第七章 Web开发实战2——商品详情页

root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli  -p 7770
127.0.0.1:7770> set i 1
OK
127.0.0.1:7770> 
root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli  -p 7772
127.0.0.1:7772> get i
"1"

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测试商品介绍SSDB集群

root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli  -p 8880
127.0.0.1:8880> set i 1
OK
127.0.0.1:8880> 
root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli  -p 8882
127.0.0.1:8882> get i
"1"

basic_master:
  listen: 127.0.0.1:1111
  hash: fnv1a_64
  distribution: ketama
  redis: true
  timeout: 1000
  hash_tag: "::"
  servers:
   - 127.0.0.1:7770:1 server1
   - 127.0.0.1:7771:1 server2

basic_slave:
  listen: 127.0.0.1:1112
  hash: fnv1a_64
  distribution: ketama
  redis: true
  timeout: 1000
  hash_tag: "::"
  servers:
   - 127.0.0.1:7772:1 server1
   - 127.0.0.1:7773:1 server2


desc_master:
  listen: 127.0.0.1:1113
  hash: fnv1a_64
  distribution: ketama
  redis: true
  timeout: 1000
  hash_tag: "::"
  servers:
   - 127.0.0.1:8880:1 server1
   - 127.0.0.1:8881:1 server2

desc_slave:
  listen: 127.0.0.1:1114
  hash: fnv1a_64
  distribution: ketama
  redis: true
  timeout: 1000
  servers:
   - 127.0.0.1:8882:1 server1
   - 127.0.0.1:8883:1 server2

other_master:
  listen: 127.0.0.1:1115
  hash: fnv1a_64
  distribution: random
  redis: true
  timeout: 1000
  hash_tag: "::"
  servers:
   - 127.0.0.1:6660:1 server1


other_slave:
  listen: 127.0.0.1:1116
  hash: fnv1a_64
  distribution: random
  redis: true
  timeout: 1000
  hash_tag: "::"
  servers:
   - 127.0.0.1:6661:1 server1
   - 127.0.0.1:6662:1 server2

root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli -p 1111
127.0.0.1:1111> set i 1
OK
127.0.0.1:1111> 
root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli -p 1112
127.0.0.1:1112> get i
"1"
127.0.0.1:1112> 
root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli -p 1113
127.0.0.1:1113> set i 1
OK
127.0.0.1:1113> 
root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli -p 1114
127.0.0.1:1114> get i
"1"
127.0.0.1:1114> 
root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli -p 1115
127.0.0.1:1115> set i 1
OK
127.0.0.1:1115> 
root@kaitao:/usr/chapter7# /usr/servers/redis-2.8.19/src/redis-cli -p 1116
127.0.0.1:1116> get i
"1"

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动态服务实现

因为真实数据是从多个子系统获取，很难模拟这么多子系统交互，所以此处我们使用假数据来进行实现。

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项目搭建?

我们使用Maven搭建Web项目，Maven知识请自行学习。

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项目依赖

本文将最小化依赖，即仅依赖我们需要的servlet、jackson、guava、jedis。?

  <dependencies>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.0.1</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>com.google.guava</groupId>
      <artifactId>guava</artifactId>
      <version>17.0</version>
    </dependency>
    <dependency>
      <groupId>redis.clients</groupId>
      <artifactId>jedis</artifactId>
      <version>2.5.2</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.3.3</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.3.3</version>
    </dependency>
  </dependencies>

guava是类似于apache commons的一个基础类库，用于简化一些重复操作，可以参考http://ifeve.com/google-guava/。?

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核心代码

com.github.zhangkaitao.chapter7.servlet.ProductServiceServlet

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String type = req.getParameter("type");
        String content = null;
        try {
            if("basic".equals(type)) {
                content = getBasicInfo(req.getParameter("skuId"));
            } else if("desc".equals(type)) {
                content = getDescInfo(req.getParameter("skuId"));
            } else if("other".equals(type)) {
                content = getOtherInfo(req.getParameter("ps3Id"), req.getParameter("brandId"));
            }
        } catch (Exception e) {
            e.printStackTrace();
            resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return;
        }
        if(content != null) {
            resp.setCharacterEncoding("UTF-8");
            resp.getWriter().write(content);
        } else {
            resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
        }
    }

根据请求参数type来决定调用哪个服务获取数据。

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基本信息服务?

    private String getBasicInfo(String skuId) throws Exception {
        Map<String, Object> map = new HashMap<String, Object>();
        //商品编号
        map.put("skuId", skuId);
        //名称
        map.put("name", "苹果（Apple）iPhone 6 (A1586) 16GB 金色 移动联通电信4G手机");
        //一级二级三级分类
        map.put("ps1Id", 9987);
        map.put("ps2Id", 653);
        map.put("ps3Id", 655);
        //品牌ID
        map.put("brandId", 14026);
        //图片列表
        map.put("imgs", getImgs(skuId));
        //上架时间
        map.put("date", "2014-10-09 22:29:09");
        //商品毛重
        map.put("weight", "400");
        //颜色尺码
        map.put("colorSize", getColorSize(skuId));
        //扩展属性
        map.put("expands", getExpands(skuId));
        //规格参数
        map.put("propCodes", getPropCodes(skuId));
        map.put("date", System.currentTimeMillis());
        String content = objectMapper.writeValueAsString(map);
        //实际应用应该是发送MQ
        asyncSetToRedis(basicInfoJedisPool, "p:" + skuId + ":", content);
        return objectMapper.writeValueAsString(map);
    }

