WebCalcAPI

A Django Rest Framework Site that provides online calculation functions through API calls. Also a guide on how to create multiple versions of django-rest-framework APIs.

Author: Jiahang Zou

Requirements

Install by running pip install -r requirements.txt The unspecified installations are for heroku usages.

Required:
- Python==2.7
- Django==1.9.1
- djangorestframework==3.3.2
Optional:
- django-rest-swagger==0.3.4 (prereq: PyYAML==3.11)
- To run asian_option example:
  - numpy==1.10.4
  - scipy==0.16.1
The versions are not strictly required, as the author simply used the newest version there is through pip install.
django-rest-swagger is an api documentation generator that is quite useful if this project becomes large-scale. However, the base status of the version is not implementing it, as it is for internal use.
Also, this project was written for the purposes of completing an intern assignment, along with goals of learning Django Rest API and practicing uses of pyenv and Heroku. So this environment does have some unnecessary setups for pyenv and heroku. It is highly suggested that you install everything under a virtual environment to avoid conflicts.

Structure

Notice this is a django-project, so it obeys all the django rules. For details, see https://www.djangoproject.com/.

The project is constructed mainly under Django Rest Framework. See its tutorial to get some main ways to construct each API. The APIs in this project is primarily for temporary calculation purposes, instead of retrieving objects from object models. Therefore, function-based views were used to design such models.

Under views.py, there are example functions of api views. Each of these is a function dealing with get requests, with related urls under urls.py. For more details, read the documentations under each function.

Adding another function

Define the function in views.py, follow the format of other functions (e.g. with api_view decorator, a description of input and output types, a try/except clause), and by taking a request and examing its arguments, return a Response object.
Add a url with the desired format in urls.py
Add your new function in api_root under views.py. Make sure the name your reverse matches the name you give in urls.py in step 2.
Testing: To run a local server, do python manage.py runserver at the base directory, and then check your localhost at port 8000: http://localhost:8000, your API should be linked there, or directly call your API with your given format.

See Detail in the following tutorial.

Example Tutorial: Adding an Add function in function-based view.

Define add in views.py.

@api_view()
def add(request):
    """
    An addition function. 
    add(
        a: int,
        b: int,
        ret: int
    )
    example call: **whatever_host**/add/?a=1&b=1
    should return a json looks like:
    {'function': 'add','result': 2}
    """
    try:
        first_number = int(request.GET.get('a'))
        second_number = int(request.GET.get('b'))
        return Response({'function': 'multiply','result': first_number + second_number})
    except Exception as e:
        return Response({'function': 'multiply','result': 'there was an error ' + str(e)})

Make sure you have all three parts of the method:

the api_view() decorator
the documentation of the function
the try/except loop with getting the request and returning the response.

Define adds url in urls.py.
```
url(r'^add/?$', views.add, name='add'),
```

Define the documentation and link in views.api_root method:

return Response({
    ...
    'add': reverse('add', request=request),
})

Test it.

scottjzou/WebCalcAPI

WebCalcAPI

Requirements

Structure

Adding another function

Example Tutorial: Adding an Add function in function-based view.