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Add meta viewer and owner tokens

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This commit is contained in:
Daan Sprenkels 2019-09-01 01:41:01 +02:00
parent 5a7394ffd3
commit 0d7f7c7808
2 changed files with 133 additions and 21 deletions
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153
handlers.go
View File

@ -6,12 +6,16 @@ package main
import (
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"fmt"
"io"
"log"
"net/http"
"net/url"
"strings"
"time"
"unicode"
"gitea.hashru.nl/dsprenkels/rushlink/gobmarsh"
"github.com/gorilla/mux"
@ -27,6 +31,7 @@ type StoredPaste struct {
State PasteState
Content []byte
Key []byte
OwnerToken [16]byte
TimeCreated time.Time
}
@ -40,9 +45,37 @@ const (
StateDeleted
)
var base64Alphabet = []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_")
const CookieOwnerToken = "owner_token"
// Base64 encoding and decoding
var base64Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
var base64Encoder = base64.NewEncoding(base64Alphabet).WithPadding(base64.NoPadding)
// Page contents
var indexContents = MustAsset("assets/index.txt")
func (t PasteType) String() (string, error) {
switch t {
case TypePaste:
return "paste", nil
case TypeRedirect:
return "redirect", nil
default:
return "", fmt.Errorf("invalid PasteType (%v)", t)
}
}
func (t PasteState) String() (string, error) {
switch t {
case StatePresent:
return "present", nil
case StateDeleted:
return "deleted", nil
default:
return "", fmt.Errorf("invalid PasteState (%v)", t)
}
}
func indexGetHandler(w http.ResponseWriter, r *http.Request) {
_, err := w.Write(indexContents)
if err != nil {
@ -53,7 +86,7 @@ func indexGetHandler(w http.ResponseWriter, r *http.Request) {
func indexPostHandler(w http.ResponseWriter, r *http.Request) {
if err := r.ParseMultipartForm(50 * 1000 * 1000); err != nil {
w.WriteHeader(http.StatusInternalServerError)
fmt.Fprintf(w, "Internal server error: %v", err)
fmt.Fprintf(w, "Internal server error: %v\n", err)
return
}
@ -62,18 +95,18 @@ func indexPostHandler(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusBadRequest)
var buf []byte
r.Body.Read(buf)
io.WriteString(w, "empty body in POST request")
io.WriteString(w, "empty body in POST request\n")
return
}
shorten_values, prs := r.PostForm["shorten"]
if !prs {
w.WriteHeader(http.StatusBadRequest)
io.WriteString(w, "no 'shorten' param supplied")
io.WriteString(w, "no 'shorten' param supplied\n")
return
}
if len(shorten_values) != 1 {
w.WriteHeader(http.StatusBadRequest)
io.WriteString(w, "only one 'shorten' param is allowed per request")
io.WriteString(w, "only one 'shorten' param is allowed per request\n")
return
}
@ -81,14 +114,18 @@ func indexPostHandler(w http.ResponseWriter, r *http.Request) {
}
func pasteGetHandler(w http.ResponseWriter, r *http.Request) {
pasteGetHandlerInner(w, r, false)
pasteGetHandlerInner(w, r, false, false)
}
func pasteGetHandlerNoRedirect(w http.ResponseWriter, r *http.Request) {
pasteGetHandlerInner(w, r, true)
pasteGetHandlerInner(w, r, true, false)
}
func pasteGetHandlerInner(w http.ResponseWriter, r *http.Request, noRedirect bool) {
func pasteGetHandlerMeta(w http.ResponseWriter, r *http.Request) {
pasteGetHandlerInner(w, r, false, true)
}
func pasteGetHandlerInner(w http.ResponseWriter, r *http.Request, noRedirect, showMeta bool) {
vars := mux.Vars(r)
key := vars["key"]
var storedPaste *StoredPaste
@ -99,14 +136,45 @@ func pasteGetHandlerInner(w http.ResponseWriter, r *http.Request, noRedirect boo
}); err != nil {
w.WriteHeader(http.StatusInternalServerError)
log.Printf("error: %v\n", err)
fmt.Fprintf(w, "internal server error: %v", err)
fmt.Fprintf(w, "internal server error: %v\n", err)
return
}
if storedPaste == nil {
w.WriteHeader(http.StatusNotFound)
fmt.Fprintf(w, "url key not found in the database")
fmt.Fprintf(w, "url key not found in the database\n")
return
}
if showMeta {
typeString, err := storedPaste.Type.String()
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
log.Printf("error: %v\n", err)
fmt.Fprintf(w, "internal server error: %v\n", err)
return
}
stateString, err := storedPaste.State.String()
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
log.Printf("error: %v\n", err)
fmt.Fprintf(w, "internal server error: %v\n", err)
return
}
isOwner := "no"
ownerToken, ok := getOwnerTokenFromRequest(r)
if ok && subtle.ConstantTimeCompare(ownerToken[:], storedPaste.OwnerToken[:]) == 1 {
isOwner = "yes"
}
w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, "key: %v\n", string(storedPaste.Key))
fmt.Fprintf(w, "type: %v\n", typeString)
fmt.Fprintf(w, "state: %v\n", stateString)
fmt.Fprintf(w, "created: %v\n", storedPaste.TimeCreated.String())
fmt.Fprintf(w, "are you the owner: %v\n", isOwner)
return
}
switch storedPaste.State {
case StatePresent:
