fix(NIP-12): correctly search for mixed-case hex-like tags

Only lowercase and even-length tag values are stored as binary BLOBs.
Previously there was an error which search results from being returned
if the tag value was mixed-case and could be interpreted as hex.

A new database migration has been created to repair the `tag` table
for existing relays.

fixes: https://todo.sr.ht/~gheartsfield/nostr-rs-relay/37

src/db.rs

@@ -2,14 +2,14 @@
 use crate::config::SETTINGS;
 use crate::error::Error;
 use crate::error::Result;
-use crate::event::Event;
+use crate::event::{single_char_tagname, Event};
 use crate::hexrange::hex_range;
 use crate::hexrange::HexSearch;
 use crate::nip05;
 use crate::schema::{upgrade_db, STARTUP_SQL};
 use crate::subscription::ReqFilter;
 use crate::subscription::Subscription;
-use crate::utils::is_hex;
+use crate::utils::{is_hex, is_lower_hex};
 use governor::clock::Clock;
 use governor::{Quota, RateLimiter};
 use hex;
@@ -300,8 +300,12 @@ pub fn write_event(conn: &mut PooledConnection, e: &Event) -> Result<usize> {
         if tag.len() >= 2 {
             let tagname = &tag[0];
             let tagval = &tag[1];
-            // if tagvalue is hex;
-            if is_hex(tagval) {
+            // only single-char tags are searchable
+            let tagchar_opt = single_char_tagname(tagname);
+            match &tagchar_opt {
+                Some(_) => {
+                    // if tagvalue is lowercase hex;
+                    if is_lower_hex(&tagval) && (tagval.len() % 2 == 0) {
                         tx.execute(
 			    "INSERT OR IGNORE INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3)",
 			    params![ev_id, &tagname, hex::decode(&tagval).ok()],
@@ -313,6 +317,9 @@ pub fn write_event(conn: &mut PooledConnection, e: &Event) -> Result<usize> {
                         )?;
                     }
                 }
+                None => {}
+            }
+        }
     }
     // if this event is replaceable update, hide every other replaceable
     // event with the same kind from the same author that was issued
@@ -388,16 +395,13 @@ fn query_from_filter(f: &ReqFilter) -> (String, Vec<Box<dyn ToSql>>) {
     // if the filter is malformed, don't return anything.
     if f.force_no_match {
         let empty_query =
-            "SELECT DISTINCT(e.content), e.created_at FROM event e WHERE 1=0"
-            .to_owned();
+            "SELECT DISTINCT(e.content), e.created_at FROM event e WHERE 1=0".to_owned();
         // query parameters for SQLite
         let empty_params: Vec<Box<dyn ToSql>> = vec![];
         return (empty_query, empty_params);
     }
 
-    let mut query =
-        "SELECT DISTINCT(e.content), e.created_at FROM event e  "
-            .to_owned();
+    let mut query = "SELECT DISTINCT(e.content), e.created_at FROM event e  ".to_owned();
     // query parameters for SQLite
     let mut params: Vec<Box<dyn ToSql>> = vec![];
 
@@ -470,7 +474,7 @@ fn query_from_filter(f: &ReqFilter) -> (String, Vec<Box<dyn ToSql>>) {
             let mut str_vals: Vec<Box<dyn ToSql>> = vec![];
             let mut blob_vals: Vec<Box<dyn ToSql>> = vec![];
             for v in val {
-                if is_hex(v) {
+                if (v.len()%2==0) && is_lower_hex(v) {
                     if let Ok(h) = hex::decode(&v) {
                         blob_vals.push(Box::new(h));
                     }
@@ -552,6 +556,7 @@ fn query_from_sub(sub: &Subscription) -> (String, Vec<Box<dyn ToSql>>) {
 /// query is immediately aborted.
 pub async fn db_query(
     sub: Subscription,
+    client_id: String,
     pool: SqlitePool,
     query_tx: tokio::sync::mpsc::Sender<QueryResult>,
     mut abandon_query_rx: tokio::sync::oneshot::Receiver<()>,
@@ -573,13 +578,18 @@ pub async fn db_query(
             let mut first_result = true;
             while let Some(row) = event_rows.next()? {
                 if first_result {
-                    debug!("time to first result: {:?}", start.elapsed());
+                    debug!(
+                        "time to first result: {:?} (cid={}, sub={:?})",
+                        start.elapsed(),
+                        client_id,
+                        sub.id
+                    );
                     first_result = false;
                 }
                 // check if this is still active
                 // TODO:  check every N rows
                 if abandon_query_rx.try_recv().is_ok() {
-                    debug!("query aborted");
+                    debug!("query aborted (sub={:?})", sub.id);
                     return Ok(());
                 }
                 row_count += 1;
@@ -598,9 +608,11 @@ pub async fn db_query(
                 })
                 .ok();
             debug!(
-                "query completed ({} rows) in {:?}",
+                "query completed ({} rows) in {:?} (cid={}, sub={:?})",
                 row_count,
-                start.elapsed()
+                start.elapsed(),
+		client_id,
+                sub.id
             );
         } else {
             warn!("Could not get a database connection for querying");

