nostr: add support for event kind 15

crates/nostr/CHANGELOG.md

@@ -68,6 +68,9 @@
 - Add `MachineReadablePrefix::Custom` variant (https://github.com/rust-nostr/nostr/pull/1258)
 - Add `RelayMetadata::{is_read, is_write}` functions (https://github.com/rust-nostr/nostr/pull/1290)
 - Add the kind number in the kind doc (https://github.com/rust-nostr/nostr/pull/1293)
+- Add `EventBuilder::private_file_msg` and `EventBuilder::file_msg`
+- Add `Kind::FileMessage`
+- Add `TagStandard::FileType`, `TagStandard::EncryptionAlgorithm`, `TagStandard::DecryptionKey` and `TagStandard::DecryptionNonce`
 
 ### Removed
 

crates/nostr/src/event/builder.rs

@@ -1556,6 +1556,30 @@ impl EventBuilder {
         Self::gift_wrap(signer, &receiver, rumor, []).await
     }
 
+    /// Private Direct file message
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    #[inline]
+    #[cfg(all(feature = "std", feature = "os-rng", feature = "nip59"))]
+    pub async fn private_file_msg<T, I>(
+        signer: &T,
+        receiver: PublicKey,
+        encrypted_file: EncryptedFile,
+        rumor_extra_tags: I,
+    ) -> Result<Event, Error>
+    where
+        T: NostrSigner,
+        I: IntoIterator<Item = Tag>,
+    {
+        let public_key: PublicKey = signer.get_public_key().await?;
+        let rumor = encrypted_file
+            .to_event_builder()?
+            .tag(Tag::public_key(receiver))
+            .tags(rumor_extra_tags)
+            .build(public_key);
+        Self::gift_wrap(signer, &receiver, rumor, []).await
+    }
+
     /// Mute list
     ///
     /// <https://github.com/nostr-protocol/nips/blob/master/51.md>

crates/nostr/src/event/kind.rs

@@ -138,6 +138,7 @@ kind_variants! {
     Seal => 13, "Seal", "<https://github.com/nostr-protocol/nips/blob/master/59.md>",
     GiftWrap => 1059, "Gift Wrap", "<https://github.com/nostr-protocol/nips/blob/master/59.md>",
     PrivateDirectMessage => 14, "Private Direct message", "<https://github.com/nostr-protocol/nips/blob/master/17.md>",
+    FileMessage => 15, "File message", "<https://github.com/nostr-protocol/nips/blob/master/17.md>",
     SetStall => 30017, "Set stall", "<https://github.com/nostr-protocol/nips/blob/master/15.md>",
     SetProduct => 30018, "Set product", "<https://github.com/nostr-protocol/nips/blob/master/15.md>",
     JobFeedback => 7000, "Job Feedback", "<https://github.com/nostr-protocol/nips/blob/master/90.md>",

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

@@ -63,12 +63,24 @@ pub enum TagKind<'a> {
     Dependency,
     /// Description
     Description,
+    /// Decryption key
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    DecryptionKey,
+    /// Decryption nonce
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    DecryptionNonce,
     /// Size of the file in pixels
     Dim,
     /// Emoji
     Emoji,
     /// Encrypted
     Encrypted,
+    /// Encryption algorithm
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    EncryptionAlgorithm,
     /// Ends
     Ends,
     /// Expiration
@@ -81,6 +93,10 @@ pub enum TagKind<'a> {
     Extension,
     /// File
     File,
+    /// File type
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    FileType,
     /// Image
     Image,
     /// License of the shared content
@@ -333,13 +349,17 @@ impl<'a> TagKind<'a> {
             Self::CurrentParticipants => "current_participants",
             Self::Dependency => "dep",
             Self::Description => "description",
+            Self::DecryptionKey => "decryption-key",
+            Self::DecryptionNonce => "decryption-nonce",
             Self::Dim => "dim",
             Self::Emoji => "emoji",
             Self::Encrypted => "encrypted",
+            Self::EncryptionAlgorithm => "encryption-algorithm",
             Self::Ends => "ends",
             Self::Expiration => "expiration",
             Self::Extension => "extension",
             Self::File => "file",
+            Self::FileType => "file-type",
             Self::Head => "HEAD",
             Self::Image => "image",
             Self::License => "license",

