Article directory
process
illustrate
- Call wx.login() to obtain the temporary login credential code and send it back to the developer server.
- Call the auth.code2Session interface in exchange for the user's unique identifier OpenID , the user's unique identifier UnionID under the WeChat open platform account (if the current mini program has been bound to the WeChat open platform account) and the session key session_key .
Afterwards, the developer server can generate a custom login status according to the user ID, which is used to identify the user's identity during the front-end and back-end interactions in the subsequent business logic.
Precautions
- Session key session_key is the key for cryptographically signing user data. In order to protect the application's own data, the developer server should not deliver the session key to the applet , nor should it provide this key to the outside world.
- The temporary login credential code can only be used once
wx.login()
Call the interface to obtain the login credentials (code). Use the credentials to exchange for user login status information, including the user's unique identifier (openid) in the current Mini Program, the unique identifier under the WeChat Open Platform account (unionid, if the current Mini Program has been bound to the WeChat Open Platform account) and this login The session key (session_key), etc. The encryption and decryption communication of user data needs to rely on the session key to complete.
parameter
| Attributes | type | Defaults | required | illustrate |
|---|---|---|---|---|
| timeout | number | no | Timeout time, unit ms Timeout time, unit ms | |
| success | function | no | Callback function for successful interface call | |
| fail | function | no | Callback function for interface call failure | |
| complete | function | no | The callback function of the end of the interface call (the call will be executed successfully or failed) |
success callback function
| Attributes | type | illustrate |
|---|---|---|
| code | string | User login credentials ( valid for five minutes ). The developer needs to call auth.code2Session in the background of the developer server, and use the code to exchange openid, unionid, session_key and other information |
wx.login({
success (res) {
if (res.code) {
//发起网络请求
wx.request({
url: 'https://example.com/onLogin',//开发的后台地址，传输code获取openid登录信息
data: {
code: res.code
}
})
} else {
console.log('登录失败！' + res.errMsg)
}
}
})
auth.code2Session
Login credential verification. Obtain the temporary login credential code through the wx.login interface and pass it to the developer server to call this interface to complete the login process.
request address
GET https://api.weixin.qq.com/sns/jscode2session?appid=APPID&secret=SECRET&js_code=JSCODE&grant_type=authorization_code
request parameters
| Attributes | type | Defaults | required | illustrate |
|---|---|---|---|---|
| appid | string | yes | Mini program appId | |
| secret | string | yes | Applet appSecret | |
| js_code | string | yes | The code obtained when logging in | |
| grant_type | string | yes | Authorization type, just fill in authorization_code here |
The applet appId and applet appSecret can be found in the development management
return value
| Attributes | type | illustrate |
|---|---|---|
| openid | string | unique user ID |
| session_key | string | session key |
| unions | string | The unique identifier of the user on the open platform, if the current Mini Program has been bound to the WeChat open platform account, it will return |
| errcode | number | error code |
| errmsg | string | error message |
Legal values for errcode
| value | illustrate |
|---|---|
| -1 | The system is busy, please try again later |
| 0 | successful request |
| 40029 | code invalid |
| 45011 | Frequency limit, 100 times per minute per user |
| 40226 | For high-risk users, applet login interception. |
combat
front-end code
The front end of the WeChat applet gets the code and sends it to the background
wx.login({
success (res) {
if (res.code) {
//发起网络请求
wx.request({
url: 'https://example.com/onLogin',//开发的后台地址，传输code获取openid登录信息
data: {
code: res.code
}
})
} else {
console.log('登录失败！' + res.errMsg)
}
}
})
backend code
The background receives the code and obtains the user's openid through the code
After the background receives the code, it creates an http request to access the WeChat background server to obtain the user's openid. If everything is normal, it will get the user's openid corresponding to the applet and the user's personal Access_token.
Two dependencies used:
<!-- json数据格式依赖 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.79</version>
</dependency>
<!-- http请求工具包依赖 -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.13</version>
</dependency>
/**
* 获取微信的openid和session_key
* @param code wx.login的code
* @return 返回JSON：openid和session_key
*/
public static JSONObject gainWxLogin(String code){
String url = "https://api.weixin.qq.com/sns/jscode2session?appid=" + AppID + "&secret=" + AppSecret + "&js_code=" + code + "&grant_type=authorization_code";
JSONObject jsonObject = null;
try {
HttpClient client = HttpClientBuilder.create().build();//构建一个Client
HttpGet get = new HttpGet(url.toString()); //构建一个GET请求
HttpResponse response = client.execute(get);//提交GET请求
HttpEntity result = response.getEntity();//拿到返回的HttpResponse的"实体"
String content = EntityUtils.toString(result);
System.out.println(content);//打印返回的信息
jsonObject = JSONObject.parseObject(content);//把信息封装为json
} catch (Exception e) {
e.printStackTrace();
}
return jsonObject;
}
The information obtained by the backend:
In this way, the openid of WeChat is obtained. The next step is to check whether the openid is already in the database. If it exists, log in. If it does not exist, register.