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A hands on project to build a wordplay solver with a web service API

Contents

• Overview
• Dev Environment Setup
  • Pipenv Setup
  • Alternative: Python venv and Pip
  • Verify Flask
• Development Milestones

Overview

This project provides an opportunity for the aspiring Pythonista to get hands-on experience with some of common tools used in the Python development ecosystem.

Libraries and tools used include:

• PyTest
• Flask
• Pipenv
• Git and GitHub

Our goal is to build a web service with a few endpoints all revolving around a wordplay solver theme:

Endpoint URL	HTTP Verb	Description
/api/score?l={letters}	GET	Returns the scrabble score of the letters
/api/word/{word}	GET	Returns whether word is in lexicon and scrabble score
/api/matches/{letters}	GET	Performs word matching in lexicon, sorted by scrabble score

Letter Scoring

Default scoring is to be calculated using Scrabble letter point values.

Point Value	Letters
1	A, E, I, L, N, O, R, S, T, U
2	D, G
3	B, C, M, P
4	F, H, V, W, Y
5	K
8	J, X
10	Q, Z

Dev Environment Setup

This project makes use of third-party packages that do not ship with Python standard library. It is recommended a Python virtual environment be configured to prevent the installed packages from conflicting with other Python projects on the host machine.

I recommend starting with pipenv and falling back to alternative tools if needed. Pipenv is a convenience tool that facilitates both managing a virtual environment as well as installing packages. Its usage is consistent across Windows and unix systems.

Alternernatively the virtual environment and packages can be configured separatetly using the Python venv library and the pip tool.

Set Up Using pipenv

The pipenv tool serves 2 roles:

1. creating and "activating" a virtual environment
2. installing 3rd party packages

Pipenv does not ship with Python and needs to be installed from the command line using pip (a.k.a. pip3).

The following commands need to be run from your command line shell.

pip3 install pipenv

Activate the virtual environment from within the repo directory:

# change to the project directory you cloned
cd wordplay
pipenv shell

Install the 3rd party packages:

pipenv install --dev

This will install Flask and PyTest libraries.

Confirm pytest is available by running the following from the command line:

pytest .

Alternative Set Up: Python venv and Pip

Change into the project directory you cloned and create a new virtual environment using the venv library:

# change to the project directory you cloned
cd wordplay
python3 -m venv venv

Activate the virtual environment.

• On Windows:

  venv\Scripts\activate.bat

• On Mac/Linux

  source venv/bin/activate

Install the 3rd party packages using pip3

pip3 install -r requirements.txt

Try running the tests:

pytest .

Verify Flask

Verify Flask launches:

python3 app.py

Open your browser to http://127.0.0.1:5000/

Milestones

1. Set up your developer environment. Confirm Flask and PyTest are installed
2. Edit wordplay.py and get score_word() functional so that the tests pass.
3. Play with Flask. Try modifying the / URL to load from a template instead of the hardcoded response string.
4. Write a function to read in the lexicon file sowpods.txt and return the contents as a list.
   The loader function should skip any empty lines or lines that start with # The words should be converted to lowercase.
5. ...