微信JSSDK接口 - 生成签名

 

微信上传下载图片功能若想使用JS-SDK接口，首先需要通过wx.config接口进行权限验证，其中参数appId、timestamp、nonceStr、signature、jsApiList需要进行赋值。

 

wx.config({
    debug: false,
    appId: 'wxe49d******43c1cd',
    timestamp: timestamp,
    nonceStr: nonceStr,
    signature: signature,
    jsApiList: ["chooseImage","previewImage","uploadImage","downloadImage"]
});

  

一、获取access_token

       access_token是公众号的全局唯一票据，公众号调用各接口时都需使用access_token。可以通过AppID和SECRET调用本接口来获取access_token。AppID和SECRET可在微信公众平台开发者中心页中获得。 

def getAccessToken()
{
    def APPID = ""
    def SECRET = ""
    
    URL url = new URL("https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=SECRET")
    def params = "APPID=" + URLEncoder.encode(APPID, 'UTF-8') + "&SECRET=" + URLEncoder.encode(SECRET, 'UTF-8')

    HttpURLConnection connection = (HttpURLConnection) url.openConnection()
    connection.setDoOutput(true)
    connection.setRequestMethod("POST")
    connection.outputStream.withWriter { Writer writer -> writer.write params }
    def response = connection.inputStream.withReader { Reader reader -> reader.text }
    def accessToken = JSON.parse(response).getAt("access_token")     
    return accessToken
}  

 注：access_token的有效期7200秒，所以必须在自己的服务全局缓存access_token值

 

二、获取jsapi_ticket

       jsapi_ticket是公众号用于调用微信JS接口的临时票据，通过access_token来获取。

def getTicket(String accessToken)
{
    URL url = new URL("https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=ACCESS_TOKEN&type=jsapi")
    def params = "ACCESS_TOKEN=" + URLEncoder.encode(accessToken, 'UTF-8')

    HttpURLConnection connection = (HttpURLConnection) url.openConnection()
    connection.setDoOutput(true)
    connection.setRequestMethod("POST")
    connection.outputStream.withWriter { Writer writer -> writer.write params }
    def response = connection.inputStream.withReader { Reader reader -> reader.text }
    def ticket = JSON.parse(response).getAt("ticket")
    return ticket
}

 注：jsapi_ticket的有效期为7200秒，由于获取jsapi_ticket的api调用次数非常有限，频繁刷新jsapi_ticket会导致api调用受限，所以必须在自己的服务全局缓存jsapi_ticket值

 

三、生成signature签名

       签名生成规则：参与签名的字段包括noncestr（随机字符串）, 有效的jsapi_ticket, timestamp（时间戳）, url（当前网页的URL，不包含#及其后面部分）。对所有待签名参数按照字段名的ASCII 码从小到大排序后，使用URL键值对的格式（即key1=value1&key2=value2…）拼接成字符串string1。这里需要注意的是所有参数名均为小写字符。对string1作sha1加密，字段名和字段值都采用原始值，不进行URL 转义。

def wxGetConfigParams()
{
    def access_token = getAccessToken()
    def jsapi_ticket = getTicket(access_token)
    def nonceStr = UUID.randomUUID().toString()
    def time = (System.currentTimeMillis() / 1000).toString()
    def timestamp = time.substring(0, time.lastIndexOf("."))
    def url = request.getRequestURL()
    def signature = getSignature(jsapi_ticket, nonceStr, timestamp, url.toString())
    
    // TODO
    // 将access_token、jsapi_ticket缓存到全局变量中
    // 将signature、nonceStr、timestamp带回到页面
}

  

def getSignature(String jsapi_ticket, String nonce_str, String timestamp, String url)
{
    def string1 = "jsapi_ticket=" + jsapi_ticket + "&noncestr=" + nonce_str + "&timestamp=" + timestamp + "&url=" + url
    MessageDigest crypt = MessageDigest.getInstance("SHA-1")
    crypt.reset()
    crypt.update(string1.getBytes("UTF-8"))
    byteToHex(crypt.digest())
}

 

def byteToHex(final byte[] hash)
{
    Formatter formatter = new Formatter()
    for (byte b :hash)
    {
        formatter.format("%02x", b)
    }
    formatter.toString()
}

 注：

（1）签名用的noncestr和timestamp必须与wx.config中的nonceStr和timestamp相同

（2）签名用的url必须是调用JS接口页面的完整URL

（3）处于安全考虑，开发者必须在服务器实现签名的逻辑

 

微信JS接口签名校验工具：http://mp.weixin.qq.com/debug/cgi-bin/sandbox?t=jsapisign