week07 codelab02 C72

我们要改一下backendserver的service

因为要写几个api还要做很多操作

我们单独写出来然后由service来调用

import json
import os
import pickle
import random
import redis
import sys

from bson.json_util import dumps
from datetime import datetime

# import common package in parent directory
sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))

import mongodb_client


REDIS_HOST = "localhost"
REDIS_PORT = 6379

# NEWS_TABLE_NAME = "news"
NEWS_TABLE_NAME = "news-test"
CLICK_LOGS_TABLE_NAME = 'click_logs'

NEWS_LIMIT = 100
NEWS_LIST_BATCH_SIZE = 10
USER_NEWS_TIME_OUT_IN_SECONDS = 600

redis_client = redis.StrictRedis(REDIS_HOST, REDIS_PORT, db=0)


def getNewsSummariesForUser(user_id, page_num):
    page_num = int(page_num)
    begin_index = (page_num - 1) * NEWS_LIST_BATCH_SIZE
    end_index = page_num * NEWS_LIST_BATCH_SIZE

    # The final list of news to be returned.
    sliced_news = []

    if redis_client.get(user_id) is not None:
        news_digests = pickle.loads(redis_client.get(user_id))

        # If begin_index is out of range, this will return empty list;
        # If end_index is out of range (begin_index is within the range), this
        # will return all remaining news ids.
        sliced_news_digests = news_digests[begin_index:end_index]
        print sliced_news_digests
        db = mongodb_client.get_db()
        sliced_news = list(db[NEWS_TABLE_NAME].find({'digest':{'$in':sliced_news_digests}}))
    else:
        db = mongodb_client.get_db()
        total_news = list(db[NEWS_TABLE_NAME].find().sort([('publishedAt', -1)]).limit(NEWS_LIMIT))
        total_news_digests = map(lambda x:x['digest'], total_news)

        redis_client.set(user_id, pickle.dumps(total_news_digests))
        redis_client.expire(user_id, USER_NEWS_TIME_OUT_IN_SECONDS)

        sliced_news = total_news[begin_index:end_index]


    for news in sliced_news:
        # Remove text field to save bandwidth.
        del news['text']
        if news['publishedAt'].date() == datetime.today().date():
            news['time'] = 'today'
    return json.loads(dumps(sliced_news))

operations.py

具体实现

可以自己设置这个过期时间

我们都是下拉获得新闻你也可以设计一个向上拉强制刷新的功能比如向上拉触发一个函数cleanRedis来强制清空redis（类似新浪知乎）这样即使100条获取完了没得获取了

也能强制刷新列表（之后写吧）

import json
import os
import pickle
import random
import redis
import sys

from bson.json_util import dumps
from datetime import datetime

# import common package in parent directory
sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))

import mongodb_client


REDIS_HOST = "localhost"
REDIS_PORT = 6379

# NEWS_TABLE_NAME = "news"
NEWS_TABLE_NAME = "news-test"
CLICK_LOGS_TABLE_NAME = 'click_logs'

NEWS_LIMIT = 100
NEWS_LIST_BATCH_SIZE = 10
USER_NEWS_TIME_OUT_IN_SECONDS = 600

redis_client = redis.StrictRedis(REDIS_HOST, REDIS_PORT, db=0)


def getNewsSummariesForUser(user_id, page_num):
    page_num = int(page_num)
    begin_index = (page_num - 1) * NEWS_LIST_BATCH_SIZE
    end_index = page_num * NEWS_LIST_BATCH_SIZE

    # The final list of news to be returned.
    sliced_news = []

    if redis_client.get(user_id) is not None:
        news_digests = pickle.loads(redis_client.get(user_id))

        # If begin_index is out of range, this will return empty list;
        # If end_index is out of range (begin_index is within the range), this
        # will return all remaining news ids.
        sliced_news_digests = news_digests[begin_index:end_index]
        print sliced_news_digests
        db = mongodb_client.get_db()
        sliced_news = list(db[NEWS_TABLE_NAME].find({'digest':{'$in':sliced_news_digests}}))
    else:
        db = mongodb_client.get_db()
        total_news = list(db[NEWS_TABLE_NAME].find().sort([('publishedAt', -1)]).limit(NEWS_LIMIT))
        total_news_digests = map(lambda x:x['digest'], total_news)

        redis_client.set(user_id, pickle.dumps(total_news_digests))
        redis_client.expire(user_id, USER_NEWS_TIME_OUT_IN_SECONDS)

        sliced_news = total_news[begin_index:end_index]


    for news in sliced_news:
        # Remove text field to save bandwidth.
        del news['text']
        if news['publishedAt'].date() == datetime.today().date():
            news['time'] = 'today'
    return json.loads(dumps(sliced_news))

operations.py

上面代码提到的比如 lamda表达式配合map摘取新闻中的digest字段

还有pickle对字符串序列化和反序列化

配合使用

我们写个test

import operations
import os
import sys

from sets import Set

# import common package in parent directory
sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))

# Start Redis and MongoDB before running following tests.

def test_getNewsSummariesForUser_basic():
    news = operations.getNewsSummariesForUser('test', 1)
    print news
    assert len(news) > 0
    print 'test_getNewsSummariesForUser_basic passed!'

def test_getNewsSummariesForUser_pagination():
    news_page_1 = operations.getNewsSummariesForUser('test', 1)
    news_page_2 = operations.getNewsSummariesForUser('test', 2)

    assert len(news_page_1) > 0
    assert len(news_page_2) > 0

    # Assert that there is no dupe news in two pages.
    digests_page_1_set = Set([news['digest'] for news in news_page_1])
    digests_page_2_set = Set([news['digest'] for news in news_page_2])
    assert len(digests_page_1_set.intersection(digests_page_2_set)) == 0

    print 'test_getNewsSummariesForUser_pagination passed!'

if __name__ == "__main__":
    test_getNewsSummariesForUser_basic()
    test_getNewsSummariesForUser_pagination()

operations_test.py

下面我们来运行一下

后端api完成让那个了

没回到前端webserver的client的Base

将原来的超链接换成router的link to

同理 loginForm也要修改

signup也是.

然后还要在NewsPannel做一些工作之前比较简单只是state保存一些信息通过loadmorenews获得更多news

现在我们state除了这些还要记录分页总页数加载完没有

然后loadmorenews

然后做个判断

然后还记得我们的获取新闻的api对象的webserver的server端的news.js是临时数据

news.js吗我们去修改一下让他从真正的后端backendserver从数据库拿数据

var express = require('express');
var router = express.Router();

var rpc_client = require('../rpc_client/rpc_client');

/* GET news summary list. */
router.get('/userId/:userId/pageNum/:pageNum', function(req, res, next) {
  console.log('Fetching news...');
  user_id = req.params['userId'];
  page_num = req.params['pageNum'];

  rpc_client.getNewsSummariesForUser(user_id, page_num, function(response) {
    res.json(response);
  });
});

/* Log news click. */
router.post('/userId/:userId/newsId/:newsId', function(req,res, next) {
  console.log('Logging news click...');
  user_id = req.params['userId'];
  news_id = req.params['newsId'];

  rpc_client.logNewsClickForUser(user_id, news_id);
  res.status(200);
});

module.exports = router;