string generation.
rand.Seed(time.Now().UnixNano())
if len(os.Args) != 3 {
log.Fatalf("Usage: %s ADDRESS DATABASE-FILE\n", os.Args[0])
}
var address string
address, dbPath = os.Args[1], os.Args[2]
// Load database.
if err := loadDatabase(); err != nil {
log.Fatalln(err)
}
// Load HTML templates from the current working directory.
m, err := filepath.Glob("*.tmpl")
if err != nil {
log.Fatalln(err)
}
for _, name := range m {
templates[name] = template.Must(template.ParseFiles("base.tmpl", name))
}
// TODO: Eventually we will need to load a font file for label printing.
// - The path might be part of configuration, or implicit by filename.
// TODO: Some routing and pages.
//
// - GET /container?id=UA1
// - GET /series?id=A
// - GET /search?q=bottle
//
// - https://stackoverflow.com/a/33880971/76313
// - POST /label?id=UA1
http.HandleFunc("/", sessionWrap(wrap(handleContainer)))
http.HandleFunc("/container", sessionWrap(wrap(handleContainer)))
http.HandleFunc("/login", wrap(handleLogin))
http.HandleFunc("/logout", sessionWrap(wrap(handleLogout)))
log.Fatalln(http.ListenAndServe(address, nil))
}
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