linuxexpert-practice-labs/labs/lfca/6-2-software-application-architecture

LFCA 6.2: Software application architecture

Calling a REST API and reading its JSON, HTTP status codes, and a first SQL database.

Before you start

Work as root (sudo -i), so ~ is /root. Answers go in /root/lab-answers/<task>. The VM needs internet access. The lab notes whether jq and SQLite are installed, and reset removes the ones it didn't find.

Tasks

1. Call a public REST API with curl and read the JSON: curl -s https://api.github.com/repos/git/git. Install jq if it's missing, pick out the repository's description with jq .description, and write it to /root/lab-answers/1.
2. Request a repository that doesn't exist with curl -i (for example https://api.github.com/repos/git/no-such-repo), find the HTTP status code, and write it to /root/lab-answers/2.
3. Install SQLite (sqlite3 on Ubuntu, sqlite on the RHEL family). In a database ~/shop.db, create a table, insert three rows and query them with SQL.

Hints

• curl -s URL | jq ., jq -r .description.
• The status code is on the first line of curl -i's output; curl -s -o /dev/null -w '%{http_code}\n' URL prints only the code.
• sqlite3 ~/shop.db, then CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT, price REAL);, INSERT INTO products (name, price) VALUES ('mug', 9.5);, SELECT * FROM products;, .tables, .quit.