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import {Address, Cell, Builder, beginCell} from "ton";
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const ONCHAIN_CONTENT_PREFIX = 0x00;
const SNAKE_PREFIX = 0x00;
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export type JettonMetaDataKeys = "name" | "description" | "image" | "symbol";
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const jettonOnChainMetadataSpec: {
[key in JettonMetaDataKeys]: "utf8" | "ascii" | undefined;
} = {
name: "utf8",
description: "utf8",
image: "ascii",
symbol: "utf8",
};
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const sha256 = (str: string) => {
const sha = new Sha256();
sha.update(str);
return Buffer.from(sha.digestSync());
};
export function buildTokenMetadataCell(data: { [s: string]: string | undefined }): Cell {
const KEYLEN = 256;
let rootCell = beginCell();
let dict = new Cell();
Object.entries(data).forEach(([k, v]: [string, string | undefined]) => {
if (!jettonOnChainMetadataSpec[k as JettonMetaDataKeys])
throw new Error(`Unsupported onchain key: ${k}`);
if (v === undefined || v === "") return;
let bufferToStore = Buffer.from(v, jettonOnChainMetadataSpec[k as JettonMetaDataKeys]);
const CELL_MAX_SIZE_BYTES = Math.floor((1023 - 8) / 8);
rootCell.storeUint(SNAKE_PREFIX, 16);
let currentCell = rootCell;
//TODO need fix dictionary writing
while (bufferToStore.length > 0) {
currentCell.storeBuffer(bufferToStore.subarray(0, CELL_MAX_SIZE_BYTES)) // how to read from Buffer???
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//currentCell.bits.writeBuffer(bufferToStore.slice(0, CELL_MAX_SIZE_BYTES));
//bufferToStore = bufferToStore.slice(CELL_MAX_SIZE_BYTES);
if (bufferToStore.length > 0) {
const newCell = new Builder();
newCell.storeRef(currentCell);
currentCell = newCell;
}
}
let dict = currentCell.endCell();
});
return beginCell().storeInt(ONCHAIN_CONTENT_PREFIX, 8).storeDict(dict).endCell();
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}
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export function parseTokenMetadataCell(contentCell: Cell): {
[s in JettonMetaDataKeys]?: string;
} {
// Note that this relies on what is (perhaps) an internal implementation detail:
// "ton" library dict parser converts: key (provided as buffer) => BN(base10)
// and upon parsing, it reads it back to a BN(base10)
// tl;dr if we want to read the map back to a JSON with string keys, we have to convert BN(10) back to hex
const toKey = (str: string) => new BN(str, "hex").toString(10);
const KEYLEN = 256;
const contentSlice = contentCell.beginParse();
if (contentSlice.readUint(8).toNumber() !== ONCHAIN_CONTENT_PREFIX)
throw new Error("Expected onchain content marker");
const dict = contentSlice.readDict(KEYLEN, (s) => {
const buffer = Buffer.from("");
const sliceToVal = (s: Slice, v: Buffer, isFirst: boolean) => {
s.toCell().beginParse();
if (isFirst && s.readUint(8).toNumber() !== SNAKE_PREFIX)
throw new Error("Only snake format is supported");
v = Buffer.concat([v, s.readRemainingBytes()]);
if (s.remainingRefs === 1) {
v = sliceToVal(s.readRef(), v, false);
}
return v;
};
return sliceToVal(s.readRef(), buffer, true);
});
const res: { [s in JettonMetaDataKeys]?: string } = {};
Object.keys(jettonOnChainMetadataSpec).forEach((k) => {
const val = dict
.get(toKey(sha256(k).toString("hex")))
?.toString(jettonOnChainMetadataSpec[k as JettonMetaDataKeys]);
if (val) res[k as JettonMetaDataKeys] = val;
});
return res;
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}