目录

// 完整的，见文章头部 git 项目
// 从私钥获取公钥
func getPubKey(privateKey string) string {
   keyb, _ := hex.DecodeString(privateKey)
   _, pubkey := btcec.PrivKeyFromBytes(keyb)
   return hex.EncodeToString(schnorr.SerializePubKey(pubkey))
}

func keyGen(opts docopt.Opts) {
   seedWords, _ := nip06.GenerateSeedWords() // 助记词
   seed := nip06.SeedFromWords(seedWords)
   sk, _ := nip06.PrivateKeyFromSeed(seed) // 私钥
   fmt.Println("seed:", seedWords)
   fmt.Println("private key:", sk)
   fmt.Println("pubkey:", getPubKey(sk)) // 公钥
}

seed: arrow suspect reunion hire project damp protect comic leopard market repair diet delay direct bid mountain rigid sister moral speed cloud dawn rain vanish
private key: 3e6d9287d017b5ca1a1219b9d403d172f5ee2df74e112e7d890b070939d1fdb4
pubkey: cb6fd58aa73d01f4e7f803ae41f80caabe2d68288f19a231a6e57571db6a1eb4

["EVENT",
	{
            "id": "21e1b711fa6a9741ab7d134d2ea5a2e6ac6c75751386b411c46438118a4c0dd4",
            "pubkey": "86ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3a3566e01eccf9a05ffa4",
            "created_at": 1679112916,
            "kind": 1, // 发文字帖子
            "tags": [
                ["e",<event_id>,<other_1>,<other_2>],
                ["p",<pubkey>],
                ....
            ],
            "content": "9988cc",
            "sig": "883af7863a63d55c207e272707894944ee763810cd0393d344f85dc9a0bc624c4cc1b28ca483008729b56602f4acaad22e084c2b44db02ecc11e238880b8fd62"
	}
]

[   "REQ", 
    "b326655084f5f1", // 一次性随机生成的请求 id
    {
	"ids": ["ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3"],
	"authors": ["86ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3a3566e01eccf9a05ffa4"],
	"kinds": [4], // 标明只加载私信的
	"#e": ["9c0c22f940bc5e8bc397206a3a3566e01eccf"], // 同时引用了这个推文
	"#p": ["86ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3a3566e01eccf9a05ffa4"],
	"since": 1679112916,
	"until": 1679112996,
	"limit": 7
    }
]

["AUTH", {
	"id": "...",
	"pubkey": "...",
	"created_at": 1669695536,
	"kind": 22242, // 固定，必须是 22242
	"tags": [
		["relay", "wss://relay.example.com/"], // 目标 relay url，会做校验
		["challenge", "challengestringhere"] // relay 返回再放进来
	],
	"content": "",
	"sig": "..."
}]

// ValidateAuthEvent checks whether event is a valid NIP-42 event for given challenge and relayURL.
// The result of the validation is encoded in the ok bool.
func ValidateAuthEvent(event *nostr.Event, challenge string, relayURL string) (pubkey string, ok bool) {
   if event.Kind != 22242 {return "", false}
   if event.Tags.GetFirst([]string{"challenge", challenge}) == nil {
      return "", false
   }
   expected, err := parseUrl(relayURL)
   if err != nil {return "", false}
   found, err := parseUrl(event.Tags.GetFirst([]string{"relay", ""}).Value())
   if err != nil {return "", false}
   if expected.Scheme != found.Scheme ||
      expected.Host != found.Host ||
      expected.Path != found.Path {
      return "", false
   }
   now := time.Now()
   if event.CreatedAt.After(now.Add(10*time.Minute)) || event.CreatedAt.Before(now.Add(-10*time.Minute)) {
      return "", false
   }
   if ok, _ := event.CheckSignature(); !ok {return "", false}
   return event.PubKey, true
}

// 验证算法：https://github.com/nostr-protocol/nips/blob/master/42.md
// 主要就是验证 client 的 challenge 是否是 relay 返回的。这个 relay 的实现是随机搞的 challenge
// 拓展的做法就是可以根据更丰富的算法生成 challenge 再返回。比如与 pubkey、时间加密后返回一个
// 特定的，在多少天内有效的，只能这个 pubkey 访问的 challenge 码
if pubkey, ok := nip42.ValidateAuthEvent(&evt, ws.challenge, auther.ServiceURL()); ok {
   ws.authed = pubkey
   ws.WriteJSON([]interface{}{"OK", evt.ID, true, "authentication success"})
} else {
   ws.WriteJSON([]interface{}{"OK", evt.ID, false, "error: failed to authenticate"})
}

package main

import (
   "encoding/json"
   "fmt"
   "log"
   "time"

   "github.com/fiatjaf/relayer"
   "github.com/fiatjaf/relayer/storage/postgresql"
   "github.com/fiatjaf/relayer/storage/sqlite3"
   "github.com/kelseyhightower/envconfig"
   "github.com/nbd-wtf/go-nostr"
)

type SqliteRelay struct {
   SQLiteDatabase string `envconfig:"SQLITE_DATABASE"`
   storage        *sqlite3.SQLite3Backend
}

func (r *SqliteRelay) Name() string {
   return "SQLiteRelay"
}

func (r *SqliteRelay) Storage() relayer.Storage {
   return r.storage
}

func (r *SqliteRelay) OnInitialized(*relayer.Server) {}

func (r *SqliteRelay) Init() error {
   return nil
}

func (r *SqliteRelay) AcceptEvent(evt *nostr.Event) bool {
   jsonb, _ := json.Marshal(evt)
   if len(jsonb) > 10000 {
      return false
   }
   return true
}

func main() {
   runSQLiteRelay()
}

func runSQLiteRelay() {
   r := SqliteRelay{}
   if err := envconfig.Process("", &r); err != nil {
      log.Fatalf("failed to read from env: %v", err)
      return
   }
   r.storage = &sqlite3.SQLite3Backend{DatabaseURL: "jdbc:sqlite:identifier.sqlite"}
   if err := relayer.StartConf(relayer.Settings{
      Host: "127.0.0.1",
      Port: "8888",
   }, &r); err != nil {
      log.Fatalf("server terminated: %v", err)
   }
}

package main

import (
   "context"
   "crypto/sha256"
   "encoding/hex"
   "encoding/json"
   "fmt"
   "time"

