/ *
* Copyright © 2018 A Bunch Tell LLC .
*
* This file is part of WriteFreely .
*
* WriteFreely is free software : you can redistribute it and / or modify
* it under the terms of the GNU Affero General Public License , included
* in the LICENSE file in this source code package .
* /
package writefreely
import (
"fmt"
"html/template"
"net/http"
"net/url"
"runtime/debug"
"strconv"
"strings"
"time"
"github.com/gorilla/sessions"
"github.com/writeas/impart"
"github.com/writeas/web-core/log"
"github.com/writeas/writefreely/page"
)
type UserLevel int
const (
UserLevelNone UserLevel = iota // user or not -- ignored
UserLevelOptional // user or not -- object fetched if user
UserLevelNoneRequired // non-user (required)
UserLevelUser // user (required)
)
type (
handlerFunc func ( app * app , w http . ResponseWriter , r * http . Request ) error
userHandlerFunc func ( app * app , u * User , w http . ResponseWriter , r * http . Request ) error
dataHandlerFunc func ( app * app , w http . ResponseWriter , r * http . Request ) ( [ ] byte , string , error )
authFunc func ( app * app , r * http . Request ) ( * User , error )
)
type Handler struct {
errors * ErrorPages
sessionStore * sessions . CookieStore
app * app
}
// ErrorPages hold template HTML error pages for displaying errors to the user.
// In each, there should be a defined template named "base".
type ErrorPages struct {
NotFound * template . Template
Gone * template . Template
InternalServerError * template . Template
Blank * template . Template
}
// NewHandler returns a new Handler instance, using the given StaticPage data,
// and saving alias to the application's CookieStore.
func NewHandler ( app * app ) * Handler {
h := & Handler {
errors : & ErrorPages {
NotFound : template . Must ( template . New ( "" ) . Parse ( "{{define \"base\"}}<html><head><title>404</title></head><body><p>Not found.</p></body></html>{{end}}" ) ) ,
Gone : template . Must ( template . New ( "" ) . Parse ( "{{define \"base\"}}<html><head><title>410</title></head><body><p>Gone.</p></body></html>{{end}}" ) ) ,
InternalServerError : template . Must ( template . New ( "" ) . Parse ( "{{define \"base\"}}<html><head><title>500</title></head><body><p>Internal server error.</p></body></html>{{end}}" ) ) ,
Blank : template . Must ( template . New ( "" ) . Parse ( "{{define \"base\"}}<html><head><title>{{.Title}}</title></head><body><p>{{.Content}}</p></body></html>{{end}}" ) ) ,
} ,
sessionStore : app . sessionStore ,
app : app ,
}
return h
}
// SetErrorPages sets the given set of ErrorPages as templates for any errors
// that come up.
func ( h * Handler ) SetErrorPages ( e * ErrorPages ) {
h . errors = e
}
// User handles requests made in the web application by the authenticated user.
// This provides user-friendly HTML pages and actions that work in the browser.
func ( h * Handler ) User ( f userHandlerFunc ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
h . handleHTTPError ( w , r , func ( ) error {
var status int
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
log . Error ( "%s: %s" , e , debug . Stack ( ) )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = http . StatusInternalServerError
}
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
} ( )
u := getUserSession ( h . app , r )
if u == nil {
err := ErrNotLoggedIn
status = err . Status
return err
}
err := f ( h . app , u , w , r )
if err == nil {
status = http . StatusOK
} else if err , ok := err . ( impart . HTTPError ) ; ok {
status = err . Status
} else {
status = http . StatusInternalServerError
}
return err
} ( ) )
}
}
// Admin handles requests on /admin routes
func ( h * Handler ) Admin ( f userHandlerFunc ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
h . handleHTTPError ( w , r , func ( ) error {
var status int
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
log . Error ( "%s: %s" , e , debug . Stack ( ) )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = http . StatusInternalServerError
}
log . Info ( fmt . Sprintf ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) ) )
} ( )
u := getUserSession ( h . app , r )
if u == nil || ! u . IsAdmin ( ) {
err := impart . HTTPError { http . StatusNotFound , "" }
status = err . Status
return err
}
err := f ( h . app , u , w , r )
if err == nil {
status = http . StatusOK
} else if err , ok := err . ( impart . HTTPError ) ; ok {
status = err . Status
} else {
status = http . StatusInternalServerError
}
return err
} ( ) )
}
}
// UserAPI handles requests made in the API by the authenticated user.
// This provides user-friendly HTML pages and actions that work in the browser.
func ( h * Handler ) UserAPI ( f userHandlerFunc ) http . HandlerFunc {
return h . UserAll ( false , f , func ( app * app , r * http . Request ) ( * User , error ) {
// Authorize user from Authorization header
t := r . Header . Get ( "Authorization" )
if t == "" {
return nil , ErrNoAccessToken
}
u := & User { ID : app . db . GetUserID ( t ) }
if u . ID == - 1 {
return nil , ErrBadAccessToken
}
return u , nil
} )
}
func ( h * Handler ) UserAll ( web bool , f userHandlerFunc , a authFunc ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
handleFunc := func ( ) error {
var status int
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
log . Error ( "%s: %s" , e , debug . Stack ( ) )
impart . WriteError ( w , impart . HTTPError { http . StatusInternalServerError , "Something didn't work quite right." } )
status = 500
}
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
} ( )
u , err := a ( h . app , r )
if err != nil {
if err , ok := err . ( impart . HTTPError ) ; ok {
status = err . Status
} else {
status = 500
}
return err
}
err = f ( h . app , u , w , r )
if err == nil {
status = 200
} else if err , ok := err . ( impart . HTTPError ) ; ok {
status = err . Status
} else {
status = 500
}
return err
}
if web {
h . handleHTTPError ( w , r , handleFunc ( ) )
} else {
h . handleError ( w , r , handleFunc ( ) )
}
}
}
func ( h * Handler ) RedirectOnErr ( f handlerFunc , loc string ) handlerFunc {
return func ( app * app , w http . ResponseWriter , r * http . Request ) error {
err := f ( app , w , r )
if err != nil {
if ie , ok := err . ( impart . HTTPError ) ; ok {
// Override default redirect with returned error's, if it's a
// redirect error.
if ie . Status == http . StatusFound {
return ie
}
}
return impart . HTTPError { http . StatusFound , loc }
}
return nil
}
}
func ( h * Handler ) Page ( n string ) http . HandlerFunc {
return h . Web ( func ( app * app , w http . ResponseWriter , r * http . Request ) error {
t , ok := pages [ n ]
if ! ok {
return impart . HTTPError { http . StatusNotFound , "Page not found." }
}
sp := pageForReq ( app , r )
err := t . ExecuteTemplate ( w , "base" , sp )
if err != nil {
log . Error ( "Unable to render page: %v" , err )
}
return err
} , UserLevelOptional )
}
func ( h * Handler ) WebErrors ( f handlerFunc , ul UserLevel ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
// TODO: factor out this logic shared with Web()
h . handleHTTPError ( w , r , func ( ) error {
var status int
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
u := getUserSession ( h . app , r )
username := "None"
if u != nil {
username = u . Username
}
log . Error ( "User: %s\n\n%s: %s" , username , e , debug . Stack ( ) )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = 500
}
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
} ( )
var session * sessions . Session
var err error
if ul != UserLevelNone {
session , err = h . sessionStore . Get ( r , cookieName )
if err != nil && ( ul == UserLevelNoneRequired || ul == UserLevelUser ) {
// Cookie is required, but we can ignore this error
log . Error ( "Handler: Unable to get session (for user permission %d); ignoring: %v" , ul , err )
}
_ , gotUser := session . Values [ cookieUserVal ] . ( * User )
if ul == UserLevelNoneRequired && gotUser {
to := correctPageFromLoginAttempt ( r )
log . Info ( "Handler: Required NO user, but got one. Redirecting to %s" , to )
err := impart . HTTPError { http . StatusFound , to }
status = err . Status
return err
} else if ul == UserLevelUser && ! gotUser {
log . Info ( "Handler: Required a user, but DIDN'T get one. Sending not logged in." )
err := ErrNotLoggedIn
status = err . Status
return err
}
}
// TODO: pass User object to function
err = f ( h . app , w , r )
if err == nil {
status = 200
} else if httpErr , ok := err . ( impart . HTTPError ) ; ok {
status = httpErr . Status
if status < 300 || status > 399 {
addSessionFlash ( h . app , w , r , httpErr . Message , session )
return impart . HTTPError { http . StatusFound , r . Referer ( ) }
}
} else {
e := fmt . Sprintf ( "[Web handler] 500: %v" , err )
if ! strings . HasSuffix ( e , "write: broken pipe" ) {
log . Error ( e )
} else {
log . Error ( e )
}
log . Info ( "Web handler internal error render" )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = 500
}
return err
} ( ) )
}
}
// Web handles requests made in the web application. This provides user-
// friendly HTML pages and actions that work in the browser.