src/event.rs

@@ -57,7 +57,7 @@ where
 }
 
 /// Attempt to form a single-char tag name.
-fn single_char_tagname(tagname: &str) -> Option<char> {
+pub fn single_char_tagname(tagname: &str) -> Option<char> {
     // We return the tag character if and only if the tagname consists
     // of a single char.
     let mut tagnamechars = tagname.chars();
@@ -301,7 +301,7 @@ mod tests {
     fn empty_event_tag_match() -> Result<()> {
         let event = simple_event();
         assert!(!event
-            .generic_tag_val_intersect("e", &HashSet::from(["foo".to_owned(), "bar".to_owned()])));
+            .generic_tag_val_intersect('e', &HashSet::from(["foo".to_owned(), "bar".to_owned()])));
         Ok(())
     }
 
@@ -312,7 +312,7 @@ mod tests {
         event.build_index();
         assert_eq!(
             event.generic_tag_val_intersect(
-                "e",
+                'e',
                 &HashSet::from(["foo".to_owned(), "bar".to_owned()])
             ),
             true

src/main.rs

@@ -1,4 +1,3 @@
-
 //! Server process
 use futures::SinkExt;
 use futures::StreamExt;
@@ -144,8 +143,8 @@ async fn handle_web_request(
             Ok(Response::builder()
                 .status(200)
                 .header("Content-Type", "text/plain")
-	       .body(Body::from("Please use a Nostr client to connect.")).unwrap()
-            )
+                .body(Body::from("Please use a Nostr client to connect."))
+                .unwrap())
         }
         (_, _) => {
             //handle any other url
@@ -533,7 +532,7 @@ async fn nostr_server(
                                     previous_query.send(()).ok();
                                 }
                                 // start a database query
-                                db::db_query(s, pool.clone(), query_tx.clone(), abandon_query_rx).await;
+                                db::db_query(s, cid.to_owned(), pool.clone(), query_tx.clone(), abandon_query_rx).await;
                             },
                             Err(e) => {
                                 info!("Subscription error: {}", e);

src/schema.rs

@@ -1,13 +1,13 @@
 //! Database schema and migrations
 use crate::db::PooledConnection;
 use crate::error::Result;
-use crate::utils::is_hex;
+use crate::event::{single_char_tagname, Event};
+use crate::utils::is_lower_hex;
 use log::*;
 use rusqlite::limits::Limit;
 use rusqlite::params;
 use rusqlite::Connection;
-
-// TODO: drop the pubkey_ref and event_ref tables
+use std::time::Instant;
 
 /// Startup DB Pragmas
 pub const STARTUP_SQL: &str = r##"
@@ -24,7 +24,7 @@ PRAGMA journal_mode=WAL;
 PRAGMA main.synchronous=NORMAL;
 PRAGMA foreign_keys = ON;
 PRAGMA application_id = 1654008667;
-PRAGMA user_version = 5;
+PRAGMA user_version = 6;
 
