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 json_to_sql() {
65        let mut buffer = Vec::new();
66        let mut bytes = Output::test(ByteWrapper(&mut buffer));
67        let test_json = serde_json::Value::Bool(true);
68        ToSql::<sql_types::Json, Pg>::to_sql(&test_json, &mut bytes).unwrap();
69        assert_eq!(buffer, b"true");
70    }
71
72    #[diesel_test_helper::test]
73    fn some_json_from_sql() {
74        let input_json = b"true";
75        let output_json: serde_json::Value =
76            FromSql::<sql_types::Json, Pg>::from_sql(PgValue::for_test(input_json)).unwrap();
77        assert_eq!(output_json, serde_json::Value::Bool(true));
78    }
79
80    #[diesel_test_helper::test]
81    fn bad_json_from_sql() {
82        let uuid: Result<serde_json::Value, _> =
83            FromSql::<sql_types::Json, Pg>::from_sql(PgValue::for_test(b"boom"));
84        assert_eq!(uuid.unwrap_err().to_string(), "Invalid Json");
85    }
86
87    #[diesel_test_helper::test]
88    fn no_json_from_sql() {
89        let uuid: Result<serde_json::Value, _> =
90            FromSql::<sql_types::Json, Pg>::from_nullable_sql(None);
91        assert_eq!(
92            uuid.unwrap_err().to_string(),
93            "Unexpected null for non-null column"
94        );
95    }
96
97    #[diesel_test_helper::test]
98    fn jsonb_to_sql() {
99        let mut buffer = Vec::new();
100        let mut bytes = Output::test(ByteWrapper(&mut buffer));
101        let test_json = serde_json::Value::Bool(true);
102        ToSql::<sql_types::Jsonb, Pg>::to_sql(&test_json, &mut bytes).unwrap();
103        assert_eq!(buffer, b"\x01true");
104    }
105
106    #[diesel_test_helper::test]
107    fn some_jsonb_from_sql() {
108        let input_json = b"\x01true";
109        let output_json: serde_json::Value =
110            FromSql::<sql_types::Jsonb, Pg>::from_sql(PgValue::for_test(input_json)).unwrap();
111        assert_eq!(output_json, serde_json::Value::Bool(true));
112    }
113
114    #[diesel_test_helper::test]
115    fn bad_jsonb_from_sql() {
116        let uuid: Result<serde_json::Value, _> =
117            FromSql::<sql_types::Jsonb, Pg>::from_sql(PgValue::for_test(b"\x01boom"));
118        assert_eq!(uuid.unwrap_err().to_string(), "Invalid Json");
119    }
120
121    #[diesel_test_helper::test]
122    fn bad_jsonb_version_from_sql() {
123        let uuid: Result<serde_json::Value, _> =
124            FromSql::<sql_types::Jsonb, Pg>::from_sql(PgValue::for_test(b"\x02true"));
125        assert_eq!(
126            uuid.unwrap_err().to_string(),
127            "Unsupported JSONB encoding version"
128        );
129    }
130
131    #[diesel_test_helper::test]
132    fn no_jsonb_from_sql() {
133        let uuid: Result<serde_json::Value, _> =
134            FromSql::<sql_types::Jsonb, Pg>::from_nullable_sql(None);
135        assert_eq!(
136            uuid.unwrap_err().to_string(),
137            "Unexpected null for non-null column"
138        );
139    }
140}
diesel/pg/types/json.rs

diesel/pg/types/
json.rs
