| 1 | // Package sites implements NIP-5A manifests and the self-hosted site door. |
| 2 | package sites |
| 3 | |
| 4 | import ( |
| 5 | "crypto/sha256" |
| 6 | "encoding/hex" |
| 7 | "errors" |
| 8 | "fmt" |
| 9 | "math/big" |
| 10 | "net/url" |
| 11 | "regexp" |
| 12 | "sort" |
| 13 | "strings" |
| 14 | |
| 15 | "fiatjaf.com/nostr" |
| 16 | "github.com/FelineStateMachine/tinyrelay/internal/event" |
| 17 | ) |
| 18 | |
| 19 | const ( |
| 20 | KindSite = 15128 |
| 21 | KindNamedSite = 35128 |
| 22 | KindSiteSnapshot = 5128 |
| 23 | ) |
| 24 | |
| 25 | var ( |
| 26 | hexPattern = regexp.MustCompile(`^[0-9a-f]{64}$` ) |
| 27 | namePattern = regexp.MustCompile(`^[a-z0-9-]{1,13}$` ) |
| 28 | pathPattern = regexp.MustCompile(`^/(?:[^/]+/)*[^/.]+\.[^/.]+$` ) |
| 29 | ) |
| 30 | |
| 31 | // Site identifies a manifest family and its addressable key. |
| 32 | type Site struct { |
| 33 | Kind int |
| 34 | PubKey string |
| 35 | D string |
| 36 | ID string |
| 37 | } |
| 38 | |
| 39 | // Base36 encodes a lowercase 32-byte hexadecimal key as a fixed-width label. |
| 40 | func Base36(value string) (string, error) { |
| 41 | if !hexPattern.MatchString(value) { |
| 42 | return "" , errors.New("expected lowercase 32-byte hex" ) |
| 43 | } |
| 44 | n := new(big.Int) |
| 45 | if _, ok := n.SetString(value, 16); !ok { |
| 46 | return "" , errors.New("invalid hexadecimal value" ) |
| 47 | } |
| 48 | value36 := n.Text(36) |
| 49 | return strings.Repeat("0" , 50-len(value36)) + value36, nil |
| 50 | } |
| 51 | |
| 52 | // Unbase36 decodes a fixed-width site label into lowercase hexadecimal. |
| 53 | func Unbase36(value string) (string, bool) { |
| 54 | if len(value) != 50 || !regexp.MustCompile(`^[0-9a-z]+$` ).MatchString(value) { |
| 55 | return "" , false |
| 56 | } |
| 57 | n, ok := new(big.Int).SetString(value, 36) |
| 58 | if !ok || n.BitLen() > 256 { |
| 59 | return "" , false |
| 60 | } |
| 61 | return fmt.Sprintf("%064x" , n), true |
| 62 | } |
| 63 | |
| 64 | // ParseSite parses an npub, named-site or snapshot label. |
| 65 | func ParseSite(label string) (Site, bool) { |
| 66 | if strings.HasPrefix(label, "npub1" ) { |
| 67 | key, ok := decodeNpub(label) |
| 68 | if ok { |
| 69 | return Site{Kind: KindSite, PubKey: key.Hex()}, true |
| 70 | } |
| 71 | } |
| 72 | if strings.HasPrefix(label, "v" ) && len(label) == 51 { |
| 73 | id, ok := Unbase36(label[1:]) |
| 74 | if ok { |
| 75 | return Site{Kind: KindSiteSnapshot, ID: id}, true |
| 76 | } |
| 77 | } |
| 78 | if len(label) < 51 || len(label) > 63 || strings.HasSuffix(label, "-" ) { |
| 79 | return Site{}, false |
| 80 | } |
| 81 | key, ok := Unbase36(label[:50]) |
| 82 | if !ok || !namePattern.MatchString(label[50:]) { |
| 83 | return Site{}, false |
| 84 | } |
| 85 | return Site{Kind: KindNamedSite, PubKey: key, D: label[50:]}, true |
| 86 | } |
| 87 | |
| 88 | // SiteLabel returns the host label represented by a manifest event. |
