Error: Can't set headers after they are sent Braintree

Question

I am currently working on an admin panel for this website I am creating, so I am able to accept payments via Braintree but I need to implement the ability to retrieve a customers transactions but once a header is sent it sends just one of them and not the whole thing. Is it possible to combine the json to an array so it will send in the one header?

CODE:

router.get('/:cid/test', function(req, res) {
  var stream = gateway.transaction.search(function (search) {
  search.customerId().is(req.params.cid);
  }, function (err, response) {
    response.each(function (err, transaction) {
      return res.render('admin/test', {transaction: transaction});
    });
  });
});

This is solely following the Braintree documentation and I know exactly why the error occurs. Any help is really appreciated and I am terrible at explaining so if you need to know more information please give me a holler!

UPDATE: So, I figured I would explore another method and I noticed the 'response' gives back an array of ids. So I will just use EJS to loop through all those and then have a seperate page for each transaction.

Answer 1

Disclaimer: I work for Braintree :)

As Robert noted, you can only call res.render (or any of the response methods that end the request) once per request (hence the error from express).

Unfortunately, you cannot treat response as an array, so you will need to use one of the two documented ways of interacting with search responses. I personally prefer the streams approach because it is clearer:

app.get('/stream', function (req, res) {
  var transactions = []
  var transactionStream = gateway.transaction.search(function (search) {
    search.customerId().is(req.params.cid);
  })

  transactionStream.on('data', function (transaction) {
    transactions.push(transaction)
  })

  transactionStream.on('error', function () { /* handle errors */ })

  transactionStream.on('end', function () {
    res.json({transactions: transactions});
  })
})

Alternately, you can use the ids property of response to compare the transactions array that you build from each to know when to end the request:

app.get('/calback', function (req, res) {
  var transactionStream = gateway.transaction.search(function (search) {
    search.customerId().is(req.params.cid);
  }, function (err, response) {
    var transactions = []
    response.each(function (err, transaction) {
      transactions.push(transaction)
      if (transactions.length === response.ids.length) {
        res.json({transactions: transactions});
      }
    })
  })
})