Hapi: Excel binary data in reply

[maxhedouin]

Hello folks,

I've been trying to create an endpoint that returns an excel or a json based on the incoming request accept header. I've been struggling quite a bit to generate the excel from my object and return it (I used the json2xls module (https://github.com/rikkertkoppes/json2xls) to generate the data).

I simply access my endpoint through chrome: http://localhost:3000/excel

Here is a snippet of the code:

'use strict';

var Hapi     = require('hapi');
var json2xls = require('json2xls');

var server = new Hapi.Server();
server.connection({port:3000});
server.route({
    method : 'GET',
    path   : '/excel',
    handler: getExcel
});
server.start(function () {
    console.log('server started!');
});

function getExcel(request, reply) {
    var jsonObject = {
        a: 1,
        b: 'stuff',
        c: new Date()
    };
    var xls = json2xls(jsonObject);
    reply(xls)
        .bytes(xls.length)
        .type('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
        .header('content-disposition', 'attachment; filename=stuff.xlsx;');
}

In this case, the endpoint retrieves a file that is corrupted and I cannot open it.

I also tried to use a Buffer in the reply with the same result:

    var xls = json2xls(jsonObject);
    var buf = new Buffer(xls);
    var res = reply(buf)
        .bytes(buf.length)
        .type('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
        .header('content-disposition', 'attachment; filename=stuff.xlsx;');

Last but not least, if I write the content to disk and retrieve it. It works properly:

    var xls = json2xls(jsonObject);
    fs.writeFileSync('stuff.xlsx', xls, 'binary');
    reply.file('stuff.xlsx');

Any help will be greatly appreciated.

Cheers,

Max

[spanditcaa]

We do similar in one of our apps with no issue. Our snippet differs in setting the content-length header vs reply.bytes()

                reply(xlsx)
                    .type('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
                    .header('Content-Disposition', 'attachment; filename="'+ filename +'.xlsx"')
                    .header('Content-Length', xlsx.length);

hope this helps.

[maxhedouin]

Interesting... I still have a corrupted xlsx as an output here... @spanditcaa What is the type of your xlsx object? (string? binary?) And how do you generate It?
To me, it seems that the problem comes from the binary format...

[ghost]

@maxhedouin Edit: Does it help if you write reply(xls).bytes(Buffer.byteLength(xls)), or var buf = new Buffer(xls, 'binary')?

[spanditcaa]

binary, made with https://www.npmjs.com/package/xlsx-style

[maxhedouin]

@kitcambridge nope.

[ghost]

:disappointed: Sorry about that; I thought it might be an issue with encoding the binary string into a buffer.

[kanongil]

You forgot to tell hapi to use the 'binary' string encoding by calling .encoding('binary') on the response. It defaults to 'utf8'.

[maxhedouin]

Thanks @kanongil. I couldn't find that in the hapijs docs.