微信开发之生成二维码，扫码关注公众号PHP

<?php
namespace app\index\controller;
use think\Controller;

/**
 * 微信类
 */
class Wechat extends Controller
{

    protected  $APPID = ‘xxxxxxxxxxx‘;
    protected  $APPSECRET = ‘xxxxxxxxxxxxxx‘;

    
    /**
    * curl请求 
    */
    public function http_curl($url, $type = ‘get‘, $res = ‘json‘, $arr = ‘‘){
        
      $cl = curl_init();
      curl_setopt($cl, CURLOPT_URL, $url);
      curl_setopt($cl, CURLOPT_RETURNTRANSFER, 1);
      curl_setopt($cl, CURLOPT_SSL_VERIFYPEER, false);
      curl_setopt($cl, CURLOPT_SSL_VERIFYHOST, false);
      if($type == ‘post‘){
        curl_setopt($cl, CURLOPT_POST, 1);
        curl_setopt($cl, CURLOPT_POSTFIELDS, $arr);
      }
      $output = curl_exec($cl);
      curl_close($cl);
      return json_decode($output, true);
      if($res == ‘json‘){
        if( curl_error($cl)){
          return curl_error($cl);
        }else{
          return json_decode($output, true);
        }
      }
    }

    /**
     * 获取 AccessToken
     */
    public function getAccessToken()
    {
        $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=".$this->APPID."&secret=".$this->APPSECRET;

        // 先判断 access_token 文件里的token是否过期，没过期继续使用，过期就更新
        $data = json_decode($this->get_php_file(ROOT_PATH."public".DS."wxtxt".DS."access_token.txt"));
        // 过期 更新
        if ($data->expire_time < time()) {
            
            $res = $this->http_curl($url);
            $access_token = $res[‘access_token‘];
            if ($access_token) {
                // 在当前时间戳的基础上加7000s (两小时)
                $data->expire_time = time() + 7000;
                $data->access_token = $res[‘access_token‘];
                $this->set_php_file(ROOT_PATH."public".DS."wxtxt".DS."access_token.txt",json_encode($data));
            }
        }else{
            // 未过期 直接使用
            $access_token = $data->access_token;
        }
        
        return $access_token;
    }
    

    // 获取存储文件中的token ticket
    private function get_php_file($filename) {
        return trim(file_get_contents($filename));
      }
      // 把token ticket 存储到文件中
      private function set_php_file($filename, $content) {
        $fp = fopen($filename, "w");
        fwrite($fp,  $content);
        fclose($fp);
      }
      
      /**
     * 生成二维码
     */
    public function getQrcode(){
        
        $token = $this->getAccessToken();
        $url = "https://api.weixin.qq.com/cgi-bin/qrcode/create?access_token=$token";
        
        $param = array();
        $param[‘action_name‘] = "QR_LIMIT_SCENE";
        $param[‘action_info‘] = array( ‘scene‘ => array( ‘scene_id‘=>‘123‘  )  );
        $param = json_encode($param);
        
        // 获取二维码的ticket和二维码图片解析地址
        $res = $this->http_curl($url, ‘post‘, ‘json‘, $param);
        // 通过ticket换取二维码
        $qrcode = "https://mp.weixin.qq.com/cgi-bin/showqrcode?ticket=".$res[‘ticket‘];
        
　　　　//输出二维码图片路径
　　　　echo "<center><img src=".$qrcode."></center>";       
    }

}