PHP开发APP接口（一）

php以json或者xml 形式返回给app。明白这点就很好说了，就是把数据包装成json或者xml，返回给APP

定义抽象APP基类：

<?php
/**
 * 定义API抽象类
*/
abstract class Api {

	const JSON = 'Json';
	const XML = 'Xml';
	const ARR = 'Array';
	
	/**
	* 定义工厂方法
	* param string $type 返回数据类型
	*/
	public static function factory($type = self::JSON) {
		$type = isset($_GET['format']) ? $_GET['format'] : $type;
		$resultClass = ucwords($type);
		require_once('./Response/' . $type . '.php');
		return new $resultClass();
	}

	abstract function response($code, $message, $data);
}

<?php
class Xml extends Api {
	public function response($code, $message = '', $data = array()) {
		if(!is_numeric($code)) {
			return '';
		}

		$result = array(
			'code' => $code,
			'message' => $message,
			'data' => $data
		);

		header('Content-Type:text/xml');
		$xml = "<?xml version='1.0' encoding='UTF-8'?>\n";
		$xml .= "<root>";
		$xml .= self::xmlToEncode($result);
		$xml .= "</root>";
		echo $xml;
	}

	public static  function xmlToEncode($result) {
		$xml = $attr = '';
		foreach($result as $key => $value) {
                    //判断键值对，如果是数字键值不允许
			if(is_numeric($key)) {
				$attr = " id='" . $key . "'";
				$key = "item";
			}
			$xml .= "<{$key}{$attr}>";
                        //以递归形式返回，主要是因为数组在xml中显示是array，必须显示出来具体键值对
			$xml .= is_array($value) ? self::xmlToEncode($value) : $value;
			$xml .= "</{$key}>\n";
		}
		return $xml;
	}
}

<?php
/**
 * 按xml方式输出通信数据
*/
class Json extends Api {
	public function response($code, $message = '', $data = array()) {
		if(!(is_numeric($code))) {
			return '';
		}

		$result = array(
			'code' => $code,
			'message' => $message,
			'data' => $data
		);

		echo json_encode($result);
		exit;
	}
}

<?php

class Response {
	const JSON = "json";
	/**
	* 按综合方式输出通信数据
	* @param integer $code 状态码
	* @param string $message 提示信息
	* @param array $data 数据
	* @param string $type 数据类型
	* return string
	*/
	public static function show($code, $message = '', $data = array(), $type = self::JSON) {
		if(!is_numeric($code)) {
			return '';
		}

		$type = isset($_GET['format']) ? $_GET['format'] : self::JSON;

		$result = array(
			'code' => $code,
			'message' => $message,
			'data' => $data,
		);

		if($type == 'json') {
			self::json($code, $message, $data);
			exit;
		} elseif($type == 'array') { //适合调试代码
			var_dump($result);
		} elseif($type == 'xml') {
			self::xmlEncode($code, $message, $data);
			exit;
		} else {
			// TODO
		}
	}
	/**
	* 按json方式输出通信数据
	* @param integer $code 状态码
	* @param string $message 提示信息
	* @param array $data 数据
	* return string
	*/
	public static function json($code, $message = '', $data = array()) {
		
		if(!is_numeric($code)) {
			return '';
		}

		$result = array(
			'code' => $code,
			'message' => $message,
			'data' => $data
		);

		echo json_encode($result);
		exit;
	}

	/**
	* 按xml方式输出通信数据
	* @param integer $code 状态码
	* @param string $message 提示信息
	* @param array $data 数据
	* return string
	*/
	public static function xmlEncode($code, $message, $data = array()) {
		if(!is_numeric($code)) {
			return '';
		}

		$result = array(
			'code' => $code,
			'message' => $message,
			'data' => $data,
		);

		header("Content-Type:text/xml");
		$xml = "<?xml version='1.0' encoding='UTF-8'?>\n";
		$xml .= "<root>\n";

		$xml .= self::xmlToEncode($result);

		$xml .= "</root>";
		echo $xml;
	}

	public static function xmlToEncode($data) {

		$xml = $attr = "";
		foreach($data as $key => $value) {
			if(is_numeric($key)) {
				$attr = " id='{$key}'";
				$key = "item";
			}
			$xml .= "<{$key}{$attr}>";
			$xml .= is_array($value) ? self::xmlToEncode($value) : $value;
			$xml .= "</{$key}>\n";
		}
		return $xml;
	}

}