func ( h * Handler ) Web ( f handlerFunc , ul UserLevel ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
h . handleHTTPError ( w , r , func ( ) error {
var status int
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
u := getUserSession ( h . app , r )
username := "None"
if u != nil {
username = u . Username
}
log . Error ( "User: %s\n\n%s: %s" , username , e , debug . Stack ( ) )
log . Info ( "Web deferred internal error render" )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = 500
}
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
} ( )
if ul != UserLevelNone {
session , err := h . sessionStore . Get ( r , cookieName )
if err != nil && ( ul == UserLevelNoneRequired || ul == UserLevelUser ) {
// Cookie is required, but we can ignore this error
log . Error ( "Handler: Unable to get session (for user permission %d); ignoring: %v" , ul , err )
}
_ , gotUser := session . Values [ cookieUserVal ] . ( * User )
if ul == UserLevelNoneRequired && gotUser {
to := correctPageFromLoginAttempt ( r )
log . Info ( "Handler: Required NO user, but got one. Redirecting to %s" , to )
err := impart . HTTPError { http . StatusFound , to }
status = err . Status
return err
} else if ul == UserLevelUser && ! gotUser {
log . Info ( "Handler: Required a user, but DIDN'T get one. Sending not logged in." )
err := ErrNotLoggedIn
status = err . Status
return err
}
}
// TODO: pass User object to function
err := f ( h . app , w , r )
if err == nil {
status = 200
} else if httpErr , ok := err . ( impart . HTTPError ) ; ok {
status = httpErr . Status
} else {
e := fmt . Sprintf ( "[Web handler] 500: %v" , err )
log . Error ( e )
log . Info ( "Web internal error render" )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = 500
}
return err
} ( ) )
}
}
func ( h * Handler ) All ( f handlerFunc ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
h . handleError ( w , r , func ( ) error {
// TODO: return correct "success" status
status := 200
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
log . Error ( "%s:\n%s" , e , debug . Stack ( ) )
impart . WriteError ( w , impart . HTTPError { http . StatusInternalServerError , "Something didn't work quite right." } )
status = 500
}
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
} ( )
// TODO: do any needed authentication
err := f ( h . app , w , r )
if err != nil {
if err , ok := err . ( impart . HTTPError ) ; ok {
status = err . Status
} else {
status = 500
}
}
return err
} ( ) )
}
}
func ( h * Handler ) Download ( f dataHandlerFunc , ul UserLevel ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
h . handleHTTPError ( w , r , func ( ) error {
var status int
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
log . Error ( "%s: %s" , e , debug . Stack ( ) )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = 500
}
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
} ( )
data , filename , err := f ( h . app , w , r )
if err != nil {
if err , ok := err . ( impart . HTTPError ) ; ok {
status = err . Status
} else {
status = 500
}
return err
}
ext := ".json"
ct := "application/json"
if strings . HasSuffix ( r . URL . Path , ".csv" ) {
ext = ".csv"
ct = "text/csv"
} else if strings . HasSuffix ( r . URL . Path , ".zip" ) {
ext = ".zip"
ct = "application/zip"
}
w . Header ( ) . Set ( "Content-Disposition" , fmt . Sprintf ( "attachment; filename=%s%s" , filename , ext ) )
w . Header ( ) . Set ( "Content-Type" , ct )
w . Header ( ) . Set ( "Content-Length" , strconv . Itoa ( len ( data ) ) )
fmt . Fprint ( w , string ( data ) )
status = 200
return nil
} ( ) )
}
}
func ( h * Handler ) Redirect ( url string , ul UserLevel ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
h . handleHTTPError ( w , r , func ( ) error {
start := time . Now ( )
var status int
if ul != UserLevelNone {
session , err := h . sessionStore . Get ( r , cookieName )
if err != nil && ( ul == UserLevelNoneRequired || ul == UserLevelUser ) {
// Cookie is required, but we can ignore this error
log . Error ( "Handler: Unable to get session (for user permission %d); ignoring: %v" , ul , err )
}