if !noRedirect {
@ -115,7 +183,7 @@ func pasteGetHandlerInner(w http.ResponseWriter, r *http.Request, noRedirect boo
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
log.Printf("error: invalid URL ('%v') in database for key '%v': %v\n", rawurl, storedPaste.Key, err)
fmt.Fprintf(w, "internal server error: invalid url in database")
fmt.Fprintf(w, "internal server error: invalid url in database\n")
return
}
http.Redirect(w, r, urlParse.String(), http.StatusSeeOther)
@ -123,11 +191,11 @@ func pasteGetHandlerInner(w http.ResponseWriter, r *http.Request, noRedirect boo
w.Write(storedPaste.Content)
case StateDeleted:
w.WriteHeader(http.StatusGone)
fmt.Fprintf(w, "key has been deleted")
fmt.Fprintf(w, "key has been deleted\n")
default:
w.WriteHeader(http.StatusInternalServerError)
log.Printf("error: invalid storedPaste.State (%v) for key '%v'\n", storedPaste.State, storedPaste.Key)
fmt.Fprintf(w, "internal server error: invalid storedPaste.State (%v)", storedPaste.State)
fmt.Fprintf(w, "internal server error: invalid storedPaste.State (%v\n)", storedPaste.State)
}
}
@ -136,34 +204,52 @@ func shortenPostHandler(w http.ResponseWriter, r *http.Request) {
userURL, err := url.ParseRequestURI(rawurl)
if err != nil {
w.WriteHeader(http.StatusBadRequest)
fmt.Fprintf(w, "invalid url (%v): %v", err, rawurl)
fmt.Fprintf(w, "invalid url (%v): %v\n", err, rawurl)
return
}
if userURL.Scheme == "" {
w.WriteHeader(http.StatusBadRequest)
fmt.Fprintf(w, "invalid url (unspecified scheme)", rawurl)
fmt.Fprintf(w, "invalid url (unspecified scheme)\n", rawurl)
return
}
if userURL.Host == "" {
w.WriteHeader(http.StatusBadRequest)
fmt.Fprintf(w, "invalid url (unspecified host)", rawurl)
fmt.Fprintf(w, "invalid url (unspecified host)\n", rawurl)
return
}
var storedPaste *StoredPaste
if err := db.Update(func(tx *bolt.Tx) error {
u, err := shortenURL(tx, userURL)
storedPaste = u
ownerKey, ok := getOwnerTokenFromRequest(r)
if ok == false {
// Owner key not supplied or invalid, generate a new one
ownerKey, err = generateOwnerToken()
if err != nil {
return errors.Wrap(err, "generating OwnerToken")
}
}
sp, err := shortenURL(tx, userURL, ownerKey)
storedPaste = sp
return err
}); err != nil {
w.WriteHeader(http.StatusInternalServerError)
log.Printf("error: %v\n", err)
fmt.Fprintf(w, "internal server error: %v", err)
fmt.Fprintf(w, "internal server error: %v\n", err)
return
}
saveURL, err := r.URL.Parse(string(storedPaste.Key))
if err != nil {
log.Printf("error: %v\n", errors.Wrap(err, "parsing url"))
}
var base64OwnerToken = make([]byte, 24)
base64Encoder.Encode(base64OwnerToken, storedPaste.OwnerToken[:])
w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, "URL saved at /%v", string(storedPaste.Key))
fmt.Fprintf(w, "URL saved at %v\n", saveURL)
isNotPrint := func(r rune) bool { return !unicode.IsPrint(r) }
fmt.Fprintf(w, "Owner key is %s\n", strings.TrimRightFunc(string(base64OwnerToken), isNotPrint))
}
// Retrieve a URL from the database
@ -184,7 +270,7 @@ func getURL(tx *bolt.Tx, key []byte) (*StoredPaste, error) {
// Add a new URL to the database
//
// Returns the new ID if the url was successfully shortened
func shortenURL(tx *bolt.Tx, userURL *url.URL) (*StoredPaste, error) {
func shortenURL(tx *bolt.Tx, userURL *url.URL, ownerKey [16]byte) (*StoredPaste, error) {
shortenBucket := tx.Bucket([]byte(BUCKET_PASTES))
if shortenBucket == nil {
return nil, fmt.Errorf("bucket %v does not exist", BUCKET_PASTES)
@ -213,6 +299,7 @@ func shortenURL(tx *bolt.Tx, userURL *url.URL) (*StoredPaste, error) {
State: StatePresent,
Content: []byte(userURL.String()),
Key: urlKey,
OwnerToken: ownerKey,
TimeCreated: time.Now().UTC(),
}
storedBytes, err := gobmarsh.Marshal(storedPaste)
@ -259,3 +346,27 @@ func generateURLKey(epoch int) ([]byte, error) {
}
return urlKey, nil
}
func generateOwnerToken() ([16]byte, error) {
var ownerKey [16]byte
_, err := rand.Read(ownerKey[:])
if err != nil {
return ownerKey, err
}
return ownerKey, nil
}
func getOwnerTokenFromRequest(r *http.Request) ([16]byte, bool) {
var ownerKey [16]byte
ownerKeyCookie, err := r.Cookie(CookieOwnerToken)
if err != nil && err != http.ErrNoCookie {
return ownerKey, false
}
if ownerKeyCookie != nil {
n, err := base64Encoder.Strict().Decode(ownerKey[:], []byte(ownerKeyCookie.Value))
if err == nil || n == 16 {
return ownerKey, true
}
}
return ownerKey, false
}

1
rushlink.go
View File

@ -48,6 +48,7 @@ func main() {
router.HandleFunc("/", indexPostHandler).Methods("POST")
router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}", pasteGetHandler).Methods("GET")
router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}/nr", pasteGetHandlerNoRedirect).Methods("GET")
router.HandleFunc("/{key:[A-Za-z0-9-_]{4,}}/meta", pasteGetHandlerMeta).Methods("GET")
// Start the server
srv := &http.Server{