rust-postgis
============
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[Documentation](https://docs.rs/postgis/)
An extension to rust-postgres, adds support for PostGIS.
- PostGIS type helper
- GCJ02 support (used offically in Mainland China)
- Tiny WKB (TWKB) support
## Usage
```rust
use postgres::{Connection, TlsMode};
use postgis::ewkb;
use postgis::LineString;
fn main() {
// conn ....
for row in &conn.query("SELECT * FROM busline", &[]).unwrap() {
let route: ewkb::LineString = row.get("route");
let last_stop = route.points().last().unwrap();
let _ = conn.execute("INSERT INTO stops (stop) VALUES ($1)", &[&last_stop]);
}
}
```
Handling NULL values:
```rust
let route = row.get_opt::<_, Option<ewkb::LineString>>("route");
match route.unwrap() {
Ok(Some(geom)) => { println!("{:?}", geom) }
Ok(None) => { /* Handle NULL value */ }
Err(err) => { println!("Error: {}", err) }
}
```
## Writing other geometry types into PostGIS
rust-postgis supports writing geometry types into PostGIS which implement the following traits:
* `Point`, `LineString`, ...
* `AsEwkbPoint`, `AsEwkbLineString`, ...
See the TWKB implementation as an example.
An example for reading a TWKB geometry and writing it back as EWKB:
```rust
use postgis::twkb;
use postgis::LineString;
for row in &conn.query("SELECT ST_AsTWKB(route) FROM busline", &[]).unwrap() {
let route: twkb::LineString = row.get(0);
let last_stop = route.points().last().unwrap();
let _ = conn.execute("INSERT INTO stops (stop) VALUES ($1)", &[&last_stop.as_ewkb()]);
}
```
## Unit tests
Unit tests which need a PostgreSQL connection are ignored by default.
To run the database tests, declare the connection in an environment variable `DBCONN`. Example:
export DBCONN=postgresql://user@localhost/testdb
Run the tests with
cargo test -- --ignored