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fiatjaf
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basic server relay code.
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7 files changed

+309
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lines changed

7 files changed

+309
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lines changed

‎relay/handlers.go‎

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package main
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import (
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"database/sql"
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"encoding/json"
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"errors"
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"net/http"
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"time"
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)
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type ErrorResponse struct {
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Error error `json:"error"`
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}
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func queryUsers(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("content-type", "application/json")
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keys := r.URL.Query()["keys"]
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found := make(map[string]int, len(keys))
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for _, key := range keys {
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var exists bool
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err := db.Get(&exists, `SELECT true FROM event WHERE pubkey = $1`, key)
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if err != nil {
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w.WriteHeader(500)
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log.Warn().Err(err).Str("key", key).Msg("failed to check existence")
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return
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}
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if exists {
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found[key] = 1
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}
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}
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json.NewEncoder(w).Encode(found)
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}
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func fetchUserUpdates(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("content-type", "application/json")
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key := r.URL.Query().Get("key")
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var lastUpdates []Event
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err := db.Select(&lastUpdates, `
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SELECT *
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FROM event
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WHERE pubkey = $1
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ORDER BY time DESC
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LIMIT 25
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`, key)
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if err == sql.ErrNoRows {
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lastUpdates = make([]Event, 0)
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} else if err != nil {
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w.WriteHeader(500)
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log.Warn().Err(err).Str("key", key).Msg("failed to fetch updates")
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return
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}
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json.NewEncoder(w).Encode(lastUpdates)
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}
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func saveUpdate(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("content-type", "application/json")
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var evt Event
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err := json.NewDecoder(r.Body).Decode(&evt)
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if err != nil {
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w.WriteHeader(400)
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return
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}
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// safety checks
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now := time.Now().UTC().Unix()
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if uint32(now-3600) > evt.Time || uint32(now+3600) < evt.Time {
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w.WriteHeader(400)
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return
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}
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// check serialization and signature
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if ok, err := evt.CheckSignature(); err != nil {
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w.WriteHeader(400)
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json.NewEncoder(w).Encode(ErrorResponse{err})
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return
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} else if !ok {
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w.WriteHeader(400)
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json.NewEncoder(w).Encode(ErrorResponse{errors.New("invalid signature")})
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return
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}
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// insert
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_, err = db.Exec(`
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INSERT INTO event (pubkey, time, kind, content, signature)
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VALUES ($1, $2, $3, $4, $5)
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`, evt.Pubkey, evt.Time, evt.Kind, evt.Content, evt.Signature)
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if err != nil {
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w.WriteHeader(500)
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log.Warn().Err(err).Str("pubkey", evt.Pubkey).Msg("failed to save")
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return
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}
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w.WriteHeader(201)
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}

‎relay/main.go‎

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package main
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import (
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"io/ioutil"
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"net/http"
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"os"
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"time"
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"github.com/gorilla/mux"
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"github.com/jmoiron/sqlx"
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"github.com/kelseyhightower/envconfig"
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"github.com/rs/cors"
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"github.com/rs/zerolog"
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)
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type Settings struct {
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Host string `envconfig:"HOST" default:"0.0.0.0"`
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Port string `envconfig:"PORT" default:"7447"`
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QLDatabase string `envconfig:"QL_DATABASE"`
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PostgresDatabase string `envconfig:"POSTGRESQL_DATABASE"`
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SQLiteDatabase string `envconfig:"SQLITE_DATABASE"`
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}
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var s Settings
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var err error
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var db *sqlx.DB
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var router = mux.NewRouter()
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var log = zerolog.New(os.Stderr).Output(zerolog.ConsoleWriter{Out: os.Stderr})
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func main() {
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err = envconfig.Process("", &s)
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if err != nil {
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log.Fatal().Err(err).Msg("couldn't process envconfig")
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}
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db, err = initDB()
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if err != nil {
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log.Fatal().Err(err).Msg("failed to open database")
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}
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err = db.Ping()
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if err != nil {
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log.Fatal().Err(err).Msg("failed to connect to database")
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}
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// create tables, ignore errors
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b, _ := ioutil.ReadFile("schema.sql")
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_, err = db.Exec(string(b))
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log.Print(err)
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router.Path("/query_users").Methods("GET").HandlerFunc(queryUsers)
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router.Path("/fetch_user_updates").Methods("GET").HandlerFunc(fetchUserUpdates)
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router.Path("/save_update").Methods("POST").HandlerFunc(saveUpdate)
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srv := &http.Server{
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Handler: cors.Default().Handler(router),
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Addr: s.Host + ":" + s.Port,
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WriteTimeout: 15 * time.Second,
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ReadTimeout: 15 * time.Second,
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}
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log.Debug().Str("addr", srv.Addr).Msg("listening")
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srv.ListenAndServe()
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}

