Added image filename implementation

.gitignore

@@ -1,2 +1,3 @@
 server
 *.json
+images/*

Makefile

@@ -1,5 +1,6 @@
 srcs += main.cpp
 srcs += helpers.cpp
+srcs += TRMNL.cpp
 
 all:
 	g++ ${srcs} -o server

README.md

@@ -20,5 +20,5 @@ Use file named `devices.json` in working directory or supply your own via config
 * From: https://github.com/yhirose/cpp-httplib
 * Version: 0.47.0
 
-# Info on API
+# Info on TRMNL API
 * https://github.com/usetrmnl/trmnl-firmware

TRMNL.cpp

@@ -0,0 +1,207 @@
+#include "TRMNL.h"
+#include "helpers.h"
+
+using std::list;
+using std::map;
+using std::optional;
+using std::string;
+
+using nlohmann::json;
+
+TRMNL::TRMNL(const string& id,
+	const string& api_key,
+	const string& friendly_id,
+	int refresh_rate)
+: m_id(id),
+m_api_key(api_key),
+m_friendly_id(friendly_id),
+m_refresh_rate(refresh_rate),
+m_update_handler()
+{}
+
+TRMNL::TRMNL(const nlohmann::json& j)
+: m_id(""),
+m_api_key(""),
+m_friendly_id(""),
+m_refresh_rate(DEFAULT_REFRESH_RATE),
+m_update_handler()
+{
+	json_extract(j, "ID", m_id);
+	json_extract(j, "api_key", m_api_key);
+	json_extract(j, "friendly_id", m_friendly_id);
+	json_extract(j, "refresh_rate", m_refresh_rate);
+}
+
+const string& TRMNL::id() const
+{
+	return m_id;
+}
+
+const string& TRMNL::api_key() const
+{
+	return m_api_key;
+}
+
+const string& TRMNL::friendly_id() const
+{
+	return m_friendly_id;
+}
+
+int TRMNL::refresh_rate() const
+{
+	return m_refresh_rate;
+}
+
+void TRMNL::id(const std::string& id)
+{
+	m_id = id;
+	if (m_update_handler)
+	{
+		m_update_handler(*this);
+	}
+}
+
+void TRMNL::api_key(const std::string& api_key)
+{
+	m_api_key = api_key;
+	if (m_update_handler)
+	{
+		m_update_handler(*this);
+	}
+}
+
+void TRMNL::friendly_id(const std::string& friendly_id)
+{
+	m_friendly_id = friendly_id;
+	if (m_update_handler)
+	{
+		m_update_handler(*this);
+	}
+}
+
+void TRMNL::refresh_rate(int refresh_rate)
+{
+	m_refresh_rate = refresh_rate;
+	if (m_update_handler)
+	{
+		m_update_handler(*this);
+	}
+}
+
+void TRMNL::set_update_handler(std::function<void (const TRMNL& trmnl)> handler)
+{
+	m_update_handler = handler;
+}
+
+string TRMNL::friendly_from_id(string id)
+{
+	size_t pos = id.find(':');
+	while (pos != string::npos)
+	{
+		id.erase(pos, 1);
+		pos = id.find(':');
+	}
+
+	if (id.size() <= 6)
+	{
+		return id;
+	}
+	else
+	{
+		return id.substr(id.size() - 6);
+	}
+}
+
+void to_json(json& j, const TRMNL& trmnl)
+{
+	j = json{
+		{"ID", trmnl.m_id},
+		{"api_key", trmnl.m_api_key},
+		{"friendly_id", trmnl.m_friendly_id},
+		{"refresh_rate", trmnl.m_refresh_rate},
+	};
+}
+
+void TRMNLContainer::TRMNL_update_handler(const TRMNL& trmnl)
+{
+	auto it = m_by_id.find(trmnl.m_id);
+	if (it == m_by_id.end())
+	{
+		return;
+	}
+
+	// An update is needed only if friendly ID changes
+	if (0 == m_by_friendly.count(trmnl.m_friendly_id))
+	{
+		m_by_friendly[trmnl.m_friendly_id] = it->second;
+	}
+}
+
+TRMNLContainer& TRMNLContainer::operator=(const TRMNLContainer& other)
+{
+	m_devices = other.m_devices;
+	m_by_id = other.m_by_id;
+	m_by_friendly = other.m_by_friendly;
+
+	for (TRMNL& device : m_devices)
+	{
+		device.set_update_handler([this](const TRMNL& trmnl){ TRMNL_update_handler(trmnl); });
+	}
+
+	return *this;
+}
+
+void TRMNLContainer::add_device(TRMNL trmnl)
+{
+	if (trmnl.m_id.empty())
+	{
+		return;
+	}
+
+	auto it = m_devices.insert(m_devices.end(), trmnl);
+
+	m_by_id[trmnl.m_id] = it;
+
+	if (!trmnl.m_friendly_id.empty())
+	{
+		m_by_friendly[trmnl.m_friendly_id] = it;
+	}
+
+	it->set_update_handler([this](const TRMNL& trmnl){ TRMNL_update_handler(trmnl); });
+}
+
+TRMNL* TRMNLContainer::get_device_by_id(const string& id)
+{
+	TRMNL* result = nullptr;
+
+	if (0 != m_by_id.count(id))
+	{
+		result = &(*m_by_id[id]);
+	}
+
+	return result;
+}
+
+TRMNL* TRMNLContainer::get_device_by_friendly(const string& friendly)
+{
+	TRMNL* result = nullptr;
+
+	if (0 != m_by_friendly.count(friendly))
+	{
+		result = &(*m_by_friendly[friendly]);
+	}
+
+	return result;
+}
+
+void TRMNLContainer::clear()
+{
+	m_by_friendly.clear();
+	m_by_id.clear();
+	m_devices.clear();
+}
+
+void to_json(json& j, const TRMNLContainer& cont)
+{
+	j = cont.m_devices;
+}

