Turn off default proxy detection

src/agent.rs

@@ -37,7 +37,7 @@ pub enum RedirectAuthHeaders {
 /// Accumulates options towards building an [Agent].
 pub struct AgentBuilder {
     config: AgentConfig,
-    no_proxy: bool,
+    try_proxy_from_env: bool,
     max_idle_connections: usize,
     max_idle_connections_per_host: usize,
     /// Cookies saved between requests.
@@ -264,7 +264,7 @@ impl AgentBuilder {
                 user_agent: format!("ureq/{}", env!("CARGO_PKG_VERSION")),
                 tls_config: TlsConfig(crate::default_tls_config()),
             },
-            no_proxy: false,
+            try_proxy_from_env: false,
             max_idle_connections: DEFAULT_MAX_IDLE_CONNECTIONS,
             max_idle_connections_per_host: DEFAULT_MAX_IDLE_CONNECTIONS_PER_HOST,
             resolver: StdResolver.into(),
@@ -280,7 +280,7 @@ impl AgentBuilder {
     // not implement clone, so we have to give ownership to the newly
     // built Agent.
     pub fn build(mut self) -> Agent {
-        if self.config.proxy.is_none() && !self.no_proxy {
+        if self.config.proxy.is_none() && self.try_proxy_from_env {
             if let Some(proxy) = Proxy::try_from_system() {
                 self.config.proxy = Some(proxy);
             }
@@ -314,16 +314,20 @@ impl AgentBuilder {
     /// # }
     /// ```
     ///
-    /// # Note
-    /// Adding a proxy will disable the automatic usage of the “system” proxy.
+    /// Adding a proxy will disable `try_proxy_from_env`.
     pub fn proxy(mut self, proxy: Proxy) -> Self {
         self.config.proxy = Some(proxy);
         self
     }
 
-    /// Don't auto detect proxy from system environment, e.g. HTTP_PROXY
-    pub fn no_proxy(mut self) -> Self {
-        self.no_proxy = true;
+    /// Attempt to detect proxy settings from the environment, i.e. HTTP_PROXY
+    ///
+    /// The default is `false`, i.e. not detecting proxy from env since this is
+    /// a potential security risk.
+    ///
+    /// If the `proxy` is set on the builder, this setting has no effect.
+    pub fn try_proxy_from_env(mut self, do_try: bool) -> Self {
+        self.try_proxy_from_env = do_try;
         self
     }