Use iteration instead of recursion for connect (#291)

This allows handling larger redirect chains.

Fixes #290

src/test/redirect.rs

@@ -35,6 +35,22 @@ fn redirect_many() {
         .get("test://host/redirect_many1")
         .call();
     assert!(matches!(result, Err(e) if e.kind() == ErrorKind::TooManyRedirects));
+
+    test::set_handler("/redirect_many1", |_| {
+        test::make_response(302, "Go here", vec!["Location: /redirect_many2"], vec![])
+    });
+    test::set_handler("/redirect_many2", |_| {
+        test::make_response(302, "Go here", vec!["Location: /redirect_many3"], vec![])
+    });
+    test::set_handler("/redirect_many3", |_| {
+        test::make_response(302, "Go here", vec!["Location: /redirect_many4"], vec![])
+    });
+    let result = builder()
+        .redirects(2)
+        .build()
+        .get("test://host/redirect_many1")
+        .call();
+    assert!(matches!(result, Err(e) if e.kind() == ErrorKind::TooManyRedirects));
 }
 
 #[test]
@@ -141,3 +157,22 @@ fn redirect_308() {
     assert_eq!(resp.status(), 200);
     assert_eq!(resp.get_url(), "test://host/valid_response");
 }
+
+#[test]
+fn too_many_redirects() {
+    for i in 0..10_000 {
+        test::set_handler(&format!("/malicious_redirect_{}", i), move |_| {
+            let location = format!("Location: /malicious_redirect_{}", i + 1);
+            test::make_response(302, "Go here", vec![&location], vec![])
+        });
+    }
+
+    test::set_handler("/malicious_redirect_10000", |unit| {
+        assert_eq!(unit.method, "GET");
+        test::make_response(200, "OK", vec![], vec![])
+    });
+
+    let req = crate::builder().redirects(10001).build();
+    let resp = req.get("test://host/malicious_redirect_0").call().unwrap();
+    assert_eq!(resp.get_url(), "test://host/malicious_redirect_10000");
+}