bring in mysql backend from relayer.

2023-10-31 16:06:44 -03:00
parent a82b9b4bde
commit 28fc5b0571
7 changed files with 371 additions and 23 deletions
--- a/go.mod
+++ b/go.mod
@@ -7,7 +7,7 @@ require (
 	github.com/bmatsuo/lmdb-go v1.8.0
 	github.com/dgraph-io/badger/v4 v4.2.0
 	github.com/elastic/go-elasticsearch/v8 v8.10.1
-	github.com/fiatjaf/khatru v0.0.3
+	github.com/go-sql-driver/mysql v1.6.0
 	github.com/jmoiron/sqlx v1.3.5
 	github.com/lib/pq v1.10.9
 	github.com/mattn/go-sqlite3 v1.14.17
@@ -16,7 +16,6 @@ require (
 )

 require (
-	github.com/andybalholm/brotli v1.0.5 // indirect
 	github.com/btcsuite/btcd/btcec/v2 v2.3.2 // indirect
 	github.com/btcsuite/btcd/chaincfg/chainhash v1.0.2 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
@@ -27,7 +26,6 @@ require (
 	github.com/dustin/go-humanize v1.0.0 // indirect
 	github.com/elastic/elastic-transport-go/v8 v8.3.0 // indirect
 	github.com/elastic/go-elasticsearch/v7 v7.6.0 // indirect
-	github.com/fasthttp/websocket v1.5.3 // indirect
 	github.com/fatih/structs v1.1.0 // indirect
 	github.com/gobwas/httphead v0.1.0 // indirect
 	github.com/gobwas/pool v0.2.1 // indirect
@@ -40,21 +38,19 @@ require (
 	github.com/google/flatbuffers v1.12.1 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/klauspost/compress v1.16.5 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/puzpuzpuz/xsync/v2 v2.5.1 // indirect
-	github.com/rs/cors v1.7.0 // indirect
-	github.com/savsgio/gotils v0.0.0-20230208104028-c358bd845dee // indirect
 	github.com/tidwall/gjson v1.14.4 // indirect
 	github.com/tidwall/match v1.1.1 // indirect
 	github.com/tidwall/pretty v1.2.0 // indirect
-	github.com/valyala/bytebufferpool v1.0.0 // indirect
-	github.com/valyala/fasthttp v1.47.0 // indirect
 	go.opencensus.io v0.22.5 // indirect
 	golang.org/x/exp v0.0.0-20230425010034-47ecfdc1ba53 // indirect
 	golang.org/x/net v0.8.0 // indirect
 	golang.org/x/sys v0.8.0 // indirect
 	google.golang.org/protobuf v1.28.1 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
--- a/go.sum
+++ b/go.sum
@@ -1,7 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/andybalholm/brotli v1.0.5 h1:8uQZIdzKmjc/iuPu7O2ioW48L81FgatrcpfFmiq/cCs=
-github.com/andybalholm/brotli v1.0.5/go.mod h1:fO7iG3H7G2nSZ7m0zPUDn85XEX2GTukHGRSepvi9Eig=
 github.com/aquasecurity/esquery v0.2.0 h1:9WWXve95TE8hbm3736WB7nS6Owl8UGDeu+0jiyE9ttA=
 github.com/aquasecurity/esquery v0.2.0/go.mod h1:VU+CIFR6C+H142HHZf9RUkp4Eedpo9UrEKeCQHWf9ao=
 github.com/bmatsuo/lmdb-go v1.8.0 h1:ohf3Q4xjXZBKh4AayUY4bb2CXuhRAI8BYGlJq08EfNA=
@@ -14,6 +12,7 @@ github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XL
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -35,12 +34,8 @@ github.com/elastic/go-elasticsearch/v7 v7.6.0 h1:sYpGLpEFHgLUKLsZUBfuaVI9QgHjS3J
 github.com/elastic/go-elasticsearch/v7 v7.6.0/go.mod h1:OJ4wdbtDNk5g503kvlHLyErCgQwwzmDtaFC4XyOxXA4=
