具有快速流式 http 响应的 nodejs

Question

我有以下测试代码：

const compression = require('compression');
const bodyParser = require('body-parser')
const cors = require('cors')
const { pool, connectionString } = require('./config')
const { handleError, ErrorHandler } = require('./error')

const app = express()
app.use(bodyParser.json())
app.use(bodyParser.urlencoded({ extended: true }))
app.use(cors())
app.use(compression());
const getEvents = (request, response) => {
    pool.connect((err, client, release) => {
        if (err) {
            throw new ErrorHandler(500, err.stack);
        }
        if(!request.query.FromTime){
            throw new ErrorHandler(400, 'Required paramter FromTime is missing.');
        }
        if(!request.query.ToTime){
            throw new ErrorHandler(400, 'Required paramter ToTime is missing.');
        }
        let fromtime = request.query.FromTime
        let totime = request.query.ToTime
        console.log("FromTime: ",fromtime," ToTime: ",totime);
        let query = 'SELECT data FROM logs WHERE time BETWEEN '+fromtime+' AND '+totime+' ORDER BY time DESC';
        console.log(query)
        var stream = client.query(query, (error, results) => {
            if (error) {
                throw new ErrorHandler(500,error);
            }
            response.status(200).json(results.rows)
        })
    })
}
...
app
  .route('/events')
  // GET endpoint
  .get(getEvents)
  // POST endpoint
  .post(addEvent)

app.use((err, req, res, next) => {
  handleError(err, res);
});
// Start server
app.listen(process.env.PORT || 3002, () => {
  console.log(`Server listening`)
})

我一直试图让这个流式传输数据，但没有成功。我确实尝试过使用 pg-query-stream 和 querystream，但最终出现以下错误，当我尝试

var stream = client.query(new QueryStream(query));
stream.pipe(response);

_http_outgoing.js:607 throw new ERR_INVALID_ARG_TYPE('first argument', ^

TypeError [ERR_INVALID_ARG_TYPE]: The first argument must be one of type string or Buffer. Received type object at write_ (_http_outgoing.js:607:11) at ServerResponse.write (_http_outgoing.js:579:10) at ServerResponse.write (/usr/src/app/node_modules/compression/index.js:89:18) at PgQueryStream.ondata (_stream_readable.js:705:22) at PgQueryStream.emit (events.js:193:13) at addChunk (_stream_readable.js:295:12) at readableAddChunk (_stream_readable.js:276:11) at PgQueryStream.Readable.push (_stream_readable.js:231:10) at cursor.read (/usr/src/app/node_modules/pg-query-stream/index.js:55:14) at Immediate.setImmediate (/usr/src/app/node_modules/pg-cursor/index.js:91:7)

Answer 1

响应流默认不支持对象模式。就像在文档中一样尝试

const JSONStream = require('JSONStream')
stream.pipe(JSONStream.stringify()).pipe(response)

具有快速流式 http 响应的 nodejs

nodejs with express streaming http response

node.js

express

pg-query