Added convenience wrappers for stringifying geojson (#229)

Co-authored-by: Jere Suikkila <jere.suikkila@live.com>

CHANGES.md

@@ -12,6 +12,7 @@
 * Added `GeometryCollection::try_from(&GeoJson)` and deprecated
   `quick_collection` for conventional naming and simpler docs.
   * <https://github.com/georust/geojson/pulls/214>
+* Added `GeoJson::to_string_pretty` as convenience wrappers around the same `serde_json` methods.
 
 ## 0.24.1
 

examples/geojson_to_string.rs

@@ -0,0 +1,18 @@
+use std::error::Error;
+use std::fs::File;
+use std::io::BufReader;
+
+use geojson::{Feature, GeoJson};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let file_reader = BufReader::new(File::open("tests/fixtures/canonical/good-feature.geojson")?);
+
+    let feature: Feature = serde_json::from_reader(file_reader)?;
+
+    let geojson: GeoJson = feature.into();
+
+    println!("{}", &geojson.to_string());
+    println!("{}", &geojson.to_string_pretty()?);
+
+    Ok(())
+}

src/geojson.rs

@@ -233,6 +233,13 @@ impl GeoJson {
     {
         serde_json::from_reader(rdr)
     }
+
+    /// Convenience wrapper for [serde_json::to_string_pretty()]
+    pub fn to_string_pretty(self) -> Result<String> {
+        ::serde_json::to_string_pretty(&self)
+            .map_err(|err| Error::MalformedJson(err))
+            .and_then(|s| Ok(s.to_string()))
+    }
 }
 
 impl TryFrom<JsonObject> for GeoJson {