camel_processor/data_format/
json.rs

1use camel_api::body::Body;
2use camel_api::data_format::DataFormat;
3use camel_api::error::CamelError;
4use serde::Deserialize;
5
6const DEFAULT_MAX_JSON_BYTES: usize = 16 * 1024 * 1024; // 16 MiB
7
8fn default_max_bytes() -> usize {
9    DEFAULT_MAX_JSON_BYTES
10}
11
12/// Configuration for [`JsonDataFormat`]. All fields have hardened defaults;
13/// setting a non-default value is the per-item explicit choice per ADR-0033.
14#[derive(Debug, Clone, Deserialize)]
15#[serde(deny_unknown_fields)]
16pub struct JsonConfig {
17    /// Maximum input size accepted by `unmarshal` (DoS cap).
18    /// Default 16 MiB. The `max_bytes` cap is inert during `marshal`
19    /// (marshal serializes; it never parses untrusted input).
20    #[serde(default = "default_max_bytes")]
21    pub max_bytes: usize,
22}
23
24impl Default for JsonConfig {
25    fn default() -> Self {
26        Self {
27            max_bytes: DEFAULT_MAX_JSON_BYTES,
28        }
29    }
30}
31
32#[derive(Debug, Clone, Default)]
33pub struct JsonDataFormat {
34    config: JsonConfig,
35}
36
37impl JsonDataFormat {
38    pub fn new(config: JsonConfig) -> Self {
39        Self { config }
40    }
41}
42
43impl DataFormat for JsonDataFormat {
44    fn name(&self) -> &str {
45        "json"
46    }
47
48    fn marshal(&self, body: Body) -> Result<Body, CamelError> {
49        match body {
50            Body::Json(v) => {
51                let s = serde_json::to_string(&v).map_err(|e| {
52                    CamelError::TypeConversionFailed(format!(
53                        "cannot marshal Body::Json to text: {e}"
54                    ))
55                })?;
56                Ok(Body::Text(s))
57            }
58            Body::Text(_) => Ok(body),
59            Body::Stream(_) => Err(CamelError::TypeConversionFailed(
60                "cannot marshal Body::Stream — add 'stream_cache' or 'convert_body_to' before this step".to_string(),
61            )),
62            // Empty body: no-op. A REST handler that produces no body (e.g. a
63            // 204 DELETE) must not 500 at marshal — leave the body empty so the
64            // reply finaliser ships an empty response (spec §8.1).
65            Body::Empty => Ok(Body::Empty),
66            Body::Xml(_) => Err(CamelError::TypeConversionFailed(
67                "JsonDataFormat::marshal only supports Body::Json, Body::Text, Body::Bytes, \
68                 and Body::Empty"
69                    .to_string(),
70            )),
71            Body::Bytes(b) => {
72                let v: serde_json::Value = serde_json::from_slice(&b).map_err(|e| {
73                    CamelError::TypeConversionFailed(format!(
74                        "cannot marshal Body::Bytes as JSON: {e}"
75                    ))
76                })?;
77                Ok(Body::Text(serde_json::to_string(&v).map_err(|e| {
78                    CamelError::TypeConversionFailed(format!(
79                        "cannot serialize JSON value to text: {e}"
80                    ))
81                })?))