    private List<String> getImgs(String skuId) {
        return Lists.newArrayList(
                "jfs/t277/193/1005339798/768456/29136988/542d0798N19d42ce3.jpg",
                "jfs/t352/148/1022071312/209475/53b8cd7f/542d079bN3ea45c98.jpg",
                "jfs/t274/315/1008507116/108039/f70cb380/542d0799Na03319e6.jpg",
                "jfs/t337/181/1064215916/27801/b5026705/542d079aNf184ce18.jpg"
        );
    }

    private List<Map<String, Object>> getColorSize(String skuId) {
        return Lists.newArrayList(
            makeColorSize(1217499, "金色", "公开版（16GB ROM）"),
            makeColorSize(1217500, "深空灰", "公开版（16GB ROM）"),
            makeColorSize(1217501, "银色", "公开版（16GB ROM）"),
            makeColorSize(1217508, "金色", "公开版（64GB ROM）"),
            makeColorSize(1217509, "深空灰", "公开版（64GB ROM）"),
            makeColorSize(1217509, "银色", "公开版（64GB ROM）"),
            makeColorSize(1217493, "金色", "移动4G版 （16GB）"),
            makeColorSize(1217494, "深空灰", "移动4G版 （16GB）"),
            makeColorSize(1217495, "银色", "移动4G版 （16GB）"),
            makeColorSize(1217503, "金色", "移动4G版 （64GB）"),
            makeColorSize(1217503, "金色", "移动4G版 （64GB）"),
            makeColorSize(1217504, "深空灰", "移动4G版 （64GB）"),
            makeColorSize(1217505, "银色", "移动4G版 （64GB）")
        );
    }
    private Map<String, Object> makeColorSize(long skuId, String color, String size) {
        Map<String, Object> cs1 = Maps.newHashMap();
        cs1.put("SkuId", skuId);
        cs1.put("Color", color);
        cs1.put("Size", size);
        return cs1;
    }

    private List<List<?>> getExpands(String skuId) {
        return Lists.newArrayList(
                (List<?>)Lists.newArrayList("热点", Lists.newArrayList("超薄7mm以下", "支持NFC")),
                (List<?>)Lists.newArrayList("系统", "苹果（IOS）"),
                (List<?>)Lists.newArrayList("系统", "苹果（IOS）"),
                (List<?>)Lists.newArrayList("购买方式", "非合约机")
        );
    }

    private Map<String, List<List<String>>> getPropCodes(String skuId) {
        Map<String, List<List<String>>> map = Maps.newHashMap();
        map.put("主体", Lists.<List<String>>newArrayList(
                Lists.<String>newArrayList("品牌", "苹果（Apple）"),
                Lists.<String>newArrayList("型号", "iPhone 6 A1586"),
                Lists.<String>newArrayList("颜色", "金色"),
                Lists.<String>newArrayList("上市年份", "2014年")
        ));
        map.put("存储", Lists.<List<String>>newArrayList(
                Lists.<String>newArrayList("机身内存", "16GB ROM"),
                Lists.<String>newArrayList("储存卡类型", "不支持")
        ));
        map.put("显示", Lists.<List<String>>newArrayList(
                Lists.<String>newArrayList("屏幕尺寸", "4.7英寸"),
                Lists.<String>newArrayList("触摸屏", "Retina HD"),
                Lists.<String>newArrayList("分辨率", "1334 x 750")
        ));
        return map;
    }

本例基本信息提供了如商品名称、图片列表、颜色尺码、扩展属性、规格参数等等数据；而为了简化逻辑大多数数据都是List/Map数据结构。?

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商品介绍服务?

    private String getDescInfo(String skuId) throws Exception {
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("content", "<div><img data-lazyload=‘http://img30.360buyimg.com/jgsq-productsoa/jfs/t448/127/574781110/103911/b3c80634/5472ba22N45400f4e.jpg‘ alt=‘‘ /><img data-lazyload=‘http://img30.360buyimg.com/jgsq-productsoa/jfs/t802/133/19465528/162152/e463e43/54e2b34aN11bceb70.jpg‘ alt=‘‘ height=‘386‘ width=‘750‘ /></div>");
        map.put("date", System.currentTimeMillis());
        String content = objectMapper.writeValueAsString(map);
        //实际应用应该是发送MQ
        asyncSetToRedis(descInfoJedisPool, "d:" + skuId + ":", content);
        return objectMapper.writeValueAsString(map);
    }

