Refactor src/index.rs and Enhance Documentation

.gitignore

@@ -1,3 +1,4 @@
 target
 Cargo.lock
 **/app_id
+.idea

Cargo.toml

@@ -17,14 +17,15 @@ env_logger = "0.9.0"
 lazy_static = "1.4.0"
 canonical-path = "2.0.2"
 pathdiff = "0.2.1"
-image = "0.24.2"
+image = "0.25"
 pdfium-render = { git = "https://github.com/ajrcarey/pdfium-render", rev = "d2559c1", features = [
     "thread_safe",
     "sync",
 ] }
 libloading = "0.7.3"
 serde_json = "1.0.82"
 serde = { version = "1.0.138", features = ["derive"] }
+serde_with = "3.6.1"
 url = { version = "2.2.2", features = ["serde"] }
 reqwest = "0.11.11"
 scraper = "0.13.0"