PHP解析小程序返回的buffer信息，并解析成图片

需要引入 GuzzleHttp 包

composer require guzzlehttp/guzzle

核心代码如下：

<?php

require __DIR__ . './vendor/autoload.php';
use GuzzleHttp\Client;
use GuzzleHttp\Exception\GuzzleException;

/**
 * get client
 * @return Client
 */
function httpGetClient()
{
    static $client ;
    if (!$client) {
        $client = new Client();
    }
    return $client;
}
//GET
function httpGet($url)
{
    $client = httpGetClient();
    $options = [
        'verify' => false,
    ];
    $response = $client->get($url,$options);
    return $response->getBody()->getContents();
}

// POSTBODY
 function httpPostBody($url, $requestData=[], $header=[])
{
    $client = httpGetClient();
    $options = [
        'headers' => $header,
        'body' => json_encode($requestData,JSON_UNESCAPED_UNICODE ),
        'verify' => false,
    ];
    $response = $client->post($url, $options);
    if ($response->getStatusCode()==200) {
        return $response->getBody()->getContents();
    }else{
        return null;
    }

}

//postForm
function httpPostForm($url, $requestData, $header)
{
    $client = new Client(['verify' => false]);
    try {
        $response = $client->request('post', $url, ['form_params' => $requestData, 'headers' => $header]);
        $response->getStatusCode(); // 200
        $response->getHeaderLine('content-type');
        if ($response->getStatusCode()==200) {
            return [true,$response->getBody()->getContents()];
        }else{
            return [false,[]];
        }
    } catch (GuzzleException $e) {

    }
    return [false,[]];

}

function getAccessToken(){
    $appid = '';
    $secret = '';
    //获取access_token
    $access_token_url = 'https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid='.$appid.'&secret='.$secret;
    $access_token_data = httpGet($access_token_url);
    $access_token_data = json_decode($access_token_data,true);
    return  $access_token_data['access_token'];
}

function getQrcode($access_token){
    $url = 'https://api.weixin.qq.com/cgi-bin/wxaapp/createwxaqrcode?access_token='.$access_token;
    $requestData = [
        'path'=>'pages/order-status/index?loose_id=1',
        'width'=>430,
    ];
    $header = [];
    return  httpPostBody($url,$requestData,$header);

}

$access_token = getAccessToken();
//$access_token = "";
$data = getQrcode($access_token);

if(is_null(json_decode($data))){
    //不是json数据， 有数据流，返回值为null
    $jpg = $data;
    //创建文件写入
    $file = fopen("img/test.jpg",'w');
    fwrite($file,$jpg);
    fclose($file);
}else{
    //不是数据流，则代表有错误发生
    $data_array = json_decode($data,true);
    print_r($data_array);
}

?>

如果提示你无法写入， 记得新建一个文件夹： img ,并给可写权限