82            }
83        }
84    }
85
86    fn unmarshal(&self, body: Body) -> Result<Body, CamelError> {
87        match body {
88            Body::Json(_) => Ok(body),
89            Body::Text(s) => {
90                if s.len() > self.config.max_bytes {
91                    return Err(CamelError::TypeConversionFailed(format!(
92                        "JSON unmarshal input {} bytes exceeds max {}",
93                        s.len(),
94                        self.config.max_bytes
95                    )));
96                }
97                let v = serde_json::from_str(&s).map_err(|e| {
98                    CamelError::TypeConversionFailed(format!(
99                        "cannot unmarshal Body::Text as JSON: {e}"
100                    ))
101                })?;
102                Ok(Body::Json(v))
103            }
104            Body::Bytes(b) => {
105                if b.len() > self.config.max_bytes {
106                    return Err(CamelError::TypeConversionFailed(format!(
107                        "JSON unmarshal input {} bytes exceeds max {}",
108                        b.len(),
109                        self.config.max_bytes
110                    )));
111                }
112                let v = serde_json::from_slice(&b).map_err(|e| {
113                    CamelError::TypeConversionFailed(format!(
114                        "cannot unmarshal Body::Bytes as JSON: {e}"
115                    ))
116                })?;
117                Ok(Body::Json(v))
118            }
119            Body::Stream(_) => Err(CamelError::TypeConversionFailed(
120                "cannot unmarshal Body::Stream directly — use UnmarshalService which auto-materializes"
121                    .to_string(),
122            )),
123            // Empty body: no-op. A body-less request (e.g. POST with no body)
124            // must skip unmarshal rather than 500 — spec §8.1: "if the body is
125            // empty, skip unmarshal".
126            Body::Empty => Ok(Body::Empty),
127            Body::Xml(_) => Err(CamelError::TypeConversionFailed(
128                "JsonDataFormat::unmarshal only supports Body::Json, Body::Text, Body::Bytes, \
129                 and Body::Empty"
130                    .to_string(),
131            )),
132        }
133    }
134}
135
136#[cfg(test)]
137mod tests {
138    use super::*;
139    use bytes::Bytes;
140    use serde_json::json;
141
142    #[test]
143    fn test_name() {
144        assert_eq!(JsonDataFormat::default().name(), "json");
145    }
146
147    #[test]
148    fn test_unmarshal_text_to_json() {
149        let body = Body::Text(r#"{"a":1}"#.to_string());
150        let result = JsonDataFormat::default().unmarshal(body).unwrap();
151        assert!(matches!(result, Body::Json(_)));
152        if let Body::Json(v) = result {
153            assert_eq!(v["a"], json!(1));
154        }
155    }
156
157    #[test]
158    fn test_unmarshal_bytes_to_json() {
159        let body = Body::Bytes(Bytes::from_static(b"{\"b\":2}"));
160        let result = JsonDataFormat::default().unmarshal(body).unwrap();
161        assert!(matches!(result, Body::Json(_)));
162    }
163
164    #[test]
165    fn test_unmarshal_invalid_json() {
166        let body = Body::Text("not json".to_string());
167        let result = JsonDataFormat::default().unmarshal(body);
168        assert!(matches!(result, Err(CamelError::TypeConversionFailed(_))));
169    }
170
171    #[test]
172    fn test_unmarshal_json_noop() {
173        let body = Body::Json(json!({"x": 1}));
174        let result = JsonDataFormat::default().unmarshal(body).unwrap();
175        assert!(matches!(result, Body::Json(_)));
176    }
177
178    #[test]
179    fn test_unmarshal_unsupported_variant() {
180        let body = Body::Xml("<root/>".to_string());
181        let result = JsonDataFormat::default().unmarshal(body);
182        assert!(matches!(result, Err(CamelError::TypeConversionFailed(_))));
183    }
184
185    #[test]
186    fn test_unmarshal_empty_is_noop() {
187        // spec §8.1: an empty request body skips unmarshal instead of erroring.
188        let result = JsonDataFormat::default().unmarshal(Body::Empty).unwrap();
189        assert!(matches!(result, Body::Empty));
190    }
191
192    #[test]
193    fn test_marshal_empty_is_noop() {
194        // spec §8.1: an empty response body marshals to empty (e.g. 204 DELETE).
