实现根据IP获取当地天气预报
访问[url]www.163.com[/url],首页的栏目里有当地的天气预报。可以猜想,这里的天气预报,应该是根据来访者的ip判断其所在地给出当地的天气情况。问了一些朋友,也证实了这一点。项目里也需要天气预报这个小栏目,同事做过一个(从其他站点抓取的),不过实现不了根据IP显示当地的天气情况,需要用户自行选择,而且抓取的站点属于小站….其可靠性值得怀疑。。所以就萌生了抓取网易的天气预报的想法。。。对页面进行分析。。发现显示天气预报的区域是一个IFrame,IFrame里嵌入了如下链接http: //news.163.com/util/position1.html,对这个地址访问直接跳转到另外一个链接[url=http://news.163.com/weather/news/qx1/56294.html]http://news.163.com/weather/news/qx1/56294.html[/url],此链接显示了天气情况,如图:wd(g9@ P[align=center][attach]208[/attach][/align] 由此可以推测[url]http://news.163.com/util/position1.html[/url],是在根据来访者的IP判断所属区域,然后返回一个该地区所对应的区位码,如: 56294代表成都。如何让网易来帮我们的站点来访者判断所属区域,并给出天气情况,并显示在自己的站点页面上呢?还得继续分析。。因为http: //news.163.com/util/position1.html,此链接一访问就转向到天气情况的链接,而无法查看源码。便猜想。。此页面肯定有些东西。。无奈之下。。WebRequest一下,出现了如下代码:8l~1UgF
[code] *mTD/Z'y,~"d
以下是引用片段: pAc%bc*l
1<script language="Javascript"> $ClD4nW_-Yb
2var city = new Array("安徽","黑龙江","山东","北京","湖北","山西","福建","湖南","陕西","甘肃","吉林","上海","广东","江苏","四川","广西","江西","天津","贵州","辽宁","西藏","海南","内蒙古","新疆","河北","宁夏","云南","河南","青海","浙江","重庆"); X&]@ VA tJ#DJ-|.l
3var weaths = new Array('58321','50953','54823','54511','57494','53772','59134','57679','57036','52889','54172','58367','59287','58238','56294','59431','58606','54527','57816','54342','55591','52856','53463','51463','53698','53614','56778','57083','52866','58457','57516'); h @&N2k r`(U
4 4?t6oSt[%E
5function getCookieVal (offset) { *h:Q)~E,a~B
6 var endstr = document.cookie.indexOf (";", offset);
7 if (endstr == -1)
8 endstr = document.cookie.length; h r7Q!O+h
9 return unescape(document.cookie.substring(offset, endstr));
10} p;E H? t]!u$m-S
11function GetCookie (name) { /Vh8w}p3RbE q
12 var arg = name + "="; @0j RmR1`1a8_p&B
13 var alen = arg.length;
14 var clen = document.cookie.length;
15 var i = 0;
16 while (i < clen) { 7n*~F;d'x|+Yi
17 var j = i + alen; 5l,D`I`W
18 if (document.cookie.substring(i, j) == arg) '[}&}0X F htP7W
19 return getCookieVal (j); |i l*U:q[ n
20 i = document.cookie.indexOf(" ", i) + 1; {1ok wh+}&`,r:M`,B*e
21 if (i == 0)
22 break; @#h2L#J"pg,V-t`1D
23 }
24 return ""; 9x(y(T qL5Y]E,B
25} 9V6?7Z]f
26function SetCookie(cookieName,cookieValue,nDays) { X.w#^%I3f;`e
27 var today = new Date(); tduJ,X9Q0I
28 var expire = new Date(); MQ"Ki!} d5U:p
29 if (nDays==null || nDays==0) nDays=1;
30 expire.setTime(today.getTime() + 3600000*24*nDays); K-X3[W D
31 document.cookie = cookieName+"="+escape(cookieValue) + ";path=/;domain=.163.com;expires="+expire.toGMTString();
32}
33function getCityWeatherID(cityname){
34 for(i=0;i<city.length;i++){ u1y GV:DQ_$HK.~
35 if(city[i]==cityname){
36 return weaths[i]; 8|(Mb,@Svz
37 }
38 }
39 return "54511"; v.l`h'?Z#U!d
40}
41 W@ J8l M9JK7|Ok
42var NTES_WeatherAddr = GetCookie("NTES_WeatherAddr");
