@stdlib/dns
Provides means for resolution of DNS names.
To use this library, import @stdlib/dns
:
import "@stdlib/dns";
Structs
DNSResolveResult
struct DNSResolveResult { prefix: Int; record: Cell?;}
Functions
dnsStringToInternal
@name(dns_string_to_internal)native dnsStringToInternal(str: String): Slice?;
Converts a DNS string to a Slice
or null
, if it’s impossible.
Source code (FunC): dns.fc#L1
dnsInternalNormalize
@name(dns_internal_normalize)native dnsInternalNormalize(src: Slice): Slice;
Normalizes the internal DNS representation of the Slice
. The passed Slice
must not have any references, otherwise an exception with exit code 134 will be thrown: Invalid argument
.
Source code (FunC): dns.fc#L125
dnsInternalVerify
@name(dns_internal_verify)native dnsInternalVerify(subdomain: Slice): Bool;
Verifies the internal DNS representation of the subdomain Slice
.
Source code (FunC): dns.fc#L81
dnsExtractTopDomainLength
fun dnsExtractTopDomainLength(subdomain: Slice): Int;
Calculates length of a top domain in the subdomain
Slice
.
Source code:
fun dnsExtractTopDomainLength(subdomain: Slice): Int { let i: Int = 0; let needBreak: Bool = false; do { let char: Int = subdomain.loadUint(8); // we do not check domain.length because it MUST contain \0 character needBreak = char == 0; if (!needBreak) { i += 8; } } until (needBreak); require(i != 0, "Invalid DNS name"); return i;}
dnsExtractTopDomain
fun dnsExtractTopDomain(subdomain: Slice): Slice;
Extracts top domain from a subdomain
Slice
.
Source code:
fun dnsExtractTopDomain(subdomain: Slice): Slice { let len: Int = dnsExtractTopDomainLength(subdomain); return subdomain.loadBits(len);}
dnsResolveNext
fun dnsResolveNext(address: Address): Cell;
Resolves an address
Address
into a Cell
.
Source code:
fun dnsResolveNext(address: Address): Cell { return beginCell() .storeUint(0xba93, 16) .storeAddress(address) .endCell();}
dnsResolveWallet
fun dnsResolveWallet(address: Address): Cell;
Resolves a wallet address
Address
into a Cell
.
Source code:
fun dnsResolveWallet(address: Address): Cell { return beginCell() .storeUint(0x9fd3, 16) .storeAddress(address) .storeUint(0, 8) .endCell();}
Traits
DNSResolver
Trait DNSResolver
provides two helper functions for DNS resolution:
- getter function
dnsresolve()
, which corresponds to its FunC variant. - virtual function
doResolveDNS()
, which creates a struct DNSResolveResult out of subdomainSlice
bits.
Source code:
trait DNSResolver { get fun dnsresolve(subdomain: Slice, category: Int): DNSResolveResult { // Normalize let delta: Int = 0; if (subdomain.preloadUint(8) == 0) { subdomain.loadUint(8); // Skip first byte delta += 8; }
// Checks correctness require(dnsInternalVerify(subdomain), "Invalid DNS name");
// Resolve let res: DNSResolveResult = self.doResolveDNS(subdomain, category); return DNSResolveResult{prefix: res.prefix + delta, record: res.record}; } virtual fun doResolveDNS(subdomain: Slice, category: Int): DNSResolveResult { return DNSResolveResult{prefix: subdomain.bits(), record: null}; }}
Usage example:
import "@stdlib/dns";
contract ExampleContract with DNSResolver { // Now, this contract has a: // 1. dnsresolve getter function // 2. doResolveDNS virtual function}