基于游标的分页 graphql

Question

我正在通过 koa 服务器从 graphql 检索数据。为此，我写了一个函数 requestData(token, queryName, cursor) 来调用 graphql。

我想重复请求，直到游标为 null 或未定义。

我总是需要使用最后一个光标：

lastCursor = edges[edges.length - 1].cursor;

在终端中我得到以下输出：

null
eyJsYXN0X2lkIjo2MTQzNTk3ODcxMjc0LCJsYXN0X3ZhbHVlIjoiNjE0MzU5Nzg3MTI3NCJ9

即使我有更多数据，我仍会收到此输出。有人可以帮我弄清楚我的代码有什么问题吗？

server.js部分

  router.post('/getAllProducts', bodyParser(), async (ctx, next) => {
    let data;
    let edges;
    let lastCursor = null;
    const { accessToken } = ctx.session;
    ctx.response.status = 200;

    requestData(accessToken, GET_ALL_PRODUCTS, lastCursor).then((res) => {
      data = res.data.data;
      edges = data.products.edges;
      lastCursor = edges[edges.length - 1].cursor;
      setTimeout(() => {
        requestData(accessToken, GET_ALL_PRODUCTS, lastCursor);
      }, 1000);
    });
  });

  function requestData(token, queryName, cursor) {
    const variables = { after: cursor };
    console.log(cursor);
    const res = axios({
      headers: {
        'X-Shopify-Access-Token': token,
      },
      method: 'post',
      data: {
        query: queryName,
        variables: variables,
      },
      url: url,
    });

    return res;
  }

Answer 1

看来您需要对您的代码实现一些递归 - 像这样：

  router.post('/getAllProducts', bodyParser(), async (ctx, next) => {
    let allProducts;
    const { accessToken } = ctx.session;
    ctx.response.status = 200;

    function loadData(cursor) {
      requestData(accessToken, GET_ALL_PRODUCTS, cursor).then((res) => {
        const data = res.data.data;
        // process data here, eg: allProducts = [...allProducts, ...data];
        const edges = data.products.edges;
        const nextCursor = edges.length ? edges[edges.length - 1].cursor : null;
        if (nextCursor) {
          setTimeout(() => {
            loadData(nextCursor);
          }, 1000);
        } else {
          // now we have all data
          sendToClient(allProducts);
        }
      });
    }
    loadData(null);
  });

  function requestData(token, queryName, cursor) {
    const variables = { after: cursor };
    console.log(cursor);
    const res = axios({
      headers: {
        'X-Shopify-Access-Token': token,
      },
      method: 'post',
      data: {
        query: queryName,
        variables: variables,
      },
      url: url,
    });

    return res;
  }

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