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其他信息服务

    private String getOtherInfo(String ps3Id, String brandId) throws Exception {
        Map<String, Object> map = new HashMap<String, Object>();
        //面包屑
        List<List<?>> breadcrumb = Lists.newArrayList();
        breadcrumb.add(Lists.newArrayList(9987, "手机"));
        breadcrumb.add(Lists.newArrayList(653, "手机通讯"));
        breadcrumb.add(Lists.newArrayList(655, "手机"));
        //品牌
        Map<String, Object> brand = Maps.newHashMap();
        brand.put("name", "苹果（Apple）");
        brand.put("logo", "BrandLogo/g14/M09/09/10/rBEhVlK6vdkIAAAAAAAFLXzp-lIAAHWawP_QjwAAAVF472.png");
        map.put("breadcrumb", breadcrumb);
        map.put("brand", brand);
        //实际应用应该是发送MQ
        asyncSetToRedis(otherInfoJedisPool, "s:" + ps3Id + ":", objectMapper.writeValueAsString(breadcrumb));
        asyncSetToRedis(otherInfoJedisPool, "b:" + brandId + ":", objectMapper.writeValueAsString(brand));
        return objectMapper.writeValueAsString(map);
    }

本例中其他信息只使用了面包屑和品牌数据。

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辅助工具

    private ObjectMapper objectMapper = new ObjectMapper();
    private JedisPool basicInfoJedisPool = createJedisPool("127.0.0.1", 1111);
    private JedisPool descInfoJedisPool = createJedisPool("127.0.0.1", 1113);
    private JedisPool otherInfoJedisPool = createJedisPool("127.0.0.1", 1115);

    private JedisPool createJedisPool(String host, int port) {
        GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
        poolConfig.setMaxTotal(100);
        return new JedisPool(poolConfig, host, port);
    }

    private ExecutorService executorService = Executors.newFixedThreadPool(10);
    private void asyncSetToRedis(final JedisPool jedisPool, final String key, final String content) {
        executorService.submit(new Runnable() {
            @Override
            public void run() {
                Jedis jedis = null;
                try {
                    jedis = jedisPool.getResource();
                    jedis.set(key, content);
                } catch (Exception e) {
                    e.printStackTrace();
                    jedisPool.returnBrokenResource(jedis);
                } finally {
                    jedisPool.returnResource(jedis);
                }

            }
        });
    }

本例使用Jackson进行JSON的序列化；Jedis进行Redis的操作；使用线程池做异步更新（实际应用中可以使用MQ做实现）。?

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  <servlet>
      <servlet-name>productServiceServlet</servlet-name>
      <servlet-class>com.github.zhangkaitao.chapter7.servlet.ProductServiceServlet</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>productServiceServlet</servlet-name>
      <url-pattern>/info</url-pattern>
  </servlet-mapping>

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打WAR包?

cd D:\workspace\chapter7
mvn clean package

此处使用maven命令打包，比如本例将得到chapter7.war，然后将其上传到服务器的/usr/chapter7/webapp，然后通过unzip chapter6.war解压。

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配置Tomcat

复制第六章使用的tomcat实例：

cd /usr/servers/
cp -r tomcat-server1 tomcat-chapter7/
vim /usr/servers/tomcat-chapter7/conf/Catalina/localhost/ROOT.xml 

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<!-- 访问路径是根，web应用所属目录为/usr/chapter7/webapp -->
<Context path="" docBase="/usr/chapter7/webapp"></Context>

指向第七章的web应用路径。

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测试?

启动tomcat实例。

/usr/servers/tomcat-chapter7/bin/startup.sh 

访问如下URL进行测试。?

http://192.168.1.2:8080/info?type=basic&skuId=1
http://192.168.1.2:8080/info?type=desc&skuId=1
http://192.168.1.2:8080/info?type=other&ps3Id=1&brandId=1

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nginx配置

vim /usr/chapter7/nginx_chapter7.conf?

upstream backend {
    server 127.0.0.1:8080 max_fails=5 fail_timeout=10s weight=1;
    check interval=3000 rise=1 fall=2 timeout=5000 type=tcp default_down=false;
    keepalive 100;
}

server {
    listen       80;
    server_name  item2015.jd.com item.jd.com d.3.cn;

    location ~ /backend/(.*) {
        #internal;
        keepalive_timeout   30s;
        keepalive_requests  1000;
        #支持keep-alive
        proxy_http_version 1.1;
        proxy_set_header Connection "";

        rewrite /backend(/.*) $1 break;
        proxy_pass_request_headers off;
        #more_clear_input_headers Accept-Encoding;
        proxy_next_upstream error timeout;
        proxy_pass http://backend;
    }
}

此处server_name 我们指定了item.jd.com(商品详情页)和d.3.cn(商品介绍)。其他配置可以参考第六章内容。另外实际生产环境要把#internal打开，表示只有本nginx能访问。

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vim /usr/servers/nginx/conf/nginx.conf

include /usr/chapter7/nginx_chapter7.conf;
#为了方便测试，注释掉example.conf
include /usr/chapter6/nginx_chapter6.conf;

#lua模块路径，其中”;;”表示默认搜索路径，默认到/usr/servers/nginx下找
lua_package_path "/usr/chapter7/lualib/?.lua;;";  #lua 模块
lua_package_cpath "/usr/chapter7/lualib/?.so;;";  #c模块

lua模块从/usr/chapter7目录加载，因为我们要写自己的模块使用。

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重启nginx?

/usr/servers/nginx/sbin/nginx -s reload ? ? ?

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绑定hosts

192.168.1.2 item.jd.com

192.168.1.2 item2015.jd.com?

