微信分享时没有缩略图时的解决方案！

商品详情页代码：

<script type="text/javascript" src="http://res.wx.qq.com/open/js/jweixin-1.2.0.js"></script>
<script type="text/javascript">

wx.config({
debug: false, // 开启调试模式,调用的所有api的返回值会在客户端alert出来，若要查看传入的参数，可以在pc端打开，参数信息会通过log打出，仅在pc端时才会打印。
appId: "{$signPackage.appId}", // 必填，公众号的唯一标识
timestamp: "{$signPackage.timestamp}", // 必填，生成签名的时间戳
nonceStr: "{$signPackage.nonceStr}", // 必填，生成签名的随机串
signature: "{$signPackage.signature}",// 必填，签名，见附录1
jsApiList: ['onMenuShareTimeline', 'onMenuShareAppMessage'] // 必填，需要使用的JS接口列表，所有JS接口列表见附录2
});

wx.ready(function(){

//IOS系统分享时读取图片路径会出现问题 用 encodeURI 来处理下
var img_url = encodeURI("http://{$smarty.server.SERVER_NAME}{$goods_share_img}");

//分享到朋友圈
wx.onMenuShareTimeline({
title: "{$goods.goods_style_name}", // 分享标题
link: "http://{$smarty.server.SERVER_NAME}{$smarty.server.REQUEST_URI}", // 分享链接，该链接域名或路径必须与当前页面对应的公众号JS安全域名一致
imgUrl: img_url, // 分享图标

success: function () {
alert('已分享');
},
cancel: function () {
alert('已取消');
}
});

//分享给微信好友
wx.onMenuShareAppMessage({
title: "{$goods.goods_style_name}", // 分享标题
desc: "{$goods.goods_style_name}", // 分享描述
link: "http://{$smarty.server.SERVER_NAME}{$smarty.server.REQUEST_URI}", // 分享链接，该链接域名或路径必须与当前页面对应的公众号JS安全域名一致
imgUrl: img_url, // 分享图标
type: '', // 分享类型,music、video或link，不填默认为link
dataUrl: '', // 如果type是music或video，则要提供数据链接，默认为空

success: function () {
alert('已分享');
},
cancel: function () {
alert('已取消');
}
});
});
</script>

PHP脚本代码：

// 微信分享 start
//把要用全部封装一个方法里，方便模版中使用
function getSignPackage() {
$jsapiTicket = getJsApiTicket();
$protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
$url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
$timestamp = time();
$nonceStr = createNonceStr();
$string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr×tamp=$timestamp&url=$url";
$signature = sha1($string);//生成签名
$signPackage = array(
"appId"     => 'wxf888b6qb96c0cf91', //自己公众号的AppId,我这里随便写一个
"nonceStr"  => $nonceStr,
"timestamp" => $timestamp,
"signature" => $signature
);
return $signPackage;
}
//生成随机字符串
function createNonceStr($length = 16) {
$chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
$str = "";
for ($i = 0; $i < $length; $i++) {
$str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
}
return $str;
}
//获取jsapi_ticket
function getJsApiTicket() {
$data = $_SESSION['jsapiticket_all'];
if ($data['expire_time'] < time()) {
$accessToken = getAccessToken();
$url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
$res = json_decode(httpGet($url));
foreach ($res as $k=>$v){
$all[$k] = $v;
}
$ticket = $all['ticket'];
if ($ticket) {
$_SESSION['jsapiticket_all']['expire_time'] = time() + 7000;
$_SESSION['jsapiticket_all']['jsapi_ticket'] = $ticket;
}
} else {
$ticket = $_SESSION['jsapiticket_all']['jsapi_ticket'];
}

return $ticket;
}
//获取AccessToken
function getAccessToken() {
$data = $_SESSION['access_token_all'];
if ($data['expire_time'] < time()) {
$url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=wxb338b6a276c0cf25&secret=28cafa17194e9241e6685260b7ebef89";
$res = json_decode(httpGet($url));
foreach ($res as $k=>$v){
$all[$k] = $v;
}
$access_token = $all['access_token'];
if ($access_token) {
$_SESSION['access_token_all']['expire_time'] = time() + 7000;
$access_token = $all['access_token'];
$_SESSION['access_token_all'] =$all;
}
} else {
$access_token = $_SESSION['access_token_all']['access_token'];
}
return $access_token;
}
//安全处理
function httpGet($url) {
$curl = curl_init();
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_TIMEOUT, 500);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, true);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, true);
curl_setopt($curl, CURLOPT_URL, $url);

$res = curl_exec($curl);
curl_close($curl);

return $res;
}

$smarty->assign('signPackage',getSignPackage()); //赋值到模板
// 微信分享end