[Node.js] Stream all things!-优快云博客

本文探讨了在Node.js中使用流(Stream)API处理大文件的优势。通过对比传统文件读取方法，流API能显著降低内存消耗，避免一次性将大量数据加载到内存中，从而提高应用性能。

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Node.js come alone with many Stream API. Stream is useful when handling large trunck of data.

For example, we have a big file to read from file system:

// create-big-file.js

const fs = require('fs')
const file = fs.createWriteStream('./big.file')

for (let i = 0; i <= 1e6; i++) {
    file.write('awefawgrga afewfa')
}

file.end();

If we are reading it using normal API:

const fs = require('fs')
const server = require('http').createServer();
server.on('request', (req, res) => {
    fs.readFile('./big.file', (err, data) => {
        if (err) throw err;

        res.end(data);
    })
});
server.listen(8000);

When running the code, we found that the normal memory cost is 8MB, when reading the large file, memory cost is 400+MB, basiclly it buffer all the file content into the memory, this is not the way we want.

Using Stream:

const fs = require('fs')
const server = require('http').createServer();
server.on('request', (req, res) => {
    /*fs.readFile('./big.file', (err, data) => {
        if (err) throw err;

        res.end(data);
    })*/
    const src = fs.createReadStream('./big.file')
    src.pipe(res)
});

server.listen(8000);

After updating the code, the memory usage of stream version stay around 30-40MB.

转载于:https://www.cnblogs.com/Answer1215/p/10516507.html