 github.com/elastic/go-elasticsearch/v8 v8.10.1 h1:JJ3i2DimYTsJcUoEGbg6tNB0eehTNdid9c5kTR1TGuI=
 github.com/elastic/go-elasticsearch/v8 v8.10.1/go.mod h1:GU1BJHO7WeamP7UhuElYwzzHtvf9SDmeVpSSy9+o6Qg=
-github.com/fasthttp/websocket v1.5.3 h1:TPpQuLwJYfd4LJPXvHDYPMFWbLjsT91n3GpWtCQtdek=
-github.com/fasthttp/websocket v1.5.3/go.mod h1:46gg/UBmTU1kUaTcwQXpUxtRwG2PvIZYeA8oL6vF3Fs=
 github.com/fatih/structs v1.1.0 h1:Q7juDM0QtcnhCpeyLGQKyg4TOIghuNXrkL32pHAUMxo=
 github.com/fatih/structs v1.1.0/go.mod h1:9NiDSp5zOcgEDl+j00MP/WkGVPOlPRLejGD8Ga6PJ7M=
-github.com/fiatjaf/khatru v0.0.3 h1:vy0Dgztx4hSCu6lGOD/vq1HBQnGBI+VU/Iq9UEXJrpE=
-github.com/fiatjaf/khatru v0.0.3/go.mod h1:8shKDuVtrdLfsuHV4FBC3qYTTXnyfOLAgKqUt4u+Okk=
 github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfCHuOE=
 github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/gobwas/httphead v0.1.0 h1:exrUm0f4YX0L7EBwZHuCF4GDp8aJfVeBrlLQrs6NqWU=
@@ -82,8 +77,10 @@ github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/compress v1.16.5 h1:IFV2oUNUzZaz+XyusxpLzpzS8Pt5rh0Z16For/djlyI=
 github.com/klauspost/compress v1.16.5/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQskQzEyD//IeE=
-github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
-github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/lib/pq v1.2.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
@@ -102,10 +99,6 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/puzpuzpuz/xsync/v2 v2.5.1 h1:mVGYAvzDSu52+zaGyNjC+24Xw2bQi3kTr4QJ6N9pIIU=
 github.com/puzpuzpuz/xsync/v2 v2.5.1/go.mod h1:gD2H2krq/w52MfPLE+Uy64TzJDVY7lP2znR9qmR35kU=
-github.com/rs/cors v1.7.0 h1:+88SsELBHx5r+hZ8TCkggzSstaWNbDvThkVK8H6f9ik=
-github.com/rs/cors v1.7.0/go.mod h1:gFx+x8UowdsKA9AchylcLynDq+nNFfI8FkUZdN/jGCU=
-github.com/savsgio/gotils v0.0.0-20230208104028-c358bd845dee h1:8Iv5m6xEo1NR1AvpV+7XmhI4r39LGNzwUL4YpMuL5vk=
-github.com/savsgio/gotils v0.0.0-20230208104028-c358bd845dee/go.mod h1:qwtSXrKuJh/zsFQ12yEE89xfCrGKK63Rr7ctU/uCo4g=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
@@ -116,10 +109,6 @@ github.com/tidwall/match v1.1.1 h1:+Ho715JplO36QYgwN9PGYNhgZvoUSc9X2c80KVTi+GA=
 github.com/tidwall/match v1.1.1/go.mod h1:eRSPERbgtNPcGhD8UCthc6PmLEQXEWd3PRB5JTxsfmM=
 github.com/tidwall/pretty v1.2.0 h1:RWIZEg2iJ8/g6fDDYzMpobmaoGh5OLl4AXtGUGPcqCs=
 github.com/tidwall/pretty v1.2.0/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
-github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
-github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
-github.com/valyala/fasthttp v1.47.0 h1:y7moDoxYzMooFpT5aHgNgVOQDrS3qlkfiP9mDtGGK9c=
-github.com/valyala/fasthttp v1.47.0/go.mod h1:k2zXd82h/7UZc3VOdJ2WaUqt1uZ/XpXAfE9i+HBC3lA=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 go.opencensus.io v0.22.5 h1:dntmOdLpSpHlVqbW5Eay97DelsZHe+55D+xC6i0dDS0=
--- a/mysql/delete.go
+++ b/mysql/delete.go
@@ -0,0 +1,12 @@
+package mysql
+
+import (
+	"context"
+
+	"github.com/nbd-wtf/go-nostr"
+)
+
+func (b MySQLBackend) DeleteEvent(ctx context.Context, evt *nostr.Event) error {
+	_, err := b.DB.ExecContext(ctx, "DELETE FROM event WHERE id = ?", evt.ID)
+	return err
+}
--- a/mysql/init.go
+++ b/mysql/init.go
@@ -0,0 +1,71 @@
+package mysql
+
+import (
+	"strings"
+
+	"github.com/fiatjaf/eventstore"
+	_ "github.com/go-sql-driver/mysql"
+	"github.com/jmoiron/sqlx"
+	"github.com/jmoiron/sqlx/reflectx"
+)
+
+const (
+	queryLimit        = 100
+	queryIDsLimit     = 500
+	queryAuthorsLimit = 500
+	queryKindsLimit   = 10
+	queryTagsLimit    = 10
+)
+
+var _ eventstore.Storage = (*MySQLBackend)(nil)
+
+var ddls = []string{
+	`CREATE TABLE IF NOT EXISTS event (
+       id char(64) NOT NULL primary key,
+       pubkey char(64) NOT NULL,
+       created_at int NOT NULL,
+       kind integer NOT NULL,
+       tags json NOT NULL,
+       content text NOT NULL,
+       sig text NOT NULL);`,
+	`CREATE INDEX pubkeyprefix ON event (pubkey);`,
+	`CREATE INDEX timeidx ON event (created_at DESC);`,
+	`CREATE INDEX kindidx ON event (kind);`,
+}
+
+func (b *MySQLBackend) Init() error {
+	db, err := sqlx.Connect("mysql", b.DatabaseURL)
+	if err != nil {
+		return err
+	}
+
+	// sqlx default is 0 (unlimited), while mysql by default accepts up to 100 connections
+	db.SetMaxOpenConns(80)
+
+	db.Mapper = reflectx.NewMapperFunc("json", sqlx.NameMapper)
+	b.DB = db
+
+	for _, ddl := range ddls {
+		_, err := b.DB.Exec(ddl)
+		if err != nil && !strings.HasPrefix(err.Error(), `Error 1061: Duplicate key name`) {
+			return err
+		}
+	}
+
+	if b.QueryLimit == 0 {
+		b.QueryLimit = queryLimit
+	}
+	if b.QueryIDsLimit == 0 {
+		b.QueryIDsLimit = queryIDsLimit
+	}
+	if b.QueryAuthorsLimit == 0 {
+		b.QueryAuthorsLimit = queryAuthorsLimit
+	}
+	if b.QueryKindsLimit == 0 {
+		b.QueryKindsLimit = queryKindsLimit
+	}
+	if b.QueryTagsLimit == 0 {
+		b.QueryTagsLimit = queryTagsLimit
+	}
+	return err
+}
--- a/mysql/mysql.go
+++ b/mysql/mysql.go
@@ -0,0 +1,15 @@
+package mysql
+
+import (
+	"github.com/jmoiron/sqlx"
+)
+
+type MySQLBackend struct {
+	*sqlx.DB
+	DatabaseURL       string
+	QueryLimit        int
+	QueryIDsLimit     int
+	QueryAuthorsLimit int
+	QueryKindsLimit   int
+	QueryTagsLimit    int
+}
--- a/mysql/query.go
+++ b/mysql/query.go
@@ -0,0 +1,189 @@
+package mysql
+
+import (
+	"context"
+	"database/sql"
+	"encoding/hex"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/jmoiron/sqlx"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+func (b MySQLBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch chan *nostr.Event, err error) {
+	ch = make(chan *nostr.Event)
+
+	query, params, err := b.queryEventsSql(filter, false)
+	if err != nil {
+		close(ch)
+		return nil, err
+	}
+
+	rows, err := b.DB.Query(query, params...)
+	if err != nil && err != sql.ErrNoRows {
+		close(ch)
+		return nil, fmt.Errorf("failed to fetch events using query %q: %w", query, err)
+	}
+
+	go func() {
+		defer rows.Close()
+		defer close(ch)
+		for rows.Next() {
+			var evt nostr.Event
+			var timestamp int64
+			err := rows.Scan(&evt.ID, &evt.PubKey, &timestamp,
+				&evt.Kind, &evt.Tags, &evt.Content, &evt.Sig)
+			if err != nil {
+				return
+			}
+			evt.CreatedAt = nostr.Timestamp(timestamp)
+			ch <- &evt
+		}
+	}()
+
+	return ch, nil
+}
+
+func (b MySQLBackend) CountEvents(ctx context.Context, filter nostr.Filter) (int64, error) {
+	query, params, err := b.queryEventsSql(filter, true)
+	if err != nil {
+		return 0, err
+	}
+
+	var count int64
+	if err = b.DB.QueryRow(query, params...).Scan(&count); err != nil && err != sql.ErrNoRows {
+		return 0, fmt.Errorf("failed to fetch events using query %q: %w", query, err)
+	}
+	return count, nil
+}
+
+func (b MySQLBackend) queryEventsSql(filter nostr.Filter, doCount bool) (string, []any, error) {
+	var conditions []string
+	var params []any
+
+	if filter.IDs != nil {
+		if len(filter.IDs) > b.QueryIDsLimit {
+			// too many ids, fail everything
+			return "", nil, nil
+		}
+
+		likeids := make([]string, 0, len(filter.IDs))
+		for _, id := range filter.IDs {
+			// to prevent sql attack here we will check if
+			// these ids are valid 32byte hex
+			parsed, err := hex.DecodeString(id)
+			if err != nil || len(parsed) != 32 {
+				continue
+			}
+			likeids = append(likeids, fmt.Sprintf("id LIKE '%x%%'", parsed))
+		}
+		if len(likeids) == 0 {
+			// ids being [] mean you won't get anything
+			return "", nil, nil
+		}
+		conditions = append(conditions, "("+strings.Join(likeids, " OR ")+")")
+	}
+
+	if filter.Authors != nil {
+		if len(filter.Authors) > b.QueryAuthorsLimit {
+			// too many authors, fail everything
+			return "", nil, nil
+		}
+
+		likekeys := make([]string, 0, len(filter.Authors))
+		for _, key := range filter.Authors {
+			// to prevent sql attack here we will check if
+			// these keys are valid 32byte hex
+			parsed, err := hex.DecodeString(key)
+			if err != nil || len(parsed) != 32 {
+				continue
+			}
+			likekeys = append(likekeys, fmt.Sprintf("pubkey LIKE '%x%%'", parsed))
+		}
+		if len(likekeys) == 0 {
+			// authors being [] mean you won't get anything
+			return "", nil, nil
+		}
+		conditions = append(conditions, "("+strings.Join(likekeys, " OR ")+")")
+	}
+
+	if filter.Kinds != nil {
+		if len(filter.Kinds) > b.QueryKindsLimit {
+			// too many kinds, fail everything
+			return "", nil, nil
+		}
+
+		if len(filter.Kinds) == 0 {
+			// kinds being [] mean you won't get anything
+			return "", nil, nil
+		}
+		// no sql injection issues since these are ints
+		inkinds := make([]string, len(filter.Kinds))
+		for i, kind := range filter.Kinds {
+			inkinds[i] = strconv.Itoa(kind)
+		}
+		conditions = append(conditions, `kind IN (`+strings.Join(inkinds, ",")+`)`)
+	}
+
+	tagQuery := make([]string, 0, 1)
+	for _, values := range filter.Tags {
+		if len(values) == 0 {
+			// any tag set to [] is wrong
+			return "", nil, nil
+		}
+
+		// add these tags to the query
+		tagQuery = append(tagQuery, values...)
+
+		if len(tagQuery) > b.QueryTagsLimit {
+			// too many tags, fail everything
+			return "", nil, nil
+		}
+	}
+
+	// we use a very bad implementation in which we only check the tag values and
+	// ignore the tag names
+	for _, tagValue := range tagQuery {
+		params = append(params, "%"+tagValue+"%")
+		conditions = append(conditions, "tags LIKE ?")
