javascript - 如何访问通过管道传输到 feedparser 的请求的响应 header

Question

我正在尝试使用请求 js 和 feedparser-promised 库来解析 RSS 提要。我可以使用以下代码解析提要。

import Bottleneck from 'bottleneck';

const feedparser = require('feedparser-promised');
const limiter = new Bottleneck({
  maxConcurrent: 1,
  minTime: 333,
});

const httpOptions = {
      uri: val.sourcefeedurl,
      resolveWithFullResponse: true,
      method: 'GET',
      pool: false,
      headers: {
        'If-None-Match': val.etag,
        'If-Modified-Since': val.LastModified,
        Connection: 'keep-alive',
        ciphers: 'DES-CBC3-SHA',
      },
    };
const response = await limiter.schedule(() => feedparser.parse(httpOptions));

但是由于我使用了 feedparser-promised 库，所以我无法从响应 header 中缓存 etag 和 Last Modified。

我试过像这样修改 feedparser-promised

'use strict';

const request = require('request');

const feedParser = require('./feedParser');

const parse = (requestOptions, feedparserOptions) => {
  const metaData = {};
  return new Promise((resolve, reject) => {
    request.get(requestOptions).on('error', reject).on('response', async resp => {
      if (resp.statusCode === 304) {
        reject('Source not modified');
      } else if (resp.statusCode === 200) {
        metaData.etagin = await resp.headers.etag;
        metaData.LastModifiedin = await resp.headers['last-modified'];
        metaData.LastModifiedLocal = await resp.headers['last-modified'];
        // console.log(metaData);
      }
    }).pipe(feedParser(feedparserOptions).on('error', reject).on('response', resolve));
  });
};

module.exports = {
  parse
};

下面是feedParser文件

'use strict';

const FeedParserStream = require('feedparser');

module.exports = (feedparserOptions, metaData) => {
  // console.log(metaData, 'herre');
  const parsedItems = [];
  const feedparser = new FeedParserStream(feedparserOptions);
  // console.log(feedparser);
  feedparser.on('readable', () => {
    // console.log(resp);
    let item;
    while (item = feedparser.read()) {
      parsedItems.push(item);
    }

    return parsedItems;
  }).on('end', function next() {
    this.emit('response', parsedItems);
  });
  return feedparser;
};

所以我的问题是如何在解析 promise 时返回响应 header 以及 parsedItems(如代码中所示)。

非常感谢您的帮助。

Answer 1

像这样传递元数据

'use strict';

const FeedParserStream = require('feedparser');

module.exports = (feedparserOptions, metaData) => {
  // console.log(metaData, 'herre');
  const parsedItems = [];
  const feedparser = new FeedParserStream(feedparserOptions);
  // console.log(feedparser);
  feedparser.on('readable', () => {
    // console.log(resp);
    let item;
    while (item = feedparser.read()) {
      parsedItems.push(item);
    }

    return parsedItems;
  }).on('end', function next() {
    this.emit('response', { parsedItems, metaData });
  });
  return feedparser;
};

你的 feed-parser promise 为

'use strict';

const request = require('request');

const feedParser = require('./feedParser');

const parse = (requestOptions, feedparserOptions) => {
  const metaData = {};
  return new Promise((resolve, reject) => {
    request.get(requestOptions).on('error', reject).on('response', async resp => {
      if (resp.statusCode === 304) {
        reject('Source not modified');
      } else if (resp.statusCode === 200) {
        metaData.etagin = await resp.headers.etag;
        metaData.LastModifiedin = await resp.headers['last-modified'];
        metaData.LastModifiedLocal = await resp.headers['last-modified'];
        // console.log(metaData);
      }
    }).pipe(feedParser(feedparserOptions, metaData).on('error', reject).on('response', resolve));
  });
};

module.exports = {
  parse
};