Writefreely
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writefreely
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writefreely/handle.go

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Add handler, page, template loading
2018-11-08 05:50:50 +01:00
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
}
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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}()
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
}())
}
}
// 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
}
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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}()
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
}
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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}()
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
}
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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}()
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
}
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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}()
// 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
}
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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}()
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)
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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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
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log.Info("\"%s %s\" %d %s \"%s\"", r.Method, r.RequestURI, status, time.Since(start), r.UserAgent())
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}()
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
}