192.168.1.2 d.3.cn

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访问如http://item.jd.com/backend/info?type=basic&skuId=1即看到结果。

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前端展示实现?

我们分为三部分实现：基础组件、商品介绍、前端展示部分。

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基础组件

首先我们进行基础组件的实现，商品介绍和前端展示部分都需要读取Redis和Http服务，因此我们可以抽取公共部分出来复用。

vim /usr/chapter7/lualib/item/common.lua

local redis = require("resty.redis")
local ngx_log = ngx.log
local ngx_ERR = ngx.ERR
local function close_redis(red)
    if not red then
        return
    end
    --释放连接(连接池实现)
    local pool_max_idle_time = 10000 --毫秒
    local pool_size = 100 --连接池大小
    local ok, err = red:set_keepalive(pool_max_idle_time, pool_size)

    if not ok then
        ngx_log(ngx_ERR, "set redis keepalive error : ", err)
    end
end

local function read_redis(ip, port, keys)
    local red = redis:new()
    red:set_timeout(1000)
    local ok, err = red:connect(ip, port)
    if not ok then
        ngx_log(ngx_ERR, "connect to redis error : ", err)
        return close_redis(red)
    end
    local resp = nil
    if #keys == 1 then
        resp, err = red:get(keys[1])
    else
        resp, err = red:mget(keys)
    end
    if not resp then
        ngx_log(ngx_ERR, "get redis content error : ", err)
        return close_redis(red)
    end

    --得到的数据为空处理
    if resp == ngx.null then
        resp = nil
    end
    close_redis(red)

    return resp
end

local function read_http(args)
    local resp = ngx.location.capture("/backend/info", {
        method = ngx.HTTP_GET,
        args = args
    })

    if not resp then
        ngx_log(ngx_ERR, "request error")
        return
    end
    if resp.status ~= 200 then
        ngx_log(ngx_ERR, "request error, status :", resp.status)
        return
    end
    return resp.body
end

local _M = {
    read_redis = read_redis,
    read_http = read_http
}
return _M

整个逻辑和第六章类似；只是read_redis根据参数keys个数支持get和mget。 比如read_redis(ip, port, {"key1"})则调用get而read_redis(ip, port, {"key1", "key2"})则调用mget。

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商品介绍

核心代码

vim /usr/chapter7/desc.lua

local common = require("item.common")
local read_redis = common.read_redis
local read_http = common.read_http
local ngx_log = ngx.log
local ngx_ERR = ngx.ERR
local ngx_exit = ngx.exit
local ngx_print = ngx.print
local ngx_re_match = ngx.re.match
local ngx_var = ngx.var

local descKey = "d:" .. skuId .. ":"
local descInfoStr = read_redis("127.0.0.1", 1114, {descKey})
if not descInfoStr then
   ngx_log(ngx_ERR, "redis not found desc info, back to http, skuId : ", skuId)
   descInfoStr = read_http({type="desc", skuId = skuId})
end
if not descInfoStr then
   ngx_log(ngx_ERR, "http not found basic info, skuId : ", skuId)
   return ngx_exit(404)
end
ngx_print("showdesc(")
ngx_print(descInfoStr)
ngx_print(")")

通过复用逻辑后整体代码简化了许多；此处读取商品介绍从集群；另外前端展示使用JSONP技术展示商品介绍。?

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nginx配置?

vim /usr/chapter7/nginx_chapter7.conf?

    location ~^/desc/(\d+)$ {
        if ($host != "d.3.cn") {
           return 403;
        }
        default_type application/x-javascript;
        charset utf-8;
        lua_code_cache on;
        set $skuId $1;
        content_by_lua_file /usr/chapter7/desc.lua;
    }

因为item.jd.com和d.3.cn复用了同一个配置文件，此处需要限定只有d.3.cn域名能访问，防止恶意访问。?

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重启nginx后，访问如http://d.3.cn/desc/1即可得到JSONP结果。

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前端展示

核心代码

vim /usr/chapter7/item.lua?

local common = require("item.common")
local item = require("item")
local read_redis = common.read_redis
local read_http = common.read_http
local cjson = require("cjson")
local cjson_decode = cjson.decode
local ngx_log = ngx.log
local ngx_ERR = ngx.ERR
local ngx_exit = ngx.exit
local ngx_print = ngx.print
local ngx_var = ngx.var


local skuId = ngx_var.skuId

--获取基本信息
local basicInfoKey = "p:" .. skuId .. ":"
local basicInfoStr = read_redis("127.0.0.1", 1112, {basicInfoKey})
if not basicInfoStr then
   ngx_log(ngx_ERR, "redis not found basic info, back to http, skuId : ", skuId)
   basicInfoStr = read_http({type="basic", skuId = skuId})
end
if not basicInfoStr then
   ngx_log(ngx_ERR, "http not found basic info, skuId : ", skuId)
   return ngx_exit(404)
end