43if (!NTES_WeatherAddr){
44 var loc = GetCookie("theaddr"); 'qoTc,H
45 if(!loc){ ;wn&YR&E+?Is
46 document.write("<script type='text/javascript' src='http://202.108.39.152/ipquery'><" + "/script>");
47 }
48}
49</script>
50<script> M%K'Z:z"{ C
51if (!NTES_WeatherAddr){
52 NTES_WeatherAddr=getCityWeatherID(loc); a8gFY7hLs2hV
53} H1P0b| G.iww
54window.location.href="http://news.163.com/weather/news/qx1/"+NTES_WeatherAddr+".html";
55</script> d-U%?W|.Q
56
57,B(|g.n5|{%I0F } S
[/code]g:]ohw~mf.xe
上面的这段js实现了对来访者IP判断并给出了天气预报结果的链接。Js里的此链接: [url]http://202.108.39.152/ipquery[/url],起到的是判断用户所在地的作用,返回的是来访者所在地省份。分析到此,想要的结果差不多就出来了…
在客户端调用这段js获得天气预报结果的链接地址,然后交给服务端来处理。(为什么要交给后台处理,而不是直接显示呢?)因为直接得出的链接页面上,有多余的链接,还应用了样式(如图一),不便为自己所用,所以得处理掉。客户端调用服务端的方法很多,最初使用了Ajax框架Anthem,实现了过后,觉得有点杀鸡用牛刀的感觉。。无聊之余。。就又用CallBack实现了一次。。感觉恰到好处。。后来又发现。。__doPostBack也可以实现客户端调用服务端方法。。看来实现这么一个功能还真是简单。。。
好了到此就实现了,自己想要的结果:(感觉有点遗憾的是只给出了省会城市的天气预报)6YX M!`8bpy4TL^9{
[align=center][attach]209[/attach][/align][align=left] 前台页面代码Defaul.aspx: [/align][align=left][code] TN%|:XEF:Cz*K(F
以下是引用片段:QUb%T+`
1<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" ResponseEncoding="GB2312" %> 8g2rJFf SB8a
2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
3<html xmlns="http://www.w3.org/1999/xhtml">
4<head runat="server"> 7QfB#u"Z uC6J
5<title></title> 7iT_9h6M-M%`o
6<script> 'o FC:a ND smV+Q"x
7var city = new Array("安徽","黑龙江","山东","北京","湖北","山西","福建","湖南","陕西","甘肃","吉林","上海","广东","江苏","四川","广西","江西","天津","贵州","辽宁","西藏","海南","内蒙古","新疆","河北","宁夏","云南","河南","青海","浙江","重庆"); ;x)n-P5`^a
8var weaths = new Array('58321','50953','54823','54511','57494','53772','59134','57679','57036','52889','54172','58367','59287','58238','56294','59431','58606','54527','57816','54342','55591','52856','53463','51463','53698','53614','56778','57083','52866','58457','57516');
9
10var NTES_WeatherAddr = GetCookie("NTES_WeatherAddr");
11if (!NTES_WeatherAddr){
12 var loc = GetCookie("theaddr"); q4p-V%UE%w:}
13 if(!loc){ '`)K^Z)Y }
14 document.write("<script type='text/javascript' src='http://202.108.39.152/ipquery'><" + "/script>"); !L#Lv`3n}dDh
15 }
16}
17
18function getCookieVal (offset) {
19 var endstr = document.cookie.indexOf (";", offset);
20 if (endstr == -1)
21 endstr = document.cookie.length; 0URN!V!] @
22 return unescape(document.cookie.substring(offset, endstr));
23} :h jP2PR\jNI
24
25function GetCookie (name) {
26 var arg = name + "=";
27 var alen = arg.length;
28 var clen = document.cookie.length; _5G7A y-G+N0^Y-M;z$LM
29 var i = 0;
30 while (i < clen) {
31 var j = i + alen; $ZM7n?}9A}w
32 if (document.cookie.substring(i, j) == arg)
33 return getCookieVal (j); $K%kT7^3VmyT+L
34 i = document.cookie.indexOf(" ", i) + 1; 4@OogJOU(\1s
35 if (i == 0)