Added documentation comments for ip_handler.

src/ip_handler/mod.rs

@@ -1,7 +1,7 @@
+use serde::Deserialize;
 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";
@@ -11,35 +11,49 @@ struct IP {
     origin: String,
 }
 
-pub async fn ip_has_changed() -> bool {
-    let current_ip = get_current_ip().await.expect("Error getting the current IP.");
+/// Returns an Option holding the current IP address if the value has changed, otherwise returns None.
+pub async fn get_ip_to_publish() -> Option<String> {
+    let current_ip = check_current_ip()
+        .await
+        .expect("Error getting the current IP.");
 
     let previous_ip = match check_previous_ip() {
         Some(x) => x,
-        None => String::new()
+        None => String::new(),
     };
 
     println!("Current IP: {}, Previous IP: {}", current_ip, previous_ip);
 
-    current_ip.ne(&previous_ip)
+    if current_ip.eq(&previous_ip) {
+        return None;
+    }
+
+    Some(current_ip)
 }
 
-async fn get_current_ip() -> Result<String, Box<dyn std::error::Error>> {
-    let resp = reqwest::get(WEBSITE_URL)
-        .await?
-        .json::<IP>()
-        .await?;
+/// Checks the current WAN IP.
+///
+/// Connects to WEBSITE_URL and retrieves the current WAN IP value.
+async fn check_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)
 }
 
+/// Stores the current IP value in the FILE_NAME.
+///
+/// # Arguments
+///
+/// * `current_ip` - A &str holding the current IP value.
 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.");
+    file.write_all(current_ip.as_ref())
+        .expect("Error writing file.");
 }
 
+/// Reads the current IP value from the FILE_NAME and returns it.
 fn check_previous_ip() -> Option<String> {
     if !Path::new(FILE_NAME).exists() {
         return None;