nostr: add NIP-31 support

Signed-off-by: Yuki Kishimoto <[email protected]>

CHANGELOG.md

@@ -33,6 +33,7 @@
 
 ### Added
 
+* nostr: add NIP-31 support ([Yuki Kishimoto])
 * nostr: add NIP-70 support ([Yuki Kishimoto])
 * nostr: add `EventId::LEN` const ([Yuki Kishimoto])
 * nostr: add `UnsignedEvent::ensure_id` method ([Yuki Kishimoto])

bindings/nostr-ffi/src/event/tag.rs

@@ -38,6 +38,10 @@ pub enum TagKind {
     ///
     /// <https://github.com/nostr-protocol/nips/blob/master/70.md>
     Protected,
+    /// Human-readable plaintext summary of what that event is about
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/31.md>
+    Alt,
     /// Relay
     RelayUrl,
     /// Nonce
@@ -125,6 +129,7 @@ impl<'a> From<tag::TagKind<'a>> for TagKind {
                 single_letter: Arc::new(single_letter.into()),
             },
             tag::TagKind::Protected => Self::Protected,
+            tag::TagKind::Alt => Self::Alt,
             tag::TagKind::Relay => Self::RelayUrl,
             tag::TagKind::Nonce => Self::Nonce,
             tag::TagKind::Delegation => Self::Delegation,
@@ -177,6 +182,7 @@ impl<'a> From<TagKind> for tag::TagKind<'a> {
         match value {
             TagKind::SingleLetter { single_letter } => Self::SingleLetter(**single_letter),
             TagKind::Protected => Self::Protected,
+            TagKind::Alt => Self::Alt,
             TagKind::RelayUrl => Self::Relay,
             TagKind::Nonce => Self::Nonce,
             TagKind::Delegation => Self::Delegation,
@@ -443,6 +449,19 @@ impl Tag {
         }
     }
 
+    /// A short human-readable plaintext summary of what that event is about
+    ///
+    /// JSON: `["alt", "<summary>"]`
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/31.md>
+    #[inline]
+    #[uniffi::constructor]
+    pub fn alt(summary: &str) -> Self {
+        Self {
+            inner: tag::Tag::alt(summary),
+        }
+    }
+
     /// Compose custom tag
     ///
     /// JSON: `["<kind>", "<value-1>", "<value-2>", ...]`
@@ -680,6 +699,12 @@ pub enum TagStandard {
     ///
     /// <https://github.com/nostr-protocol/nips/blob/master/70.md>
     Protected,
+    /// A short human-readable plaintext summary of what that event is about
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/31.md>
+    Alt {
+        summary: String,
+    },
 }
 
 impl From<tag::TagStandard> for TagStandard {
@@ -853,6 +878,7 @@ impl From<tag::TagStandard> for TagStandard {
             tag::TagStandard::LabelNamespace(label) => Self::LabelNamespace { namespace: label },
             tag::TagStandard::Label(labels) => Self::Label { label: labels },
             tag::TagStandard::Protected => Self::Protected,
+            tag::TagStandard::Alt(summary) => Self::Alt { summary },
         }
     }
 }
@@ -1000,6 +1026,7 @@ impl TryFrom<TagStandard> for tag::TagStandard {
             TagStandard::LabelNamespace { namespace } => Ok(Self::LabelNamespace(namespace)),
             TagStandard::Label { label } => Ok(Self::Label(label)),
             TagStandard::Protected => Ok(Self::Protected),
+            TagStandard::Alt { summary } => Ok(Self::Alt(summary)),
         }
     }
 }

bindings/nostr-js/src/event/tag.rs

@@ -356,6 +356,18 @@ impl JsTag {
         }
     }
 
+    /// A short human-readable plaintext summary of what that event is about
+    ///
+    /// JSON: `["alt", "<summary>"]`
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/31.md>
+    #[inline]
+    pub fn alt(summary: &str) -> Self {
+        Self {
+            inner: Tag::alt(summary),
+        }
+    }
+
     /// Check if is a standard event tag with `root` marker
     #[inline]
     #[wasm_bindgen(js_name = isRoot)]

