attempt parsing of port only if colon was found

without this change, urls like 5.my.s3.cluster were misinterpreted and
  the '5' parsed as the port of the url.

Bug:
* the getline() function puts the entire input string into the
  destination string, if the delimiter was not found.
  This leads to the entire host string being fed to the stoi()
  function to parse the port.

Fix:
* applied suggestion by @balamurugana

src/http.cc

@@ -140,18 +140,22 @@ Url Url::Parse(std::string value) {
   unsigned int port = 0;
   struct sockaddr_in6 dst;
   if (inet_pton(AF_INET6, host.c_str(), &(dst.sin6_addr)) <= 0) {
-    if (host.front() != '[' || host.back() != ']') {
+    if ((host.front() != '[' || host.back() != ']') && utils::Contains(host, ':')) {
       std::stringstream ss(host);
       std::string portstr;
       while (std::getline(ss, portstr, ':')) {
       }
 
       if (!portstr.empty()) {
-        try {
-          port = static_cast<unsigned>(std::stoi(portstr));
+        char* str_end{};
+        const long l = std::strtol(portstr.c_str(), &str_end, 10);
+        size_t length = std::distance(portstr.c_str(), const_cast<const char*>(str_end));
+        if (length == portstr.size()) {
+          if (l < 1 || l > 65535) {
+            return Url{};
+          }
+          port = static_cast<int>(l);
           host = host.substr(0, host.rfind(":" + portstr));
-        } catch (const std::invalid_argument&) {
-          port = 0;
         }
       }
     }

tests/tests.cc

@@ -699,6 +699,36 @@ class Tests {
       throw;
     }
   }
+
+  void TestBaseUrl() {
+    std::cout << "TestBaseUrl()" << std::endl;
+    std::vector<std::tuple<std::string, std::string, bool, int>> tests = {
+	{"http://localhost:9000", "localhost", false, 9000},
+	{"http://localhost", "localhost", false, 0},
+	{"http://localhost:80", "localhost", false, 0},
+	{"https://localhost:9443", "localhost", true, 9443},
+	{"https://localhost", "localhost", true, 0},
+	{"https://5.localhost.foo", "5.localhost.foo", true, 0},
+	{"https://5.localhost.foo:9000", "5.localhost.foo", true, 9000},
+    };
+    for (auto& [url, host, https, port] : tests) {
+      minio::s3::BaseUrl base_url(url);
+      if (base_url.host != host) {
+	throw std::runtime_error("BaseUrl(" + url +").host: expected: " + host +
+				 ", got: " + base_url.host);
+      }
+      if (base_url.https != https) {
+	throw std::runtime_error("BaseUrl("+ url +").https: expected: " +
+				 std::to_string(https) +
+				 ", got: " + std::to_string(base_url.https));
+      }
+      if (base_url.port != port) {
+	throw std::runtime_error("BaseUrl("+ url +").port: expected: " +
+				 std::to_string(port) +
+				 ", got: " + std::to_string(base_url.port));
+      }
+    }
+  }
 };  // class Tests
 
 int main(int /*argc*/, char* /*argv*/[]) {
@@ -756,6 +786,7 @@ int main(int /*argc*/, char* /*argv*/[]) {
   tests.RemoveObjects();
   tests.SelectObjectContent();
   tests.ListenBucketNotification();
+  tests.TestBaseUrl();
 
   return EXIT_SUCCESS;
 }