feat: Add output to file option (#221)

* feat: Add output to file option

* Fix message

* Address unreachable code

* Make less changes

* Test saving JWT to a file

* fmt

* Address code review comments

- moved tempdir to dev dependencies
- removed old style import
- refactored exit code logic into main
- covered print_decoded_token in tests

* Remove unnecessary exit call

Co-authored-by: Marcin Lewandowski <mlewandowski@pl.ibm.com>

Cargo.toml

@@ -23,3 +23,6 @@ chrono = "0.4"
 parse_duration = "2.1.1"
 atty = "0.2"
 base64 = "0.21.0"
+
+[dev-dependencies]
+tempdir = "0.3.7"

src/cli_config.rs

@@ -2,6 +2,7 @@ use crate::translators::{PayloadItem, SupportedTypes};
 use crate::utils::parse_duration_string;
 use clap::{Parser, Subcommand, ValueEnum};
 use jsonwebtoken::Algorithm;
+use std::path::PathBuf;
 
 #[derive(Parser, Debug)]
 #[clap(name = "jwt")]
@@ -94,6 +95,11 @@ pub struct EncodeArgs {
     #[clap(long, short = 'S')]
     #[clap(value_parser)]
     pub secret: String,
+
+    /// The path of the file to write the result to (suppresses default standard output)
+    #[clap(long = "out", short = 'o')]
+    #[clap(value_parser)]
+    pub output_path: Option<PathBuf>,
 }
 
 #[derive(Debug, Clone, Parser)]
@@ -130,6 +136,11 @@ pub struct DecodeArgs {
     #[clap(long = "ignore-exp")]
     #[clap(value_parser)]
     pub ignore_exp: bool,
+
+    /// The path of the file to write the result to (suppresses default standard output, implies JSON format)
+    #[clap(long = "out", short = 'o')]
+    #[clap(value_parser)]
+    pub output_path: Option<PathBuf>,
 }
 
 #[allow(clippy::upper_case_acronyms)]

src/main.rs

@@ -1,5 +1,6 @@
 use clap::Parser;
 use cli_config::{App, Commands, EncodeArgs};
+use std::process::exit;
 use translators::decode::{decode_token, print_decoded_token};
 use translators::encode::{encode_token, print_encoded_token};
 
@@ -22,13 +23,23 @@ fn main() {
             warn_unsupported(arguments);
 
             let token = encode_token(arguments);
+            let output_path = &arguments.output_path;
 
-            print_encoded_token(token);
+            exit(match print_encoded_token(token, output_path) {
+                Ok(_) => 0,
+                _ => 1,
+            });
         }
         Commands::Decode(arguments) => {
             let (validated_token, token_data, format) = decode_token(arguments);
+            let output_path = &arguments.output_path;
 
-            print_decoded_token(validated_token, token_data, format);
+            exit(
+                match print_decoded_token(validated_token, token_data, format, output_path) {
+                    Ok(_) => 0,
+                    _ => 1,
+                },
+            );
         }
-    }
+    };
 }

src/translators/decode.rs

@@ -1,6 +1,6 @@
 use crate::cli_config::{translate_algorithm, DecodeArgs};
 use crate::translators::Payload;
-use crate::utils::slurp_file;
+use crate::utils::{slurp_file, write_file};
 use base64::engine::general_purpose::STANDARD as base64_engine;
 use base64::Engine as _;
 use jsonwebtoken::errors::{ErrorKind, Result as JWTResult};
@@ -9,7 +9,7 @@ use serde_derive::{Deserialize, Serialize};
 use serde_json::to_string_pretty;
 use std::collections::HashSet;
 use std::io;
-use std::process::exit;
+use std::path::PathBuf;
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum OutputFormat {
@@ -18,9 +18,9 @@ pub enum OutputFormat {
 }
 
 #[derive(Debug, Serialize, Deserialize, PartialEq)]
-struct TokenOutput {
-    header: Header,
-    payload: Payload,
+pub struct TokenOutput {
+    pub header: Header,
+    pub payload: Payload,
 }
 
 impl TokenOutput {
@@ -147,7 +147,8 @@ pub fn print_decoded_token(
     validated_token: JWTResult<TokenData<Payload>>,
     token_data: JWTResult<TokenData<Payload>>,
     format: OutputFormat,
-) {
+    output_path: &Option<PathBuf>,
+) -> JWTResult<()> {
     if let Err(err) = &validated_token {
         match err.kind() {
             ErrorKind::InvalidToken => {
@@ -193,23 +194,26 @@ pub fn print_decoded_token(
                 err
             ),
         };
+        return Err(validated_token.err().unwrap());
     }
 
