Split crates and clean up structure of codebase (#294)

Co-authored-by: Jiahao XU <Jiahao_XU@outlook.com>

crates/lib/src/helpers/remote.rs

@@ -0,0 +1,62 @@
+use std::env;
+
+use bytes::Bytes;
+use futures_util::stream::Stream;
+use log::debug;
+use reqwest::{tls, Client, ClientBuilder, Method, Response};
+use url::Url;
+
+use crate::errors::BinstallError;
+
+pub fn create_reqwest_client(
+    secure: bool,
+    min_tls: Option<tls::Version>,
+) -> Result<Client, BinstallError> {
+    const USER_AGENT: &str = concat!(env!("CARGO_PKG_NAME"), "/", env!("CARGO_PKG_VERSION"));
+
+    let mut builder = ClientBuilder::new().user_agent(USER_AGENT);
+
+    if secure {
+        builder = builder
+            .https_only(true)
+            .min_tls_version(tls::Version::TLS_1_2);
+    }
+
+    if let Some(ver) = min_tls {
+        builder = builder.min_tls_version(ver);
+    }
+
+    Ok(builder.build()?)
+}
+
+pub async fn remote_exists(
+    client: Client,
+    url: Url,
+    method: Method,
+) -> Result<bool, BinstallError> {
+    let req = client
+        .request(method.clone(), url.clone())
+        .send()
+        .await
+        .map_err(|err| BinstallError::Http { method, url, err })?;
+    Ok(req.status().is_success())
+}
+
+pub(crate) async fn create_request(
+    client: &Client,
+    url: Url,
+) -> Result<impl Stream<Item = reqwest::Result<Bytes>>, BinstallError> {
+    debug!("Downloading from: '{url}'");
+
+    client
+        .get(url.clone())
+        .send()
+        .await
+        .and_then(|r| r.error_for_status())
+        .map_err(|err| BinstallError::Http {
+            method: Method::GET,
+            url,
+            err,
+        })
+        .map(Response::bytes_stream)
+}