I am setting up our project to integrate with a shipping platform called Endicia which has the ability to insert new rows into our database when a package is shipped.
How can I detect from python when a new row has been inserted?
My solution for now would be to query the DB every 30 seconds or so for new rows... is there another solution to send a signal from postgres to python?
You'd set up a custom command that is run by the manage.py file.
You'd put it in `yourapp/management/commands/' folder. Make sure to add an init.py file to both the management and commands folder or the command won't work. Then you create the code for the custom command.
Then, see this related question about running a shell script when changes are made to a postgres database. The answer there was to use PL/sh. You'll need to figure that part out on your own, but basically however you do it, the end result is that the script should call something like /path/to/app/manage.py command_name
Related
I want to run a django query from a string and put the output into a variable
in my DRF project, the client sends a django query:
{'query': 'model.objects.all()'}
and I need to return the result of this query.
I tried using exec('model.objects.all()') but i can't assign the output to a variable, i also tried using subprocess.run([sys.executable, "-c", 'model.objects.all()'], capture_output=True, text=True) but subrocess doesn't find the model
There's a huge amount of setting up needed before a process using Django models can work correctly. That's why manage.py shell exists.
If you want to perform Django operations outside the context of a Django server, write a management command. You can then invoke it from the command line, from cron, from other Python scripts ... wherever.
I'm using django-rest-framework as backend and postgresql as the database. The database might be changed by raw SQL script and I want to get notified in the backend when those changes happen so that I can notify different users about the change.
I've checked about posts like https://gist.github.com/pkese/2790749 for receiving notification in python and some SQL scripts for
CREATE TRIGGER rec_notify_trig AFTER INSERT OR UPDATE OR DELETE ON rec
FOR EACH ROW EXECUTE PROCEDURE rec_notify_func()
My question is that I don't know how to hook them together in the django-rest-framework, like where should I put the SQL script, where to put the python settup so that I can connect them together. Any advice will be appreciated.
I would create an endpoint on the djangorestframework side to accept a notification.
Then, in your rec_notify_func() you can call out and hit your endpoint where you can perform any enduser notification necessary.
CREATE EXTENSION plpython3u;
CREATE FUNCTION rec_notify_func(notification_endpoint_uri text) RETURNS text AS $$
from urllib.request import urlopen
data = urlopen(notification_endpoint_uri)
return data.read()
$$ LANGUAGE plpython3u;
NOTE:
You need to have plpython installed on the system in order to enable the extension.
On ubuntu something like this:
sudo apt-get install postgresql-plpython3-9.6
I am very new to Appcelerator, i've got my head around using Alloy to lay the content of my apps out, and have got to grips with using the Firefox extension to create an SQLite database. I'm stuck at putting the two together though. I've tried the Ti.UI.Database.Install but I'm not 100% which JS file to add that coding to, or where to copy the DB file to. I've followed a few threads and tutorials, tried putting the .db file into the resources folder, lib folder etc but keep coming up with errors. If someone could just talk me through the basic steps that would be great.
This is about using a predefined sqlite database in your app, meaning you want to install a db with preloaded records in its tables.
app/assets is a good place for your_database.sql;
then in app/alloy.js
Ti.Database.install('/your_database.sql', 'your_database')
finally configure the adapter attribute in your alloy's models with:
type: "sql",
db_file: "your_database.sql",
db_name: "your_database",
collection_name: "your_table_name"
Anyway, if you do not need to preload a database, you only have to define your models (here, in example, app/models/foobars.js) and configure their adapter with
type: "sql",
collection_name: "foobars"
This way Alloy will take care to create and install the database (including a foobars table) for you.
I'm curious what the point of the structure.sql file is. It seems to be updated and created every time rails migrations are run. So it seems to be a visual representation of our database. What else can it be used for?
When one runs structure:load, what does it do? What does it mean to load a structure file into a database? Why would you need to do that?
Should one be committing the structure.sql file?
Seems like your rails app is configured to use the sql schema format
#/config/application.rb
...
config.active_record.schema_format = :sql
...
the structure.sql is in place of a schema.db.
Running db:structure:load ( or db:schema:load) will load your entire database. You only need to do this when bringing on a new app instance from scratch. After awhile, your migration files will become quite lengthy and it will be better to do a load first, then a migration when bringing up a new app instance
I am just starting with Django, and I would like to make an app that uses my existing sqlite db.
I read the docs and I found that you can create models from a db, using inspectdb; altho I can't find an example of how you use that command, on an existing db.
I copied the db file inside the directory of my project, ran the command and I see that a sqlite3 file is created in my directory project.
Altho the file has nothing to do with the database that I made. I tried to pass the db name to the inspectdb command but it says that it doesn't accept parameters.
So how can I actually tell the command to use my db to create the model for my app?
There must be some obvious step that I am missing...this is what I did:
-created the project
-created the app
-copied my db inside the project folder
-ran inspectdb
But I see the model empty, and a new db called db.sqlite3 created
Found the answer: there is a variable that has to be set, to define which one is the db that the application will use. the default is set to "db.sqlite3", which explain why I am getting this behavior.
Once you modify the name with the database that I already made, the command run without issues.
Not sure if it is just me getting stomped, but this info about the name that has to be changed was not mentioned anywhere...
Thanks