Add function to start a resource-stream connection

At the moment the start_stream function very simply prints out each
response as it arrives.

crates/rdsys-backend/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "rdsys-backend"
+name = "rdsys_backend"
 version = "0.1.0"
 edition = "2021"
 
@@ -7,4 +7,7 @@ edition = "2021"
 
 [dependencies]
 serde_json = "1"
+futures-util = { version = "0.3"}
 serde = { version = "1", features = ["derive"]}
+
+reqwest = { version = "0.11", features = ["stream"]}

crates/rdsys-backend/src/http.rs

@@ -0,0 +1,52 @@
+use reqwest::Client;
+use futures_util::StreamExt;
+use std::io;
+
+#[derive(Debug)]
+pub enum Error {
+    Reqwest (reqwest::Error),
+    Io (io::Error),
+    JSON (serde_json::Error),
+}
+
+impl From<serde_json::Error> for Error {
+    fn from(value: serde_json::Error) -> Self {
+        Self::JSON(value)
+    }
+}
+
+impl From<reqwest::Error> for Error {
+    fn from(value: reqwest::Error) -> Self {
+        Self::Reqwest(value)
+    }
+}
+
+impl From<io::Error> for Error {
+    fn from(value: io::Error) -> Self {
+        Self::Io(value)
+    }
+}
+
+pub async fn start_stream(api_endpoint: String, name: String, token: String, resource_types: Vec<String> ) -> Result<(), Error> {
+
+    let req = crate::ResourceRequest {
+        request_origin: name,
+        resource_types: resource_types,
+    };
+    let json = serde_json::to_string(&req)?;
+
+    let auth_value = format!("Bearer {}",token);
+
+    let client = Client::new();
+    let mut stream = client.get(api_endpoint)
+        .header("Authorization", &auth_value)
+        .body(json)
+        .send()
+        .await?
+        .bytes_stream();
+
+    while let Some(chunk) = stream.next().await {
+        println!("Chunk: {:?}", chunk?);
+    };
+    Ok(())
+}

crates/rdsys-backend/src/lib.rs

@@ -2,6 +2,8 @@ use std::collections::HashMap;
 
 use serde::{Deserialize, Serialize};
 
+pub mod http;
+
 #[derive(Serialize)]
 pub struct ResourceRequest {
     request_origin: String,