spacedust: add subject prefix filtering

Cargo.lock

···
 [[package]]
 name = "fjall"
 version = "2.11.2"
-source = "git+https://github.com/fjall-rs/fjall.git#42d811f7c8cc9004407d520d37d2a1d8d246c03d"
+source = "git+https://github.com/fjall-rs/fjall.git?rev=fb229572bb7d1d6966a596994dc1708e47ec57d8#fb229572bb7d1d6966a596994dc1708e47ec57d8"
 dependencies = [
  "byteorder",
  "byteview",
···
  "clap",
  "dropshot",
  "env_logger",
- "fjall 2.11.2 (git+https://github.com/fjall-rs/fjall.git)",
+ "fjall 2.11.2 (git+https://github.com/fjall-rs/fjall.git?rev=fb229572bb7d1d6966a596994dc1708e47ec57d8)",
  "getrandom 0.3.3",
  "http",
  "jetstream",

spacedust/src/error.rs

···
     TooManySourcesWanted,
     #[error("more wantedSubjectDids were requested than allowed (max 10,000)")]
     TooManyDidsWanted,
+    #[error("more wantedSubjectPrefixes were requested than allowed (max 100)")]
+    TooManySubjectPrefixesWanted,
     #[error("more wantedSubjects were requested than allowed (max 50,000)")]
     TooManySubjectsWanted,
 }

spacedust/src/server.rs

···
     #[serde(default)]
     pub wanted_subjects: HashSet<String>,
     #[serde(default)]
+    pub wanted_subject_prefixes: HashSet<String>,
+    #[serde(default)]
     pub wanted_subject_dids: HashSet<String>,
     #[serde(default)]
     pub wanted_sources: HashSet<String>,
···
     ///
     /// The at-uri must be url-encoded
     ///
-    /// Pass this parameter multiple times to specify multiple collections, like
+    /// Pass this parameter multiple times to specify multiple subjects, like
     /// `wantedSubjects=[...]&wantedSubjects=[...]`
     pub wanted_subjects: String,
+    /// One or more at-uri, URI, or DID prefixes to receive links about
+    ///
+    /// The uri must be url-encoded
+    ///
+    /// Pass this parameter multiple times to specify multiple prefixes, like
+    /// `wantedSubjectPrefixes=[...]&wantedSubjectPrefixes=[...]`
+    pub wanted_subject_prefixes: String,
     /// One or more DIDs to receive links about
     ///
-    /// Pass this parameter multiple times to specify multiple collections
+    /// Pass this parameter multiple times to specify multiple subjects
     pub wanted_subject_dids: String,
     /// One or more link sources to receive links about
     ///

spacedust/src/subscriber.rs

···
         let query = &self.query;
 
         // subject + subject DIDs are logical OR
-        if !(query.wanted_subjects.is_empty() && query.wanted_subject_dids.is_empty()
+        if !(query.wanted_subjects.is_empty()
+            && query.wanted_subject_prefixes.is_empty()
+            && query.wanted_subject_dids.is_empty()
             || query.wanted_subjects.contains(&properties.subject)
+            || query
+                .wanted_subject_prefixes
+                .iter()
+                .any(|p| properties.subject.starts_with(p))
             || properties
                 .subject_did
                 .as_ref()
···
         }
         if opts.wanted_subject_dids.len() > 10_000 {
             return Err(SubscriberUpdateError::TooManyDidsWanted);
+        }
+        if opts.wanted_subject_prefixes.len() > 100 {
+            return Err(SubscriberUpdateError::TooManySubjectPrefixesWanted);
         }
         if opts.wanted_subjects.len() > 50_000 {
             return Err(SubscriberUpdateError::TooManySubjectsWanted);