refactor: Put paste model in separate file
This commit is contained in:
Daan Sprenkels
parent
f36ed4a4c7
commit
0ecdaafe2f
@ -8,6 +8,9 @@ the command line.
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## USAGE
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# Upload a file
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curl -F'file=@yourfile.png' <a href="{{Request.Host}}">{{Request.Host}}</a>
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# Shorten a URL
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curl -F'shorten=http://example.com/some/long/url' <a href="{{Request.Host}}">{{Request.Host}}</a>
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@ -6,6 +6,9 @@ the command line.
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## USAGE
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# Upload a file
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curl -F'file=@yourfile.png' {{Request.Host}}
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# Shorten a URL
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curl -F'shorten=http://example.com/some/long/url' {{Request.Host}}
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@ -1,15 +1,12 @@
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package handlers
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import (
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"crypto/rand"
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"crypto/subtle"
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"encoding/base64"
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"encoding/hex"
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"fmt"
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"log"
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"net/http"
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"net/url"
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"strings"
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"time"
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"github.com/gorilla/mux"
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@ -17,31 +14,6 @@ import (
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bolt "go.etcd.io/bbolt"
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"gitea.hashru.nl/dsprenkels/rushlink/db"
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"gitea.hashru.nl/dsprenkels/rushlink/gobmarsh"
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)
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type pasteType int
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type pasteState int
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type storedPaste struct {
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Type pasteType
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State pasteState
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Content []byte
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Key string
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DeleteToken string
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TimeCreated time.Time
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}
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const (
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typeUndef pasteType = 0
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typePaste = 1
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typeRedirect = 2
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)
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const (
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stateUndef pasteState = 0
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statePresent = 1
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stateDeleted = 2
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)
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type viewPaste uint
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@ -106,17 +78,17 @@ func viewPasteHandlerMeta(w http.ResponseWriter, r *http.Request) {
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func viewPasteHandlerInner(w http.ResponseWriter, r *http.Request, flags viewPaste) {
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vars := mux.Vars(r)
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key := vars["key"]
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var storedPaste *storedPaste
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var p *paste
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if err := db.DB.View(func(tx *bolt.Tx) error {
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var err error
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storedPaste, err = getURL(tx, key)
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p, err = getPaste(tx, key)
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return err
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}); err != nil {
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log.Printf("error: %v\n", err)
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renderInternalServerError(w, r, err)
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return
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}
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if storedPaste == nil {
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if p == nil {
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renderError(w, r, http.StatusNotFound, "url key not found in the database")
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return
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}
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@ -130,7 +102,7 @@ func viewPasteHandlerInner(w http.ResponseWriter, r *http.Request, flags viewPas
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if deleteToken == "" {
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canDelete.String = "undefined"
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} else {
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if subtle.ConstantTimeCompare([]byte(deleteToken), []byte(storedPaste.DeleteToken)) == 1 {
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if subtle.ConstantTimeCompare([]byte(deleteToken), []byte(p.DeleteToken)) == 1 {
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canDelete.Bool = true
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canDelete.String = "correct"
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} else {
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@ -139,31 +111,31 @@ func viewPasteHandlerInner(w http.ResponseWriter, r *http.Request, flags viewPas
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}
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data := map[string]interface{}{
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"Paste": storedPaste,
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"Paste": p,
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"CanDelete": canDelete,
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}
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render(w, r, "pasteMeta", data)
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return
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}
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switch storedPaste.State {
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switch p.State {
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case statePresent:
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if flags&viewNoRedirect == 0 {
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rawurl := string(storedPaste.Content)
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rawurl := string(p.Content)
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urlParse, err := url.Parse(rawurl)
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if err != nil {
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log.Printf("error: invalid URL ('%v') in database for key '%v': %v\n", rawurl, storedPaste.Key, err)
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log.Printf("error: invalid URL ('%v') in database for key '%v': %v\n", rawurl, p.Key, err)
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renderInternalServerError(w, r, "invalid url in database")
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return
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}
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http.Redirect(w, r, urlParse.String(), http.StatusSeeOther)
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}
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w.Write(storedPaste.Content)
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w.Write(p.Content)
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case stateDeleted:
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renderError(w, r, http.StatusGone, "paste has been deleted")
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default:
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log.Printf("error: invalid storedPaste.State (%v) for key '%v'\n", storedPaste.State, storedPaste.Key)
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msg := fmt.Sprintf("internal server error: invalid storedPaste.State (%v\n)", storedPaste.State)
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log.Printf("error: invalid paste.State (%v) for key '%v'\n", p.State, p.Key)
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msg := fmt.Sprintf("internal server error: invalid paste.State (%v\n)", p.State)
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renderInternalServerError(w, r, msg)
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}
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}
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@ -210,18 +182,18 @@ func newRedirectPasteHandler(w http.ResponseWriter, r *http.Request) {
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return
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}
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var storedPaste *storedPaste
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var paste *paste
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if err := db.DB.Update(func(tx *bolt.Tx) error {
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// Generate a new delete token for this paste
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var err error
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storedPaste, err = shortenURL(tx, userURL)
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paste, err = shortenURL(tx, userURL)
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return err
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}); err != nil {
