update image_download.rs

src/bin/image_download.rs

@@ -1,3 +1,34 @@
-fn main() {
-    println!("Download an image from the web using reqwest");
+use error_chain::error_chain;
+use std::{fs::File, io::copy};
+use tempfile::Builder;
+
+error_chain! {
+    foreign_links {
+        Io(std::io::Error);
+        HttpRequest(reqwest::Error);
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    let tmp_dir = Builder::new().prefix("image_download").tempdir()?;
+    let target = String::from("https://www.rust-lang.org/logos/rust-logo-512x512.png");
+    let response = reqwest::get(&target).await?;
+    let mut destination = {
+        let file_name = response
+            .url()
+            .path_segments()
+            .and_then(|segments| segments.last())
+            .and_then(|name| if name.is_empty() { None } else { Some(name) })
+            .unwrap_or("tmp.bin");
+        println!("File to download: '{}'", file_name);
+        let file_name = tmp_dir.path().join(file_name);
+        println!("Located at: '{:?}'", file_name);
+        File::create(file_name)?
+    };
+    let tmp_dir = tmp_dir.into_path();
+    println!("Temp directory: '{:?}'", tmp_dir);
+    let content = response.bytes().await?;
+    copy(&mut content.as_ref(), &mut destination)?;
+    Ok(())
 }