Add devserver_loader beginning

Author: ryanmcdermott

devserver/BUILD

@@ -2,4 +2,10 @@ filegroup(
     name = "main",
     srcs = glob(["main.cc", "httplib/httplib.h", "argparse/argparse.h"]),
     visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "devserver_loader",
+    srcs = glob(["devserver_loader.js"]),
+    visibility = ["//visibility:public"],
 )

devserver/defs.bzl

@@ -11,7 +11,7 @@ def devserver(name, port, static_file, workspace_name, data = []):
             "--workspace_name=%s" % workspace_name,
             "--package_name=%s" % native.package_name(),
         ],
-        data = data,
+        data = data + [Label("@rules_devserver//devserver:devserver_loader")],
         deps = ["@bazel_tools//tools/cpp/runfiles"],
         linkopts = ["-lpthread"],
     )

devserver/devserver_loader.js

@@ -0,0 +1 @@
+console.log("inside devserver_loader.js");

devserver/main.cc

@@ -1,7 +1,10 @@
 #include <iostream>
 
-#include "external/rules_devserver/devserver/argparse/argparse.h"
-#include "external/rules_devserver/devserver/httplib/httplib.h"
+// #include "external/rules_devserver/devserver/argparse/argparse.h"
+// #include "external/rules_devserver/devserver/httplib/httplib.h"
+
+#include "devserver/argparse/argparse.h"
+#include "devserver/httplib/httplib.h"
 #include "tools/cpp/runfiles/runfiles.h"
 
 using bazel::tools::cpp::runfiles::Runfiles;
@@ -63,20 +66,39 @@ int main(int argc, char **argv) {
     DEBUG_LOG("package_name: " << args::get(package_name));
   }
 
-  const std::string path = runfiles->Rlocation(workspace_name + "/");
+  const std::string workspace_root = runfiles->Rlocation(workspace_name + "/");
+  DEBUG_LOG("workspace_root: " << workspace_root << "\n\n");
 
   const std::string static_file_path =
-      path + args::get(package_name) + "/" + args::get(static_file);
+      workspace_root + args::get(package_name) + "/" + args::get(static_file);
   DEBUG_LOG("static_file_path: " << static_file_path);
 
   std::string static_file_contents;
   static_file_contents = GetFileContents(static_file_path);
-  DEBUG_LOG("static_file_contents: " << static_file_contents)
 
+  const std::regex re("<\\/head>");
+  const std::string replacement =
+      "<script src=\"/devserver_loader.js\"></script></head>";
+  static_file_contents =
+      std::regex_replace(static_file_contents, re, replacement);
+
+  DEBUG_LOG("static_file_contents: " << static_file_contents);
   svr.Get("/", [&static_file_contents](const httplib::Request &req,
                                        httplib::Response &res) {
     res.set_content(static_file_contents, "text/html");
   });
 
+  svr.Get("/devserver_loader.js", [&workspace_root](const httplib::Request &req,
+                                                    httplib::Response &res) {
+    const std::string devserver_loader_path =
+        workspace_root + "devserver/devserver_loader.js";
+    DEBUG_LOG("devserver_loader_path: " << devserver_loader_path);
+
+    std::string devserver_loader_contents;
+    devserver_loader_contents = GetFileContents(devserver_loader_path);
+
+    res.set_content(devserver_loader_contents, "text/javascript");
+  });
+
   svr.listen(kHost, args::get(port));
 }