-    match (format, token_data) {
-        (OutputFormat::Json, Ok(token)) => {
-            println!("{}", to_string_pretty(&TokenOutput::new(token)).unwrap())
+    match (output_path.as_ref(), format, token_data) {
+        (Some(path), _, Ok(token)) => {
+            let json = to_string_pretty(&TokenOutput::new(token)).unwrap();
+            write_file(path, json.as_bytes());
+            println!("Wrote jwt to file {}", path.display());
+        }
+        (None, OutputFormat::Json, Ok(token)) => {
+            println!("{}", to_string_pretty(&TokenOutput::new(token)).unwrap());
         }
-        (_, Ok(token)) => {
+        (None, _, Ok(token)) => {
             bunt::println!("\n{$bold}Token header\n------------{/$}");
             println!("{}\n", to_string_pretty(&token.header).unwrap());
             bunt::println!("{$bold}Token claims\n------------{/$}");
             println!("{}", to_string_pretty(&token.claims).unwrap());
         }
-        (_, Err(_)) => exit(1),
+        (_, _, Err(err)) => return Err(err),
     }
 
-    exit(match validated_token {
-        Err(_) => 1,
-        Ok(_) => 0,
-    })
+    Ok(())
 }

src/translators/encode.rs

@@ -1,6 +1,6 @@
 use crate::cli_config::{translate_algorithm, EncodeArgs};
 use crate::translators::{Payload, PayloadItem};
-use crate::utils::slurp_file;
+use crate::utils::{slurp_file, write_file};
 use atty::Stream;
 use base64::engine::general_purpose::STANDARD as base64_engine;
 use base64::Engine as _;
@@ -9,7 +9,7 @@ use jsonwebtoken::errors::Result as JWTResult;
 use jsonwebtoken::{encode, Algorithm, EncodingKey, Header};
 use serde_json::{from_str, Value};
 use std::io;
-use std::process::exit;
+use std::path::PathBuf;
 
 fn create_header(alg: Algorithm, kid: Option<&String>) -> Header {
     let mut header = Header::new(alg);
@@ -113,20 +113,27 @@ pub fn encode_token(arguments: &EncodeArgs) -> JWTResult<String> {
         .and_then(|secret| encode(&header, &claims, &secret))
 }
 
-pub fn print_encoded_token(token: JWTResult<String>) {
-    match token {
-        Ok(jwt) => {
+pub fn print_encoded_token(
+    token: JWTResult<String>,
+    output_path: &Option<PathBuf>,
+) -> JWTResult<()> {
+    match (output_path.as_ref(), token) {
+        (Some(path), Ok(jwt)) => {
+            write_file(path, jwt.as_bytes());
+            println!("Wrote jwt to file {}", path.display());
+        }
+        (None, Ok(jwt)) => {
             if atty::is(Stream::Stdout) {
                 println!("{}", jwt);
             } else {
                 print!("{}", jwt);
-            }
-            exit(0);
+            };
         }
-        Err(err) => {
+        (_, Err(err)) => {
             bunt::eprintln!("{$red+bold}Something went awry creating the jwt{/$}\n");
             eprintln!("{}", err);
-            exit(1);
+            return Err(err);
         }
     }
+    Ok(())
 }

src/utils.rs

@@ -1,9 +1,14 @@
 use std::fs;
+use std::path::Path;
 
 pub fn slurp_file(file_name: &str) -> Vec<u8> {
     fs::read(file_name).unwrap_or_else(|_| panic!("Unable to read file {}", file_name))
 }
 
+pub fn write_file(path: &Path, content: &[u8]) {
+    fs::write(path, content).unwrap_or_else(|_| panic!("Unable to write file {}", path.display()))
+}
+
 pub fn parse_duration_string(val: &str) -> Result<i64, String> {
     let mut base_val = val.replace(" ago", "");