handle optional tags, add warning log level

src/argument.rs

@@ -15,7 +15,7 @@ pub struct Argument {
     #[arg(short, long, default_value_t = 60)]
     pub update: u64,
 
-    /// Show output (`d` by default)
-    #[arg(short, long, default_value_t = String::from("d"))]
+    /// Show output (`dw` by default)
+    #[arg(short, long, default_value_t = String::from("dw"))]
     pub output: String,
 }

src/main.rs

@@ -32,27 +32,53 @@ fn crawl(source: &str, target: &str, output: &Output) -> Result<(), Box<dyn Erro
 
     let mut total = 0;
     let mut exist = 0;
-    for item in Channel::read_from(&get(source)?.bytes()?[..])?.items() {
+    for item in Channel::read_from(&get(source)?.bytes()?[..])?
+        .items()
+        .iter()
+    {
         total += 1;
 
-        let path = &path(target, item.pub_date().unwrap(), true)?;
+        // handle item data
+        let mut data = Vec::new();
 
-        if metadata(path).is_ok() {
-            exist += 1;
-            continue;
+        let path = match item.pub_date() {
+            Some(pub_data) => {
+                let path = path(target, pub_data, true)?;
+                if metadata(&path).is_ok() {
+                    exist += 1;
+                    continue; // skip existing records
+                }
+                data.push(format!("# {pub_data}"));
+                path
+            }
+            None => {
+                output.warning("item skipped as `pub_date` is required by application");
+                continue;
+            }
+        };
+
+        if let Some(description) = item.description() {
+            data.push(description.to_string());
         }
 
-        let mut file = File::create(path)?;
+        if let Some(content) = item.content() {
+            data.push(content.to_string());
+        }
 
-        file.write_all(
-            format!(
-                "# {}\n\n{}\n\n=> {}",
-                item.pub_date().unwrap(),
-                item.description().unwrap(),
-                item.link().unwrap()
-            )
-            .as_bytes(),
-        )?;
+        /* @TODO local storage
+        if let Some(enclosure) = item.enclosure() {
+            match enclosure.mime_type.as_str() {
+                "image/jpeg" => todo!(),
+                _ => todo!(),
+            }
+        } */
+
+        if let Some(link) = item.link() {
+            data.push(format!("=> {link}"));
+        }
+
+        // record item to static file
+        File::create(&path)?.write_all(data.join("\n\n").as_bytes())?;
     }
 
     output.debug(&format!(

src/output.rs

@@ -3,6 +3,7 @@ use std::time::SystemTime;
 
 struct Level {
     debug: bool,
+    warning: bool,
 }
 
 pub struct Output(Level);
@@ -11,7 +12,7 @@ impl Output {
     pub fn build(level: &str) -> Self {
         Self(Level {
             debug: level.contains("d"),
-            // @TODO other flags
+            warning: level.contains("w"),
         })
     }
 
@@ -20,6 +21,12 @@ impl Output {
             eprintln!("[debug] [{}] {message}", time());
         }
     }
+
+    pub fn warning(&self, message: &str) {
+        if self.0.warning {
+            eprintln!("[warning] [{}] {message}", time());
+        }
+    }
 }
 
 fn time() -> String {