Implement Readings endpoint for read

Author: canmor

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.19)
+project(developer_joyofenergy_cpp_beast)
+
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_BINARY_DIR})
+set(CMAKE_CXX_STANDARD 17)
+
+add_subdirectory(rest)
+add_executable(app main.cpp)
+target_link_libraries(app PRIVATE rest)
+
+enable_testing()
+add_subdirectory(test)

conanfile.txt

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+[requires]
+boost/1.76.0
+gtest/1.11.0
+nlohmann_json/3.9.1
+
+[generators]
+cmake_find_package
+
+[options]
+boost:header_only=True

main.cpp

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+#include <iostream>
+
+#include "rest/server.h"
+
+int main(int argc, char *argv[]) {
+    if (argc != 4) {
+        std::cerr << "Usage: app <address> <kPort> <concurrency>\n"
+                  << "Example:\n"
+                  << "    http-server-async 0.0.0.0 8080 1\n";
+        return EXIT_FAILURE;
+    }
+    auto const address = argv[1];
+    auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
+    auto const threads = std::max<int>(1, std::atoi(argv[3]));
+    server a{threads};
+    a.run(address, port);
+    char wait;
+    std::cin >> wait;
+    return EXIT_SUCCESS;
+}

rest/CMakeLists.txt

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+add_subdirectory(service)
+add_subdirectory(controller)
+add_library(rest)
+target_sources(rest PRIVATE server.cpp)
+target_include_directories(rest INTERFACE ..)
+target_link_libraries(rest PUBLIC controller)

rest/configuration.h

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+#ifndef DEVELOPER_JOYOFENERGY_CPP_BEAST_CONFIGURATION_H
+#define DEVELOPER_JOYOFENERGY_CPP_BEAST_CONFIGURATION_H
+
+#include <domain/ElectricityReading.h>
+#include <domain/PricePlan.h>
+
+#include "generator.h"
+
+constexpr auto DR_EVILS_DARK_ENERGY_ENERGY_SUPPLIER = "Dr Evil's Dark Energy";
+constexpr auto THE_GREEN_ECO_ENERGY_SUPPLIER = "The Green Eco";
+constexpr auto POWER_FOR_EVERYONE_ENERGY_SUPPLIER = "Power for Everyone";
+
+constexpr auto MOST_EVIL_PRICE_PLAN_ID = "price-plan-0";
+constexpr auto RENEWABLES_PRICE_PLAN_ID = "price-plan-1";
+constexpr auto STANDARD_PRICE_PLAN_ID = "price-plan-2";
+
+constexpr auto SARAHS_SMART_METER_ID = "smart-meter-0";
+constexpr auto PETERS_SMART_METER_ID = "smart-meter-1";
+constexpr auto CHARLIES_SMART_METER_ID = "smart-meter-2";
+constexpr auto ANDREAS_SMART_METER_ID = "smart-meter-3";
+constexpr auto ALEXS_SMART_METER_ID = "smart-meter-4";
+
+std::vector<PricePlan> price_plans() {
+    // todo
+    //    pricePlans.add(new PricePlan(MOST_EVIL_PRICE_PLAN_ID, "Dr Evil's Dark Energy", BigDecimal.TEN, emptyList()));
+    //    pricePlans.add(new PricePlan(RENEWABLES_PRICE_PLAN_ID, "The Green Eco", BigDecimal.valueOf(2), emptyList()));
+    //    pricePlans.add(new PricePlan(STANDARD_PRICE_PLAN_ID, "Power for Everyone", BigDecimal.ONE, emptyList()));
+    return {};
+}
+
+std::unordered_map<std::string, std::string> smart_meter_to_price_plan_accounts() {
+    return {{SARAHS_SMART_METER_ID,   MOST_EVIL_PRICE_PLAN_ID},
+            {PETERS_SMART_METER_ID,   RENEWABLES_PRICE_PLAN_ID},
+            {CHARLIES_SMART_METER_ID, MOST_EVIL_PRICE_PLAN_ID},
+            {ANDREAS_SMART_METER_ID,  STANDARD_PRICE_PLAN_ID},
+            {ALEXS_SMART_METER_ID,    RENEWABLES_PRICE_PLAN_ID}};
+};
+
+auto readings() {
+    std::unordered_map<std::string, std::vector<ElectricityReading>> result;
+    for (auto &[meter, plan] : smart_meter_to_price_plan_accounts()) {
+        result[meter] = generator{}.generate(20);
+    }
+    return result;
+}
+
+#endif  // DEVELOPER_JOYOFENERGY_CPP_BEAST_CONFIGURATION_H

