From f69328a8e9178ea4aeb9987e04958166eb0ed1bc Mon Sep 17 00:00:00 2001
From: Martin Pitt <martin@piware.de>
Date: Fri, 16 Sep 2022 11:17:26 +0200
Subject: [PATCH 1/1] tokio-tutorial-jbarszczewski: Add GET/POST parsing

---
 tokio-tutorial-jbarszczewski/src/main.rs | 34 ++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/tokio-tutorial-jbarszczewski/src/main.rs b/tokio-tutorial-jbarszczewski/src/main.rs
index e1c7800..57af76b 100644
--- a/tokio-tutorial-jbarszczewski/src/main.rs
+++ b/tokio-tutorial-jbarszczewski/src/main.rs
@@ -1,4 +1,6 @@
-use tokio::io::AsyncWriteExt;
+use std::str;
+
+use tokio::io::{ AsyncReadExt, AsyncWriteExt };
 use tokio::net::{TcpListener, TcpStream};
 
 #[tokio::main]
@@ -12,7 +14,35 @@ async fn main() {
 }
 
 async fn handle_connection(mut stream: TcpStream) {
-    let contents = "{\"balance\": 0.00}";
+    // Read the first 16 characters from the incoming stream
+    let mut buffer = [0; 16];
+    assert!(stream.read(&mut buffer).await.unwrap() >= 16);
+    // First 4 characters are used to detect HTTP method
+    let method_type = match str::from_utf8(&buffer[0..4]) {
+        Ok(v) => v,
+        Err(e) => panic!("Invalid UTF-8 sequence: {}", e),
+    };
+
+    let contents = match method_type {
+        "GET " => {
+            // todo: return real balance
+            format!("{{\"balance\": {}}}", 0.0)
+        }
+        "POST" => {
+            // Take characters after 'POST /' until whitespace is detected.
+            let input: String = buffer[6..16]
+                .iter()
+                .take_while(|x| **x != 32u8)
+                .map(|x| *x as char)
+                .collect();
+            let balance_update = input.parse::<f32>().unwrap();
+            // todo: add balance update handling
+            format!("{{\"balance\": {}}}", balance_update)
+        }
+        _ => {
+            panic!("Invalid HTTP method!")
+        }
+    };
 
     let response = format!(
         "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\nContent-Length: {}\r\n\r\n{}",
-- 
2.39.2