Initial commit for HostRedirector

CMakeLists.txt

@@ -271,6 +271,7 @@ set(DROGON_SOURCES
     lib/src/Redirector.cc
     lib/src/SessionManager.cc
     lib/src/SlashRemover.cc
+	lib/src/HostRedirector.cc
     lib/src/SlidingWindowRateLimiter.cc
     lib/src/StaticFileRouter.cc
     lib/src/TaskTimeoutFlag.cc
@@ -717,6 +718,7 @@ set(DROGON_PLUGIN_HEADERS
     lib/inc/drogon/plugins/RealIpResolver.h
     lib/inc/drogon/plugins/Hodor.h
     lib/inc/drogon/plugins/SlashRemover.h
+	lib/inc/drogon/plugins/HostRedirector.h
     lib/inc/drogon/plugins/GlobalFilters.h
     lib/inc/drogon/plugins/PromExporter.h)
 

lib/inc/drogon/plugins/HostRedirector.h

@@ -0,0 +1,74 @@
+/**
+ *  @file HostRedirector.h
+ *  @author Mis1eader
+ *
+ *  Copyright 2023, Mis1eader.  All rights reserved.
+ *  https://github.com/an-tao/drogon
+ *  Use of this source code is governed by a MIT license
+ *  that can be found in the License file.
+ *
+ *  Drogon
+ *
+ */
+
+#pragma once
+
+#include "drogon/plugins/Plugin.h"
+#include "drogon/utils/FunctionTraits.h"
+#include <json/value.h>
+#include <memory>
+#include <unordered_map>
+
+namespace drogon::plugin
+{
+/**
+ * @brief The HostRedirector plugin redirects requests with respect to rules.
+ * The json configuration is as follows:
+ *
+ * @code
+  {
+     "name": "drogon::plugin::HostRedirector",
+     "dependencies": ["drogon::plugin::Redirector"],
+     "config": {
+         "rules": {
+             "www.example.com": [
+                 "10.10.10.1",
+                 "example.com",
+                 "search.example.com",
+                 "ww.example.com"
+             ],
+             "images.example.com": [
+                 "image.example.com"
+             ],
+             "www.example.com/maps": [
+                 "map.example.com",
+                 "maps.example.com"
+             ]
+         }
+     }
+  }
+  @endcode
+ *
+ * Enable the plugin by adding the configuration to the list of plugins in the
+ * configuration file.
+ * */
+class DROGON_EXPORT HostRedirector
+    : public drogon::Plugin<HostRedirector>,
+      public std::enable_shared_from_this<HostRedirector>
+{
+  public:
+    HostRedirector()
+    {
+    }
+
+    void initAndStart(const Json::Value &config) override;
+    void shutdown() override;
+
+  private:
+    bool redirectingAdvice(const drogon::HttpRequestPtr &,
+                           std::string &,
+                           bool &);
+
+    std::unordered_map<std::string, std::string> rules_;
+};
+}  // namespace drogon::plugin

lib/src/HostRedirector.cc

@@ -0,0 +1,75 @@
+#include <drogon/plugins/HostRedirector.h>
+#include <drogon/plugins/Redirector.h>
+#include <drogon/HttpAppFramework.h>
+#include "drogon/utils/FunctionTraits.h"
+#include <functional>
+#include <memory>
+#include <string>
+#include <string_view>
+
+using namespace drogon;
+using namespace drogon::plugin;
+using std::string;
+using std::string_view;
+
+bool HostRedirector::redirectingAdvice(const HttpRequestPtr& req,
+                                       string& host,
+                                       bool& pathChanged)
+{
+    const string& reqHost = host.empty() ? req->getHeader("host") : host;
+    auto find = rules_.find(reqHost);
+    if (find != rules_.end())
+        host = find->second;
+
+    // TODO: some may need to change the path as well
+
+    return true;
+}
+
+void HostRedirector::initAndStart(const Json::Value& config)
+{
+    if (config.isMember("rules"))
+    {
+        const auto& rules = config["rules"];
+        if (rules.isObject())
+        {
+            for (const auto& redirectTo : rules)
+            {
+                if (!redirectTo.isString())
+                    continue;
+
+                const string redirectToStr = redirectTo.asString();
+                for (const auto& redirectFrom : rules[redirectToStr])
+                {
+                    if (!redirectFrom.isString())
+                        continue;
+
+                    rules_[redirectFrom.asString()] = redirectToStr;
+                }
+            }
+        }
+    }
+    std::weak_ptr<HostRedirector> weakPtr = shared_from_this();
+    auto redirector = app().getPlugin<Redirector>();
+    if (!redirector)
+    {
+        LOG_ERROR << "Redirector plugin is not found!";
+        return;
+    }
+    redirector->registerRedirectHandler([weakPtr](const HttpRequestPtr& req,
+                                                  string&,
+                                                  string& host,
+                                                  bool& pathChanged) -> bool {
+        auto thisPtr = weakPtr.lock();
+        if (!thisPtr)
+        {
+            return false;
+        }
+        return thisPtr->redirectingAdvice(req, host, pathChanged);
+    });
+}
+
+void HostRedirector::shutdown()
+{
+    LOG_TRACE << "HostRedirector plugin is shutdown!";
+}

lib/src/SlashRemover.cc

@@ -150,8 +150,7 @@ static inline void removeExcessiveSlashes(string& url,
         removeDuplicateSlashes(url, start.second);
 }
 
-static inline bool handleReq(const drogon::HttpRequestPtr& req,
-                             uint8_t removeMode)
+static inline bool handleReq(const HttpRequestPtr& req, uint8_t removeMode)
 {
     switch (removeMode)
     {