Storing unstructured data with ramses to be searched with Ramses-API? - python

I would like to give my users the possibility to store unstructured data in JSON-Format, alongside the structured data, via an API generated with Ramses.
Since the data is made available via Elasticsearch, I try to achieve that this data is indexed and searchable, too.
I can't find any mentioning in the docs or searching.
Would this be possible and how would one do it?
Cheers /Carsten

I put an answer here because needed to give a several docs links and this is a new SO account limited to a couple: https://gitter.im/ramses-tech/ramses?at=56bc0c7a4dfe1fa71ffc0b61

This is Chrisses answer, copied from gitter.im:
You can use the dict field type for "unstructured data", as it takes arbitrary json. If the db engine is postgres, it uses jsonfield under the hood, and if the db engine is mongo, it's converted to a bson document as usual. Either way it should index automatically as expected in ES and will be queryable through the Ramses API.
The following ES queries are supported on documents/fields: nefertari-readthedocs-org/en/stable/making_requests.html#query-syntax-for-elasticsearch
See the docs for field types here, start at the high level (ramses) and it should "just work", but you can see what the code is mapped to at each level below down to the db if desired:
ramses: ramses-readthedocs-org/en/stable/fields.html
nefertari (underlying web framework): nefertari-readthedocs-org/en/stable/models.html#wrapper-api
nefertari-sqla (postgres-specific engine): nefertari-sqla-readthedocs-org/en/stable/fields.html
nefertari-mongodb (mongo-specific engine): nefertari-mongodb-readthedocs-org/en/stable/fields.html
Let us know how that works out, sounds like it could be a useful thing. So far we've just used that field type to hold data like user settings that the frontend wants to persist but for which the API isn't concerned.

Related

CRUD web application with Bigquery?

I have a bigquery table about 200 rows, i need to insert,delete and update values in this through a web interface(the table cannot be migrated to any other relational or non-relational database).
The web application will be deployed in google-cloud on app-engine and the user who acts as admin and owner privileges on Bigquery will be able to create and delete records and the other users with view permissions on the dataset in bigquery will be able to view records only.
I am planning to use the scripting language as python,
server(django or flask or any other)-> not sure which one is better
The web application should be displayed as a data-grid like appearance with buttons create,delete or view visiblility according to their roles.
I have not done anything like this in python,bigquery and django. I am already familiar with calling bigquery from python-client but to call in a web interface and in a transactional way, i am totally new.
I am seeing examples only related to django with their inbuilt model and not with big-query.
Can anyone please help me and clarify whether this is possible to implement and how?
I was able to achieve all of "C R U D" on Bigquery with the help of SQLAlchemy, though I had make a lot of concessions like if i use sqlalchemy class i needed to use a false primary key as Bigquery does not use any primary key and for storing sessions i needed to use file based session On Django for updates and create sqlalchemy does not allow without primary key, so i used raw sql part of SqlAlchemy. Thanks to the #mhawke who provided the hint for me to carry out this exericse
No, at most you could achieve the "R" of "CRUD." BigQuery isn't a transactional database, it's for querying vast amounts of data and preparing the results as an immutable view.
It doesn't provide a method to modify the source data directly and even if you did you'd need to run the query again. Also important to note are that queries are asynchronous and require much longer to perform than traditional databases.
The only reasonable solution would be to export the table data to GCS and then import it into a normal database for querying. Alternatively if you can't use another database and since you said there are only 1,000 rows you could perform your CRUD actions directly on that exported CSV.

Use django to expose python functions on the web

I have not worked with Django seriously and my only experience is the tutorials on their site.
I am trying to write my own application now, and what I want is to have some sort of API. My idea is that I will later be able to use it with a client written in any other language.
I have the simplest of all apps, a model that has a name and surname field.
So the idea is that I can now write an app lets say in c++ that will send two strings to my Django app so they can be saved in the database as name, surname respectively.
What I know until now is to create a form so a user can enter that information, or have the information in the url, and of curse adding them myself from the admin menu.
What I want though is some other better way, maybe creating a packet that contains that data. Later my client sends this data to my Django webpage and it will extract the info and save it as needed. But I do not know how to do this.
If my suggested method is a good idea, then I would like an example of how this is done. If not the I would like suggestions for possible things I could try out.
Typically, as stated by #DanielRoseman, you certainly want to:
Create a REST API to get data from another web site
Get data, typically in JSON or XML, that will contain all the required data (name and surname)
In the REST controller, Convert this data to the Model and save the Model to the database
Send an answer.
More information here: http://www.django-rest-framework.org/

