diesel/pg/types/
json.rs

1//! Support for JSON and `jsonb` values under PostgreSQL.
2
3extern crate serde_json;
4
5use std::io::prelude::*;
6
7use crate::deserialize::{self, FromSql};
8use crate::pg::{Pg, PgValue};
9use crate::serialize::{self, IsNull, Output, ToSql};
10use crate::sql_types;
11
12#[cfg(all(feature = "postgres_backend", feature = "serde_json"))]
13impl FromSql<sql_types::Json, Pg> for serde_json::Value {
14    fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
15        serde_json::from_slice(value.as_bytes()).map_err(|_| "Invalid Json".into())
16    }
17}
18
19#[cfg(all(feature = "postgres_backend", feature = "serde_json"))]
20impl ToSql<sql_types::Json, Pg> for serde_json::Value {
21    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
22        serde_json::to_writer(out, self)
23            .map(|_| IsNull::No)
24            .map_err(Into::into)
25    }
26}
27
28#[cfg(all(feature = "postgres_backend", feature = "serde_json"))]
29impl FromSql<sql_types::Jsonb, Pg> for serde_json::Value {
30    fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
31        let bytes = value.as_bytes();
32        let first_byte = bytes
33            .first()
34            .ok_or("Received an empty response from the server")?;
35
36        if *first_byte != 1 {
37            return Err("Unsupported JSONB encoding version".into());
38        }
39        // That's an empty slice if there is only
40        // one response byte
41        serde_json::from_slice(&bytes[1..]).map_err(|_| "Invalid Json".into())
42    }
43}
44
45#[cfg(all(feature = "postgres_backend", feature = "serde_json"))]
46impl ToSql<sql_types::Jsonb, Pg> for serde_json::Value {
47    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
48        out.write_all(&[1])?;
49        serde_json::to_writer(out, self)
50            .map(|_| IsNull::No)
51            .map_err(Into::into)
52    }
53}
54
55#[cfg(test)]
56mod tests {
57    use crate::deserialize::FromSql;
58    use crate::pg::{Pg, PgValue};
59    use crate::query_builder::bind_collector::ByteWrapper;
60    use crate::serialize::{Output, ToSql};
61    use crate::sql_types;
62
63    #[diesel_test_helper::test]
64    fn regression_json_float_survives_a_round_trip() {
65        crate::test_helpers::assert_floats_survive_a_json_round_trip::<sql_types::Json, Pg>(
66            |bytes| FromSql::<sql_types::Json, Pg>::from_sql(PgValue::for_test(bytes)),
67        );
68        crate::test_helpers::assert_floats_survive_a_json_round_trip::<sql_types::Jsonb, Pg>(
69            |bytes| FromSql::<sql_types::Jsonb, Pg>::from_sql(PgValue::for_test(bytes)),
70        );
71    }
72
73    #[diesel_test_helper::test]
74    fn json_to_sql() {
75        let mut buffer = Vec::new();
76        let mut bytes = Output::test(ByteWrapper(&mut buffer));
77        let test_json = serde_json::Value::Bool(true);
78        ToSql::<sql_types::Json, Pg>::to_sql(&test_json, &mut bytes).unwrap();
79        assert_eq!(buffer, b"true");
80    }
81
82    #[diesel_test_helper::test]
83    fn some_json_from_sql() {
84        let input_json = b"true";
85        let output_json: serde_json::Value =
86            FromSql::<sql_types::Json, Pg>::from_sql(PgValue::for_test(input_json)).unwrap();
87        assert_eq!(output_json, serde_json::Value::Bool(true));
88    }
89
90    #[diesel_test_helper::test]
91    fn bad_json_from_sql() {
92        let uuid: Result<serde_json::Value, _> =
93            FromSql::<sql_types::Json, Pg>::from_sql(PgValue::for_test(b"boom"));
94        assert_eq!(uuid.unwrap_err().to_string(), "Invalid Json");
95    }
96
97    #[diesel_test_helper::test]
98    fn no_json_from_sql() {
99        let uuid: Result<serde_json::Value, _> =
100            FromSql::<sql_types::Json, Pg>::from_nullable_sql(None);
101        assert_eq!(
102            uuid.unwrap_err().to_string(),
103            "Unexpected null for non-null column"
104        );
105    }
106
107    #[diesel_test_helper::test]
108    fn jsonb_to_sql() {
109        let mut buffer = Vec::new();
110        let mut bytes = Output::test(ByteWrapper(&mut buffer));
111        let test_json = serde_json::Value::Bool(true);
112        ToSql::<sql_types::Jsonb, Pg>::to_sql(&test_json, &mut bytes).unwrap();
113        assert_eq!(buffer, b"\x01true");
114    }
115
116    #[diesel_test_helper::test]
117    fn some_jsonb_from_sql() {
118        let input_json = b"\x01true";
119        let output_json: serde_json::Value =
120            FromSql::<sql_types::Jsonb, Pg>::from_sql(PgValue::for_test(input_json)).unwrap();
121        assert_eq!(output_json, serde_json::Value::Bool(true));
122    }
123
124    #[diesel_test_helper::test]
125    fn bad_jsonb_from_sql() {
126        let uuid: Result<serde_json::Value, _> =
127            FromSql::<sql_types::Jsonb, Pg>::from_sql(PgValue::for_test(b"\x01boom"));
128        assert_eq!(uuid.unwrap_err().to_string(), "Invalid Json");
129    }
130
131    #[diesel_test_helper::test]
132    fn bad_jsonb_version_from_sql() {
133        let uuid: Result<serde_json::Value, _> =
134            FromSql::<sql_types::Jsonb, Pg>::from_sql(PgValue::for_test(b"\x02true"));
135        assert_eq!(
136            uuid.unwrap_err().to_string(),
137            "Unsupported JSONB encoding version"
138        );
139    }
140
141    #[diesel_test_helper::test]
142    fn no_jsonb_from_sql() {
143        let uuid: Result<serde_json::Value, _> =
144            FromSql::<sql_types::Jsonb, Pg>::from_nullable_sql(None);
145        assert_eq!(
146            uuid.unwrap_err().to_string(),
147            "Unexpected null for non-null column"
148        );
149    }
150}
diesel/pg/types/json.rs

diesel/pg/types/
json.rs