local basicInfo = cjson_decode(basicInfoStr)
local ps3Id = basicInfo["ps3Id"]
local brandId = basicInfo["brandId"]
--获取其他信息
local breadcrumbKey = "s:" .. ps3Id .. ":"
local brandKey = "b:" .. brandId ..":"
local otherInfo = read_redis("127.0.0.1", 1116, {breadcrumbKey, brandKey}) or {}
local breadcrumbStr = otherInfo[1]
local brandStr = otherInfo[2]
if breadcrumbStr then
   basicInfo["breadcrumb"] = cjson_decode(breadcrumbStr)
end
if brandStr then
   basicInfo["brand"] = cjson_decode(brandStr)
end
if not breadcrumbStr and not brandStr then
   ngx_log(ngx_ERR, "redis not found other info, back to http, skuId : ", brandId)
   local otherInfoStr = read_http({type="other", ps3Id = ps3Id, brandId = brandId})
   if not otherInfoStr then
       ngx_log(ngx_ERR, "http not found other info, skuId : ", skuId)
   else
     local otherInfo = cjson_decode(otherInfoStr)
     basicInfo["breadcrumb"] = otherInfo["breadcrumb"]
     basicInfo["brand"] = otherInfo["brand"]
   end
end

local name = basicInfo["name"]
--name to unicode
basicInfo["unicodeName"] = item.utf8_to_unicode(name)
--字符串截取，超长显示...
basicInfo["moreName"] = item.trunc(name, 10)
--初始化各分类的url
item.init_breadcrumb(basicInfo)
--初始化扩展属性
item.init_expand(basicInfo)
--初始化颜色尺码
item.init_color_size(basicInfo)
local template = require "resty.template"
template.caching(true)
template.render("item.html", basicInfo)

整个逻辑分为四部分：1、获取基本信息；2、根据基本信息中的关联关系获取其他信息；3、初始化/格式化数据；4、渲染模板。??

?

初始化模块?

vim /usr/chapter7/lualib/item.lua?

local bit = require("bit")
local utf8 = require("utf8")
local cjson = require("cjson")
local cjson_encode = cjson.encode
local bit_band = bit.band
local bit_bor = bit.bor
local bit_lshift = bit.lshift
local string_format = string.format
local string_byte = string.byte
local table_concat = table.concat

--utf8转为unicode
local function utf8_to_unicode(str)
    if not str or str == "" or str == ngx.null then
        return nil
    end
    local res, seq, val = {}, 0, nil
    for i = 1, #str do
        local c = string_byte(str, i)
        if seq == 0 then
            if val then
                res[#res + 1] = string_format("%04x", val)
            end

           seq = c < 0x80 and 1 or c < 0xE0 and 2 or c < 0xF0 and 3 or
                              c < 0xF8 and 4 or --c < 0xFC and 5 or c < 0xFE and 6 or
                              0
            if seq == 0 then
                ngx.log(ngx.ERR, ‘invalid UTF-8 character sequence‘ .. ",,," .. tostring(str))
                return str
            end

            val = bit_band(c, 2 ^ (8 - seq) - 1)
        else
            val = bit_bor(bit_lshift(val, 6), bit_band(c, 0x3F))
        end
        seq = seq - 1
    end
    if val then
        res[#res + 1] = string_format("%04x", val)
    end
    if #res == 0 then
        return str
    end
    return "\\u" .. table_concat(res, "\\u")
end

--utf8字符串截取
local function trunc(str, len)
   if not str then
     return nil
   end

   if utf8.len(str) > len then
      return utf8.sub(str, 1, len) .. "..."
   end
   return str
end

--初始化面包屑
local function init_breadcrumb(info)
    local breadcrumb = info["breadcrumb"]
    if not breadcrumb then
       return
    end

    local ps1Id = breadcrumb[1][1]
    local ps2Id = breadcrumb[2][1]
    local ps3Id = breadcrumb[3][1]

    --此处应该根据一级分类查找url
    local ps1Url = "http://shouji.jd.com/"
    local ps2Url = "http://channel.jd.com/shouji.html"
    local ps3Url = "http://list.jd.com/list.html?cat=" .. ps1Id .. "," .. ps2Id .. "," .. ps3Id

    breadcrumb[1][3] = ps1Url
    breadcrumb[2][3] = ps2Url
    breadcrumb[3][3] = ps3Url
end

--初始化扩展属性
local function init_expand(info)
   local expands = info["expands"]
   if not expands then
     return
   end
   for _, e in ipairs(expands) do
      if type(e[2]) == "table" then
         e[2] = table_concat(e[2], "，")
      end
   end
end

--初始化颜色尺码
local function init_color_size(info)
   local colorSize = info["colorSize"]

   --颜色尺码JSON串
   local colorSizeJson = cjson_encode(colorSize)
   --颜色列表（不重复）
   local colorList = {}
   --尺码列表（不重复）
   local sizeList = {}
   info["colorSizeJson"] = colorSizeJson
   info["colorList"] = colorList
   info["sizeList"] = sizeList

   local colorSet = {}
   local sizeSet = {}
   for _, cz in ipairs(colorSize) do
      local color = cz["Color"]
      local size = cz["Size"]
      if color and color ~= "" and not colorSet[color] then
         colorList[#colorList + 1] = {color = color, url = "http://item.jd.com/" ..cz["SkuId"] .. ".html"}
         colorSet[color] = true
      end
      if size and size ~= "" and not sizeSet[size] then
         sizeList[#sizeList + 1] = {size = size, url = "http://item.jd.com/" ..cz["SkuId"] .. ".html"}
         sizeSet[size] = ""
      end
   end
end

local _M = {
   utf8_to_unicode = utf8_to_unicode,
   trunc = trunc,
   init_breadcrumb = init_breadcrumb,
   init_expand = init_expand,
   init_color_size = init_color_size
}

return _M

比如utf8_to_unicode代码之前已经见过了，其他的都是一些逻辑代码。

?