Format data in Google App Engine Differently

Is it possible to represent data in Google App Engine's datastore view differently in Python?
For example, if I create a list of ndb.KeyProperty(repeated=True) when I look in the datastore it shows up as: [datastore_types.Key.from_path(u'User', 6544293208522752L, _app=u'dev~appstuffhere')]
Is there any way to change the representation of that to something else? I was working with __str__, __unicode__, and __repr__ to see if that is what App Engine looks to for representing this data, but to no avail.
I would prefer to see a list of User Names rather than that datastore_types.Key.from_path representation.
Is this possible?
The datastore viewer doesn't know about your models at all. It purely goes on the entity kinds in the datastore, which are independent of the models themselves.
As Paul says in the comment, if you need a different representation you'll need to build it yourself. To get the usernames from the key properties you'd need to actually fetch the data (remember, the datastore is not a relational db, so there's no such thing as a join):
usernames = ', '.join(e.username for e in ndb.get_multi(e.users))

Couchdb/Mongodb Application/Logic layer, like Oracle DB

At my work, we use Oracle for our database. Which works great. I am not the main db admin, but I do work with it. One thing I like is that the DB has a built in logic layer using PL/SQL which ca handle logic related to saving the data and retrieve it. I really like this because it allows our MVC application (PHP/Zend Framework) to be lighter, and makes it easier to tie in another platform into the data, such as desktop or mobile.
Although, I have a personal project where I want to use couchdb or mongodb, and I want to try and accomplish a similar goal. outside of the mvc/framework, I want to have an API layer that the main applications talk to. they dont actually talk directly to the database. They specify the design document (couchdb) or something similar for mongo, to get the results. And that API layer will validate the incoming data and make sure that data itself is saved and updated properly. Such as saving a new user, in the framework I only need to send a json obejct with the keys/values that need to be saved and the api layer saves the data in the proper places where needed.
This API would probably have a UI, but only for administrative purposes and to make my life easier. In general it will always reply with json strings, or pre-rendered/cached html in some cases. Since each api layer would be specific to the application anyways.
I was wondering if anyone has done anything like this, or had any tips on nethods I could accomplish this. I am currently looking to write my application in python, and the front end will likely be something like Angularjs. Although I am also looking at node.js for a back end.
We do this exact thing at my current job. We have MongoDB on the back end, a RESTful API on top of it and then PHP/Zend on the front end.
Most of our data is read only, so we import that data into MongoDB and then the RESTful API (in Java) just serves it up.
Some things to think about with this approach:
Write generic sorting/paging logic in your API. You'll need this for lists of data. The user can pass in things like http://yourapi.com/entity/1?pageSize=10&page=3.
Make sure to create appropriate indexes in Mongo to match what people will query on. Imagine you are storing users. Make an index in Mongo on the user id field, or just use the _id field that is already indexed in all your calls.
Make sure to include all relevant data in a given document. Mongo doesn't do joins like you're used to in Oracle. Just keep in mind modeling data is very different with a document database.
You seem to want to write a layer (the middle tier API) that is database agnostic. That's a good goal. Just be careful not to let Mongo specific terminology creep into your exposed API. Mongo has specific operators/concepts that you'll need to mask with more generic terms. For example, they have a $set operator. Don't expose that directly.
Finally after having a decent amount of experience with CouchDB and Mongo, I'd definitely go with Mongo.

Getting text from db as django dictionary

I recently joined a company which is using django to build their product. I'm currently responsible for one of the apps, which was already developed a little bit before I was here.
One of the entities in the app has a json dictionary attribute, which has been kept in the db as a text field. Also, this attribute is marked in the model as a text field. So, as you can imagine it's not being handled correctly.
I wanted to change this and set it as a json field using https://github.com/bradjasper/django-jsonfield , which works really well.
However, I've run into a peculiar problem. Previous data stored in the db was not correctly handled and since it was unicode data, the text field in the db looks like:
{u'key': u'value'}
Now when the entity manager tries to load those values using the json field, it of course breaks since it's no longer a valid json string.
I've done some research on how to overcome this, but haven't found nothing.
My question:
Do you have any suggestion on how to overcome this? It can be any type of solution.
Something that I can run over night altering that field to transform it to a valid json string.
Some changes to the json-field code, which enables it to correctly handle these values.
Additional info
We use postgres with psycopg2 as django's db backend.
Thank you very much.
You're probably just going to need to iterate over the whole table, load the field, convert it into a real Python dict, and dump it back out with json.dumps. ast.literal_eval is a good choice for the conversion stage because it works like the built-in eval but is more restricted, so less risky to your system.
for obj in MyModel.objects.all():
value = ast.literal_eval(obj.dict_value)
obj.dict_value = json.dumps(value)
value.save()

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