use retry mechanism for fetching data

src/misc.rs

@@ -110,3 +110,36 @@ fn delete_all_in_dir<P: AsRef<Path>>(dir_path: P) -> std::io::Result<()> {
 
     Ok(())
 }
+
+pub(crate) fn fetch_with_retries(url: &str) -> Result<String, Error> {
+    let mut attempts = 0;
+    let max_attempts = 100;
+
+    loop {
+        match ureq::get(url).call() {
+            Ok(response) => {
+                // If the request is successful, return the response body
+                match response.into_string() {
+                    Ok(d) => return Ok(d),
+                    Err(e) => return Err(e.into()),
+                }
+            }
+            Err(ureq::Error::Transport(_)) => {
+                // Increment the attempt counter
+                attempts += 1;
+
+                // Check if the maximum number of attempts has been reached
+                if attempts >= max_attempts {
+                    return Err(Error::new("Maximum attempts reached."));
+                }
+
+                // TODO: Implement a backoff strategy here. As a simple example, we sleep for 1 second.
+                std::thread::sleep(std::time::Duration::from_secs(1));
+            }
+            Err(e) => {
+                // For non-transport errors, return the error immediately.
+                return Err(e.into());
+            }
+        }
+    }
+}

src/paragraph/mod.rs

@@ -29,7 +29,7 @@ use log::info;
 
 use crate::{
     law::LawBuilder,
-    misc::{get_cache_dir, Error},
+    misc::{fetch_with_retries, get_cache_dir, Error},
 };
 
 use self::parser::Risdok;
@@ -138,7 +138,7 @@ fn fetch(url: &str) -> Result<String, Error> {
         Ok(data) => Ok(data),
         Err(_) => {
             info!("Not finding url {url} in the cache, downloading...");
-            let data = ureq::get(url).call()?.into_string()?;
+            let data = fetch_with_retries(url)?;
             let path = Path::new(&expected_filename);
             if let Some(parent) = path.parent() {
                 // Try to create the directory (and any necessary parent directories)