Crate pgde

A simple library for consuming tokio_postgres::row::Row data into structs that derive the RowConsumer trait.

Most of the complex PostgreSQL types are not supported, namely arrays. Consequently Vec types on structs are not currently supported.

Features

Feature	Description	Extra dependencies	Default
consume_json	Implements consume_json on classes that derive the RowConsumer trait	serde, serde_json	No
json	Implements consume on serde_json::Value	serde_json	No
uuid	Implements consume on uuid::Uuid	uuid	No

Examples

consume

You may use consume to consume PostgreSQL row data into a struct like so.

#[derive(RowConsumer)]
struct Foo {
    Id: i32,
    Data: String,
}

...

let query = "select * from public.\"Foo\";";

match Foo::consume(&conn, query, &[]).await {
    Ok(v) => ..., // v is of type Vec<Foo>
    Err(v) => ...,
};

This crate implements from_row on the following types so that consume can be used in a similar fashion.

Type	Feature
bool	default
i8	default
i16	default
i32	default
u32	default
i64	default
f32	default
f64	default
String	default
SystemTime	default
IpAddr	default
serde_json::Value	json
uuid::Uuid	uuid

let query = "select Id from public.\"Foo\";";

match i32::consume(&conn, query, &[]).await {
    Ok(v) => ..., // v is of type Vec<i32>
    Err(v) => ...,
};

Features

The json and uuid features provide consume on serde_json::Value and uuid::Uuid for json and uuid data types in PostgreSQL.

With the consume_json feature you get access to consume_json, which returns json data in a String.

#[derive(Serialize, RowConsumer)]
struct Foo { ... }

...

match Foo::consume_json(&conn, query, &[]).await {
    Ok(v) => ..., // v is of type String
    Err(v) => ...,
};

Testing

Testing requires access to a PostgreSQL database with no tables. Setting the following environment variables will allow you to test.

Environment Variable	Description
PGDE_DB_HOST	The host that the database can be accessed at.
POSTGRES_USER	The user credential to provide.
POSTGRES_PASSWORD	The password to provide.
POSTGRES_DB	The name of the database to use for testing.

To test, you would then run.

cargo test --tests --all-features

Macros

• pg_type_expr_implementation
  A macro for implementing from_row on primitive types that defaults to a provided expression. Used internally to implement from_row on SystemTime and IpAddr.
• pg_type_implementation
  A macro for implementing from_row on primitive types. Used internally to implement from_row on bool, i32, String, etc.

Enums

• ConsumeError
  Errors that may occur during row consumption.

Traits

• RowConsumer
  The derivable trait for implementing PostgreSQL row consumption.