+	}
+
+	if filter.Since != nil {
+		conditions = append(conditions, "created_at >= ?")
+		params = append(params, filter.Since)
+	}
+	if filter.Until != nil {
+		conditions = append(conditions, "created_at <= ?")
+		params = append(params, filter.Until)
+	}
+
+	if len(conditions) == 0 {
+		// fallback
+		conditions = append(conditions, "true")
+	}
+
+	if filter.Limit < 1 || filter.Limit > b.QueryLimit {
+		params = append(params, b.QueryLimit)
+	} else {
+		params = append(params, filter.Limit)
+	}
+
+	var query string
+	if doCount {
+		query = sqlx.Rebind(sqlx.BindType("mysql"), `SELECT
+          COUNT(*)
+        FROM event WHERE `+
+			strings.Join(conditions, " AND ")+
+			" ORDER BY created_at DESC LIMIT ?")
+	} else {
+		query = sqlx.Rebind(sqlx.BindType("mysql"), `SELECT
+          id, pubkey, created_at, kind, tags, content, sig
+        FROM event WHERE `+
+			strings.Join(conditions, " AND ")+
+			" ORDER BY created_at DESC LIMIT ?")
+	}
+
+	return query, params, nil
+}
--- a/mysql/save.go
+++ b/mysql/save.go
@@ -0,0 +1,76 @@
+package mysql
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/fiatjaf/eventstore"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+func (b *MySQLBackend) SaveEvent(ctx context.Context, evt *nostr.Event) error {
+	deleteQuery, deleteParams, shouldDelete := deleteBeforeSaveSql(evt)
+	if shouldDelete {
+		_, _ = b.DB.ExecContext(ctx, deleteQuery, deleteParams...)
+	}
+
+	sql, params, _ := saveEventSql(evt)
+	res, err := b.DB.ExecContext(ctx, sql, params...)
+	if err != nil {
+		return err
+	}
+
+	nr, err := res.RowsAffected()
+	if err != nil {
+		return err
+	}
+
+	if nr == 0 {
+		return eventstore.ErrDupEvent
+	}
+
+	return nil
+}
+
+func deleteBeforeSaveSql(evt *nostr.Event) (string, []any, bool) {
+	// react to different kinds of events
+	var (
+		query        = ""
+		params       []any
+		shouldDelete bool
+	)
+	if evt.Kind == nostr.KindSetMetadata || evt.Kind == nostr.KindContactList || (10000 <= evt.Kind && evt.Kind < 20000) {
+		// delete past events from this user
+		query = `DELETE FROM event WHERE pubkey = ? AND kind = ?`
+		params = []any{evt.PubKey, evt.Kind}
+		shouldDelete = true
+	} else if evt.Kind == nostr.KindRecommendServer {
+		// delete past recommend_server events equal to this one
+		query = `DELETE FROM event WHERE pubkey = ? AND kind = ? AND content = ?`
+		params = []any{evt.PubKey, evt.Kind, evt.Content}
+		shouldDelete = true
+	} else if evt.Kind >= 30000 && evt.Kind < 40000 {
+		// NIP-33
+		d := evt.Tags.GetFirst([]string{"d"})
+		if d != nil {
+			query = `DELETE FROM event WHERE pubkey = ? AND kind = ? AND tags LIKE ?`
+			params = []any{evt.PubKey, evt.Kind, d.Value()}
+			shouldDelete = true
+		}
+	}
+
+	return query, params, shouldDelete
+}
+
+func saveEventSql(evt *nostr.Event) (string, []any, error) {
+	const query = `INSERT INTO event (
+	id, pubkey, created_at, kind, tags, content, sig)
+	VALUES (?, ?, ?, ?, ?, ?, ?)`
+
+	var (
+		tagsj, _ = json.Marshal(evt.Tags)
+		params   = []any{evt.ID, evt.PubKey, evt.CreatedAt, evt.Kind, tagsj, evt.Content, evt.Sig}
+	)
+
+	return query, params, nil
+}