模板html片段??

       var pageConfig = {
            compatible: true,
            product: {
                skuid: {* skuId *},
                name: ‘{* unicodeName *}‘,
                skuidkey:‘AFC266E971535B664FC926D34E91C879‘,
                href: ‘http://item.jd.com/{* skuId *}.html‘,
                src: ‘{* imgs[1] *}‘,
                cat: [{* ps1Id *},{* ps2Id *},{* ps3Id *}],
                brand: {* brandId *},
                tips: false,
                pType: 1,
                venderId:0,
                shopId:‘0‘,
                specialAttrs:["HYKHSP-0","isDistribution","isHaveYB","isSelfService-0","isWeChatStock-0","packType","IsNewGoods","isCanUseDQ","isSupportCard","isCanUseJQ","isOverseaPurchase-0","is7ToReturn-1","isCanVAT"],
                videoPath:‘‘,
                desc: ‘http://d.3.cn/desc/{* skuId *}‘
            }
        };
        var warestatus = 1;                
        {% if colorSizeJson then %} var ColorSize = {* colorSizeJson *};{% end %}
                {-raw-}
                try{(function(flag){ if(!flag){return;} if(window.location.hash == ‘#m‘){var exp = new Date();exp.setTime(exp.getTime() + 30 * 24 * 60 * 60 * 1000);document.cookie = "pcm=1;expires=" + exp.toGMTString() + ";path=/;domain=jd.com";return;}else{var cook=document.cookie.match(new RegExp("(^| )pcm=([^;]*)(;|$)"));if(cook&&cook.length>2&&unescape(cook[2])=="2"){flag=false;}} var userAgent = navigator.userAgent; if(userAgent){ userAgent = userAgent.toUpperCase();if(userAgent.indexOf("PAD")>-1){return;} var mobilePhoneList = ["IOS","IPHONE","ANDROID","WINDOWS PHONE"];for(var i=0,len=mobilePhoneList.length;i<len;i++){ if(userAgent.indexOf(mobilePhoneList[i])>-1){var url="http://m.jd.com/product/"+pageConfig.product.skuid+".html";if(flag){window.showtouchurl=true;}else{window.location.href = url;}break;}}}})((function(){var json={"6881":3,"1195":3,"10011":3,"6980":3,"12360":3};if(json[pageConfig.product.cat[0]+""]==1||json[pageConfig.product.cat[1]+""]==2||json[pageConfig.product.cat[2]+""]==3){return false;}else{return true;}})());}catch(e){}
                {-raw-}

{* var *}输出变量，{% code %} 写代码片段，{-raw-} 不进行任何处理直接输出。

?

面包屑

<div class="breadcrumb">
    <strong><a href=‘{* breadcrumb[1][3] *}‘>{* breadcrumb[1][2] *}</a></strong>
    <span>
        &nbsp;&gt;&nbsp;
        <a href=‘{* breadcrumb[2][3] *}‘>{* breadcrumb[2][2] *}</a>
        &nbsp;&gt;&nbsp;
        <a href=‘{* breadcrumb[3][3] *}‘>{* breadcrumb[3][2] *}</a>
        &nbsp;&gt;&nbsp;
    </span>
    <span>
        {% if brand then %}
        <a href=‘http://www.jd.com/pinpai/{* ps3Id *}-{* brandId *}.html‘>{* brand[‘name‘] *}</a>
        &nbsp;&gt;&nbsp;
       {% end %}
       <a href=‘http://item.jd.com/{* skuId *}.html‘>{* moreName *}</a>
    </span>
</div>

?

图片列表

<div id="spec-n1" class="jqzoom" onclick="window.open(‘http://www.jd.com/bigimage.aspx?id={* skuId *}‘)" clstag="shangpin|keycount|product|spec-n1">
    <img data-img="1" width="350" height="350" src="http://img14.360buyimg.com/n1/{* imgs[1] *}" alt="{* name *}"/>
</div>
<div id="spec-list" clstag="shangpin|keycount|product|spec-n5">
    <a href="javascript:;" class="spec-control" id="spec-forward"></a>
    <a href="javascript:;" class="spec-control" id="spec-backward"></a>
    <div class="spec-items">
        <ul class="lh">
            {% for _, img in ipairs(imgs) do %}
            <li><img class=‘img-hover‘ alt=‘{* name *}‘ src=‘http://img14.360buyimg.com/n5/{* img *}‘ data-url=‘{* img *}‘ data-img=‘1‘ width=‘50‘ height=‘50‘></li>
            {% end %}
        </ul>
    </div>
</div>

??

