feat: Add proxy support including HTTP_PROXY, HTTPS_PROXY detection (#115)

This commit introduces proxy handling functionality for the hyper
transport, including automatic instrumentation through environment
variables.

If HTTPS_PROXY is defined, all HTTPS traffic will potentially be routed
through this proxy.

If HTTP_PROXY is ALSO specified, then HTTP traffic will be routed
through it. However, if HTTP_PROXY is specified without HTTPS_PROXY,
then all traffic (http and https) will be routed through the HTTP_PROXY.

Author: keelerm84

contract-tests/src/bin/sse-test-api/stream_entity.rs

@@ -131,7 +131,9 @@ impl Inner {
             transport_builder = transport_builder.read_timeout(Duration::from_millis(timeout_ms));
         }
 
-        let transport = transport_builder.build_https();
+        let transport = transport_builder
+            .build_https()
+            .map_err(|e| format!("Failed to build HTTPS transport: {e:?}"))?;
 
         Ok(Box::new(
             client_builder

eventsource-client/Cargo.toml

@@ -26,9 +26,11 @@ base64 = "0.22.1"
 hyper = { version = "1.0", features = ["client", "http1", "http2"], optional = true }
 hyper-util = { version = "0.1", features = ["client-legacy", "http1", "http2", "tokio"], optional = true }
 http-body-util = { version = "0.1", optional = true }
+hyper-http-proxy = { version = "1.1.0", optional = true }
 hyper-rustls = { version = "0.27", default-features = false, features = ["http1", "http2", "native-tokio", "ring", "tls12", "webpki-roots"], optional = true }
 hyper-timeout = { version = "0.5", optional = true }
 tower = { version = "0.4", optional = true }
+no-proxy = { version = "0.3.6", default-features = false }
 
 [dev-dependencies]
 env_logger = "0.10.0"
@@ -41,5 +43,5 @@ proptest = "1.0.0"
 
 [features]
 default = ["hyper"]
-hyper = ["dep:hyper", "dep:hyper-util", "dep:http-body-util", "dep:hyper-timeout", "dep:tower"]
+hyper = ["dep:hyper", "dep:hyper-util", "dep:http-body-util", "dep:hyper-timeout", "dep:tower", "dep:hyper-http-proxy"]
 hyper-rustls = ["hyper", "dep:hyper-rustls"]

eventsource-client/examples/tail.rs

@@ -59,7 +59,7 @@ async fn run_with_http(url: &str, auth_header: &str) -> Result<(), Box<dyn std::
     let transport = es::HyperTransport::builder()
         .connect_timeout(Duration::from_secs(10))
         .read_timeout(Duration::from_secs(30))
-        .build_http();
+        .build_http()?;
 
     let client = es::ClientBuilder::for_url(url)?
         .header("Authorization", auth_header)?
@@ -85,7 +85,7 @@ async fn run_with_https(url: &str, auth_header: &str) -> Result<(), Box<dyn std:
     let transport = es::HyperTransport::builder()
         .connect_timeout(Duration::from_secs(10))
         .read_timeout(Duration::from_secs(30))
-        .build_https();
+        .build_https()?;
 
     let client = es::ClientBuilder::for_url(url)?
         .header("Authorization", auth_header)?

eventsource-client/src/lib.rs

@@ -57,6 +57,7 @@ mod event_parser;
 mod response;
 mod retry;
 mod transport;
+
 #[cfg(feature = "hyper")]
 mod transport_hyper;