Moved IP Handling code to its own module.

src/ip_handler/mod.rs

@@ -0,0 +1,54 @@
+use std::fs::File;
+use std::io::{Read, Write};
+use std::path::Path;
+use serde::{Deserialize, Serialize};
+
+const FILE_NAME: &'static str = "ddns_ip";
+const WEBSITE_URL: &'static str = "https://httpbin.org/ip";
+
+#[derive(Deserialize)]
+struct IP {
+    origin: String,
+}
+
+pub async fn ip_has_changed() -> bool {
+    let current_ip = get_current_ip().await.expect("Error getting the current IP.");
+
+    let previous_ip = match check_previous_ip() {
+        Some(x) => x,
+        None => String::new()
+    };
+
+    println!("Current IP: {}, Previous IP: {}", current_ip, previous_ip);
+
+    current_ip.ne(&previous_ip)
+}
+
+async fn get_current_ip() -> Result<String, Box<dyn std::error::Error>> {
+    let resp = reqwest::get(WEBSITE_URL)
+        .await?
+        .json::<IP>()
+        .await?;
+
+    record_current_ip(&resp.origin);
+
+    Ok(resp.origin)
+}
+
+fn record_current_ip(current_ip: &str)  {
+    let mut file = File::create(FILE_NAME).expect("Error creating file.");
+    file.write_all(current_ip.as_ref()).expect("Error writing file.");
+}
+
+fn check_previous_ip() -> Option<String> {
+    if !Path::new(FILE_NAME).exists() {
+        return None;
+    }
+
+    let mut file = File::open(FILE_NAME).ok()?;
+    let mut contents = String::new();
+    file.read_to_string(&mut contents)
+        .expect("Error reading file.");
+
+    return Some(contents);
+}