2. Obtaining the Alipay user ID

You must wait until the H5 page is loaded and then start to obtain the Alipay user ID. Otherwise, the H5 page loading process is to be very slow because the H5 page will be loaded after you get the result of obtaining the Alipay user ID.

The buyer’s Alipay ID (buyer_id) is required as one of the request parameters of the alipay.acquire.create interface. Therefore, to complete a payment transaction, firstly you must obtain the buyer’s Alipay user ID by completing the following steps:

1. Construct the openauth link and then guide the user to visit this link.
2. The authorization will occur silently and redirection page occurs automatically. In this case, users will be automatically redirected to the configured callback page, and the auth_code will be passed. With the auth code, the alipay.system.oauth.token API is called to obtain the Alipay user ID.

URL format:

https://openauth.alipay.com/oauth2/publicAppAuthorize.htm?app_id=APPID&scope=auth_base&redirect_uri=ENCODED_URL

Description of URL parameters

About the redirect_uri:

The API verifies whether the redirect_uri configured in the authorization link is consistent with that in the corresponding application at the Developer Center.

For example:

If the link configured in the application by the developer is: https://auth.example.com/authCallBack , then the redirect_uri is https%3A%2F%2Fauth.example.com%2FauthCallBack. After configuration, URLs under this domain name （auth.example.com）, such as http://auth.example.com/authCallBack、https://auth.example.com/authRedirect、https://auth.example.com/ can support OAuth 2.0 –based authentication.

However, http://www.example.com/、http://example.com would not be supported for web-based authentication.

When the user is redirected to the callback page， Alipay will add request parameters into the callback including auth_code, app_id, scope and so on. An example of the request is as below:

http://example.com/doc/toAuthPage.html?app_id=2014101500013658&source=alipay_wallet&scope=auth_base&auth_code=ca34ea491e7146cc87d25fca24c4cD11

Among which,auth_code=ca34ea491e7146cc87d25fca24c4cD11

Interface name: alipay.system.oauth.token

For the information about request and response parameters and error codes, refer to the API doc

The developer can obtain the Alipay user ID by using auth_code. As the token to obtain the Alipay user ID, the auth_code returned is unique in each authorization. Each auth_code can be used only once and will automatically be expired in one day.

Sample request:

REQUEST URL: https:/https://globalopenapi.alipay.com/gateway.do
REQUEST METHOD: POST
CONTENT:
    app_id=2014070100171525
    method=alipay.system.oauth.token
    charset=GBK
    sign_type=RSA2
    timestamp=2014-01-01 08:08:08
    sign=rXaTEfJ7WTDsP1DWRPHARW3uOr19+fzlngMCJBvbhP1XPEa9qZwGGng9oMDloABpJMT2SGeOj46+BUkqCGRO9fH90Vci3hOH01BfYnbhJz3ADK2h7gpjlponx4/sxELN6f2GXi51XKiHKnxMA9XpLLo68q+roY0M/ZFQ1UdnqeM=
    version=1.0
    grant_type=authorization_code
    code=4b203fe6c11548bcabd8da5bb087a83b

Request parameters

Synchronous response sample

{
    "alipay_system_oauth_token_response": {
        "code": "10000",
        "msg": "Success",
        "access_token": "publicpBa869cad0990e4e17a57ecf7c5469a4b2",
        "user_id": "2088411964574197",
        "alipay_user_id": "20881007434917916336963360919773",
        "expires_in": 300,
        "re_expires_in": 300,
        "refresh_token": "publicpB0ff17e364f0743c79b0b0d7f55e20bfc"
    },
    "sign": "xDffQVBBelDiY/FdJi4/a2iQV1I7TgKDFf/9BUCe6+l1UB55YDOdlCAir8CGlTfa0zLYdX0UaYAa43zY2jLhCTDG+d6EjhCBWsNY74yTdiM95kTNsREgAt4PkOkpsbyZVXdLIShxLFAqI49GIv82J3YtzBcVDDdDeqFcUhfasII="
}

Synchronous response parameters

In this condition we only focus on user_id