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log.Printf("error: %v\n", err)
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renderInternalServerError(w, r, err)
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return
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}
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data := map[string]interface{}{"Paste": storedPaste}
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data := map[string]interface{}{"Paste": paste}
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render(w, r, "newRedirectPasteSuccess", data)
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}
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@ -238,18 +210,13 @@ func deletePasteHandler(w http.ResponseWriter, r *http.Request) {
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var errorCode int
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if err := db.DB.Update(func(tx *bolt.Tx) error {
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paste, err := getURL(tx, key)
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p, err := getPaste(tx, key)
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if err != nil {
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errorCode = http.StatusNotFound
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return err
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}
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if subtle.ConstantTimeCompare([]byte(deleteToken), []byte(paste.DeleteToken)) == 1 {
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// Replace the old paste with a new empty paste
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return savePaste(tx, key, storedPaste{
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Key: paste.Key,
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State: stateDeleted,
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DeleteToken: paste.DeleteToken,
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})
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if subtle.ConstantTimeCompare([]byte(deleteToken), []byte(p.DeleteToken)) == 1 {
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p.delete(tx)
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}
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errorCode = http.StatusForbidden
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return errors.New("invalid delete token")
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@ -260,58 +227,13 @@ func deletePasteHandler(w http.ResponseWriter, r *http.Request) {
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}
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}
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// Retrieve a URL from the database
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func getURL(tx *bolt.Tx, key string) (*storedPaste, error) {
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pastesBucket := tx.Bucket([]byte(db.BUCKET_PASTES))
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if pastesBucket == nil {
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return nil, errors.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
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}
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storedBytes := pastesBucket.Get([]byte(key))
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if storedBytes == nil {
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return nil, nil
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}
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storedPaste := &storedPaste{}
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err := gobmarsh.Unmarshal(storedBytes, storedPaste)
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return storedPaste, err
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}
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// Add a new URL to the database
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//
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// Returns the new ID if the url was successfully shortened
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func shortenURL(tx *bolt.Tx, userURL *url.URL) (*storedPaste, error) {
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pastesBucket := tx.Bucket([]byte(db.BUCKET_PASTES))
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if pastesBucket == nil {
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return nil, errors.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
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}
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// Generate a key until it is not in the database, this occurs in O(log N),
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// where N is the amount of keys stored in the url-shorten database.
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epoch := 0
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var urlKey string
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for {
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var err error
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urlKey, err = generateURLKey(epoch)
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func shortenURL(tx *bolt.Tx, userURL *url.URL) (*paste, error) {
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pasteKey, err := generatePasteKey(tx)
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if err != nil {
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return nil, errors.Wrap(err, "url-key generation failed")
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}
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found := pastesBucket.Get([]byte(urlKey))
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if found == nil {
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break
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}
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isReserved := false
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for _, reservedKey := range ReservedPasteKeys {
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if strings.HasPrefix(urlKey, reservedKey) {
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isReserved = true
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break
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}
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}
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if !isReserved {
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break
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}
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epoch++
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return nil, errors.Wrap(err, "generating paste key")
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}
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// Also generate a deleteToken
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@ -321,78 +243,18 @@ func shortenURL(tx *bolt.Tx, userURL *url.URL) (*storedPaste, error) {
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}
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// Store the new key
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storedPaste := storedPaste{
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p := paste{
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Type: typeRedirect,
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State: statePresent,
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Content: []byte(userURL.String()),
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Key: urlKey,
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Key: pasteKey,
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DeleteToken: deleteToken,
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TimeCreated: time.Now().UTC(),
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}
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if err := savePaste(tx, urlKey, storedPaste); err != nil {
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if err := p.save(tx); err != nil {
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return nil, err
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}
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return &storedPaste, nil
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}
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func savePaste(tx *bolt.Tx, key string, paste storedPaste) error {
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bucket := tx.Bucket([]byte(db.BUCKET_PASTES))
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if bucket == nil {
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return errors.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
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}
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buf, err := gobmarsh.Marshal(paste)
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if err != nil {
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return errors.Wrap(err, "encoding for database failed")
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}
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if err := bucket.Put([]byte(key), buf); err != nil {
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return errors.Wrap(err, "database transaction failed")
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}
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return nil
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}
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func generateURLKey(epoch int) (string, error) {
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urlKey := make([]byte, 4+epoch)
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_, err := rand.Read(urlKey)
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if err != nil {
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return "", err
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}
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// Put all the values in the range 0..64 for easier base64-encoding
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for i := 0; i < len(urlKey); i++ {
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urlKey[i] &= 0x3F
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}
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// Implement truncate-resistance by forcing the prefix to
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// 0b111110xxxxxxxxxx
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// ^----- {epoch} ones followed by a single 0
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//
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// Example when epoch is 1: prefix is 0b10.
