根据ip判断返回城市名称查询当地天气

<?php
header("content-type:text/html;charset=utf-8");
date_default_timezone_set("Asia/Shanghai");
error_reporting(0);
// 根据IP判断城市
$user_ip = $_SERVER['REMOTE_ADDR'];
$url ="http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=json&ip=$user_ip";
$address = file_get_contents($url);
$address_arr = json_decode($address);　　//返回对象，需要转换为数组

//以上海为例

stdClass Object
	(
	[ret] => 1
	[start] => -1
	[end] => -1
	[country] => 中国
	[province] => 上海
	[city] => 上海
	[district] =>
	[isp] =>
	[type] =>
	[desc] =>
	)

function object_array($array){
　　if(is_object($array)){
　　　　$array = (array)$array;
　　}
　　if(is_array($array)){
　　　　foreach($array as $key=>$value){
　　　　　　$array[$key] = object_array($value);
　　　　}
　　}
　　return $array;
}

//通过该函数转化为数组
$address_arr = object_array($address_arr);

// print_r($address_arr);

Array
	(
	[ret] => 1
	[start] => -1
	[end] => -1
	[country] => 中国
	[province] => 上海
	[city] => 上海
	[district] =>
	[isp] =>
	[type] =>
	[desc] =>
	)

$city = $address_arr["city"];  

//输出为上海，获得城市通过百度天气API查询当地天气

$con=file_get_contents("http://api.map.baidu.com/telematics/v3/weather?location=$city&output=json&ak=spmMww7Eoqcmf3FXbnLyDUwL");　　//注意ak值需要进入百度接口注册，附上地址：http://lbsyun.baidu.com/apiconsole/key
$con = json_decode($con);

print_r($con);

stdClass Object
	(
	[error] => 0
	[status] => success
	[date] => 2016-09-23
	[results] => Array
	(
	[0] => stdClass Object
	(
	[currentCity] => 上海
	[pm25] => 42
	[index] => Array
	(
	[0] => stdClass Object
	(
	[title] => 穿衣
	[zs] => 热
	[tipt] => 穿衣指数
	[des] => 天气热，建议着短裙、短裤、短薄外套、T恤等夏季服装。
	)
	[1] => stdClass Object
	(
	[title] => 洗车
	[zs] => 较适宜
	[tipt] => 洗车指数
	[des] => 较适宜洗车，未来一天无雨，风力较小，擦洗一新的汽车至少能保持一天。
	)
	[2] => stdClass Object
	(
	[title] => 旅游
	[zs] => 适宜
	[tipt] => 旅游指数
	[des] => 天气较好，但丝毫不会影响您出行的心情。温度适宜又有微风相伴，适宜旅游。
	)
	[3] => stdClass Object
	(
	[title] => 感冒
	[zs] => 少发
	[tipt] => 感冒指数
	[des] => 各项气象条件适宜，无明显降温过程，发生感冒机率较低。
	)
	[4] => stdClass Object
	(
	[title] => 运动
	[zs] => 较适宜
	[tipt] => 运动指数
	[des] => 天气较好，户外运动请注意防晒。推荐您进行室内运动。
	)
	[5] => stdClass Object
	(
	[title] => 紫外线强度
	[zs] => 弱
	[tipt] => 紫外线强度指数
	[des] => 紫外线强度较弱，建议出门前涂擦SPF在12-15之间、PA+的防晒护肤品。
	)
	)
	[weather_data] => Array
	(
	[0] => stdClass Object
	(
	[date] => 周五 09月23日 (实时：26℃)
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/duoyun.png
	[weather] => 多云
	[wind] => 东风微风
	[temperature] => 27 ~ 21℃
	)
	[1] => stdClass Object
	(
	[date] => 周六
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/duoyun.png
	[weather] => 多云
	[wind] => 东风微风
	[temperature] => 28 ~ 23℃
	)
	[2] => stdClass Object
	(
	[date] => 周日
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/yin.png
	[weather] => 多云转阴
	[wind] => 东风微风
	[temperature] => 28 ~ 23℃
	)
	[3] => stdClass Object
	(
	[date] => 周一
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/yin.png
	[weather] => 多云转阴
	[wind] => 东北风微风
	[temperature] => 29 ~ 25℃
	)
	)
	)
	)
	)

$arr = object_array($con);  //继续转成数组操作

$detail = $arr["results"][0]["weather_data"];
$city = $arr["results"][0]["currentCity"];

print_r($detail);

Array
	(
	[0] => Array
	(
	[date] => 周五 09月23日 (实时：26℃)
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/duoyun.png
	[weather] => 多云
	[wind] => 东风微风
	[temperature] => 27 ~ 21℃
	)
	[1] => Array
	(
	[date] => 周六
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/duoyun.png
	[weather] => 多云
	[wind] => 东风微风
	[temperature] => 28 ~ 23℃
	)
	[2] => Array
	(
	[date] => 周日
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/yin.png
	[weather] => 多云转阴
	[wind] => 东风微风
	[temperature] => 28 ~ 23℃
	)
	[3] => Array
	(
	[date] => 周一
	[dayPictureUrl] => http://api.map.baidu.com/images/weather/day/duoyun.png
	[nightPictureUrl] => http://api.map.baidu.com/images/weather/night/yin.png
	[weather] => 多云转阴
	[wind] => 东北风微风
	[temperature] => 29 ~ 25℃
	)
	)

//获得天气数据，根据自己需求进行调整

?>