介绍
DAS API 方法最多只返回 1000 条记录。如果您需要检索超过 1000 项，您将需要对记录进行分页。这是通过多次 API 调用并遍历多个数据“页面”来实现的。我们支持两种机制：基于页面的分页和键集分页。我们建议初学者使用基于页面的分页。这是最简单且最好的入门方式。键集分页推荐给需要高效查询大（50 万以上）数据集的高级用户。
排序选项
使用 DAS API，您可以按不同字段对数据进行排序：id: 按资产 ID 的二进制排序（默认）。created: 按资产创建日期排序。recent_action: 按资产最后更新日期排序（不推荐）。none: 不对数据进行排序（不推荐）。
分页选项
基于页面
使用此方法，用户指定页码和每页所需的项目数。要迭代到下一页，增加页码。这对于大多数用例来说简单、直观且快速。示例
示例
Report incorrect code
Copy
Ask AI
const url = `https://mainnet.helius-rpc.com/?api-key=<api_key>`
const example = async () => {
let page = 1;
let items = [];
while (true) {
const response = await fetch(url, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify({
jsonrpc: '2.0',
id: 'my-id',
method: 'searchAssets',
params: {
grouping: ['collection', '5PA96eCFHJSFPY9SWFeRJUHrpoNF5XZL6RrE1JADXhxf'],
page: page,
limit: 1000,
sortBy: { sortBy: 'id', sortDirection: 'asc' },
},
}),
});
const { result } = await response.json();
if (result.items.length == 0) {
console.log('No items remaining');
break;
} else {
console.log(`Processing results from page ${page}`);
items.push(...result.items);
page += 1;
}
}
console.log(`Got ${items.length} total items`);
};
example();
Keyset
使用此方法，用户通过提供过滤数据集的条件来定义页面。例如，您可以说：“获取所有ID > X但ID < Y的资产”。用户可以通过在每次调用中修改X或Y来遍历整个数据集。我们提供两种keyset分页方法：- 基于游标 – 使用更简单但灵活性较低。
- 基于范围 – 更复杂但非常灵活。
Keyset分页仅在按
id排序时支持。基于游标
没有任何分页参数的DAS查询将返回一个游标。您可以将游标提供给DAS API以从上次中断的地方继续。示例
示例
Report incorrect code
Copy
Ask AI
const url = `https://mainnet.helius-rpc.com/?api-key=<api_key>`
const example = async () => {
let items = [];
let cursor;
while (true) {
let params = {
grouping: ['collection', '5PA96eCFHJSFPY9SWFeRJUHrpoNF5XZL6RrE1JADXhxf'],
limit: 1000,
sortBy: { sortBy: 'id', sortDirection: 'asc' },
} as any;
if (cursor != undefined) {
params.cursor = cursor;
}
const response = await fetch(url, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify({
jsonrpc: '2.0',
id: 'my-id',
method: 'searchAssets',
params: params,
}),
});
const { result } = await response.json();
if (result.items.length == 0) {
console.log('No items remaining');
break;
} else {
console.log(`Processing results for cursor ${cursor}`);
cursor = result.cursor;
items.push(...result.items);
}
}
console.log(`Got ${items.length} total items`);
};
example();
在撰写本文时，游标将是响应的最后一个资产ID；然而，游标设计是灵活的，可以支持任何字符串。
基于范围
要跨范围查询，您可以指定before和/或after。查询本质上与“获取所有在X之后但在Y之前的资产”相同。您可以通过更新每次调用的before或after参数来遍历数据集。
示例
示例
Report incorrect code
Copy
Ask AI
const url = `https://mainnet.helius-rpc.com/?api-key=<api_key>`
const example = async () => {
// Two NFTs from the Tensorian collection.
// The "start" item has a lower asset ID (in binary) than the "end" item.
