First server executable

.gitignore

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+server
+*.json

Makefile

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+srcs += main.cpp
+srcs += helpers.cpp
+
+all:
+	g++ ${srcs} -o server
+
+.PHONY: all

README.md

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+# Required packages for building (Ubuntu 24.04)
+`build-essential`
+
+# Usage
+### Configuration
+Use file named `config.json` in working directory or supply your own via first argument.
+For configuration example see `config_example.json`.
+
+### Devices
+Use file named `devices.json` in working directory or supply your own via configuration file.
+**Note: This file will be managed by the server when devices successfully register.**
+
 # Libraries
 
 ### JSON

config_example.json

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+{
+	// Required
+	"host": "localhost",
+	"port": 0,
+
+	// Optional
+	"devices_filename": "devices.json",
+	"cert_file": "path/to/file",
+	"key_file": "path/to/file"
+}

helpers.cpp

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+#include "helpers.h"
+
+#include <fstream>
+
+using nlohmann::json;
+
+using std::endl;
+using std::ifstream;
+using std::istream;
+using std::ostream;
+using std::string;
+
+bool read_config_json(json& cfg, const string& filename, ostream* log)
+{
+	ifstream cfg_file(filename);
+
+	if (!cfg_file.is_open())
+	{
+		if (nullptr != log)
+		{
+			*log << "Could not open config file" << endl;
+		}
+		return false;
+	}
+
+	return read_config_json(cfg, cfg_file, log);
+}
+
+bool read_config_json(json& cfg, istream& in, ostream* log)
+{
+	// Parse with comments
+	try
+	{
+		cfg = json::parse(in, nullptr, true, true);
+	}
+	catch (const std::exception &e)
+	{
+		if (nullptr != log)
+		{
+			*log << e.what() << endl;
+		}
+		return false;
+	}
+
+	return true;
+}
+
+bool json_extract(const json& j, const string& key, string& out)
+{
+	bool result = false;
+
+	if (j.contains(key) && j[key].is_string())
+	{
+		out = j[key];
+		result = true;
+	}
+
+	return result;
+}
+
+bool json_extract(const json& j, const string& key, int& out)
+{
+	bool result = false;
+
+	if (j.contains(key) && j[key].is_number_integer())
+	{
+		out = j[key];
+		result = true;
+	}
+
+	return result;
+}
+
+bool json_extract(const json& j, const string& key, bool& out)
+{
+	bool result = false;
+
+	if (j.contains(key) && j[key].is_boolean())
+	{
+		out = j[key];
+		result = true;
+	}
+
+	return result;
+}
+
+bool json_extract(const json& j, const string& key, uint16_t& out)
+{
+	bool result = false;
+
+	if (j.contains(key) && j[key].is_number_integer())
+	{
+		if ((j[key] >= 0) && (j[key] <= UINT16_MAX))
+		{
+			out = j[key];
+			result = true;
+		}
+	}
+
+	return result;
+}

helpers.h

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+#ifndef HELPERS_H_
+#define HELPERS_H_
+
+#include <iostream>
+#include <string>
+
+#include <stdint.h>
+
+#include "json.hpp"
+
+
+// Reads configuration json from supplied filename
+// cfg - output json
+// filename - filepath from which to read json
+// log - ostream to log human readable errors to - can be nullptr
+// Returns - true if read and parse is successful
+bool read_config_json(nlohmann::json& cfg, const std::string& filename, std::ostream* log);
+
+// Reads configuration json from supplied istream
+// cfg - output json
+// in - istream from which to read json
+// log - ostream to log human readable errors to - can be nullptr
+// Returns - true if read and parse is successful
+bool read_config_json(nlohmann::json& cfg, std::istream& in, std::ostream* log);
+
+// JSON Extraction Helpers
+// out value is modified only if an extraction happened
+// Returns - whether an extraction happened
+bool json_extract(const nlohmann::json& j, const std::string& key, std::string& out);
+bool json_extract(const nlohmann::json& j, const std::string& key, int& out);
+bool json_extract(const nlohmann::json& j, const std::string& key, bool& out);
+bool json_extract(const nlohmann::json& j, const std::string& key, uint16_t& out);
+
+#endif // HELPERS_H_

main.cpp

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+#include <iostream>
+#include <memory>
+#include <string>
+
+#include <stdint.h>
+
+#include "httplib.h"
+#include "json.hpp"
+
+#include "helpers.h"
+
+using nlohmann::json;
+
+using namespace std;
+
+int main(int argc, char **argv)
+{
+	string config_filename = "config.json";
+	string devices_filename = "devices.json";
+	string host = "";
+	string cert_file = "";
+	string key_file = "";
+	uint16_t port = 0;
+	shared_ptr<httplib::Server> server = nullptr;
+
+	bool ok;
+	json cfg;
+
+	if (argc > 2)
+	{
+		config_filename = argv[1];
+	}
+
+	ok = read_config_json(cfg, config_filename, &cout);
+	if (!ok)
+	{
+		return -1;
+	}
+
+	json_extract(cfg, "devices_filename", devices_filename);
+	json_extract(cfg, "host", host);
+	json_extract(cfg, "port", port);
+	// json_extract(cfg, "cert_file", cert_file);
+	// json_extract(cfg, "key_file", cert_file);
+
+	if (host.empty())
+	{
+		cout << "host not provided" << endl;
+		return -1;
+	}
+
+	if (0 == port)
+	{
+		cout << "port number not provided" << endl;
+		return -1;
+	}
+
+	if (!cert_file.empty() && !key_file.empty())
+	{
+		// TODO: Implement SSL Server Properly
+	}
+	else
+	{
+		server = make_shared<httplib::Server>();
+	}
+
+	server->listen(host, port);
+	server->Get("/api/setup", [](const httplib::Request& req, httplib::Response& res)
+	{
+		cout << req.headers.size() << endl;
+		for (auto header : req.headers)
+		{
+			cout << header.first << ": " << header.second << endl;
+		}
+		res.status = 400;
+	});
+
+	return 0;
+}