fix(rust/signed_doc): update metadata to require content type

* ContentType::Json is default

Author: saibatizoku

rust/signed_doc/examples/mk_signed_doc.rs

@@ -204,10 +204,7 @@ fn cose_protected_header() -> coset::Header {
 }
 
 fn build_empty_cose_doc(doc_bytes: Vec<u8>, meta: &Metadata) -> coset::CoseSign {
-    let mut builder = coset::HeaderBuilder::new();
-
-    if let Some(content_type) = meta.content_type() {
-        builder = builder.content_format(CoapContentFormat::from(content_type));
+    let mut builder = coset::HeaderBuilder::new().content_format(CoapContentFormat::from(meta.content_type()));
     }
 
     if let Some(content_encoding) = meta.content_encoding() {

rust/signed_doc/meta.schema.json

@@ -115,6 +115,7 @@
     "required": [
         "type",
         "id",
-        "ver"
+        "ver",
+        "content-type"
     ]
 }

rust/signed_doc/src/metadata/content_type.rs

@@ -17,6 +17,12 @@ pub enum ContentType {
     Json,
 }
 
+impl Default for ContentType {
+    fn default() -> Self {
+        Self::Json
+    }
+}
+
 impl Display for ContentType {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
         match self {

rust/signed_doc/src/metadata/mod.rs

@@ -32,6 +32,12 @@ pub struct Metadata {
     id: DocumentId,
     /// Document Version `UUIDv7`.
     ver: DocumentVersion,
+    /// Document Payload Content Type.
+    #[serde(default, rename = "content-type")]
+    content_type: ContentType,
+    /// Document Payload Content Encoding.
+    #[serde(default, rename = "content-encoding")]
+    content_encoding: Option<ContentEncoding>,
     /// Reference to the latest document.
     #[serde(rename = "ref")]
     doc_ref: Option<DocumentRef>,
@@ -41,12 +47,6 @@ pub struct Metadata {
     reply: Option<DocumentRef>,
     /// Reference to the document section.
     section: Option<String>,
-    /// Document Payload Content Type.
-    #[serde(default, rename = "content-type")]
-    content_type: Option<ContentType>,
-    /// Document Payload Content Encoding.
-    #[serde(default, rename = "content-encoding")]
-    content_encoding: Option<ContentEncoding>,
     /// Metadata Content Errors
     #[serde(skip)]
     content_errors: Vec<String>,
@@ -109,7 +109,7 @@ impl Metadata {
 
     /// Returns the Document Content Type, if any.
     #[must_use]
-    pub fn content_type(&self) -> Option<ContentType> {
+    pub fn content_type(&self) -> ContentType {
         self.content_type
     }
 
@@ -130,7 +130,7 @@ impl Display for Metadata {
         writeln!(f, "  template: {:?},", self.template)?;
         writeln!(f, "  reply: {:?},", self.reply)?;
         writeln!(f, "  section: {:?}", self.section)?;
-        writeln!(f, "  content_type: {:?}", self.content_type)?;
+        writeln!(f, "  content_type: {}", self.content_type)?;
         writeln!(f, "  content_encoding: {:?}", self.content_encoding)?;
         writeln!(f, "}}")
     }
@@ -146,7 +146,7 @@ impl Default for Metadata {
             template: None,
             reply: None,
             section: None,
-            content_type: None,
+            content_type: ContentType::default(),
             content_encoding: None,
             content_errors: Vec::new(),
         }
@@ -173,7 +173,7 @@ impl From<&coset::ProtectedHeader> for Metadata {
         match protected.header.content_type.as_ref() {
             Some(iana_content_type) => {
                 match ContentType::try_from(iana_content_type) {
-                    Ok(content_type) => metadata.content_type = Some(content_type),
+                    Ok(content_type) => metadata.content_type = content_type,
                     Err(e) => {
                         errors.push(format!("Invalid Document Content-Type: {e}"));
                     },