feat: add ProblemDetails module for Verifiable Credentials Data Model…

… v2.0

crates/claims/crates/vc/src/v2/algorithm/mod.rs

@@ -0,0 +1,5 @@
+//! [Algorithms](https://www.w3.org/TR/vc-data-model-2.0/#algorithms) in Verifiable Credentials Data Model v2.0
+
+mod problem_details;
+
+pub use problem_details::ProblemDetails;

crates/claims/crates/vc/src/v2/algorithm/problem_details.rs

@@ -0,0 +1,169 @@
+use std::fmt;
+
+use serde::{Serialize, Serializer};
+
+/// [Problem Details](https://www.w3.org/TR/vc-data-model-2.0/#problem-details).
+#[derive(Debug, Serialize)]
+pub struct ProblemDetails {
+    #[serde(rename = "type", serialize_with = "serialize_problem_type")]
+    problem_type: Box<dyn ProblemType>,
+
+    #[serde(skip_serializing_if = "Option::is_none")]
+    code: Option<i32>,
+
+    title: String,
+    detail: String,
+}
+
+impl ProblemDetails {
+    pub fn new<T: ProblemType>(problem_type: T, title: String, detail: String) -> Self {
+        let code = problem_type.code();
+        Self {
+            problem_type: Box::new(problem_type),
+            code: Some(code),
+            title,
+            detail,
+        }
+    }
+
+    /// `type` property.
+    pub fn r#type(&self) -> &str {
+        self.problem_type.url()
+    }
+
+    /// `code` property.
+    pub fn code(&self) -> Option<i32> {
+        self.code
+    }
+
+    /// `title` property.
+    pub fn title(&self) -> &str {
+        &self.title
+    }
+
+    /// `detail` property.
+    pub fn detail(&self) -> &str {
+        &self.detail
+    }
+}
+
+fn serialize_problem_type<S>(
+    problem_type: &Box<dyn ProblemType>,
+    serializer: S,
+) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    serializer.serialize_str(&problem_type.to_string())
+}
+
+/// Problem `type`.
+///
+/// Implementations can define custom problem types.
+pub trait ProblemType: fmt::Display + fmt::Debug + Send + Sync + 'static {
+    fn url(&self) -> &'static str;
+    fn code(&self) -> i32;
+}
+
+/// Predefined `type`s in <https://www.w3.org/TR/vc-data-model-2.0/#problem-details>.
+#[derive(Clone, Debug, Serialize)]
+#[serde(rename_all = "SCREAMING_SNAKE_CASE")]
+pub enum PredefinedProblemType {
+    ParsingError,
+    CryptographicSecurityError,
+    MalformedValueError,
+    RangeError,
+}
+
+impl ProblemType for PredefinedProblemType {
+    fn url(&self) -> &'static str {
+        match self {
+            PredefinedProblemType::ParsingError => {
+                "https://www.w3.org/TR/vc-data-model#PARSING_ERROR"
+            }
+            PredefinedProblemType::CryptographicSecurityError => {
+                "https://www.w3.org/TR/vc-data-model#CRYPTOGRAPHIC_SECURITY_ERROR"
+            }
+            PredefinedProblemType::MalformedValueError => {
+                "https://www.w3.org/TR/vc-data-model#MALFORMED_VALUE_ERROR"
+            }
+            PredefinedProblemType::RangeError => "https://www.w3.org/TR/vc-data-model#RANGE_ERROR",
+        }
+    }
+
+    fn code(&self) -> i32 {
+        match self {
+            PredefinedProblemType::ParsingError => -64,
+            PredefinedProblemType::CryptographicSecurityError => -65,
+            PredefinedProblemType::MalformedValueError => -66,
+            PredefinedProblemType::RangeError => -67,
+        }
+    }
+}
+
+impl fmt::Display for PredefinedProblemType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.url())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_serialize_problem_details_parsing_error() {
+        let problem = ProblemDetails::new(
+            PredefinedProblemType::ParsingError,
+            "Parsing Error".to_string(),
+            "Failed to parse the request body.".to_string(),
+        );
+        let json = serde_json::to_string(&problem).expect("Failed to serialize ProblemDetails");
+        assert_eq!(
+            json,
+            r#"{"type":"https://www.w3.org/TR/vc-data-model#PARSING_ERROR","code":-64,"title":"Parsing Error","detail":"Failed to parse the request body."}"#
+        );
+    }
+
+    #[test]
+    fn test_serialize_problem_details_cryptographic_security_error() {
+        let problem = ProblemDetails::new(
+            PredefinedProblemType::CryptographicSecurityError,
+            "Cryptographic Security Error".to_string(),
+            "Failed to verify the cryptographic proof.".to_string(),
+        );
+        let json = serde_json::to_string(&problem).expect("Failed to serialize ProblemDetails");
+        assert_eq!(
+            json,
+            r#"{"type":"https://www.w3.org/TR/vc-data-model#CRYPTOGRAPHIC_SECURITY_ERROR","code":-65,"title":"Cryptographic Security Error","detail":"Failed to verify the cryptographic proof."}"#
+        );
+    }
+
+    #[test]
+    fn test_serialize_problem_details_malformed_value_error() {
+        let problem = ProblemDetails::new(
+            PredefinedProblemType::MalformedValueError,
+            "Malformed Value Error".to_string(),
+            "The request body contains a malformed value.".to_string(),
+        );
+        let json = serde_json::to_string(&problem).expect("Failed to serialize ProblemDetails");
+        assert_eq!(
+            json,
+            r#"{"type":"https://www.w3.org/TR/vc-data-model#MALFORMED_VALUE_ERROR","code":-66,"title":"Malformed Value Error","detail":"The request body contains a malformed value."}"#
+        );
+    }
+
+    #[test]
+    fn test_serialize_problem_details_range_error() {
+        let problem = ProblemDetails::new(
+            PredefinedProblemType::RangeError,
+            "Range Error".to_string(),
+            "The request body contains a value out of range.".to_string(),
+        );
+        let json = serde_json::to_string(&problem).expect("Failed to serialize ProblemDetails");
+        assert_eq!(
+            json,
+            r#"{"type":"https://www.w3.org/TR/vc-data-model#RANGE_ERROR","code":-67,"title":"Range Error","detail":"The request body contains a value out of range."}"#
+        );
+    }
+}

crates/claims/crates/vc/src/v2/mod.rs

@@ -5,9 +5,11 @@ use iref::Iri;
 
 use crate::syntax::RequiredContext;
 
+mod algorithm;
 mod data_model;
 pub mod syntax;
 
+pub use algorithm::ProblemDetails;
 pub use data_model::*;
 pub use syntax::{Context, JsonCredential, JsonCredentialTypes, SpecializedJsonCredential};