1. user down order result notification
`Notification path: callBackUrl in "User down Interface" `Request method：POST
| field | type | nickname | description |
|---|---|---|---|
| merchOrderId | String | down order number | down order number submitted by the merchant |
| status | String | status | down Order status，“finish”success，“pending”in progress，“fail”fail |
| amount | Integer | amount | down Order amount |
| sign | String | sign | sign |
Parameters (form)：
Verify sign rules：
1.Simplify the information in the form except sign into map key-value pairs
2.Sort the key-value pairs in positive order by the name of the key
`Sorting Alphabetically would be example: `Before sorting: merchUserId => “user0000005”
address => “address00000005"
After sorting: address => “address00000005"
merchUserId => “user0000005”
3.Encode into get request format in the sorted order
example:address=address00000005&merchUserId=user0000005&status=true
`4.Splice the md5key string from the merchant information directly after the get request string to get the signature source. `For example, the md5key value is merchmd5Key
example:address=address00000005&merchUserId=user0000005&status=truemerchmd5Key
5.The result of step 4 is md5 encrypted to get the final signature value ownSign
6.Verify whether the received sign is the same as the self-calculated signature value ownSign. If they are the same, it is a trusted notification request.
Return "SUCCESS" string indicates that the notification is successful, and other returned results are notification failures; if the notification fails, mpay will retry the notification for a certain number of times, and will stop automatic notification after reaching a certain number of times, then you need to manually notify in the merchant backend.