rust-db-play/src/main.rs

extern crate clap;
extern crate r2d2;
extern crate r2d2_sqlite;
extern crate rusqlite;
extern crate simple_error;

use clap::{App, SubCommand};
use r2d2::Pool;
use r2d2_sqlite::SqliteConnectionManager;
use rusqlite::params;
use serde_json::{Map, Value};
use serde_rusqlite::from_row;
use serde_rusqlite::Result as SRResult;
use simple_error::*;

fn main() -> Result<(), SimpleError> {
    let matches = App::new("Rust DB Play")
        .version("1.0")
        .author("Jonathan Altman <jonathan@async.io>")
        .about("Test out Rust database result serialization")
        .subcommand(SubCommand::with_name("sqlite").about("Test on sqlite"))
        .subcommand(SubCommand::with_name("postgres").about("Test on postgres"))
        .get_matches();

    return match matches.subcommand_name() {
        Some("sqlite") => test_sqlite(),
        Some("postgres") => test_postgres(),
        None => bail!("No database specified"),
        _ => bail!("Unknown database specified"),
    };
}

fn test_postgres() -> Result<(), SimpleError> {
    println!("Postgres: Not implemented yet");
    return Ok(());
}

fn test_sqlite() -> Result<(), SimpleError> {
    let (pool, table_name) = setup_sqlite().unwrap();
    return match test_sqlite_json(pool, &table_name) {
        Ok(()) => Ok(()),
        // @TODO (2019-11-19, Jonathan) Extract sqlite error here
        Err(_) => bail!("Error in testing sqlite"),
    };
}

fn setup_sqlite() -> SRResult<(Pool<SqliteConnectionManager>, String)> {
    fn setup_pool() -> Pool<SqliteConnectionManager> {
        let manager = SqliteConnectionManager::memory();
        let pool = Pool::new(manager).unwrap();
        pool
    }
    fn setup_db_structure(pool: &Pool<SqliteConnectionManager>, table_name: &str) -> SRResult<()> {
        let conn = pool.get().unwrap();
        conn.execute(
            format!(
                "CREATE TABLE {} (
                  id              INTEGER PRIMARY KEY,
                  name            TEXT NOT NULL,
                  time_created    TEXT NOT NULL,
                  data            BLOB,
                  data_null       BLOB
                  )",
                table_name
            )
            .as_str(),
            params![],
        )?;

        conn.execute(
            "INSERT INTO person (name, time_created, data, data_null)
                  VALUES (?1, ?2, ?3, ?4)",
            params![
                "Steven".to_string(),
                time::get_time(),
                "This is some text".to_string(),
                None as Option<Vec<u8>>
            ],
        )?;
        Ok(())
    }

    const TABLE_NAME: &str = "person";
    let pool = setup_pool();
    setup_db_structure(&pool, TABLE_NAME)?;
    Ok((pool, TABLE_NAME.to_string()))
}

fn test_sqlite_json(pool: Pool<SqliteConnectionManager>, table_name: &String) -> SRResult<()> {
    let conn = pool.get().unwrap();
    let mut stmt = conn.prepare(&format!("SELECT * FROM {}", table_name))?;
    let result_iter = stmt.query_map(params![], |row| {
        Ok(from_row::<Map<String, Value>>(row).unwrap())
    })?;
    for cur_result in result_iter {
        println!(
            "Found row {:?}",
            serde_json::to_string(&cur_result.unwrap()).unwrap()
        );
    }
    Ok(())
}