This document provides an overview of using APIs, Postman, and Python to build a web application. It discusses researching and selecting an API, making requests using Postman, and constructing query strings. It then covers integrating an API into a Django web framework application in Python. The document demonstrates building a prototype app that retrieves economic indicator data from the World Bank API and displays it. It identifies opportunities for further developing the app, such as adding additional indicators and views.

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2. What will I learn?
How to:
• Research and choose an API suited for your application
• Use Postman for making requests to APIs
• Construct query strings with parameters
• Annotate and share Postman research
• Start developing a Python Django Web App

3. Chapter I: APIs

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6. Impact of API on Development
For REST requests in JSON:
• Is the correct type of data available?
• Language? Currency? Year-Range?
• Are there examples of query strings/calls?
• Are the endpoints well documented?
• Are the parameters clearly defined?
• Is it easy to construct a query string?
• How complex is the data object to parse in the program?
• Should I implement client-side caching of API calls?
• 100% Uptime/Availability?

7. Chapter II: Postman for Developers

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9. Our prototype must show GDP/PIL in Italy
GDP:
Monetary measure of the market value of all final goods and
services produced in a period (quarterly or yearly)
of time. Nominal GDP estimates are commonly used to
determine the economic performance of a whole country or
region, and to make international comparisons.
Source: https://en.wikipedia.org/wiki/Gross_domestic_product

10. World Bank API: Example
Constructing an API call with query parameters
http://api.worldbank.org/countries/it/indicators/NY.GDP.MKTP.CD?format=json&per_page=500&date=1975:2015
Endpoint Query parameters

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16. Postman UI: Add info in “Description”
Add a description to clarify research
goals and to enlighten your colleagues.

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20. Chapter III: from Postman to Python

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22. Django Web Framework
• Django Project has multiple applications:
• Core application
• Module “applications” represent a single aspect of a project.
• DB: SQLite for development only (PostGres, MySQL, NoSQL)
• APPS are registered in the settings.py file:
INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
[… ecc.]
’analista.apps.AnalistaConfig’….. (ecc)
]

23. Analista/ resides at parent level of directory
analista/
__init__.py
admin.py
apps.py
migrations/
__init__.py
models.py
tests.py
views.py
manage.py

24. MTV vs. MVC?
Django uses MTV
Model(M) is a model of the data access layer. It defines:
- How to access data
- How to validate data
- What are the relationships between the data
Template (T) is the presentation layer. It defines:
- How something should be displayed on a Web page
View (V) is the business logic layer. Defines the logic that:
- Accesses the model and references the appropriate template(s).

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29. Let’s Build an App!
AnalistApp
https://analistapp.glitch.me
NOTE: Use only Google Chrome to view prototype

30. Model: Economic Indicators
GDP:
Monetary measure of the market value of all final goods and
services produced in a period (quarterly or yearly) of time.
GNI:
Total domestic and foreign output claimed by residents of a
country, consisting of gross domestic product (GDP), plus factor
incomes earned by foreign residents, minus income earned in
the domestic economy by nonresidents.
FDI:
Investment in the form of a controlling ownership in
a business in one country by an entity based in another
country.[1].
Sources: https://en.wikipedia.org/wiki/Gross_domestic_product; https://en.wikipedia.org/wiki/Foreign_direct_investment;
https://en.wikipedia.org/wiki/Gross_national_income

31. There are many possibilities
for further development:
We can do more research on the API to learn what other resources are
available to us.
We can make new requests using different economic indicators
• GNI
• FDI
(see previous page)
We can develop new views that will display different economic
indicators in views.py.
We should return to wireframes to develop user stories and our epic.

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34. Other information
Goodbye to POSTMAN for Google Chrome:
• http://blog.getpostman.com/2017/11/01/goodbye-postman-chrome-
app/
You can download the native POSTMAN application here:
• https://www.getpostman.com/apps

35. Works Cited
Django Girls Tutorial (Italiano): https://tutorial.djangogirls.org/it/
Django Girls Tutorial (Inglese):
https://www.gitbook.com/book/djangogirls/djangogirls-tutorial/details
Django Documentation: https://docs.djangoproject.com/en/1.11/intro/tutorial01/
Postman Community Survey:
http://pages.getpostman.com/rs/067-UMD-991/images/Postman-Survey-Results-
Infographic.pdf
Programmable Web:
https://www.programmableweb.com/news/programmableweb-api-directory-
eclipses-17000-api-economy-continues-surge/research/2017/03/13
Ultimate Django: https://ultimatedjango.com/
World Bank API:
https://datahelpdesk.worldbank.org/knowledgebase/articles/898581-api-basic-
call-structure