| 89 | func SiteLabel(e event.Event) string { |
| 90 | switch e.Kind { |
| 91 | case KindSite: |
| 92 | key, err := nostr.PubKeyFromHex(e.PubKey) |
| 93 | if err != nil { |
| 94 | return "" |
| 95 | } |
| 96 | return encodeNpub(key) |
| 97 | case KindNamedSite: |
| 98 | key, err := Base36(e.PubKey) |
| 99 | if err != nil { |
| 100 | return "" |
| 101 | } |
| 102 | return key + event.Tag(e, "d" ) |
| 103 | case KindSiteSnapshot: |
| 104 | key, err := Base36(e.ID) |
| 105 | if err != nil { |
| 106 | return "" |
| 107 | } |
| 108 | return "v" + key |
| 109 | default: |
| 110 | return "" |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | // SitePaths returns the path tags in manifest order. |
| 115 | func SitePaths(e event.Event) [][]string { |
| 116 | paths := make([][]string, 0) |
| 117 | for _, tag := range e.Tags { |
| 118 | if len(tag) > 0 && tag[0] == "path" { |
| 119 | paths = append(paths, tag) |
| 120 | } |
| 121 | } |
| 122 | return paths |
| 123 | } |
| 124 | |
| 125 | // Aggregate hashes the canonical path and blob mappings in a manifest. |
| 126 | func Aggregate(paths [][]string) string { |
| 127 | lines := make([]string, 0, len(paths)) |
| 128 | for _, tag := range paths { |
| 129 | if len(tag) == 3 && tag[0] == "path" { |
| 130 | lines = append(lines, tag[2]+" " +tag[1]+"\n" ) |
| 131 | } |
| 132 | } |
| 133 | sort.Strings(lines) |
| 134 | sum := sha256.Sum256([]byte(strings.Join(lines, "" ))) |
| 135 | return hex.EncodeToString(sum[:]) |
| 136 | } |
| 137 | |
| 138 | // ValidateManifest checks a site manifest's paths, aggregate and lineage. |
| 139 | func ValidateManifest(e event.Event) error { |
| 140 | if e.Kind != KindSite && e.Kind != KindNamedSite && e.Kind != KindSiteSnapshot { |
| 141 | return nil |
| 142 | } |
| 143 | dTags := tagsNamed(e, "d" ) |
| 144 | if (e.Kind == KindNamedSite && (len(dTags) != 1 || !namePattern.MatchString(dTags[0][1]))) || (e.Kind != KindNamedSite && len(dTags) != 0) { |
| 145 | return errors.New("invalid: site d tag" ) |
| 146 | } |
| 147 | paths := SitePaths(e) |
| 148 | if len(paths) == 0 { |
| 149 | return errors.New("invalid: site needs a path" ) |
| 150 | } |
| 151 | seen := map[string]bool{} |
| 152 | for _, tag := range paths { |
| 153 | if len(tag) != 3 || !pathPattern.MatchString(tag[1]) || strings.ContainsAny(tag[1], "\\?#\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x7f" ) || hasDotSegment(tag[1]) || !hexPattern.MatchString(tag[2]) { |
| 154 | return errors.New("invalid: site path" ) |
| 155 | } |
| 156 | if seen[tag[1]] { |
| 157 | return errors.New("invalid: duplicate site path" ) |
| 158 | } |
| 159 | seen[tag[1]] = true |
| 160 | } |
| 161 | if err := validateAggregate(e); err != nil { |
| 162 | return err |
| 163 | } |
| 164 | return validateLineage(e) |
| 165 | } |
| 166 | |
| 167 | func validateAggregate(e event.Event) error { |
| 168 | x := tagsNamed(e, "x" ) |
| 169 | if len(x) > 1 || (e.Kind == KindSiteSnapshot && len(x) != 1) { |