   "github.com/btcsuite/btcd/btcec/v2"
   "github.com/btcsuite/btcd/btcec/v2/schnorr"
   "github.com/nbd-wtf/go-nostr"
)

func main() {
   ctx := context.Background()
   pubkey := "86ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3a3566e01eccf9a05ffa4"
   privateKey := "8d137174f49cce2590d3a30f89a9dd9865b319ef3a94e24b37cfa106ff85259c"
   // 加载并订阅
   // sendREQ(ctx, pubkey, privateKey)
   // 发文字贴文
   sendEVENT(ctx, pubkey, privateKey, "hello world")
}

func newRelay(ctx context.Context) *nostr.Relay {
   relay, err := nostr.RelayConnect(ctx, "http://127.0.0.1:8888")
   if err != nil {
      panic(fmt.Errorf("failed to connect to relay: %w", err))
   }
   return relay
}

func sendREQ(ctx context.Context, pubkey, privateKey string) {
   filter := nostr.Filter{
      IDs:     nil,
      Kinds:   []int{nostr.KindTextNote}, // 只订阅短文
      Authors: []string{pubkey},          // 只订阅这个作者发的
      Tags:    nil,
      Since:   nil,
      Until:   nil,
      Limit:   100,
   }
   req := newRelay(ctx).PrepareSubscription()
   req.Sub(ctx, nostr.Filters{filter})
   // 在这里接受所有的返回并打印
   for event := range req.Events { // Events 会在 unsub 函数内被关闭
      bys, _ := event.MarshalJSON()
      fmt.Println("receive event:-------", string(bys))
   }
}

func sendEVENT(ctx context.Context, pubkey, privateKey, content string) {
   helloTxtEvent := nostr.Event{
      ID:        "", // signEventAndCalculateID 中赋值
      PubKey:    pubkey,
      CreatedAt: time.Now(),
      Kind:      nostr.KindTextNote, // 1 短文
      Tags:      nil,                // 我们没其他的功能，这里 tag 留空
      Content:   content,
      Sig:       "", // signEventAndCalculateID 中赋值
   }
   if err := signEventAndCalculateID(&helloTxtEvent, privateKey); err != nil {
      panic(fmt.Errorf("signEventAndCalculateID err: %w", err))
   }
   if sendStatus, err := newRelay(ctx).Publish(ctx, helloTxtEvent); err != nil {
      panic(fmt.Errorf("publish err: %w", err))
   } else {
      bys, _ := json.Marshal(helloTxtEvent)
      fmt.Println(fmt.Sprintf("send event status [%s] event data: %s", sendStatus, string(bys)))
   }
}

func signEventAndCalculateID(evt *nostr.Event, privateKey string) error {
   h := sha256.Sum256(evt.Serialize())
   s, err := hex.DecodeString(privateKey)
   if err != nil {
      return fmt.Errorf("Sign called with invalid private key '%s': %w", privateKey, err)
   }
   sk, _ := btcec.PrivKeyFromBytes(s)
   sig, err := schnorr.Sign(sk, h[:])
   if err != nil {
      return err
   }
   evt.ID = hex.EncodeToString(h[:])             // id 赋值
   evt.Sig = hex.EncodeToString(sig.Serialize()) // 生成签名信息
   return nil
}

send event status [success] event data: {"id":"d80f68baee57f2cbb231f44df27ddbf22728b9649083386a44f01cdf159b398a","pubkey":"86ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3a3566e01eccf9a05ffa4","created_at":1679144385,"kind":1,"tags":[],"content":"hello world","sig":"fdb4570c73cfded2c8a29b8ca926a5a400b81246b676f5090651949806f3741c40d2df8542c70f6dbdbff4ada3123cb285fcdcb0fdf499b2bd41a97ed5f4f3bb"}

receive event:------- {"id":"d80f68baee57f2cbb231f44df27ddbf22728b9649083386a44f01cdf159b398a","pubkey":"86ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3a3566e01eccf9a05ffa4","created_at":1679144385,"kind":1,"tags":[],"content":"hello world","sig":"fdb4570c73cfded2c8a29b8ca926a5a400b81246b676f5090651949806f3741c40d2df8542c70f6dbdbff4ada3123cb285fcdcb0fdf499b2bd41a97ed5f4f3bb"}
receive event:------- {"id":"c0965330b8f703cdb24916f8c74e54264ecdfebe098e79c7bec0e5586bd1ec9a","pubkey":"86ab84ff172fa8104bf9c0c22f940bc5e8bc397206a3a3566e01eccf9a05ffa4","created_at":1679143318,"kind":1,"tags":[],"content":"hello world","sig":"3d4636b45fff22a984b9cd5b5e56fec4fcc065455a2c049441f67512d1c7a6d78608dfd8a53a0fd6540ec63c3cde1d0553c8471811ac7068042116ede258754c"}