rest/controller/CMakeLists.txt

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+add_library(controller INTERFACE)
+find_package(Boost REQUIRED)
+find_package(nlohmann_json REQUIRED)
+target_link_libraries(controller INTERFACE Boost::headers nlohmann_json::nlohmann_json service)

rest/controller/MeterReadingController.h

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+#ifndef DEVELOPER_JOYOFENERGY_CPP_BEAST_METERREADINGCONTROLLER_H
+#define DEVELOPER_JOYOFENERGY_CPP_BEAST_METERREADINGCONTROLLER_H
+
+#include <service/ElectricityReadingService.h>
+
+#include <ctime>
+#include <iomanip>
+
+#include <boost/beast/http.hpp>
+#include <nlohmann/json.hpp>
+
+namespace http = boost::beast::http;
+
+namespace detail {
+    auto toRfc3339(std::chrono::time_point<std::chrono::system_clock> time) {
+        std::stringstream ss;
+        const auto ctime = std::chrono::system_clock::to_time_t(time);
+        ss << std::put_time(std::gmtime(&ctime), "%FT%T");
+        return ss.str();
+    }
+
+    auto renderReadingAsJson(const ElectricityReading &r) {
+        return nlohmann::json{{"time",    toRfc3339(r.getTime())},
+                              {"reading", r.getReading()}};
+    }
+}  // namespace detail
+
+class MeterReadingController {
+public:
+    MeterReadingController(ElectricityReadingService &meterReadingService) : meterReadingService(meterReadingService) {}
+
+    http::response<http::string_body>
+    Read(const http::request<http::string_body> &req, const std::vector<std::string> &queries) {
+        const auto &meterId = queries[0];
+        auto readings = meterReadingService.GetReading(meterId);
+
+        if (!readings) {
+            return {http::status::not_found, req.version()};
+        }
+        http::response<http::string_body> res{http::status::ok, req.version()};
+        res.set(http::field::content_type, "application/json");
+        res.keep_alive(req.keep_alive());
+        auto results = nlohmann::json::array();
+        std::transform(readings->begin(), readings->end(), std::back_inserter(results), &detail::renderReadingAsJson);
+        nlohmann::json j;
+        j["readings"] = results;
+        res.body() = j.dump();
+        res.prepare_payload();
+        return res;
+    }
+
+private:
+    ElectricityReadingService &meterReadingService;
+};
+
+#endif  // DEVELOPER_JOYOFENERGY_CPP_BEAST_METERREADINGCONTROLLER_H

rest/domain/CMakeLists.txt

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+add_library(domain INTERFACE)
+target_include_directories(domain INTERFACE ..)

rest/domain/ElectricityReading.h

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+#ifndef DEVELOPER_JOYOFENERGY_CPP_BEAST_ELECTRICITYREADING_H
+#define DEVELOPER_JOYOFENERGY_CPP_BEAST_ELECTRICITYREADING_H
+
+#include <chrono>
+#include <ctime>
+
+class ElectricityReading {
+public:
+    using time_point_type = std::chrono::time_point<std::chrono::system_clock>;
+
+    ElectricityReading(time_point_type time, size_t reading) : time(time), reading(reading) {}
+
+    time_point_type getTime() const { return time; }
+
+    size_t getReading() const { return reading; }
+
+private:
+    time_point_type time;
+    size_t reading;
+};
+
+#endif  // DEVELOPER_JOYOFENERGY_CPP_BEAST_ELECTRICITYREADING_H

rest/domain/PricePlan.h

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+#ifndef DEVELOPER_JOYOFENERGY_CPP_BEAST_PRICEPLAN_H
+#define DEVELOPER_JOYOFENERGY_CPP_BEAST_PRICEPLAN_H
+
+class PricePlan {
+    // todo:
+};
+
+#endif  // DEVELOPER_JOYOFENERGY_CPP_BEAST_PRICEPLAN_H