Add OpenAPI generator

controllers/ApiController.cc

@@ -4,7 +4,10 @@
 #include <drogon/orm/Exception.h>
 
 #include <json/json.h>
+#include <filesystem>
+#include <fstream>
 #include <memory>
+#include <sstream>
 
 using drogon::HttpResponse;
 using drogon::HttpResponsePtr;
@@ -27,6 +30,12 @@ Json::Value mysqlReadyBody(bool ready)
     body["dependencies"]["mysql"] = ready;
     return body;
 }
+
+std::string openApiSpecPath()
+{
+    const auto &config = drogon::app().getCustomConfig()["openapi"];
+    return config.get("spec_path", "build/openapi/visione.openapi.json").asString();
+}
 }
 
 void ApiController::health(
@@ -70,3 +79,55 @@ void ApiController::ready(
             jsonResponse(std::move(body), k503ServiceUnavailable));
     }
 }
+
+void ApiController::openApi(
+    const drogon::HttpRequestPtr &,
+    std::function<void(const HttpResponsePtr &)> &&callback)
+{
+    const auto path = openApiSpecPath();
+    std::ifstream file(path, std::ios::binary);
+    if (!file)
+    {
+        Json::Value body;
+        body["error"] = "openapi_spec_not_generated";
+        body["message"] = "Run cmake --build build or the openapi target.";
+        body["path"] = path;
+        callback(jsonResponse(std::move(body), drogon::k404NotFound));
+        return;
+    }
+
+    std::ostringstream buffer;
+    buffer << file.rdbuf();
+    auto response = HttpResponse::newHttpResponse();
+    response->setStatusCode(drogon::k200OK);
+    response->setContentTypeCode(drogon::CT_APPLICATION_JSON);
+    response->setBody(buffer.str());
+    callback(response);
+}
+
+void ApiController::docs(
+    const drogon::HttpRequestPtr &,
+    std::function<void(const HttpResponsePtr &)> &&callback)
+{
+    static const std::string html = R"(<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>Visione API Docs</title>
+  <link rel="stylesheet" href="https://unpkg.com/swagger-ui-dist@5/swagger-ui.css">
+</head>
+<body>
+  <div id="swagger-ui"></div>
+  <script src="https://unpkg.com/swagger-ui-dist@5/swagger-ui-bundle.js"></script>
+  <script>
+    window.ui = SwaggerUIBundle({ url: "/api/v1/openapi.json", dom_id: "#swagger-ui" });
+  </script>
+</body>
+</html>)";
+
+    auto response = HttpResponse::newHttpResponse();
+    response->setStatusCode(drogon::k200OK);
+    response->setContentTypeCode(drogon::CT_TEXT_HTML);
+    response->setBody(html);
+    callback(response);
+}