Send an http request in mysql trigger after insert

问题:

I am working in PHP.I have to created a mysql trigger which fires an http request after insertion on table.Below is the code.

DELIMITER @@
CREATE TRIGGER Test_Trigger
AFTER INSERT ON insertsms
FOR EACH ROW
BEGIN
  SET @tt_json = (SELECT json_object(id,addtime,title) 
                  FROM insertsms WHERE id = NEW.id LIMIT 1);
  SET @tt_resu = (SELECT http_put(CONCAT('--url localhost--')));
END;
@@
DELIMITER ;

But I am getting errors like

Message: SQLSTATE[42000]: Syntax error or access violation: 1305 FUNCTION emg.json_object does not exist

Message: SQLSTATE[42000]: Syntax error or access violation: 1305 FUNCTION emg.http_put does not exist

How to remove this error? I was not able to download the supporting files containing these functions.I have tested in localhost.Is there any other way to achieve my requirement? Please anyone help me..

回答1:

Although it's technically possible I'd strongly discourage you from going this route for several reasons:

1. Using UDFs is a security risk on its own. UDFs are available to all database users - you cannot grant EXECUTE privileges for them.

2. Doing any non-transactional operations in a trigger is simply wrong. Data changes made by DML statement (in your case it's an update) can and will be rolled back in a real world scenario. You won't be able to undo your http calls.

3. You're prolonging the time for insert transaction possibly causing lock-wait-timeouts for other update/insert operations.

Highly recommended reading:

• The Trouble with Triggers

---

Now most likely what you need is a work queue e.g. beanstalked. Using such specialized middleware is much better than organizing queues with database.