snapfinder-lib

API Documentation

Introduction

snapfinder-lib is a node library for locating retailers that participate in the SNAP (formerly known as Food Stamps) program. It uses data provided by the USDA and imported daily into a MongoDB database to return nearby retailers for a given address, region, or geographic area in U.S. The library can be used to support developers who wish to import data and query their own MongoDB instance through this library instead of accessing the hosted REST API. The hosted REST API also uses this library and is also open source as a separate project.

spapfinder-lib was developed as a collaboration between the GSA and the private sector, sponsored by ITSource Technology Inc., as an Open Source project in support of the Federal Government's commitment to Open Data.

snapfinder-lib can be used to support both open source and commercial app development, as well as to support state and private websites, or any agency, organization, or enterprise that wishes to use or incorporate information regarding SNAP retailer locations.

The project is Open Source under the MIT License and available on GitHub.

Goals

• To make a positive contribution to society by leveraging Open Data
• To demonstrate a successful model of Open Source collaboration between a Federal Agency and the private sector development community
• To provide a well-documented example of creating and hosting a REST API based on Node and MongoDB. Development, version control, testing, and hosting can be done using free, cloud-based tools and services accessible from any computer with access to a browser.

What is SNAP?

SNAP stands for the Supplemental Nutrition Assistance Program mandated by the Federal Government and supervised by states to help millions of individuals and families who need financial assistance to buy food. Formerly known as the Food Stamp Program, SNAP provides an economic benefit as well as well as serving to eliminate hunger.

Today, instead of food stamps, eligible recipients are issued Electronic Benefit Transfer (EBT) cards. These cards can be used to purchase food and beverage items authorized by the USDA's SNAP program at retailers that accept EBT transactions.

The USDA Food and Nutrition Service maintains and publishes a list of retailers (vendors) across the country that welcome SNAP EBT customers. Data is stored in files in Comma Separated Value (CSV) format, which typically can be read by spreadsheet programs, such as Microsoft Excel.

SNAP Data

SNAP Retailer Locator data is harvested from data published by the USDA Food and Nutrition Service at the following URL:

• http://www.snapretailerlocator.com/export/Nationwide.zip

Resource Format

The URL retrieves a zip file that stores a single CSV file with a .csv extension. The name of the file represents the publish date; for example:

store_locations_2013_07_16.csv

The content data fields are:

CSV Field	JSON name
Store_Name	storeName
Longitude	longitude
Latitude	latitude
Address	address1
Address Line #2	address2
City	city
State	state
Zip5	zip5
Zip4	zip4

SNAP Data

Harvesting SNAP Data

The SNAP data file is periodically downloaded for updates, parsed, and then stored in a MongoDB database.

This harvesting processed is triggered by a CRON job scheduled at cron.io. The job is currently configured to run once per day. When the job runs, it POSTs a request to the following URI:

http://api.snapfinder.org/v1/jobs/harvest

How to test harvesting data during the Government Shutdown

(details)

https://docs.google.com/uc?export=download&id=0B1CcNQn50OzNUmlab1FPbVJRQnc

snapcsv.js

The code for retrieving and parsing the file is in lib/snapcsv.js. This module exports two functions:

• parser returns a new Parser instance with parseStream and parseFile methods for parsing SNAP data in CSV format. Parser emits record (for each row), end, and error events.

• importer returns a new Importer instance with an import method that handles retrieving the remote zip file, extracting the stored CSV file, and parsing the data. Importer emits data (for each record parsed from the input), end, and error events.

snapdb.js

The code for storing the parsed data is in lib/snabdb.js. It exports the following functions used by the harvesting job.

• connect connects to the database
• saveStore saves a store record (see above table for JSON field names)

More details are in the MongoDB section.

MongoDB

The database is hosted at MongoLab. MongoLab provides cloud database services for MongoDB and offers a free plan for up to 0.5 GB of storage. Current storage requirements are less than 80 MB.

The database is named snapdb and contains the following collections:

Collection	Description
metadata	Information about the data, such as active store collection
harvestLog	Results of harvest job, including status and stores processed count
store-###	The latest retailer collection (pointed to by metadata/currentStoreCollection)

Database Collections

Each store document (row) in the store collection contains all the fields named in the SNAP Data table above, along with a standard MongoDB _id field.

Development

One of the goals of this project is to provide a documented example of building an API using open source tools available online.

Developers need:

• A GitHub account
• A Cloud9 account