Reportato

The goal of Reportato is to provide a Django-ish approach to easily get CSV or Google Spreadsheet generated reports.

This is still a very alpha version, and this documentation may lie.

Note: Generating a report can take a long time if the table you're generating your report from is large. You might want to avoid forcing your users to experience this latency, e.g. by generating the report regularly on a cron and allowing them to download the most recent copy, or by fetching the report via AJAX so you can show your user pictures of kittens while they wait.

Basic configuration

With Reportato, the way you declare how your report should look is similar to Django's ModelForms:

#### reporters.py

from reportato.reporters import ModelReporter

from .models import Journalist

class JournalistReporter(ModelReporter):

    class Meta:
        model = Journalist
        fields = ('first_name', 'last_name', 'email')
        custom_headers = {
            'first_name': 'Different header'
        }

    def get_email_column(self, instance):
        return instance.email.replace('@', '< AT >')

#### usage example
>>> from journalists.models import Journalist
>>> from journalists.reporters import JournalistReporter
>>> reporter = JournalistReporter()  # by default uses model.objects.all(), can use any queryset
>>> reporter.get_header_row()
[u'Different header', u'Last name', u'Email']
>>> [row for row in reporter.get_rows()]
[
  [u'Angelica', u'Edlund', u'angelicaedlund <AT> engadget.com'],
  [u'Arnold', u'Ofarrell', u'arnoldofarrell <AT> reddit.com'],
 # ...
]

Documentation

Model Reporters

To create a report for a given model, you just need to write a class that will inherit from reportato.reporters.ModelReporter, and indicate which model you want to report on. A very simple example:

from reportato.reporters import ModelReporter

class MyReport(ModelReporter):

    class Meta:
        model = MyModel

By default this will generate reports with every field on MyModel. You can especify which fields to include by using the fields variable:

    # ...
    class Meta:
        model = MyModel
        fields = ('field1', 'field2', 'field3')

The header row will be generated based on the model field's verbose_name value, or a simple capitalization of the field name if it doesn't have a verbose_name. If you want to override that, you can do it using custom_headers:

    # ...
    class Meta:
        model = MyModel
        custom_headers {
            'field1': 'Very cool header'
        }

The way reportato resolves each given field is very simple:

• Checks if the reporter class has some method named get_FIELDNAME_column(instance). If it does, uses it. Otherwise:
• Checks if the given FIELDNAME is accessible directly through the instance.
• Will raise a reportato.reporters.UndefinedField exception if neither of those are defined.

What this means is that you can define whatever you want in your report as a field while you have the proper get_FIELDNAME_column method. And also will be able to use model's fields, decorators or even aggregated fields.

As an example:

    # ...
    def get_field1_column(self, instance):
        return instance.field1.replace('_', '-')

To create the report, you need to instantiate the object using a list of objects or a queryset. If you do not pass one, it will take all the objects for the given model:

>>> MyReport()  # report with MyModel.objects.all()
>>> MyReport(MyModel.objects.filter(something=something_else))

Additionally, you can define what fields you want to see on your report during creation time using the visible_fields parameter:

>>> MyReport(visible_fields=['first_name', 'last_name'])

This way your reporter will only show those fields, even if you had more on your Reporter definition. This allows you to build custom logic if the final user wants to customise what columns he/she wants to see each time.

Other methods:

get_header_row()

Returns an ordered list with the CSV headers

get_row(instance)

Returns a sorted dict with the value of each field for the given instance

get_rows()

Returns an iterable with an ordered list of the values for the given fields.

reportato.views.BaseCSVGeneratorView

Are you a CBV fan? It's your lucky day, because reportato provides a base view from which you can inherit for building your own stuff.

BaseCSVGeneratorView inherits from Django's django.views.generic.ListView meaning that it needs a model or a queryset to work with. Internally, BaseCSVGeneratorView will use get_queryset() method to resolve the list of objects to report with.

reporter_class

Class attribute to define the class of the reporter you are going to use on this view. Should inherit from ModelReporter. If you need to decide what reporter to use in execution time, override get_reporter_class() method instead.

writer_class

Class attribute to define the CSV writer class. By default uses UnicodeWriter, as implemented on Python documentation.

WRITE_HEADER

Flag to determine whether to include the headers in the report or not.

file_name

Class attribute to define the file name for the generated report. If you want something more dynamic, you should override get_file_name() method.

write_csv()

Method that receiving an input flow (HttpResponse, io.BytesIO...) uses reporter's method to write into such flow.

Further examples

Report as a Google Sheet

The initial plan was to add some features to automatically create spreadsheets from given reports. However, I changed my mind during implementation because it made certain assumptions about how the tool needed to implement OAuth and felt that it was overkill.

Instead, I'm providing some examples of how to do it using this library. The basic undersanding is that we need to dump the CSV file into a BytesIO and upload it to Google Drive using google-api-python-client.

import io

# google apiclient dependencies
import httplib2
from apiclient.discovery import build
from apiclient.http import MediaIoBaseUpload

from reporters.views import BaseCSVGeneratorView
from .models import MyModel
from .reports import MyReport

class MyReportToSpreadsheet(BaseCSVGeneratorView):
    model = MyModel
    reporter_class = MyReport

    def get(self, request, *args, **kwargs):
        outfile = io.BytesIO()
        self.write_csv(outfile)
        # now outfile is filled with the CSV we want.
        # we need to fetch the user credentials using OAuth, not covering it here
        credentials = request.user.oauth_credentials
        http = credentials.authorize(httplib2.Http())

        service = build(
            serviceName='drive',
            version='v2',
            developerKey=settings.GOOGLE_API_KEY,
            http=http
        )

        media_body = MediaIoBaseUpload(
            outfile,
            mimetype='text/csv',
            resumable=False
        )

        body = {
            "title": title,
            "description": description,
            "mimeType": 'text/csv'
        }

        uploaded_file = service.files().insert(
            body=body,
            media_body=media_body,
            convert=True  # to convert CSV's to Spreadsheet
        ).execute()

        return HttpResponseRedirect(uploaded_file['alternateLink'])

Running tests

Running reportato tests is dead simple. First, you need a virtualenv. I highly recommend to use virtualenvrapper for it. Having it installed, you'll just need to:

$ mkvirtualenv reportato  # will create the virtualenv
$ workon reportato  # will activate the virtualenv
# deactivate  # will deactivate it

In order to run the tests we need Django and Mock:

$ pip install Django Mock

Once those dependencies are installed, you can run the tests simply with:

$ python runtests.py

Future plans

• Add custom columns that aren't part of a model for adding aggregates
• Make some sort of Mixin for making the upload to Google Sheets easier
• Use values_list instead of composing the models for trying to be more efficient
• Provide helpers for deferring the report generation to GAE task queues