improvement: add error handling

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rivet-head-cli"
-version = "1.3.0"
+version = "1.4.0"
 edition = "2021"
 description = "The CLI for interacting with the Rivet Head API"
 readme = "README.md"

src/main.rs

@@ -2,11 +2,41 @@
 
 // dependencies
 use clap::Parser;
-use reqwest::Error;
 use std::collections::HashMap;
 use std::io::{self, Write};
 
-// command line arguments
+// a enum type to represent possible application errors
+#[derive(Debug)]
+enum AppError {
+    ReqwestError(reqwest::Error),
+    IOError(std::io::Error),
+}
+
+// implement the From trait to convert a reqwest::Error type to an AppError type
+impl From<reqwest::Error> for AppError {
+    fn from(err: reqwest::Error) -> Self {
+        AppError::ReqwestError(err)
+    }
+}
+
+// implement the From trait to convert a std::io::Error type to an AppError type
+impl From<std::io::Error> for AppError {
+    fn from(err: std::io::Error) -> Self {
+        AppError::IOError(err)
+    }
+}
+
+// implement the Display trait for the AppError type
+impl std::fmt::Display for AppError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            AppError::ReqwestError(err) => write!(f, "Request Error: {}", err),
+            AppError::IOError(err) => write!(f, "IO Error: {}", err),
+        }
+    }
+}
+
+// struct type to represent the command line arguments
 #[derive(Parser, Debug)]
 #[command(name = "Rivet Head CLI", author = "Jeff Mitchell", version = "1.2", about = "CLI app to work with the Rivet Head API", long_about = None)]
 struct Args {
@@ -20,8 +50,9 @@ struct Args {
     thoughts: Option<String>,
 }
 
+// main function
 #[tokio::main]
-async fn main() -> Result<(), Error> {
+async fn main() -> Result<(), AppError> {
     // parse the command line arguments
     let args = Args::parse();
 
@@ -40,7 +71,7 @@ async fn main() -> Result<(), Error> {
             let mut stdout = io::stdout();
             writeln!(stdout, "Status: {}", res.status()).expect("Unable to write to stdout");
             let body = res.text().await?;
-            writeln!(stdout, "Body:\n\n{:?}", body).expect("Unable to write to stdout");
+            writeln!(stdout, "Body:\n\n{:?}", body)?;
         }
 
         verb if verb == "post" => {
@@ -56,9 +87,9 @@ async fn main() -> Result<(), Error> {
 
             // print the status code and body
             let mut stdout = io::stdout();
-            writeln!(stdout, "Status: {}", res.status()).expect("Unable to write to stdout");
+            writeln!(stdout, "Status: {}", res.status())?;
             let body = res.text().await?;
-            writeln!(stdout, "Body: {:?}", body).expect("Unable to write to stdout");
+            writeln!(stdout, "Body: {:?}", body)?;
         }
 
         verb if verb == "put" => {
@@ -74,16 +105,15 @@ async fn main() -> Result<(), Error> {
 
             // print the status code and body
             let mut stdout = io::stdout();
-            writeln!(stdout, "Status: {}", res.status()).expect("Unable to write to stdout");
+            writeln!(stdout, "Status: {}", res.status())?;
             let body = res.text().await?;
-            writeln!(stdout, "Body: {:?}", body).expect("Unable to write to stdout");
+            writeln!(stdout, "Body: {:?}", body)?;
         }
 
         // handle incorrectly spelled verbs
         _ => {
             let mut stdout = io::stdout();
-            writeln!(stdout, "Invalid verb, enter get, post, put or delete")
-                .expect("Unable to write to stdout");
+            writeln!(stdout, "Invalid verb, enter get, post, put or delete")?;
         }
     }