 -- Event Table
 CREATE TABLE IF NOT EXISTS event (
@@ -53,7 +53,7 @@ id INTEGER PRIMARY KEY,
 event_id INTEGER NOT NULL, -- an event ID that contains a tag.
 name TEXT, -- the tag name ("p", "e", whatever)
 value TEXT, -- the tag value, if not hex.
-value_hex BLOB, -- the tag value, if it can be interpreted as a hex string.
+value_hex BLOB, -- the tag value, if it can be interpreted as a lowercase hex string.
 FOREIGN KEY(event_id) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CASCADE
 );
 CREATE INDEX IF NOT EXISTS tag_val_index ON tag(value);
@@ -103,7 +103,7 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
     if curr_version == 0 {
         match conn.execute_batch(INIT_SQL) {
             Ok(()) => {
-                info!("database pragma/schema initialized to v4, and ready");
+                info!("database pragma/schema initialized to v6, and ready");
             }
             Err(err) => {
                 error!("update failed: {}", err);
@@ -154,7 +154,6 @@ PRAGMA user_version = 3;
                 panic!("database could not be upgraded");
             }
         }
-        info!("Starting transaction");
         // iterate over every event/pubkey tag
         let tx = conn.transaction()?;
         {
@@ -166,7 +165,7 @@ PRAGMA user_version = 3;
                 let tag_name: String = row.get(1)?;
                 let tag_value: String = row.get(2)?;
                 // this will leave behind p/e tags that were non-hex, but they are invalid anyways.
-                if is_hex(&tag_value) {
+                if is_lower_hex(&tag_value) {
                     tx.execute(
                         "INSERT INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3);",
                         params![event_id, tag_name, hex::decode(&tag_value).ok()],
@@ -225,9 +224,63 @@ PRAGMA user_version=5;
             }
         }
     } else if curr_version == 5 {
-        debug!("Database version was already current");
-    } else if curr_version > 5 {
-        panic!("Database version is newer than supported by this executable");
+        info!("database schema needs update from 5->6");
+        // We need to rebuild the tags table.  iterate through the
+        // event table.  build event from json, insert tags into a
+        // fresh tag table.  This was needed due to a logic error in
+        // how hex-like tags got indexed.
+        let start = Instant::now();
+        let tx = conn.transaction()?;
+        {
+            // Clear out table
+            tx.execute("DELETE FROM tag;", [])?;
+            let mut stmt = tx.prepare("select id, content from event order by id;")?;
+            let mut tag_rows = stmt.query([])?;
+            while let Some(row) = tag_rows.next()? {
+                // we want to capture the event_id that had the tag, the tag name, and the tag hex value.
+                let event_id: u64 = row.get(0)?;
+                let event_json: String = row.get(1)?;
+                let event: Event = serde_json::from_str(&event_json)?;
+                // look at each event, and each tag, creating new tag entries if appropriate.
+                for t in event.tags.iter().filter(|x| x.len() > 1) {
+                    let tagname = t.get(0).unwrap();
+                    let tagnamechar_opt = single_char_tagname(tagname);
+                    if tagnamechar_opt.is_none() {
+                        continue;
+                    }
+                    // safe because len was > 1
+                    let tagval = t.get(1).unwrap();
+                    // insert as BLOB if we can restore it losslessly.
+                    // this means it needs to be even length and lowercase.
+                    if (tagval.len() % 2 == 0) && is_lower_hex(&tagval) {
+                        tx.execute(
+                            "INSERT INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3);",
+                            params![event_id, tagname, hex::decode(&tagval).ok()],
+                        )?;
+                    } else {
+                        // otherwise, insert as text
+                        tx.execute(
+                            "INSERT INTO tag (event_id, name, value) VALUES (?1, ?2, ?3);",
+                            params![event_id, tagname, &tagval],
+                        )?;
+                    }
+                }
+            }
+            tx.execute("PRAGMA user_version = 6;", [])?;
+        }
+        tx.commit()?;
+        info!("database schema upgraded v5 -> v6 in {:?}", start.elapsed());
+        // vacuum after large table modification
+        let start = Instant::now();
+        conn.execute("VACUUM;", [])?;
+        info!("vacuumed DB after tags rebuild in {:?}", start.elapsed());
+    } else if curr_version == 6 {
+        debug!("Database version was already current (v6)");
+    } else if curr_version > 7 {
+        panic!(
+            "Database version is newer than supported by this executable (v{})",
+            curr_version
+        );
     }
 
     // Setup PRAGMA

src/subscription.rs

@@ -1,7 +1,6 @@
 //! Subscription and filter parsing
 use crate::error::Result;
 use crate::event::Event;
-use log::*;
 use serde::de::Unexpected;
 use serde::{Deserialize, Deserializer, Serialize};
 use serde_json::Value;
@@ -80,9 +79,7 @@ impl<'de> Deserialize<'de> for ReqFilter {
             } else if key == "authors" {
                 rf.authors = Deserialize::deserialize(val).ok();
             } else if key.starts_with('#') && key.len() > 1 && val.is_array() {
-                info!("testing tag search char: {}", key);
                 if let Some(tag_search) = tag_search_char_from_filter(key) {
-                    info!("found a character from the tag search: {}", tag_search);
                     if ts.is_none() {
                         // Initialize the tag if necessary
                         ts = Some(HashMap::new());

src/utils.rs

@@ -13,3 +13,21 @@ pub fn unix_time() -> u64 {
 pub fn is_hex(s: &str) -> bool {
     s.chars().all(|x| char::is_ascii_hexdigit(&x))
 }
+
+/// Check if a string contains only lower-case hex chars.
+pub fn is_lower_hex(s: &str) -> bool {
+    s.chars().all(|x| {
+        (char::is_ascii_lowercase(&x) || char::is_ascii_digit(&x)) && char::is_ascii_hexdigit(&x)
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn lower_hex() {
+        let hexstr = "abcd0123";
+        assert_eq!(is_lower_hex(hexstr), true);
+    }
+}