‎relay/schema.sql‎

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CREATE TABLE event (
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pubkey text NOT NULL,
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time integer NOT NULL,
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kind integer NOT NULL,
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content text NOT NULL,
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signature text NOT NULL
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)
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CREATE INDEX pubkeytime ON event (pubkey, time);

‎relay/settings_postgresql.go‎

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// +build postgres
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package main
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import (
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"github.com/jmoiron/sqlx"
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_ "github.com/lib/pq"
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)
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func initDB() (*sqlx.DB, error) {
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return sqlx.Connect("postgres", s.PostgresDatabase)
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}

‎relay/settings_ql.go‎

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// +build !postgres !sqlite
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package main
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import (
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_ "github.com/cznic/ql/driver"
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"github.com/jmoiron/sqlx"
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)
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func initDB() (*sqlx.DB, error) {
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return sqlx.Connect("ql2", s.QLDatabase)
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}

‎relay/settings_sqlite.go‎

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// +build sqlite
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package main
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import (
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"github.com/jmoiron/sqlx"
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_ "github.com/mattn/go-sqlite3"
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)
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func initDB() (*sqlx.DB, error) {
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return sqlx.Connect("sqlite3", s.SQLITE_DATABASE)
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}

‎relay/types.go‎

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package main
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import (
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"bytes"
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"crypto/sha256"
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"encoding/binary"
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"encoding/hex"
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"fmt"
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"github.com/btcsuite/btcd/btcec"
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)
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const (
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EventSetMetadata uint8 = 0
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EventTextNote uint8 = 1
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EventDelete uint8 = 2
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EventRecommendServer uint8 = 3
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)
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type Event struct {
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Pubkey string `db:"pubkey"`
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Time uint32 `db:"time"`
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Kind uint8 `db:"kind"`
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// - set_metadata
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// - text_note
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// - delete
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Content string `db:"content"`
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Signature string `db:"signature"`
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}
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// Serialize outputs a byte array that can be hashed/signed to identify/authenticate
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// this event. An error will be returned if anything is malformed.
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func (evt *Event) Serialize() ([]byte, error) {
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b := bytes.Buffer{}
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// version: 0
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b.Write([]byte{0})
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// pubkey
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pubkeyb, err := hex.DecodeString(evt.Pubkey)
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if err != nil {
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return nil, err
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}
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pubkey, err := btcec.ParsePubKey(pubkeyb, btcec.S256())
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if err != nil {
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return nil, fmt.Errorf("error parsing pubkey: %w", err)
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}
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if evt.Pubkey != hex.EncodeToString(pubkey.SerializeCompressed()) {
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return nil, fmt.Errorf("pubkey is not serialized in compressed format")
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}
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if _, err = b.Write(pubkeyb); err != nil {
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return nil, err
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}
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// time
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var timeb [4]byte
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binary.BigEndian.PutUint32(timeb[:], evt.Time)
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if _, err := b.Write(timeb[:]); err != nil {
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return nil, err
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}
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// kind
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var kindb [1]byte
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kindb[0] = evt.Kind
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if _, err := b.Write(kindb[:]); err != nil {
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return nil, err
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}
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// content
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if _, err = b.Write([]byte(evt.Content)); err != nil {
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return nil, err
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}
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return b.Bytes(), nil
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}
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// CheckSignature checks if the signature is valid for the serialized event.
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// It will call Serialize() and return an error if that raises an error or if
81+
// the signature itself is invalid.
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func (evt Event) CheckSignature() (bool, error) {
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serialized, err := evt.Serialize()
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if err != nil {
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return false, fmt.Errorf("serialization error: %w", err)
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}
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// validity of these is checked by Serialize()
89+
pubkeyb, _ := hex.DecodeString(evt.Pubkey)
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pubkey, _ := btcec.ParsePubKey(pubkeyb, btcec.S256())
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bsig, err := hex.DecodeString(evt.Signature)
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if err != nil {
94+
return false, fmt.Errorf("signature is invalid hex: %w", err)
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}
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signature, err := btcec.ParseDERSignature(bsig, btcec.S256())
97+
if err != nil {
98+
return false, fmt.Errorf("failed to parse DER signature: %w", err)
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}
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hash := sha256.Sum256(serialized)
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return signature.Verify(hash[:], pubkey), nil
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}

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