2 files changed, 85 insertions, 0 deletions
diff --git a/src/download.rs b/src/download.rs
new file mode 100644
index 0000000..537dae3
--- /dev/null
+++ b/src/download.rs
@@ -0,0 +1,46 @@
+use std::path::{Path, PathBuf};
+
+use anyhow::Error;
+use fehler::throws;
+use hyper::{body::HttpBody, Client, header::CONTENT_TYPE, Uri};
+use tokio::fs;
+use tokio::io::AsyncWriteExt;
+
+use super::Args;
+
+#[throws]
+pub(crate) async fn download(url: Uri, args: &Args) {
+    let output_file_path = if let Some(output) = &args.output_document {
+        Some(output.clone())
+    } else {
+        let url_path = Path::new(url.path());
+        match (url_path.file_name(), url.path().ends_with('/')) {
+            (Some(file_name), false) => Some(PathBuf::from(file_name)),
+            _ => None,
+        }
+    };
+
+    let client = Client::new();
+    let mut response = client.get(url.clone()).await?;
+    if !response.status().is_success() {
+        panic!("non-success response code {} in URL {}", response.status(), url);
+    }
+
+    let output_file_path = if let Some(path) = output_file_path {
+        path
+    } else {
+        let content_type = response.headers().get(CONTENT_TYPE);
+        let extension = content_type
+            .and_then(|mime_type| mime_type.to_str().ok())
+            .and_then(|mime_type| mime2ext::mime2ext(mime_type))
+            .map(|x| format!(".{}", x))
+            .unwrap_or_default();
+        PathBuf::from(format!("index{}", extension))
+    };
+
+    let mut output_file = fs::File::create(output_file_path).await.expect("couldn't open output file!");
+
+    while let Some(data) = response.body_mut().data().await {
+        output_file.write_all(&data?).await?;
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..da1ae1f
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,39 @@
+use std::mem;
+use std::path::PathBuf;
+
+use anyhow::Error;
+use hyper::Uri;
+use structopt::StructOpt;
+
+mod download;
+use download::download;
+
+#[derive(StructOpt, Debug)]
+struct Args {
+    /// Specify output filename (will cause an error if multiple URLs are given)
+    #[structopt(short = "O", long)]
+    output_document: Option<PathBuf>,
+
+    /// The URLs to download
+    urls: Vec<Uri>,
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Error> {
+    let (args, urls) = {
+        let mut args: Args = Args::from_args();
+        let urls = mem::take(&mut args.urls);
+        (args, urls)
+    };
+    if urls.len() != 1 && args.output_document.is_some() {
+        panic!("can't use the same output file for multiple URLs!")
+    }
+
+    let download_handles = urls
+        .into_iter()
+        .map(|url| download(url, &args));
+    let downloads = futures::future::join_all(download_handles);
+    let _downloads = downloads.await;
+
+    Ok(())
+}