Python Version: 3.6.6
SQLAlchemy version: 1.2.12
PostgreSQL version: 10.5
This is my fist time using PGSQL over MySQL or SQLite and my first project
using SQLAlchemy over SQLite or the Django ORM. I'm also not very good at
programming in general so please forgive the simple questions.
I have a script that I'm using to record incoming messages from an API
and/or a websocket, including edits to messages. The script is using
upserts to save data to the database. I tried adding an event listeners for
updates and inserts but the event listeners are not firing off their
function when a message is inserted or updated. Here is the test code I'm
working with:
class User(newBase):
__tablename__ = 'user'
__table_args__ = {'autoload':True}
class Message(newBase):
__tablename__ = 'message'
__table_args__ = {'autoload':True}
class Lobby(newBase):
__tablename__ = 'lobby'
__table_args__ = {'autoload':True}
class Community(newBase):
__tablename__ = 'community'
__table_args__ = {'autoload':True}
for table in tables:
for row in _yield_limit(olddb.query(table), table.frame):
logging.debug(row.frame)
messagedata = row.raw
message = wsrsi.sortframe(messagedata)
if message[0] == 'message':
message = message[1]
if message.iserased == True:
eraser = message.erasedby
eraserid = eraser.id
userInsert(eraser)
else:
eraser = None
eraserid = None
userInsert(message.author)
messageins = insert(Message).values(
id = message.id,
iserased = message.iserased,
erasedby = eraserid,
author = message.author.id,
body = message.body,
private = message.isprivate,
created = convTime(message.timecreated),
edited = convTime(message.timeedited),
lobby = message.lobbyid,
usermentions = message.mentions,
)
message_dict = {
c.name: c
for c in messageins.excluded
}
update_message = messageins.on_conflict_do_update(
index_elements = ["id"],
set_=message_dict
)
try:
newdb.execute(update_message)
except IntegrityError as e:
print('Foreign key violation error, logging.')
with open('fkerrors.txt', 'a+') as f:
f.write(str(e)+'\n')
f.write(str(message.raw))
f.write('\n================================\n')
f.close()
except ValueError as e:
if str(e) == 'A string literal cannot contain NUL (0x00)
characters.':
print('Null character found in message')
with open('nullerrors.txt', 'a+') as f:
f.write(str(e)+'\n')
f.write(str(message.raw))
f.write('\n================================\n')
f.close
For reference, `table` is an array of tables from an old MySQL database
I've inherited that I'm migrating to PGSQL.
This is my event listener code:
@listens_for(Message, 'before_update')
def saveHistory(mapper, connect, target):
historicaldata = dict(target)
print("SaveHistory triggered\n")
event.listen(Message, 'before_insert', saveHistory)
event.listen(Message, 'before_update', saveHistory)
I've tried arranging this in several different ways including using the
decorator on the table classes but no matter how I structure this the event
listener does not fire on insert. I've done a lot of searching but I
haven't been able to find any information on using event listeners
specifically with PGSQL upserts so I don't know if the problem is with my
code or if it's just not supported when using upserts. Am I doing something
wrong?
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
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