Question

我的应用程序中有一个上传文件，它会接收一个加密的文件。进行解密时，我正在另一个文件中写入json。完成此操作后，我有一个500MB的json文件。

注意：我的json的属性是动态的。

如何解析此json，我读到有关 stream-json / Parser 的信息，但无法实现。

const {parser} = require('stream-json/Parser');

static async _recoverObj(pathAnalise) {

    let readStream = fs.createReadStream(pathAnalise, {encoding: 'utf8', highWaterMark: 1024});

    function createJson(stream) {

        let decipher = crypto.createDecipher('aes-128-ecb', 'AmbientalRuralBR');

        return new Promise((resolve) => {

            stream.on('data', chunk => {

                let newDecrypt = decipher.update(chunk, 'base64', 'utf8');

                fs.appendFile('./data.json', newDecrypt, function() {
                    console.log('Saved!');
                });

            });

            stream.on('end', () => {

                fs.appendFile('./data.json', '"}', function() {
                    resolve();
                });

            });

        });

    }

    const result = await createJson(readStream);

    function getParse() {

        return new Promise((resolve) => {

            let jsonData = './data.json';
            let pipeline = fs.createReadStream(jsonData).pipe(parser());

            let objectCounter = 0;
            pipeline.on('data', data => {

                data.name === 'startObject' && ++objectCounter

            });

            pipeline.on('end', () => {

                console.log(`Found ${objectCounter} objects.`);
                resolve();

            });

        });

    }

    let dataAnalyze = await getParse();

    return dataAnalyze;

}

任何人都知道如何进行此解析吗？

我的解决方案：

我使用了https://www.npmjs.com/package/big-json

const json = require('big-json');

static async _recoverObj(pathAnalise) {

    var readStream = fs.createReadStream(pathAnalise, {encoding: 'utf8', highWaterMark: 1024 * 2});

    function createJson(stream) {

        var decipher = crypto.createDecipher('aes-128-ecb', 'AmbientalRuralBR');

        return new Promise((resolve) => {

            stream.on('data', chunk => {

                var newDecrypt = decipher.update(chunk, 'base64', 'utf8');

                fs.appendFile('./data.json', newDecrypt, function() {
                    console.log('Saved!');
                });

            });

            stream.on('end', () => {
                fs.appendFile('./data.json', '"}', function() {
                    resolve();
                });

            });

        });

    }

    await streamToString(readStream);

    function getParse() {

        return new Promise((resolve) => {

            var jsonData = './max.json';
            var myObj = [];
            const readStream = fs.createReadStream(jsonData);
            const parseStream = json.createParseStream();

            parseStream.on('data', function(pojo) {
                myObj = pojo;
            });

            parseStream.on('end', function() {
                resolve(myObj);
            });

            readStream.pipe(parseStream);

        });

    }

    let dataAnalyze = await getParse();

    return dataAnalyze;

}

Answer 1

一旦包含包含json的文本字符串，就可以使用JSON.parse()来将其转换为对象，以便以后与之交互：

var json = '{"result":true, "count":42}';
obj = JSON.parse(json);

console.log(obj.count);
// expected output: 42

console.log(obj.result);
// expected output: true

如何解析500mb的json文件？

1 个答案: