momento_functions_host/
encoding.rs

1//! Encoding and decoding of byte array payloads
2
3use std::convert::Infallible;
4
5/// Required to be implemented by encode error types.
6pub trait EncodeError: std::error::Error + 'static {}
7
8impl EncodeError for Infallible {}
9
10impl EncodeError for serde_json::Error {}
11
12/// A payload which can be converted to a vector of bytes
13pub trait Encode {
14    /// The error type returned when encoding fails.
15    type Error: EncodeError;
16    /// Convert the payload to a vector of bytes
17    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error>;
18}
19
20impl Encode for Vec<u8> {
21    type Error = Infallible;
22    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
23        Ok(self)
24    }
25}
26impl Encode for &[u8] {
27    type Error = Infallible;
28    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
29        Ok(self)
30    }
31}
32impl Encode for String {
33    type Error = Infallible;
34    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
35        Ok(self.into_bytes())
36    }
37}
38impl Encode for &str {
39    type Error = Infallible;
40    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
41        Ok(self.as_bytes())
42    }
43}
44impl Encode for Option<Vec<u8>> {
45    type Error = Infallible;
46    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
47        match self {
48            Some(v) => Ok(v),
49            None => Ok(Vec::new()),
50        }
51    }
52}
53impl Encode for () {
54    type Error = Infallible;
55    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
56        Ok([])
57    }
58}
59impl Encode for serde_json::Value {
60    type Error = serde_json::Error;
61    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
62        serde_json::to_vec(&self)
63    }
64}
65
66/// Required to be implemented by extract error types.
67pub trait ExtractError: std::error::Error + 'static {}
68
69impl ExtractError for Infallible {}
70
71impl ExtractError for serde_json::Error {}
72
73/// Payload extractor for encodings
74pub trait Extract: Sized {
75    /// The error type returned when extraction fails.
76    type Error: ExtractError;
77    /// Convert from a payload to a value
78    fn extract(payload: Vec<u8>) -> Result<Self, Self::Error>;
79}
80
81impl Extract for Vec<u8> {
82    type Error = Infallible;
83    fn extract(payload: Vec<u8>) -> Result<Self, Self::Error> {
84        Ok(payload)
85    }
86}
87
88/// JSON encoding and decoding
89pub struct Json<T>(pub T);
90impl<T: serde::de::DeserializeOwned> Extract for Json<T> {
91    type Error = serde_json::Error;
92    fn extract(payload: Vec<u8>) -> Result<Self, Self::Error> {
93        Ok(Json(serde_json::from_slice(&payload)?))
94    }
95}
96
97impl<T: serde::Serialize> Encode for Json<T> {
98    type Error = serde_json::Error;
99    fn try_serialize(self) -> Result<impl Into<Vec<u8>>, Self::Error> {
100        serde_json::to_vec(&self.0)
101    }
102}
momento_functions_host/encoding.rs

momento_functions_host/
encoding.rs
