transmet/route_handlers.go

package main

import (
	"github.com/gorilla/mux"
	"github.com/gorilla/sessions"
	"net/http"
	"github.com/dballard/transmet/user"
	"fmt"
	"time"
	"io/ioutil"
	"regexp"
	"strings"
	"strconv"
	"github.com/dballard/transmet/categories"
	"github.com/dballard/transmet/news"
	"bytes"
	txtTemplate "text/template"
	"net/url"
)

func GetFlashes(session *sessions.Session) map[string]interface{} {
	var flashes = make(map[string]interface{})
	flashes["error"] = session.Flashes(flash_err)
	flashes["info"] = session.Flashes(flash_info)
	return flashes
}

func sessionWipe(session *sessions.Session) {
	session.Values = make(map[interface{}]interface{})
}

func initSessionUser(r *http.Request) (*user.User, *sessions.Session) {
	session, _ := store.Get(r, "c_user")
	if session.Values["username"] == nil {
		return nil, session
	}

	return user.NewUserFromUsername(db, session.Values["username"].(string)), session
}

// wrapper for handlers requiring a User
func userHandler(next func(http.ResponseWriter, *http.Request, *user.User)) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		user, _ := initSessionUser(r)
		if user == nil {
			http.Redirect(w, r, "/login", http.StatusFound)
		} else {
			next(w, r, user)
		}
	}
}

// wrapper for handlers forking on GET and POST
//   r.HandleFunc("/login", getPostHandler(LoginFormHandler, LoginPostHandler))
func getPostHandler(getFn, postFn func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method == "GET" {
			getFn(w, r)
		} else { // POST
			postFn(w, r)
		}
	}
}

func ShowTemplate(template string, w http.ResponseWriter, data map[string]interface{}) {
	err := templates[template].Execute(w, data)
	if err != nil {
		fmt.Println("Exec err: ", err)
	}
	// TODO: show error 500 page
}	

// Log in page handler
func LoginFormHandler(w http.ResponseWriter, r *http.Request) {
	session, _ := store.Get(r, "c_user")
	flashes := GetFlashes(session)
	session.Save(r, w)
	
	ShowTemplate("login", w, map[string]interface{}{"flashes": flashes})
}

// handler for login POST
//  TODO: proper per account and client flood control rate limiting
//    currently weak per call slow down is by-passable at scale
func LoginPostHandler(w http.ResponseWriter, r *http.Request) {
	time.Sleep(500 * time.Millisecond) // WEAK poor mans rate limiting for logins
	r.ParseForm()
	username := r.PostFormValue("username")
	// lookup user
	password := r.PostFormValue("password")
	user := user.NewUserFromAuth(db, username, password)
	if user != nil {
		session, _ := store.Get(r, "c_user")
		session.Values["username"] = user.Username
		session.Save(r, w)
		if r.URL.Query().Get("url") != "" {
		    http.Redirect(w, r, "/add?" + r.URL.RawQuery, http.StatusFound)
		}
		http.Redirect(w, r, "/", http.StatusFound)
	} else {
		time.Sleep(500 * time.Millisecond) // WEAK bypassable poor mans rate limiting for failed logins
		session, _ := store.Get(r, "c_user")
		session.AddFlash("Username or password", flash_err)
		session.Save(r, w)
		http.Redirect(w, r, "/login?"+r.URL.RawQuery, http.StatusFound)
	}
}

// logout POST handler
func LogoutHandler(w http.ResponseWriter, r *http.Request, user *user.User) {
	session, _ := store.Get(r, "c_user")
	//session.Options = &sessions.Options{MaxAge: -1}
	sessionWipe(session)
	session.Save(r, w)
	http.Redirect(w, r, "/", http.StatusFound)
}

func getUrlTitle(url string) string {
    resp, err := http.Get(url)
    if err != nil {
        fmt.Println("Error looking up link", url, ":", err)
    } else {
        body, err := ioutil.ReadAll(resp.Body)
        if err != nil {
            fmt.Println("Error reading link", url, ":", err)
        } else {
            re := regexp.MustCompile("< *[Tt][Ii][Tt][Ll][Ee] *>(.*)</ *[Tt][Ii][Tt][Ll][Ee] *>")
            title := re.FindStringSubmatch(string(body))
            if title != nil {
                return strings.TrimSpace(title[1])
            }
        }
    }
    return ""
}