// We will traverse in ascending order.
let start = '6CeKtAYX5USSvPCQicwFsvN4jQSHNxQuFrX2bimWrNey';
let end = 'CzTP4fUbdfgKzwE6T94hsYV7NWf1SzuCCsmJ6RP1xsDw';
let sortDirection = 'asc';
let after = start;
let before = end;
let items = [];
while (true) {
const response = await fetch(url, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify({
jsonrpc: '2.0',
id: 'my-id',
method: 'searchAssets',
params: {
grouping: ['collection', '5PA96eCFHJSFPY9SWFeRJUHrpoNF5XZL6RrE1JADXhxf'],
limit: 1000,
after: after,
before: before,
sortBy: { sortBy: 'id', sortDirection: sortDirection },
},
}),
});
const { result } = await response.json();
if (result.items.length == 0) {
console.log('No items remaining');
break;
} else {
console.log(`Processing results with (after: ${after}, before: ${before})`);
after = result.items[result.items.length - 1].id;
items.push(...result.items);
}
}
console.log(`Got ${items.length} total items`);
};
example();
使用Keyset的并行查询（高级）
需要查询大型数据集（例如，整个压缩NFT集合）的高级用户必须出于性能原因使用基于keyset的分页。以下示例展示了用户如何通过划分Solana地址范围并利用before/after参数进行并行查询。这种方法快速、高效且安全。如果您有任何问题或需要帮助，请随时在Discord上联系我们！示例
示例
在下面的示例中，我们扫描整个 Tensorian 集合（约 10k 条记录）。它将 Solana 地址空间划分为 8 个范围，并同时扫描这些范围。您会注意到，这个示例比其他任何示例都要快得多。
Report incorrect code
Copy
Ask AI
import base58 from 'bs58';
const url = `https://mainnet.helius-rpc.com/?api-key=<api_key>`
const main = async () => {
let numParitions = 8;
let partitons = partitionAddressRange(numParitions);
let promises = [];
for (const [i, partition] of partitons.entries()) {
let [s, e] = partition;
let start = bs58.encode(s);
let end = bs58.encode(e);
console.log(`Parition: ${i}, Start: ${start}, End: ${end}`);
let promise: Promise<number> = new Promise(async (resolve, reject) => {
let current = start;
let totalForPartition = 0;
while (true) {
const response = await fetch(url, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify({
jsonrpc: '2.0',
id: 'my-id',
method: 'searchAssets',
params: {
grouping: ['collection', '5PA96eCFHJSFPY9SWFeRJUHrpoNF5XZL6RrE1JADXhxf'],
limit: 1000,
after: current,
before: end,
sortBy: { sortBy: 'id', sortDirection: 'asc' },
},
}),
});
const { result } = await response.json();
totalForPartition += result.items.length;
console.log(`Found ${totalForPartition} total items in parition ${i}`);
if (result.items.length == 0) {
break;
} else {
current = result.items[result.items.length - 1].id;
}
}
resolve(totalForPartition);
});
promises.push(promise);
}
let results = await Promise.all(promises);
let total = results.reduce((a, b) => a + b, 0);
console.log(`Got ${total} total items`);
};
// Function to convert a BigInt to a byte array
function bigIntToByteArray(bigInt: bigint): Uint8Array {
const bytes = [];
let remainder = bigInt;
while (remainder > 0n) {
// use 0n for bigint literal
bytes.unshift(Number(remainder & 0xffn));
remainder >>= 8n;
}
while (bytes.length < 32) bytes.unshift(0); // pad with zeros to get 32 bytes
return new Uint8Array(bytes);
}
function partitionAddressRange(numPartitions: number) {
let N = BigInt(numPartitions);
// Largest and smallest Solana addresses in integer form.
// Solana addresses are 32 byte arrays.
const start = 0n;
const end = 2n ** 256n - 1n;
// Calculate the number of partitions and partition size
const range = end - start;
const partitionSize = range / N;
// Calculate partition ranges
const partitions: Uint8Array[][] = [];
for (let i = 0n; i < N; i++) {
const s = start + i * partitionSize;
const e = i === N - 1n ? end : s + partitionSize;
partitions.push([bigIntToByteArray(s), bigIntToByteArray(e)]);
}
return partitions;
}
main();