implement persist_images_selector, minimize codebase by using bail, change image table structure to use sha256 hash as the unique image identity

crates/mysql/database/0.1.0.sql

@@ -1,5 +1,5 @@
 -- MySQL Script generated by MySQL Workbench
--- пт, 09-січ-2026 17:57:03 +0200
+-- сб, 10-січ-2026 14:27:50 +0200
 -- Model: New Model    Version: 1.0
 -- MySQL Workbench Forward Engineering
 
@@ -92,10 +92,12 @@ ENGINE = InnoDB;
 -- -----------------------------------------------------
 CREATE TABLE IF NOT EXISTS `rssto`.`image` (
   `image_id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
-  `source` VARCHAR(2048) NOT NULL,
+  `sha256` CHAR(64) NOT NULL,
+  `src` VARCHAR(2048) NULL,
+  `url` VARCHAR(2048) NULL,
   `data` MEDIUMBLOB NOT NULL,
   PRIMARY KEY (`image_id`),
-  UNIQUE INDEX `source_UNIQUE` (`source` ASC) VISIBLE)
+  UNIQUE INDEX `hash_UNIQUE` (`sha256` ASC) VISIBLE)
 ENGINE = InnoDB;
 
 

crates/mysql/src/table.rs

@@ -37,7 +37,13 @@ pub struct Provider {
 #[derive(Debug, PartialEq, Eq, FromRow)]
 pub struct Image {
     pub image_id: u64,
-    pub source: String,
+    /// Keep image unique by comparing its data hash
+    pub sha256: String,
+    /// Original `src` tag value to post-replacing
+    pub src: Option<String>,
+    /// Resolved absolute URL
+    pub url: Option<String>,
+    /// Image data, MEDIUMBLOB (16M)
     pub data: Vec<u8>,
 }
 

crates/mysql/src/transaction.rs

@@ -115,17 +115,23 @@ impl Transaction {
         Ok(self.tx.last_insert_id().unwrap())
     }
 
-    pub fn images_total_by_source(&mut self, source: &str) -> Result<usize, Error> {
-        Ok(self
-            .tx
-            .exec_first("SELECT COUNT(*) FROM `image` WHERE `source` = ?", (source,))?
-            .unwrap_or(0))
+    pub fn image_id_by_sha256(&mut self, sha256: &str) -> Result<Option<u64>, Error> {
+        self.tx.exec_first(
+            "SELECT `image_id` FROM `image` WHERE `sha256` = ? LIMIT 1",
+            (sha256,),
+        )
     }
 
-    pub fn insert_image(&mut self, source: &str, data: &[u8]) -> Result<u64, Error> {
+    pub fn insert_image(
+        &mut self,
+        sha256: &str,
+        src: Option<&str>,
+        url: Option<&str>,
+        data: &[u8],
+    ) -> Result<u64, Error> {
         self.tx.exec_drop(
-            "INSERT INTO `image` SET `source` = ?, `data` = ?",
-            (source, data),
+            "INSERT INTO `image` SET `sha256` = ?, `src` = ?, `url` = ?, `data` = ?",
+            (sha256, src, url, data),
         )?;
         Ok(self.tx.last_insert_id().unwrap())
     }