// ?url=
func addFormHandler(w http.ResponseWriter, r *http.Request, user *user.User) {
    categories.LoadCategories(db)
    
    session, _ := store.Get(r, "c_user")
    flashes := GetFlashes(session)
    popup := session.Values["popup"]
    delete(session.Values, "popup")
	title := session.Values["title"]
	delete(session.Values, "title")
	link := session.Values["link"]
	delete(session.Values, "link")
	description := session.Values["description"]
	delete(session.Values, "description")
	session.Save(r, w)
	
	if link != nil {
		fmt.Println("link: '" + link.(string) + "'")
	    //TODO category_id
		ShowTemplate("add", w, map[string]interface{}{"user": user, "flashes": flashes, "categories": categories.CategoriesTree, "link": link, "title": title, "description": description, "popup": popup})
		return
	}
    
    var url = r.URL.Query().Get("url")
    reHttp := regexp.MustCompile("^https?://")
    if url != "" && ! reHttp.Match([]byte(url)) {
        url = "http://" + url
    } 
    
    title = r.URL.Query().Get("title")
    if title == "" && url != "" {
        title = getUrlTitle(url)
    }
    
    popup = r.URL.Query().Get("popup")
    
	ShowTemplate("add", w, map[string]interface{}{"user": user, "flashes": flashes, "link": url, "categories": categories.CategoriesTree, "title": title, "popup": popup})
}

func addPostHandler(w http.ResponseWriter, r *http.Request, user *user.User) {
	session, _ := store.Get(r, "c_user")
	var news news.News
	
	news.Title, _ = url.QueryUnescape(r.FormValue("title"))
	news.Notes, _ = url.QueryUnescape(r.FormValue("notes"))
	news.Url = r.FormValue("link")
	popup := r.FormValue("popup")
	category_id, err := strconv.Atoi(r.FormValue("category"))
	if err != nil {
	    category_id = -1
	}
	news.Category_id = category_id
	
	err = (&news).Insert(db)
	if err != nil {
	    session.AddFlash("Error saving news: " + err.Error(), flash_err)
	    session.Values["title"] = news.Title
	    session.Values["link"] = news.Url
	    session.Values["notes"] = news.Notes
	    session.Values["popup"] = popup
		session.Save(r, w)
	    http.Redirect(w, r, "/add", http.StatusFound)
	} else {
	    // TODO auto close? redirect
	    session.AddFlash("Added news \""+news.Title+"\"", flash_info)
		session.Save(r, w)
		if popup == "1" {
		    http.Redirect(w, r, "/added", http.StatusFound)
		} else {
	    	http.Redirect(w, r, "/", http.StatusFound)
	    }
	}
}

func templateFormHandler(w http.ResponseWriter, r *http.Request, user *user.User) {
	session, _ := store.Get(r, "c_user")
    flashes := GetFlashes(session)
    session.Save(r, w)
    
    news, count, err := news.Unexported(db)
	if err != nil {
	    return
	}
	
	var templateBuf bytes.Buffer
	template, err := txtTemplate.ParseFiles("templates/html_template.txt")
	if err != nil {
	    fmt.Println("Error processing html_tempalte:" , err)
	}
	err = template.Execute(&templateBuf, map[string]interface{}{"news": news})
	if err != nil {
		fmt.Println("Exec err: ", err)
	}
    
	ShowTemplate("list", w, map[string]interface{}{"user": user, "flashes": flashes, "template": &templateBuf, "count": count, "url": config.Url})
}

func exportHandler(w http.ResponseWriter, r *http.Request, user *user.User) {
	session, _ := store.Get(r, "c_user")
	
	err := news.MarkExported(db)
	
	if err != nil {
	    session.AddFlash("Error marking last batch of news exported", flash_err)
	} else {
		session.AddFlash("Last batch of news marked exported", flash_info)
	}
	session.Save(r, w)
    http.Redirect(w, r, "/", http.StatusFound)
}

func addedHandler(w http.ResponseWriter, r *http.Request, user *user.User) {
	session, _ := store.Get(r, "c_user")
    flashes := GetFlashes(session)
    session.Save(r, w)
    ShowTemplate("added", w, map[string]interface{}{"user": user, "flashes": flashes})
}

func init_route_handlers() {
    http.Handle("/js/", http.StripPrefix("/js/", http.FileServer(http.Dir("js/"))))
	http.Handle("/css/", http.StripPrefix("/css/", http.FileServer(http.Dir("css/"))))
	http.Handle("/fonts/", http.StripPrefix("/fonts", http.FileServer(http.Dir("fonts/"))))

	r := mux.NewRouter()
	
	r.HandleFunc("/login", getPostHandler(LoginFormHandler, LoginPostHandler))
	r.HandleFunc("/logout", userHandler(LogoutHandler))

	r.HandleFunc("/add", getPostHandler(userHandler(addFormHandler), userHandler(addPostHandler)))
	r.HandleFunc("/", userHandler(templateFormHandler))
	r.HandleFunc("/export", userHandler(exportHandler))
	r.HandleFunc("/added", userHandler(addedHandler))
	
	
	http.Handle("/", r)
}