_ , gotUser := session . Values [ cookieUserVal ] . ( * User )
if ul == UserLevelNoneRequired && gotUser {
to := correctPageFromLoginAttempt ( r )
log . Info ( "Handler: Required NO user, but got one. Redirecting to %s" , to )
err := impart . HTTPError { http . StatusFound , to }
status = err . Status
return err
} else if ul == UserLevelUser && ! gotUser {
log . Info ( "Handler: Required a user, but DIDN'T get one. Sending not logged in." )
err := ErrNotLoggedIn
status = err . Status
return err
}
}
status = sendRedirect ( w , http . StatusFound , url )
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
return nil
} ( ) )
}
}
func ( h * Handler ) handleHTTPError ( w http . ResponseWriter , r * http . Request , err error ) {
if err == nil {
return
}
if err , ok := err . ( impart . HTTPError ) ; ok {
if err . Status >= 300 && err . Status < 400 {
sendRedirect ( w , err . Status , err . Message )
return
} else if err . Status == http . StatusUnauthorized {
q := ""
if r . URL . RawQuery != "" {
q = url . QueryEscape ( "?" + r . URL . RawQuery )
}
sendRedirect ( w , http . StatusFound , "/login?to=" + r . URL . Path + q )
return
} else if err . Status == http . StatusGone {
p := & struct {
page . StaticPage
Content * template . HTML
} {
StaticPage : pageForReq ( h . app , r ) ,
}
if err . Message != "" {
co := template . HTML ( err . Message )
p . Content = & co
}
h . errors . Gone . ExecuteTemplate ( w , "base" , p )
return
} else if err . Status == http . StatusNotFound {
h . errors . NotFound . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
return
} else if err . Status == http . StatusInternalServerError {
log . Info ( "handleHTTPErorr internal error render" )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
return
} else if err . Status == http . StatusAccepted {
impart . WriteSuccess ( w , "" , err . Status )
return
} else {
p := & struct {
page . StaticPage
Title string
Content template . HTML
} {
pageForReq ( h . app , r ) ,
fmt . Sprintf ( "Uh oh (%d)" , err . Status ) ,
template . HTML ( fmt . Sprintf ( "<p style=\"text-align: center\" class=\"introduction\">%s</p>" , err . Message ) ) ,
}
h . errors . Blank . ExecuteTemplate ( w , "base" , p )
return
}
impart . WriteError ( w , err )
return
}
impart . WriteError ( w , impart . HTTPError { http . StatusInternalServerError , "This is an unhelpful error message for a miscellaneous internal error." } )
}
func ( h * Handler ) handleError ( w http . ResponseWriter , r * http . Request , err error ) {
if err == nil {
return
}
if err , ok := err . ( impart . HTTPError ) ; ok {
if err . Status >= 300 && err . Status < 400 {
sendRedirect ( w , err . Status , err . Message )
return
}
// if strings.Contains(r.Header.Get("Accept"), "text/html") {
impart . WriteError ( w , err )
// }
return
}
if IsJSON ( r . Header . Get ( "Content-Type" ) ) {
impart . WriteError ( w , impart . HTTPError { http . StatusInternalServerError , "This is an unhelpful error message for a miscellaneous internal error." } )
return
}
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
}
func correctPageFromLoginAttempt ( r * http . Request ) string {
to := r . FormValue ( "to" )
if to == "" {
to = "/"
} else if ! strings . HasPrefix ( to , "/" ) {
to = "/" + to
}
return to
}
func ( h * Handler ) LogHandlerFunc ( f http . HandlerFunc ) http . HandlerFunc {
return func ( w http . ResponseWriter , r * http . Request ) {
h . handleHTTPError ( w , r , func ( ) error {
status := 200
start := time . Now ( )
defer func ( ) {
if e := recover ( ) ; e != nil {
log . Error ( "Handler.LogHandlerFunc\n\n%s: %s" , e , debug . Stack ( ) )
h . errors . InternalServerError . ExecuteTemplate ( w , "base" , pageForReq ( h . app , r ) )
status = 500
}
// TODO: log actual status code returned
log . Info ( "\"%s %s\" %d %s \"%s\"" , r . Method , r . RequestURI , status , time . Since ( start ) , r . UserAgent ( ) )
} ( )
f ( w , r )
return nil
} ( ) )
}
}
func sendRedirect ( w http . ResponseWriter , code int , location string ) int {
w . Header ( ) . Set ( "Location" , location )
w . WriteHeader ( code )
return code
}
