implement local image features

crates/mysql/src/connection.rs

@@ -80,11 +80,15 @@ impl Connection {
         )
     }
 
-    pub fn images(&mut self, limit: Option<usize>) -> Result<Vec<Image>, Error> {
-        self.conn.query(format!(
-            "SELECT `image_id`, `source`, `data` FROM `image` LIMIT {}",
-            limit.unwrap_or(DEFAULT_LIMIT)
-        ))
+    pub fn image(&mut self, image_id: u64) -> Result<Option<Image>, Error> {
+        self.conn.exec_first(
+            "SELECT `image_id`,
+                    `sha256`,
+                    `src`,
+                    `url`,
+                    `data` FROM `image` WHERE `image_id` = ?",
+            (image_id,),
+        )
     }
 
     pub fn provider_id_by_name(&mut self, name: &str) -> Result<Option<u64>, Error> {

crates/mysql/src/transaction.rs

@@ -107,6 +107,19 @@ impl Transaction {
         Ok(self.tx.last_insert_id().unwrap())
     }
 
+    pub fn replace_content_description(
+        &mut self,
+        content_id: u64,
+        from: &str,
+        to: &str,
+    ) -> Result<(), Error> {
+        self.tx.exec_drop(
+            "UPDATE `content` SET `description` = REPLACE(`description`, ?, ?)
+                              WHERE`content_id` = ?",
+            (from, to, content_id),
+        )
+    }
+
     pub fn insert_content_image(&mut self, content_id: u64, image_id: u64) -> Result<u64, Error> {
         self.tx.exec_drop(
             "INSERT INTO `content_image` SET `content_id` = ?, `image_id` = ?",