jsonb_pretty function

diesel/src/pg/expression/functions.rs

@@ -3,6 +3,7 @@
 use super::expression_methods::InetOrCidr;
 use crate::expression::functions::define_sql_function;
 use crate::pg::expression::expression_methods::ArrayOrNullableArray;
+use crate::pg::expression::expression_methods::JsonbOrNullableJsonb;
 use crate::pg::expression::expression_methods::MaybeNullableValue;
 use crate::pg::expression::expression_methods::MultirangeOrNullableMultirange;
 use crate::pg::expression::expression_methods::MultirangeOrRangeMaybeNullable;
@@ -1634,3 +1635,75 @@ define_sql_function! {
         text_array: Arr,
     ) -> Arr::Out;
 }
+
+#[cfg(feature = "postgres_backend")]
+define_sql_function! {
+    /// Converts the given json value to pretty-printed, indented text
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # include!("../../doctest_setup.rs");
+    /// #
+    /// # fn main() {
+    /// #     #[cfg(feature = "serde_json")]
+    /// #     run_test().unwrap();
+    /// # }
+    /// #
+    /// # #[cfg(feature = "serde_json")]
+    /// # fn run_test() -> QueryResult<()> {
+    /// #     use diesel::dsl::jsonb_pretty;
+    /// #     use serde_json::json;
+    /// #     use diesel::sql_types::Jsonb;
+    /// #     let connection = &mut establish_connection();
+    /// let result = diesel::select(jsonb_pretty::<Jsonb, _>(json!([{"f1":1,"f2":null},2,null,3])))
+    ///     .get_result::<String>(connection)?;
+    ///
+    /// assert_eq!(r#"[
+    ///     {
+    ///         "f1": 1,
+    ///         "f2": null
+    ///     },
+    ///     2,
+    ///     null,
+    ///     3
+    /// ]"#, result);
+    ///
+    /// let result = diesel::select(jsonb_pretty::<Jsonb, _>(json!({"a": 1, "b": "cd"})))
+    ///     .get_result::<String>(connection)?;
+    ///
+    /// assert_eq!(r#"{
+    ///     "a": 1,
+    ///     "b": "cd"
+    /// }"#, result);
+    ///
+    /// let result = diesel::select(jsonb_pretty::<Jsonb, _>(json!("abc")))
+    ///     .get_result::<String>(connection)?;
+    ///
+    /// assert_eq!(r#""abc""#, result);
+    ///
+    /// let result = diesel::select(jsonb_pretty::<Jsonb, _>(json!(22)))
+    ///     .get_result::<String>(connection)?;
+    ///
+    /// assert_eq!(r#"22"#, result);
+    ///
+    /// let result = diesel::select(jsonb_pretty::<Jsonb, _>(json!(false)))
+    ///     .get_result::<String>(connection)?;
+    ///
+    /// assert_eq!(r#"false"#, result);
+    ///
+    /// let result = diesel::select(jsonb_pretty::<Jsonb, _>(json!(null)))
+    ///     .get_result::<String>(connection)?;
+    ///
+    /// assert_eq!(r#"null"#, result);
+    ///
+    /// let result = diesel::select(jsonb_pretty::<Jsonb, _>(json!({})))
+    ///     .get_result::<String>(connection)?;
+    ///
+    /// assert_eq!(r#"{
+    /// }"#, result);
+    /// #     Ok(())
+    /// # }
+    /// ```
+    fn jsonb_pretty<E: JsonbOrNullableJsonb + SingleValue>(e: E) -> Text;
+}

diesel/src/pg/expression/helper_types.rs

@@ -486,3 +486,8 @@ pub type to_jsonb<E> = super::functions::to_jsonb<SqlTypeOf<E>, E>;
 #[allow(non_camel_case_types)]
 #[cfg(feature = "postgres_backend")]
 pub type json_object<A> = super::functions::json_object<SqlTypeOf<A>, A>;
+
+/// Return type of [`jsonb_pretty(jsonb)`](super::functions::jsonb_pretty())
+#[allow(non_camel_case_types)]
+#[cfg(feature = "postgres_backend")]
+pub type jsonb_pretty<E> = super::functions::jsonb_pretty<SqlTypeOf<E>, E>;

diesel_derives/tests/auto_type.rs

@@ -438,6 +438,7 @@ fn postgres_functions() -> _ {
         to_json(pg_extras::id),
         to_jsonb(pg_extras::id),
         json_object(pg_extras::text_array),
+        jsonb_pretty(pg_extras::jsonb),
     )
 }