| 170 | return errors.New("invalid: site x tag" ) |
| 171 | } |
| 172 | if len(x) == 1 && (len(x[0]) != 3 || x[0][2] != "aggregate" || x[0][1] != Aggregate(SitePaths(e))) { |
| 173 | return errors.New("invalid: site aggregate hash" ) |
| 174 | } |
| 175 | return nil |
| 176 | } |
| 177 | |
| 178 | func validateLineage(e event.Event) error { |
| 179 | a, A := tagsNamed(e, "a" ), tagsNamed(e, "A" ) |
| 180 | for _, tag := range append(append([][]string{}, a...), A...) { |
| 181 | if len(tag) != 2 || !validReference(tag[1]) { |
| 182 | return errors.New("invalid: site lineage" ) |
| 183 | } |
| 184 | } |
| 185 | if e.Kind == KindSiteSnapshot && len(a) != 1 { |
| 186 | return errors.New("invalid: snapshot source" ) |
| 187 | } |
| 188 | if e.Kind != KindSiteSnapshot && len(a) != len(A) { |
| 189 | return errors.New("invalid: copied site lineage" ) |
| 190 | } |
| 191 | return nil |
| 192 | } |
| 193 | |
| 194 | func validReference(value string) bool { |
| 195 | parts := strings.Split(value, ":" ) |
| 196 | if len(parts) != 3 || !hexPattern.MatchString(parts[1]) || parts[0] != fmt.Sprint(KindSite) && parts[0] != fmt.Sprint(KindNamedSite) { |
| 197 | return false |
| 198 | } |
| 199 | return parts[0] == fmt.Sprint(KindSite) && parts[2] == "" || parts[0] == fmt.Sprint(KindNamedSite) && namePattern.MatchString(parts[2]) |
| 200 | } |
| 201 | |
| 202 | func tagsNamed(e event.Event, name string) [][]string { |
| 203 | out := make([][]string, 0) |
| 204 | for _, tag := range e.Tags { |
| 205 | if len(tag) > 0 && tag[0] == name { |
| 206 | out = append(out, tag) |
| 207 | } |
| 208 | } |
| 209 | return out |
| 210 | } |
| 211 | func hasDotSegment(path string) bool { |
| 212 | for _, part := range strings.Split(path, "/" ) { |
| 213 | if part == "." || part == ".." { |
| 214 | return true |
| 215 | } |
| 216 | } |
| 217 | return false |
| 218 | } |
| 219 | |
| 220 | func SiteType(path string) string { |
| 221 | ext := strings.ToLower(strings.TrimPrefix(path, "." )) |
| 222 | i := strings.LastIndexByte(ext, '.' ) |
| 223 | if i >= 0 { |
| 224 | ext = ext[i+1:] |
| 225 | } |
| 226 | if typ := map[string]string{"html" : "text/html; charset=utf-8" , "htm" : "text/html; charset=utf-8" , "css" : "text/css" , "js" : "text/javascript" , "mjs" : "text/javascript" , "json" : "application/json" , "svg" : "image/svg+xml" , "png" : "image/png" , "jpg" : "image/jpeg" , "jpeg" : "image/jpeg" , "gif" : "image/gif" , "webp" : "image/webp" , "ico" : "image/x-icon" , "txt" : "text/plain; charset=utf-8" , "xml" : "application/xml" , "wasm" : "application/wasm" , "woff" : "font/woff" , "woff2" : "font/woff2" , "pdf" : "application/pdf" }[ext]; typ != "" { |
| 227 | return typ |
| 228 | } |
| 229 | return "application/octet-stream" |
| 230 | } |
| 231 | |
| 232 | func RequestedPath(raw string) (string, bool) { |
| 233 | decoded, err := url.PathUnescape(raw) |
| 234 | return decoded, err == nil |
| 235 | } |