tokio-pg-mapper
tokio_postgres-mapper is a proc-macro designed to make mapping from postgresql
tables to structs simple.
Why?
It can be frustrating to write a lot of boilerplate and, ultimately, duplicated code for mapping from postgres Rows into structs.
For example, this might be what someone would normally write:
extern crate postgres;
use postgres::rows::Row;
pub struct User {
pub id: i64,
pub name: String,
pub email: Option<String>,
}
impl From<Row> for User {
fn from(row: Row) -> Self {
Self {
id: row.get("id"),
name: row.get("name"),
email: row.get("email"),
}
}
}
// code to execute a query here and get back a row
let user = User::from(row); // this can panicThis becomes worse when manually implementating using the non-panicking
get_opt method variant.
Using this crate, the boilerplate is removed, and panicking and non-panicking implementations are derived:
extern crate tokio_pg_mapper_derive;
extern crate tokio_pg_mapper;
use tokio_pg_mapper::FromTokioPostgresRow;
use tokio_pg_mapper_derive::PostgresMapper;
#[derive(PostgresMapper)]
pub struct User {
pub id: i64,
pub name: String,
pub email: Option<String>,
}
// Code to execute a query here and get back a row might now look like:
let stmt = "SELECT * FROM user WHERE username = $1 AND password = $2";
let result = client.query_one(stmt, &[&5, "asdf"]).await?;
let user = User::from_row(result).unwrap(); // or from_row_ref(&result)
The two crates
This repository contains two crates: postgres-mapper which contains an Error
enum and traits for converting from a tokio-postgres Row
without panicking, and postgres-mapper-derive which contains the proc-macro.
Installation
Install tokio-pg-mapper-derive and tokio-pg-mapper from crates.io
License
ISC.
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent