У меня есть API, который создает zip-файл с использованием модуля архиватора, в котором я хотел бы передать zip-файл в качестве респонента и загрузить его на стороне клиента.Однако, когда я пытаюсь передать zip-файл обратно, я получаю сообщение об ошибке Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client.
Что вызывает эту проблему?
Вот как выглядит мой API, создающий zip:
reports.get ('/ xxx /: fileName', async (req, res) => {
var s3 = new AWS.S3();
var archiver = require('archiver');
var filenames = "xxx,xxx"
var str_array = filenames.split(',');
for (var i = 0; i < str_array.length; i++) {
var filename = str_array[i].trim();
localFileName = './temp/' + filename.substring(filename.indexOf("/") + 1);
file = fs.createWriteStream(localFileName, {flags: 'a', encoding: 'utf-8',mode: 0666});
file.on('error', function(e) { console.error(e); });
s3.getObject({
Bucket: config.xxx,
Key: filename
})
.on('error', function (err) {
console.log(err);
})
.on('httpData', function (chunk) {
file.on('open', function(){
file.write(chunk);
});
})
.on('httpDone', function () {
file.end();
})
.send();
}
res.end("Files have been downloaded successfully")
// create a file to stream archive data to.
var output = fs.createWriteStream('example.zip');
var archive = archiver('zip', {
zlib: { level: 9 } // Sets the compression level.
});
// listen for all archive data to be written
// 'close' event is fired only when a file descriptor is involved
output.on('close', function() {
console.log(archive.pointer() + ' total bytes');
console.log('archiver has been finalized and the output file descriptor has closed.');
});
// This event is fired when the data source is drained no matter what was the data source.
// It is not part of this library but rather from the NodeJS Stream API.
// @see: https://nodejs.org/api/stream.html#stream_event_end
output.on('end', function() {
console.log('Data has been drained');
});
// good practice to catch warnings (ie stat failures and other non-blocking errors)
archive.on('warning', function(err) {
if (err.code === 'ENOENT') {
// log warning
} else {
// throw error
throw err;
}
});
// good practice to catch this error explicitly
archive.on('error', function(err) {
throw err;
});
// pipe archive data to the file
archive.pipe(output);
// append files from a sub-directory, putting its contents at the root of archive
archive.directory('./temp', false);
// finalize the archive (ie we are done appending files but streams have to finish yet)
// 'close', 'end' or 'finish' may be fired right after calling this method so register to them beforehand
archive.finalize();
const filePath = "./example.zip" // or any file format
res.writeHead(200, {"Content-Type": "text/html"});
fs.createReadStream(path.resolve(__dirname, 'example.zip')).pipe(res);
return;
});