getting Error as 'Error: Can't set headers after they are sent' in my node.js service

Question

下面是我的代码，

app.get("/getList", function (req, resp) {
    process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
    var client = ldap.createClient({
        url: 'ldap://my_ip:389'
    });

    client.bind('cn=pratik', 'pratik', function (err) {
        return resp.send(err);
    });

    var opts = {
        filter: '(objectclass=classToSearch)',
        scope: 'sub',
        attributes: ['ipaddress']
      };
      var entries= {};
      var i=0;
      client.search('o=a', opts, function(err, res) {


        res.on('searchEntry', function(entry) {
          console.log('entry: ' + JSON.stringify(entry.object));
            oxe[i] = entry.object;
            i++;
        });
        res.on('end', function(result) {
            console.log("pratik");
            console.log(entries);
            return resp.send(entries);
          });
});

这里，当我打印条目时，它显示正确的结果，但没有发送响应。我可以将错误视为“错误：发送后无法设置 headers”。下面是完整的错误：

_http_outgoing.js:357
throw new Error('Can\'t set headers after they are sent.');
^

Error: Can't set headers after they are sent.
at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:357:11)

我该如何解决这个错误？

Answer 1

这是因为您调用了 resp.send 两次：在 client.bind 回调和 res.on("end") 回调中。

我建议将第二个作业放在 bind 回调中，这样你就可以检查错误，如果有错误，你就停在那里。

如果成功，那么我会发送entries。

app.get("/getList", function(req, resp) {
  process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
  var client = ldap.createClient({
    url: 'ldap://my_ip:389'
  });

  client.bind('cn=pratik', 'pratik', function(err) {
    if (err) return resp.send(err);
    var opts = {
      filter: '(objectclass=classToSearch)',
      scope: 'sub',
      attributes: ['ipaddress']
    };
    var entries = {};
    var i = 0;
    client.search('o=a', opts, function(err, res) {
      res.on('searchEntry', function(entry) {
        console.log('entry: ' + JSON.stringify(entry.object));
        oxe[i] = entry.object;
        i++;
      });
      res.on('end', function(result) {
        console.log("pratik");
        console.log(entries);
        return resp.send(entries);
      });
    });
  });
});

getting Error as 'Error: Can't set headers after they are sent' in my node.js service

getting Error as 'Error: Can't set headers after they are sent' in my node.js service

node.js

express

ldapjs