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i := 0
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for i < epoch {
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// Set this bit to 1
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limb := i / 6
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bit := i % 6
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urlKey[limb] |= 1 << uint(5-bit)
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i++
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}
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// Finally set the next bit to 0
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limb := i / 6
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bit := i % 6
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urlKey[limb] &= ^(1 << uint(5-bit))
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// Convert this ID to a canonical base64 notation
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for i := range urlKey {
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urlKey[i] = base64Alphabet[urlKey[i]]
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}
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return string(urlKey), nil
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}
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func generateDeleteToken() (string, error) {
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var deleteToken [16]byte
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_, err := rand.Read(deleteToken[:])
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if err != nil {
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return "", err
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}
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return hex.EncodeToString(deleteToken[:]), nil
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return &p, nil
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}
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func getDeleteTokenFromRequest(r *http.Request) string {
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159
handlers/paste.go
Normal file
159
handlers/paste.go
Normal file
@ -0,0 +1,159 @@
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package handlers
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import (
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"crypto/rand"
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"encoding/hex"
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"strings"
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"time"
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"gitea.hashru.nl/dsprenkels/rushlink/db"
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"gitea.hashru.nl/dsprenkels/rushlink/gobmarsh"
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"github.com/pkg/errors"
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bolt "go.etcd.io/bbolt"
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)
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type pasteType int
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type pasteState int
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type paste struct {
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Type pasteType
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State pasteState
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Content []byte
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Key string
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DeleteToken string
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TimeCreated time.Time
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}
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const (
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typeUndef pasteType = 0
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typePaste = 1
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typeRedirect = 2
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)
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const (
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stateUndef pasteState = 0
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statePresent = 1
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stateDeleted = 2
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)
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// Retrieve a paste from the database
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func getPaste(tx *bolt.Tx, key string) (*paste, error) {
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pastesBucket := tx.Bucket([]byte(db.BUCKET_PASTES))
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if pastesBucket == nil {
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return nil, errors.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
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}
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storedBytes := pastesBucket.Get([]byte(key))
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if storedBytes == nil {
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return nil, nil
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}
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p := &paste{}
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err := gobmarsh.Unmarshal(storedBytes, p)
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return p, err
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}
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func (p *paste) save(tx *bolt.Tx) error {
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bucket := tx.Bucket([]byte(db.BUCKET_PASTES))
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if bucket == nil {
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return errors.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
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}
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buf, err := gobmarsh.Marshal(p)
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if err != nil {
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return errors.Wrap(err, "encoding for database failed")
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}
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if err := bucket.Put([]byte(p.Key), buf); err != nil {
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return errors.Wrap(err, "database transaction failed")
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}
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return nil
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}
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func (p paste) delete(tx *bolt.Tx) error {
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// Replace the old paste with a new empty paste
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return (&paste{
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Key: p.Key,
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State: stateDeleted,
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DeleteToken: p.DeleteToken,
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}).save(tx)
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}
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// Generate a key until it is not in the database, this occurs in O(log N),
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// where N is the amount of keys stored in the url-shorten database.
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func generatePasteKey(tx *bolt.Tx) (string, error) {
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pastesBucket := tx.Bucket([]byte(db.BUCKET_PASTES))
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if pastesBucket == nil {
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return "", errors.Errorf("bucket %v does not exist", db.BUCKET_PASTES)
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}
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epoch := 0
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var key string
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for {
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var err error
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key, err = generatePasteKeyInner(epoch)
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if err != nil {
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return "", errors.Wrap(err, "url-key generation failed")
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}
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found := pastesBucket.Get([]byte(key))
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if found == nil {
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break
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}
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isReserved := false
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for _, reservedKey := range ReservedPasteKeys {
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if strings.HasPrefix(key, reservedKey) {
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isReserved = true
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break
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}
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}
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if !isReserved {
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break
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}
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epoch++
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}
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return key, nil
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}
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func generatePasteKeyInner(epoch int) (string, error) {
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urlKey := make([]byte, 4+epoch)
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_, err := rand.Read(urlKey)
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if err != nil {
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return "", err
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}
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// Put all the values in the range 0..64 for easier base64-encoding
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for i := 0; i < len(urlKey); i++ {
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urlKey[i] &= 0x3F
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}
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// Implement truncate-resistance by forcing the prefix to
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// 0b111110xxxxxxxxxx
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// ^----- {epoch} ones followed by a single 0
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//
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// Example when epoch is 1: prefix is 0b10.
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i := 0
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for i < epoch {
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// Set this bit to 1
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limb := i / 6
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bit := i % 6
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urlKey[limb] |= 1 << uint(5-bit)
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i++
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}
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// Finally set the next bit to 0
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limb := i / 6
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bit := i % 6
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urlKey[limb] &= ^(1 << uint(5-bit))
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// Convert this ID to a canonical base64 notation
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for i := range urlKey {
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urlKey[i] = base64Alphabet[urlKey[i]]
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}
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return string(urlKey), nil
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}
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func generateDeleteToken() (string, error) {
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var deleteToken [16]byte
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_, err := rand.Read(deleteToken[:])
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if err != nil {
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return "", err
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}
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return hex.EncodeToString(deleteToken[:]), nil
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}
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