Protect the session_key from external libs. Clean-up config docs.

lib/src/config/config.rs

@@ -1,6 +1,8 @@
 use std::collections::HashMap;
 use std::net::ToSocketAddrs;
 use std::path::Path;
+use std::cell::RefCell;
+use std::fmt;
 
 use config::Environment::*;
 use config::{self, Environment, ConfigError};
@@ -8,13 +10,13 @@ use config::{self, Environment, ConfigError};
 use logger::LoggingLevel;
 use toml::Value;
 
-#[derive(Debug, PartialEq, Clone)]
+#[derive(PartialEq)]
 pub struct Config {
     pub address: String,
     pub port: usize,
     pub log_level: LoggingLevel,
-    pub session_key: Option<String>,
     pub env: Environment,
+    session_key: RefCell<Option<String>>,
     extra: HashMap<String, Value>,
     filename: String,
 }
@@ -41,7 +43,7 @@ impl Config {
                     address: "localhost".to_string(),
                     port: 8000,
                     log_level: LoggingLevel::Normal,
-                    session_key: None,
+                    session_key: RefCell::new(None),
                     extra: HashMap::new(),
                     env: env,
                     filename: filename.to_string(),
@@ -52,7 +54,7 @@ impl Config {
                     address: "0.0.0.0".to_string(),
                     port: 80,
                     log_level: LoggingLevel::Normal,
-                    session_key: None,
+                    session_key: RefCell::new(None),
                     extra: HashMap::new(),
                     env: env,
                     filename: filename.to_string(),
@@ -63,7 +65,7 @@ impl Config {
                     address: "0.0.0.0".to_string(),
                     port: 80,
                     log_level: LoggingLevel::Critical,
-                    session_key: None,
+                    session_key: RefCell::new(None),
                     extra: HashMap::new(),
                     env: env,
                     filename: filename.to_string(),
@@ -101,7 +103,7 @@ impl Config {
                 return Err(self.bad_type(name, val, "a 192-bit base64 string"));
             }
 
-            self.session_key = Some(key.to_string());
+            self.session_key = RefCell::new(Some(key.to_string()));
         } else if name == "log" {
             let level_str = parse!(self, name, val, as_str, "a string")?;
             self.log_level = match level_str.parse() {
@@ -116,6 +118,16 @@ impl Config {
         Ok(())
     }
 
+    #[inline(always)]
+    pub fn take_session_key(&self) -> Option<String> {
+        self.session_key.borrow_mut().take()
+    }
+
+    #[inline(always)]
+    pub fn extras<'a>(&'a self) -> impl Iterator<Item=(&'a String, &'a Value)> {
+        self.extra.iter()
+    }
+
     pub fn get_str<'a>(&'a self, name: &str) -> config::Result<&'a str> {
         let value = self.extra.get(name).ok_or_else(|| ConfigError::NotFound)?;
         parse!(self, name, value, as_str, "a string")
@@ -143,11 +155,6 @@ impl Config {
         }
     }
 
-    #[inline(always)]
-    pub fn extras<'a>(&'a self) -> impl Iterator<Item=(&'a String, &'a Value)> {
-        self.extra.iter()
-    }
-
     // Builder pattern below, mostly for testing.
 
     #[inline(always)]
@@ -170,7 +177,7 @@ impl Config {
 
     #[inline(always)]
     pub fn session_key(mut self, var: String) -> Self {
-        self.session_key = Some(var);
+        self.session_key = RefCell::new(Some(var));
         self
     }
 
@@ -180,3 +187,10 @@ impl Config {
         self
     }
 }
+
+impl fmt::Debug for Config {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Config[{}] {{ address: {}, port: {}, log_level: {:?} }}",
+               self.env, self.address, self.port, self.log_level)
+    }
+}

lib/src/config/mod.rs

@@ -11,8 +11,8 @@ use std::env;
 
 pub use self::error::{ConfigError, ParsingError};
 pub use self::environment::Environment;
+pub use self::config::Config;
 use self::Environment::*;
-use self::config::Config;
 
 use toml::{self, Table};
 use logger::{self, LoggingLevel};
@@ -23,7 +23,7 @@ const CONFIG_FILENAME: &'static str = "Rocket.toml";
 
 pub type Result<T> = ::std::result::Result<T, ConfigError>;
 
-#[derive(Debug, PartialEq, Clone)]
+#[derive(Debug, PartialEq)]
 pub struct RocketConfig {
     pub active_env: Environment,
     config: HashMap<Environment, Config>,
@@ -152,14 +152,16 @@ impl RocketConfig {
 ///
 /// # Panics
 ///
-/// If there is a problem, prints a nice error message and bails.
+/// If there is a problem, prints a nice error message and bails. This function
+/// also panics if it is called more than once.
 ///
 /// # Thread-Safety
 ///
 /// This function is _not_ thread-safe. It should be called by a single thread.
+#[doc(hidden)]
 pub fn init() -> &'static Config {
-    if let Some(config) = active() {
-        return config;
+    if active().is_some() {
+        panic!("Configuration has already been initialized!")
     }
 
     let bail = |e: ConfigError| -> ! {
@@ -192,6 +194,7 @@ pub fn init() -> &'static Config {
     }
 }
 
+/// Retrieve the active configuration, if there is one.
 pub fn active() -> Option<&'static Config> {
     unsafe { CONFIG.as_ref().map(|c| c.active()) }
 }
@@ -225,9 +228,9 @@ mod test {
         );
 
         ($env:expr, $rconfig:expr, $econfig:expr) => (
-            match $rconfig.clone() {
-                Ok(config) => assert_eq!(config.get($env), &$econfig),
-                Err(e) => panic!("Config {} failed: {:?}", stringify!($rconfig), e)
+            match $rconfig {
+                Ok(ref config) => assert_eq!(config.get($env), &$econfig),
+                Err(ref e) => panic!("Config {} failed: {:?}", stringify!($rconfig), e)
             }
         );
     }
@@ -306,11 +309,12 @@ mod test {
             pi = 3.14
         "#;
 
-        let mut expected = default_config(Development);
-        expected.address = "1.2.3.4".to_string();
-        expected.port = 7810;
-        expected.log_level = LoggingLevel::Critical;
-        expected.session_key = Some("01234567890123456789012345678901".to_string());
+        let mut expected = default_config(Development)
+                .address("1.2.3.4".to_string())
+                .port(7810)
+                .log_level(LoggingLevel::Critical)
+                .session_key("01234567890123456789012345678901".into());
+
         expected.set("template_dir", &Value::String("mine".into())).unwrap();
         expected.set("json", &Value::Boolean(true)).unwrap();
         expected.set("pi", &Value::Float(3.14)).unwrap();

lib/src/rocket.rs

@@ -235,7 +235,7 @@ impl Rocket {
                White.paint(&config.address),
                White.paint(&config.port));
         info_!("logging: {:?}", White.paint(config.log_level));
-        info_!("session key: {}", White.paint(config.session_key.is_some()));
+        info_!("session key: {}", White.paint(config.take_session_key().is_some()));
         for (name, value) in config.extras() {
             info_!("{} {}: {}", Yellow.paint("[extra]"), name, White.paint(value));
         }