Merge pull request #198 from code0-tech/#196-expect-runtime-error

expect runtime error from taurus

Author: raphael-goetz

adapter/rest/src/content_type.rs

@@ -0,0 +1,318 @@
+use hyper::{
+    HeaderMap,
+    header::{CONTENT_TYPE, HeaderValue},
+};
+use tucana::shared::{
+    Value, number_value,
+    value::Kind::{self, StringValue},
+};
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum BodyFormat {
+    Json,
+    TextPlain,
+    Unknown,
+}
+
+#[derive(Debug)]
+pub enum BodyParseError {
+    UnsupportedContentType { observed: String },
+    InvalidUtf8(std::str::Utf8Error),
+    InvalidJson(serde_json::Error),
+}
+
+impl std::fmt::Display for BodyParseError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::UnsupportedContentType { observed } => {
+                write!(f, "unsupported content type: {}", observed)
+            }
+            Self::InvalidUtf8(err) => write!(f, "invalid UTF-8 body: {}", err),
+            Self::InvalidJson(err) => write!(f, "invalid JSON body: {}", err),
+        }
+    }
+}
+
+impl std::error::Error for BodyParseError {}
+
+#[derive(Debug)]
+pub enum BodyEncodeError {
+    UnsupportedContentType { observed: String },
+    InvalidJson(serde_json::Error),
+}
+
+impl std::fmt::Display for BodyEncodeError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::UnsupportedContentType { observed } => {
+                write!(f, "unsupported content type: {}", observed)
+            }
+            Self::InvalidJson(err) => write!(f, "failed to encode JSON body: {}", err),
+        }
+    }
+}
+
+impl std::error::Error for BodyEncodeError {}
+
+pub fn parse_body_from_headers(
+    headers: &HeaderMap<HeaderValue>,
+    body: &[u8],
+) -> Result<Option<Value>, BodyParseError> {
+    parse_body(get_content_type(headers), body)
+}
+
+pub fn parse_body(
+    content_type: Option<&str>,
+    body: &[u8],
+) -> Result<Option<Value>, BodyParseError> {
+    if body.is_empty() {
+        return Ok(None);
+    }
+
+    match classify_content_type(content_type) {
+        BodyFormat::Json => parse_json_body(body),
+        BodyFormat::TextPlain => parse_text_body(body),
+        BodyFormat::Unknown => {
+            // If there is no content type
+            if content_type.is_none()
+                && let Ok(value) = parse_text_body(body)
+            {
+                return Ok(value);
+            }
+
+            Err(BodyParseError::UnsupportedContentType {
+                observed: content_type.unwrap_or("<missing>").to_string(),
+            })
+        }
+    }
+}
+
+pub fn encode_body(content_type: Option<&str>, value: Value) -> Result<Vec<u8>, BodyEncodeError> {
+    match classify_content_type(content_type) {
+        BodyFormat::Json => encode_json_body(value),
+        BodyFormat::TextPlain => encode_text_body(value),
+        BodyFormat::Unknown => {
+            // Missing content type falls back to JSON.
+            if content_type.is_none() {
+                return encode_json_body(value);
+            }
+
+            Err(BodyEncodeError::UnsupportedContentType {
+                observed: content_type.unwrap_or("<missing>").to_string(),
+            })
+        }
+    }
+}
+
+pub fn classify_content_type(content_type: Option<&str>) -> BodyFormat {
+    let Some(raw) = content_type else {
+        return BodyFormat::Unknown;
+    };
+
+    let essence = raw
+        .split(';')
+        .next()
+        .unwrap_or(raw)
+        .trim()
+        .to_ascii_lowercase();
+
+    if essence == "application/json" || essence.ends_with("+json") {
+        return BodyFormat::Json;
+    }
+
+    if essence == "text/plain" {
+        return BodyFormat::TextPlain;
+    }
+
+    BodyFormat::Unknown
+}
+
+fn parse_json_body(body: &[u8]) -> Result<Option<Value>, BodyParseError> {
+    let json_value =
+        serde_json::from_slice::<serde_json::Value>(body).map_err(BodyParseError::InvalidJson)?;
+    Ok(Some(tucana::shared::helper::value::from_json_value(
+        json_value,
+    )))
+}
+
+fn parse_text_body(body: &[u8]) -> Result<Option<Value>, BodyParseError> {
+    let text = std::str::from_utf8(body).map_err(BodyParseError::InvalidUtf8)?;
+    Ok(Some(Value {
+        kind: Some(StringValue(text.to_string())),
+    }))
+}
+
+fn encode_json_body(value: Value) -> Result<Vec<u8>, BodyEncodeError> {
+    let json_val = tucana::shared::helper::value::to_json_value(value);
+    serde_json::to_vec_pretty(&json_val).map_err(BodyEncodeError::InvalidJson)
+}
+
+fn encode_text_body(value: Value) -> Result<Vec<u8>, BodyEncodeError> {
+    if let Some(text) = scalar_to_text(&value) {
+        return Ok(text.into_bytes());
+    }
+
+    // For lists/objects, return valid JSON text as the plain-text body.
+    encode_json_body(value)
+}
+
+fn scalar_to_text(value: &Value) -> Option<String> {
+    match value.kind.as_ref() {
+        Some(Kind::NullValue(_)) | None => Some("null".to_string()),
+        Some(Kind::BoolValue(v)) => Some(v.to_string()),
+        Some(Kind::StringValue(v)) => Some(v.clone()),
+        Some(Kind::NumberValue(v)) => match v.number.as_ref() {
+            Some(number_value::Number::Integer(i)) => Some(i.to_string()),
+            Some(number_value::Number::Float(f)) => Some(f.to_string()),
+            None => Some("null".to_string()),
+        },
+        _ => None,
+    }
+}
+
+fn get_content_type(headers: &HeaderMap<HeaderValue>) -> Option<&str> {
+    headers.get(CONTENT_TYPE).and_then(|h| h.to_str().ok())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tucana::shared::{NumberValue, Struct, Value};
+
+    #[test]
+    fn classify_json_content_type_with_charset() {
+        let format = classify_content_type(Some("application/json; charset=utf-8"));
+        assert_eq!(format, BodyFormat::Json);
+    }
+
+    #[test]
+    fn classify_vendor_json_content_type() {
+        let format = classify_content_type(Some("application/problem+json"));
+        assert_eq!(format, BodyFormat::Json);
+    }
+
+    #[test]
+    fn classify_text_plain_content_type() {
+        let format = classify_content_type(Some("text/plain; charset=utf-8"));
+        assert_eq!(format, BodyFormat::TextPlain);
+    }
+
+    #[test]
+    fn parse_json_body_to_struct_value() {
+        let body = br#"{"hello":"world","ok":true}"#;
+        let parsed = parse_body(Some("application/json"), body).unwrap();
+
+        let Some(Value {
+            kind: Some(Kind::StructValue(Struct { fields })),
+        }) = parsed
+        else {
+            panic!("expected struct value");
+        };
+
+        assert!(fields.contains_key("hello"));
+        assert!(fields.contains_key("ok"));
+    }
+
+    #[test]
+    fn parse_text_body_to_string_value() {
+        let body = b"hello";
+        let parsed = parse_body(Some("text/plain"), body).unwrap();
+
+        let Some(Value {
+            kind: Some(Kind::StringValue(v)),
+        }) = parsed
+        else {
+            panic!("expected string value");
+        };
+
+        assert_eq!(v, "hello");
+    }
+
+    #[test]
+    fn parse_unsupported_content_type_fails() {
+        let body = br#"<root />"#;
+        let err = parse_body(Some("application/xml"), body).unwrap_err();
+
+        assert!(matches!(err, BodyParseError::UnsupportedContentType { .. }));
+    }
+
+    #[test]
+    fn encode_json_body_from_struct_value() {
+        let value = Value {
+            kind: Some(Kind::StructValue(Struct {
+                fields: [(
+                    "hello".to_string(),
+                    Value {
+                        kind: Some(Kind::StringValue("world".to_string())),
+                    },
+                )]
+                .into_iter()
+                .collect(),
+            })),
+        };
+
+        let encoded = encode_body(Some("application/json"), value).unwrap();
+        let parsed: serde_json::Value = serde_json::from_slice(&encoded).unwrap();
+
+        assert_eq!(parsed["hello"], "world");
+    }
+
+    #[test]
+    fn encode_text_body_from_string_value() {
+        let value = Value {
+            kind: Some(Kind::StringValue("hello".to_string())),
+        };
+
+        let encoded = encode_body(Some("text/plain"), value).unwrap();
+        assert_eq!(encoded, b"hello".to_vec());
+    }
+
+    #[test]
+    fn encode_text_body_from_number_value() {
+        let value = Value {
+            kind: Some(Kind::NumberValue(NumberValue {
+                number: Some(number_value::Number::Integer(42)),
+            })),
+        };
+
+        let encoded = encode_body(Some("text/plain"), value).unwrap();
+        assert_eq!(encoded, b"42".to_vec());
+    }
+
+    #[test]
+    fn encode_text_body_from_struct_value_falls_back_to_json_text() {
+        let value = Value {
+            kind: Some(Kind::StructValue(Struct {
+                fields: [(
+                    "answer".to_string(),
+                    Value {
+                        kind: Some(Kind::NumberValue(NumberValue {
+                            number: Some(number_value::Number::Integer(42)),
+                        })),
+                    },
+                )]
+                .into_iter()
+                .collect(),
+            })),
+        };
+
+        let encoded = encode_body(Some("text/plain"), value).unwrap();
+        let body_text = String::from_utf8(encoded).unwrap();
+
+        assert!(body_text.contains("\"answer\""));
+        assert!(body_text.contains("42"));
+    }
+
+    #[test]
+    fn encode_unknown_content_type_fails() {
+        let value = Value {
+            kind: Some(Kind::StringValue("x".to_string())),
+        };
+
+        let err = encode_body(Some("application/xml"), value).unwrap_err();
+        assert!(matches!(
+            err,
+            BodyEncodeError::UnsupportedContentType { .. }
+        ));
+    }
+}