week07 codelab02 C72

ss

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))

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))

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()

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;

所以我们回去带上这两个参数

ok

再回到webserver  server去

然后我们的真正的后端backend server

具体实现

等这些操作完成后又回到web server的server去了

我们洗个test验证一下

我们先将后端骑起来

 

他说找不到这个方法

我们去看看

 在运行

 返回空 因为没有这个userid

下面前端和后端调通（从网页上看到效果）

首先在web server的client先build一下（将前端页面文件传到build文件中）

然后去server 起一个端口 npm start 就可以只开一个端口来调试了