crates/nostr/README.md

@@ -134,7 +134,7 @@ The following crate feature flags are available:
 |     ✅     | [28 - Public Chat](https://github.com/nostr-protocol/nips/blob/master/28.md)                                    |
 |     ❌     | [29 - Relay-based Groups](https://github.com/nostr-protocol/nips/blob/master/29.md)                             |
 |     ✅     | [30 - Custom Emoji](https://github.com/nostr-protocol/nips/blob/master/30.md)                                   |
-|     ❌     | [31 - Dealing with Unknown Events](https://github.com/nostr-protocol/nips/blob/master/31.md)                    |
+|     ✅     | [31 - Dealing with Unknown Events](https://github.com/nostr-protocol/nips/blob/master/31.md)                    |
 |     ✅     | [32 - Labeling](https://github.com/nostr-protocol/nips/blob/master/32.md)                                       |
 |     ❌     | [34 - `git` stuff](https://github.com/nostr-protocol/nips/blob/master/34.md)                                    |
 |     ❌     | [35 - Torrents](https://github.com/nostr-protocol/nips/blob/master/35.md)                                       |

crates/nostr/src/event/tag/kind.rs

@@ -19,6 +19,10 @@ pub enum TagKind<'a> {
     ///
     /// <https://github.com/nostr-protocol/nips/blob/master/70.md>
     Protected,
+    /// Human-readable plaintext summary of what that event is about
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/31.md>
+    Alt,
     /// Relay
     Relay,
     /// Nonce
@@ -108,6 +112,7 @@ impl<'a> fmt::Display for TagKind<'a> {
         match self {
             Self::SingleLetter(s) => write!(f, "{s}"),
             Self::Protected => write!(f, "-"),
+            Self::Alt => write!(f, "alt"),
             Self::Relay => write!(f, "relay"),
             Self::Nonce => write!(f, "nonce"),
             Self::Delegation => write!(f, "delegation"),
@@ -157,6 +162,7 @@ impl<'a> From<&'a str> for TagKind<'a> {
     fn from(kind: &'a str) -> Self {
         match kind {
             "-" => Self::Protected,
+            "alt" => Self::Alt,
             "relay" => Self::Relay,
             "nonce" => Self::Nonce,
             "delegation" => Self::Delegation,

crates/nostr/src/event/tag/mod.rs

@@ -289,6 +289,19 @@ impl Tag {
         Self::from_standardized_without_cell(TagStandard::Protected)
     }
 
+    /// A short human-readable plaintext summary of what that event is about
+    ///
+    /// JSON: `["alt", "<summary>"]`
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/31.md>
+    #[inline]
+    pub fn alt<T>(summary: T) -> Self
+    where
+        T: Into<String>,
+    {
+        Self::from_standardized_without_cell(TagStandard::Alt(summary.into()))
+    }
+
     /// Compose custom tag
     ///
     /// JSON: `["<kind>", "<value-1>", "<value-2>", ...]`
@@ -500,6 +513,8 @@ mod tests {
             Tag::from_standardized_without_cell(TagStandard::Protected).to_vec()
         );
 
+        assert_eq!(vec!["alt", "something"], Tag::alt("something").to_vec());
+
         assert_eq!(
             vec!["content-warning"],
             Tag::from_standardized_without_cell(TagStandard::ContentWarning { reason: None })
@@ -877,6 +892,11 @@ mod tests {
 
         assert_eq!(Tag::parse(&["-"]).unwrap(), Tag::protected());
 
+        assert_eq!(
+            Tag::parse(&["alt", "something"]).unwrap(),
+            Tag::alt("something")
+        );
+
         assert_eq!(
             Tag::parse(&["content-warning"]).unwrap(),
             Tag::from_standardized_without_cell(TagStandard::ContentWarning { reason: None })

crates/nostr/src/event/tag/standard.rs

@@ -171,6 +171,10 @@ pub enum TagStandard {
     ///
     /// <https://github.com/nostr-protocol/nips/blob/master/70.md>
     Protected,
+    /// A short human-readable plaintext summary of what that event is about
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/31.md>
+    Alt(String),
 }
 
 impl TagStandard {
@@ -339,6 +343,7 @@ impl TagStandard {
                     character: Alphabet::L,
                     uppercase: true,
                 }) => Ok(Self::LabelNamespace(tag_1.to_string())),
+                TagKind::Alt => Ok(Self::Alt(tag_1.to_string())),
                 TagKind::Dim => Ok(Self::Dim(ImageDimensions::from_str(tag_1)?)),
                 _ => Err(Error::UnknownStardardizedTag),
             };
@@ -552,6 +557,7 @@ impl TagStandard {
                 uppercase: false,
             }),
             Self::Protected => TagKind::Protected,
+            Self::Alt(..) => TagKind::Alt,
         }
     }
 
@@ -786,6 +792,7 @@ impl From<TagStandard> for Vec<String> {
                 tag
             }
             TagStandard::Protected => vec![tag_kind],
+            TagStandard::Alt(summary) => vec![tag_kind, summary],
         }
     }
 }