add application configuration to replace Rocket.toml

peach-web/src/config.rs

@@ -1,54 +1,53 @@
-// Kind thanks to Alex Wennerberg (https://alexwennerberg.com/) for writing
-// this code and offered it under the 0BSD (BDS 0-Clause) license.
+//! Define the configuration parameters for the web application.
+//!
+//! Sets default values and updates them if the corresponding environment
+//! variables have been set.
 
-use std::fs::File;
-use std::io::{self, BufRead};
-use std::path::Path;
+use std::env;
+
+// environment variable keys to check for
+const ENV_VARS: [&str; 4] = ["STANDALONE_MODE", "DISABLE_AUTH", "ADDR", "PORT"];
 
-// Ini-like key=value configuration with global config only (no subsections).
-#[derive(Debug, PartialEq)]
 pub struct Config {
-    pub disable_auth: bool,
     pub standalone_mode: bool,
+    pub disable_auth: bool,
+    pub addr: String,
+    pub port: String,
 }
 
 impl Default for Config {
     fn default() -> Self {
         Self {
-            disable_auth: false,
             standalone_mode: true,
+            disable_auth: false,
+            addr: "127.0.0.1".to_string(),
+            port: "8000".to_string(),
         }
     }
 }
 
 impl Config {
-    pub fn match_kv(&mut self, key: &str, value: &str) {
-        match key {
-            "disable_auth" => self.disable_auth = value.parse().unwrap(),
-            "standalone_mode" => self.standalone_mode = value.parse().unwrap(),
-            _ => {}
-        }
-    }
-}
+    pub fn new() -> Config {
+        // define default config values
+        let mut config = Config::default();
 
-impl Config {
-    pub fn from_file<P: AsRef<Path>>(path: P) -> Result<Config, std::io::Error> {
-        let file = File::open(path)?;
-        let mut conf = Config::default();
-
-        for l in io::BufReader::new(file).lines() {
-            let line = l?;
-            if line.is_empty() {
-                continue;
-            }
-            if let Some(i) = line.find('=') {
-                let key = &line[..i];
-                let value = &line[i + 1..];
-                conf.match_kv(key, value);
-            } else {
-                // panic!("Invalid config")
+        // check for the environment variables in our config
+        for key in ENV_VARS {
+            // if a variable (key) has been set, check the value
+            if let Ok(val) = env::var(key) {
+                // if the value is of the correct type, update the config value
+                match key {
+                    "STANDALONE_MODE" if val.as_str() == "true" => config.standalone_mode = true,
+                    "STANDALONE_MODE" if val.as_str() == "false" => config.standalone_mode = false,
+                    "DISABLE_AUTH" if val.as_str() == "true" => config.disable_auth = true,
+                    "DISABLE_AUTH" if val.as_str() == "false" => config.disable_auth = false,
+                    "ADDR" => config.addr = val,
+                    "PORT" => config.port = val,
+                    _ => (),
+                }
             }
         }
-        Ok(conf)
+
+        config
     }
 }