195        let result = JsonDataFormat::default().marshal(Body::Empty).unwrap();
196        assert!(matches!(result, Body::Empty));
197    }
198
199    #[test]
200    fn test_unmarshal_stream_rejected() {
201        use camel_api::body::{StreamBody, StreamMetadata};
202        use futures::stream;
203        use std::sync::Arc;
204        use tokio::sync::Mutex;
205
206        let stream = stream::iter(vec![Ok(Bytes::from_static(b"data"))]);
207        let body = Body::Stream(StreamBody {
208            stream: Arc::new(Mutex::new(Some(Box::pin(stream)))),
209            metadata: StreamMetadata::default(),
210        });
211        let result = JsonDataFormat::default().unmarshal(body);
212        assert!(matches!(result, Err(CamelError::TypeConversionFailed(_))));
213    }
214
215    #[test]
216    fn test_marshal_json_to_text() {
217        let body = Body::Json(json!({"key": "value"}));
218        let result = JsonDataFormat::default().marshal(body).unwrap();
219        match result {
220            Body::Text(s) => assert!(s.contains("\"key\"")),
221            _ => panic!("expected Body::Text"),
222        }
223    }
224
225    #[test]
226    fn test_marshal_text_noop() {
227        let body = Body::Text("already text".to_string());
228        let result = JsonDataFormat::default().marshal(body).unwrap();
229        assert_eq!(result, Body::Text("already text".to_string()));
230    }
231
232    #[test]
233    fn test_marshal_unsupported_variant() {
234        let body = Body::Xml("<root/>".to_string());
235        let result = JsonDataFormat::default().marshal(body);
236        assert!(matches!(result, Err(CamelError::TypeConversionFailed(_))));
237    }
238
239    #[test]
240    fn test_marshal_bytes_to_text() {
241        let body = Body::Bytes(Bytes::from_static(b"{\"key\":\"val\"}"));
242        let result = JsonDataFormat::default().marshal(body).unwrap();
243        match result {
244            Body::Text(s) => assert!(s.contains("\"key\"")),
245            _ => panic!("expected Body::Text"),
246        }
247    }
248
249    #[test]
250    fn test_marshal_invalid_bytes_returns_error() {
251        let body = Body::Bytes(Bytes::from_static(b"not json"));
252        let result = JsonDataFormat::default().marshal(body);
253        assert!(matches!(result, Err(CamelError::TypeConversionFailed(_))));
254    }
255
256    #[test]
257    fn test_unmarshal_text_size_cap() {
258        // Build a valid JSON string exceeding the 16 MiB cap.
259        let big = format!(r#"{{"k":"{}"}}"#, "x".repeat(16 * 1024 * 1024 + 10));
260        let body = Body::Text(big);
261        let result = JsonDataFormat::default().unmarshal(body);
262        assert!(result.is_err(), "expected error for oversized JSON text");
263        let msg = format!("{}", result.unwrap_err());
264        assert!(
265            msg.contains("exceeds") && msg.contains("max"),
266            "error should mention size cap: {msg}"
267        );
268    }
269
270    #[test]
271    fn test_unmarshal_bytes_size_cap() {
272        let big = format!(r#"{{"k":"{}"}}"#, "x".repeat(16 * 1024 * 1024 + 10));
273        let body = Body::Bytes(bytes::Bytes::from(big));
274        let result = JsonDataFormat::default().unmarshal(body);
275        assert!(result.is_err());
276    }
277
278    #[test]
279    fn test_unmarshal_text_with_raised_max_bytes() {
280        let big = format!(r#"{{"k":"{}"}}"#, "x".repeat(17 * 1024 * 1024));
281        let body = Body::Text(big);
282        let df = JsonDataFormat::new(JsonConfig {
283            max_bytes: 20 * 1024 * 1024,
284        });
285        let result = df.unmarshal(body);
286        assert!(result.is_ok(), "should accept under raised cap");
287    }
288
289    #[test]
290    fn test_unmarshal_default_rejects_oversized() {
291        let big = format!(r#"{{"k":"{}"}}"#, "x".repeat(17 * 1024 * 1024));
292        let body = Body::Text(big);
293        let df = JsonDataFormat::default();
294        let result = df.unmarshal(body);
295        assert!(result.is_err(), "should reject over default 16 MiB");
296    }
297}
camel_processor/data_format/json.rs

camel_processor/data_format/
json.rs