颜色尺码选择

<div class="dt">选择颜色：</div>
    <div class="dd">
        {% for _, color in ipairs(colorList) do %}
            <div class="item"><b></b><a href="{* color[‘url‘] *}" title="{* color[‘color‘] *}"><i>{* color[‘color‘] *}</i></a></div>
        {% end %}
    </div>
</div>
<div id="choose-version" class="li">
    <div class="dt">选择版本：</div>
    <div class="dd">
        {% for _, size in ipairs(sizeList) do %}
            <div class="item"><b></b><a href="{* size[‘url‘] *}" title="{* size[‘size‘] *}">{* size[‘size‘] *}</a></div>
        {% end %}
    </div>
</div>

?

扩展属性

<ul id="parameter2" class="p-parameter-list">
    <li title=‘{* name *}‘>商品名称：{* name *}</li>
    <li title=‘{* skuId *}‘>商品编号：{* skuId *}</li>
    {% if brand then %}
    <li title=‘{* brand["name"] *}‘>品牌： <a href=‘http://www.jd.com/pinpai/{* ps3Id *}-{* brandId *}.html‘ target=‘_blank‘>{* brand["name"] *}</a></li>
    {% end %}
    {% if date then %}
    <li title=‘{* date *}‘>上架时间：{* date *}</li>
    {% end %}
    {% if weight then %}
    <li title=‘{* weight *}‘>商品毛重：{* weight *}</li>
    {% end %}
    {% for _, e in pairs(expands) do %}
    <li title=‘{* e[2] *}‘>{* e[1] *}：{* e[2] *}</li>
    {% end %}
</ul>

?

规格参数

<table cellpadding="0" cellspacing="1" width="100%" border="0" class="Ptable">
    {% for group, pc in pairs(propCodes) do  %}
    <tr><th class="tdTitle" colspan="2">{* group *}</th><tr>
    {% for _, v in pairs(pc) do %}
    <tr><td class="tdTitle">{* v[1] *}</td><td>{* v[2] *}</td></tr>
    {% end %}
    {% end %}
</table>

??

nginx配置?

vim /usr/chapter7/nginx_chapter7.conf??

    #模板加载位置
    set $template_root "/usr/chapter7";


    location ~ ^/(\d+).html$ {
        if ($host !~ "^(item|item2015)\.jd\.com$") {
           return 403;
        }
        default_type ‘text/html‘;
        charset utf-8;
        lua_code_cache on;
        set $skuId $1;
        content_by_lua_file /usr/chapter7/item.lua;
    }

??

测试

重启nginx，访问http://item.jd.com/1217499.html可得到响应内容，本例和京东的商品详情页的数据是有些出入的，输出的页面可能是缺少一些数据的。

?

优化

local cache

对于其他信息，对数据一致性要求不敏感，而且数据量很少，完全可以在本地缓存全量；而且可以设置如5-10分钟的过期时间是完全可以接受的；因此可以lua_shared_dict全局内存进行缓存。具体逻辑可以参考

local nginx_shared = ngx.shared
--item.jd.com配置的缓存
local local_cache = nginx_shared.item_local_cache
local function cache_get(key)
    if not local_cache then
        return nil
    end
    return local_cache:get(key)
end

local function cache_set(key, value)
    if not local_cache then
        return nil
    end
    return local_cache:set(key, value, 10 * 60) --10分钟
end

local function get(ip, port, keys)
    local tables = {}
    local fetchKeys = {}
    local resp = nil
    local status = STATUS_OK
    --如果tables是个map #tables拿不到长度
    local has_value = false
    --先读取本地缓存
    for i, key in ipairs(keys) do
        local value = cache_get(key)
        if value then
            if value == "" then
                value = nil
            end
            tables[key] = value
            has_value = true
        else
            fetchKeys[#fetchKeys + 1] = key
        end
    end

    --如果还有数据没获取 从redis获取
    if #fetchKeys > 0 then
        if #fetchKeys == 1 then
            status, resp = redis_get(ip, port, fetchKeys[1])
        else
            status, resp = redis_mget(ip, port, fetchKeys)
        end
        if status == STATUS_OK then
            for i = 1, #fetchKeys do
                 local key = fetchKeys[i]
                 local value = nil
                 if #fetchKeys == 1 then
                    value = resp
                 else
                    value = get_data(resp, i)
                 end
                 tables[key] = value
                  has_value = true
                  cache_set(key, value or "", ttl)
            end
        end
    end
    --如果从缓存查到 就认为ok
    if has_value and status == STATUS_NOT_FOUND then
        status = STATUS_OK
    end
    return status, tables
end

?

nginx proxy cache

为了防止恶意刷页面/热点页面访问频繁，我们可以使用nginx proxy_cache做页面缓存，当然更好的选择是使用CDN技术，如通过Apache Traffic Server、Squid、Varnish。

1、nginx.conf配置

    proxy_buffering on;
    proxy_buffer_size 8k;
    proxy_buffers 256 8k;
    proxy_busy_buffers_size 64k;
    proxy_temp_file_write_size 64k;
    proxy_temp_path /usr/servers/nginx/proxy_temp;
    #设置Web缓存区名称为cache_one，内存缓存空间大小为200MB，1分钟没有被访问的内容自动清除，硬盘缓存空间大小为30GB。
    proxy_cache_path  /usr/servers/nginx/proxy_cache levels=1:2 keys_zone=cache_item:200m inactive=1m max_size=30g;

增加proxy_cache的配置，可以通过挂载一块内存作为缓存的存储空间。更多配置规则请参考http://nginx.org/cn/docs/http/ngx_http_proxy_module.html。?