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

@@ -306,6 +306,22 @@ pub enum TagStandard {
     /// List of web URLs
     Web(Vec<Url>),
     Word(String),
+    /// File type
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    FileType(String),
+    /// Encryption algorithm. Note: NIP17 specifies that the encryption algorithm is aes-gcm
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    EncryptionAlgorithm,
+    /// Decryption key
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    DecryptionKey(String),
+    /// Decryption nonce
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/17.md>
+    DecryptionNonce(u128),
 }
 
 impl TagStandard {
@@ -750,6 +766,10 @@ impl TagStandard {
             Self::Protected => TagKind::Protected,
             Self::Alt(..) => TagKind::Alt,
             Self::Web(..) => TagKind::Web,
+            Self::FileType(..) => TagKind::FileType,
+            Self::EncryptionAlgorithm => TagKind::EncryptionAlgorithm,
+            Self::DecryptionKey(..) => TagKind::DecryptionKey,
+            Self::DecryptionNonce(..) => TagKind::DecryptionNonce,
         }
     }
 
@@ -1083,6 +1103,15 @@ impl From<TagStandard> for Vec<String> {
                 tag.extend(urls.into_iter().map(|url| url.to_string()));
                 tag
             }
+            TagStandard::FileType(mime) => vec![tag_kind, mime],
+            TagStandard::EncryptionAlgorithm => {
+                // NIP17 specifies that the encryption algorithm is aes-gcm
+                //
+                // <https://github.com/nostr-protocol/nips/blob/master/17.md>
+                vec![tag_kind, "aes-gcm".to_string()]
+            }
+            TagStandard::DecryptionKey(key) => vec![tag_kind, key],
+            TagStandard::DecryptionNonce(nonce) => vec![tag_kind, nonce.to_string()],
         };
 
         // Tag can't be empty, require at least 1 value

crates/nostr/src/nips/nip17.rs

@@ -6,7 +6,65 @@
 //!
 //! <https://github.com/nostr-protocol/nips/blob/master/17.md>
 
-use crate::{Event, RelayUrl, TagStandard};
+#![allow(clippy::wrong_self_convention)]
+
+use url::Url;
+
+use crate::event::builder::{Error, EventBuilder};
+use crate::{Event, Kind, RelayUrl, Tag, TagStandard};
+
+/// Encrypted file
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct EncryptedFile {
+    /// URL of the encrypted file
+    pub url: Url,
+    /// File type (e.g. "image/png", "application/pdf")
+    pub file_type: String,
+    /// Decryption key
+    pub decryption_key: String,
+    /// Decryption nonce
+    pub decryption_nonce: u128,
+    /// SHA256 hash of the file
+    pub hash: hashes::sha256::Hash,
+}
+
+impl EncryptedFile {
+    pub(crate) fn to_event_builder(self) -> Result<EventBuilder, Error> {
+        let mut tags: Vec<Tag> = Vec::with_capacity(5);
+
+        // Add file type
+        if !self.file_type.is_empty() {
+            tags.push(Tag::from_standardized_without_cell(TagStandard::FileType(
+                self.file_type,
+            )));
+        }
+
+        // Add decryption key
+        if !self.decryption_key.is_empty() {
+            tags.push(Tag::from_standardized_without_cell(
+                TagStandard::DecryptionKey(self.decryption_key),
+            ));
+        }
+
+        // Add decryption nonce
+        tags.push(Tag::from_standardized_without_cell(
+            TagStandard::DecryptionNonce(self.decryption_nonce),
+        ));
+
+        // Add hash
+        tags.push(Tag::from_standardized_without_cell(TagStandard::Sha256(
+            self.hash,
+        )));
+
+        // Add encryption algorithm
+        tags.push(Tag::from_standardized_without_cell(
+            TagStandard::EncryptionAlgorithm,
+        ));
+
+        // Build
+        Ok(EventBuilder::new(Kind::FileMessage, self.url).tags(tags))
+    }
+}
 
 /// Extracts the relay list
 ///