?

?

2、nginx_chapter7.conf配置

与server指令配置同级

############ 测试时使用的动态请求
map $host $item_dynamic {
    default                    "0";
    item2015.jd.com            "1";
}

即如果域名为item2015.jd.com则item_dynamic=1。

    location ~ ^/(\d+).html$ {
        set $skuId $1;
        if ($host !~ "^(item|item2015)\.jd\.com$") {
           return 403;
        }

        expires 3m;
        proxy_cache cache_item;
        proxy_cache_key $uri;
        proxy_cache_bypass $item_dynamic;
        proxy_no_cache $item_dynamic;
        proxy_cache_valid 200 301 3m;
        proxy_cache_use_stale updating error timeout invalid_header http_500 http_502 http_503 http_504;
        proxy_pass_request_headers off;
        proxy_set_header Host $host;
        #支持keep-alive
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        proxy_pass http://127.0.0.1/proxy/$skuId.html;
        add_header X-Cache ‘$upstream_cache_status‘;
    }

    location ~ ^/proxy/(\d+).html$ {
        allow 127.0.0.1;
        deny all;
        keepalive_timeout   30s;
        keepalive_requests  1000;
        default_type ‘text/html‘;
        charset utf-8;
        lua_code_cache on;
        set $skuId $1;
        content_by_lua_file /usr/chapter7/item.lua;
    }

proxy_cache_key：缓存key为uri，不包括host和参数，这样不管用户怎么通过在url上加随机数都是走缓存的；

proxy_cache_bypass：nginx不从缓存取响应的条件，可以写多个；如果存在一个字符串条件且不是“0”，那么nginx就不会从缓存中取响应内容；此处如果我们使用的host为item2015.jd.com时就不会从缓存取响应内容；

proxy_no_cache：nginx不将响应内容写入缓存的条件，可以写多个；如果存在一个字符串条件且不是“0”，那么nginx就不会从将响应内容写入缓存；此处如果我们使用的host为item2015.jd.com时就不会将响应内容写入缓存；

proxy_cache_valid：为不同的响应状态码设置不同的缓存时间，此处我们对200、301缓存3分钟；

proxy_cache_use_stale：什么情况下使用不新鲜（过期）的缓存内容；配置和proxy_next_upstream内容类似；此处配置了如果连接出错、超时、404、500等都会使用不新鲜的缓存内容；此外我们配置了updating配置，通过配置它可以在nginx正在更新缓存（其中一个Worker进程）时（其他的Worker进程）使用不新鲜的缓存进行响应，这样可以减少回源的数量；

proxy_pass_request_headers：我们不需要请求头，所以不传递；

proxy_http_version 1.1和proxy_set_header Connection ""：支持keepalive；

add_header X-Cache ‘$upstream_cache_status‘：添加是否缓存命中的响应头；比如命中HIT、不命中MISS、不走缓存BYPASS；比如命中会看到X-Cache：HIT响应头；

allow/deny：允许和拒绝访问的ip列表，此处我们只允许本机访问；

keepalive_timeout 30s和keepalive_requests 1000：支持keepalive；

?

nginx_chapter7.conf清理缓存配置

    location /purge {
        allow     127.0.0.1;
        allow     192.168.0.0/16;
        deny      all;
        proxy_cache_purge  cache_item $arg_url;
    }

只允许内网访问。访问如http://item.jd.com/purge?url=/11.html；如果看到Successful purge说明缓存存在并清理了。

?

3、修改item.lua代码?

--添加Last-Modified，用于响应304缓存
ngx.header["Last-Modified"] = ngx.http_time(ngx.now())

local template = require "resty.template"
template.caching(true)
template.render("item.html", basicInfo)
~                                         

在渲染模板前设置Last-Modified，用于判断内容是否变更的条件，默认Nginx通过等于去比较，也可以通过配置if_modified_since指令来支持小于等于比较；如果请求头发送的If-Modified-Since和Last-Modified匹配则返回304响应，即内容没有变更，使用本地缓存。此处可能看到了我们的Last-Modified是当前时间，不是商品信息变更的时间；商品信息变更时间由：商品信息变更时间、面包屑变更时间和品牌变更时间三者决定的，因此实际应用时应该取三者最大的；还一个问题就是模板内容可能变了，但是商品信息没有变，此时使用Last-Modified得到的内容可能是错误的，所以可以通过使用ETag技术来解决这个问题，ETag可以认为是内容的一个摘要，内容变更后摘要就变了。

?

GZIP压缩

修改nginx.conf配置文件

   gzip on;
   gzip_min_length  4k;
   gzip_buffers     4 16k;
   gzip_http_version 1.0;
   gzip_proxied        any;  #前端是squid的情况下要加此参数，否则squid上不缓存gzip文件
   gzip_comp_level 2;
   gzip_types       text/plain application/x-javascript text/css application/xml;
   gzip_vary on;

此处我们指定至少4k时才压缩，如果数据太小压缩没有意义。??

?

?

到此整个商品详情页逻辑就介绍完了，一些细节和运维内容需要在实际开发中实际处理，无法做到面面俱到。

?