TRMNL.h

@@ -0,0 +1,76 @@
+#ifndef TRMNL_H_
+#define TRMNL_H_
+
+#include <functional>
+#include <list>
+#include <map>
+#include <optional>
+#include <string>
+
+#include "json.hpp"
+
+constexpr int DEFAULT_REFRESH_RATE = 300;
+
+class TRMNL
+{
+private:
+	std::string m_id;
+	std::string m_api_key;
+	std::string m_friendly_id;
+	int m_refresh_rate;
+
+	std::function<void (const TRMNL& trmnl)> m_update_handler;
+
+public:
+	// Constructors
+	TRMNL(const std::string& id = "",
+		const std::string& api_key = "",
+		const std::string& friendly_id = "",
+		int refresh_rate = DEFAULT_REFRESH_RATE);
+
+	TRMNL(const nlohmann::json& j);
+
+	// Getters
+	const std::string& id() const;
+	const std::string& api_key() const;
+	const std::string& friendly_id() const;
+	int refresh_rate() const;
+
+	// Setters
+	void id(const std::string& id);
+	void api_key(const std::string& api_key);
+	void friendly_id(const std::string& friendly_id);
+	void refresh_rate(int refresh_rate);
+
+	void set_update_handler(std::function<void (const TRMNL& trmnl)> handler);
+
+	static std::string friendly_from_id(std::string id);
+
+	friend void to_json(nlohmann::json& j, const TRMNL& trmnl);
+	friend class TRMNLContainer;
+};
+
+class TRMNLContainer
+{
+private:
+	std::list<TRMNL> m_devices;
+	std::map<std::string, std::list<TRMNL>::iterator> m_by_id;
+	std::map<std::string, std::list<TRMNL>::iterator> m_by_friendly;
+
+	void TRMNL_update_handler(const TRMNL& trmnl);
+
+public:
+	TRMNLContainer() = default;
+	TRMNLContainer& operator=(const TRMNLContainer& other);
+
+	void add_device(TRMNL trmnl);
+
+	TRMNL* get_device_by_id(const std::string& id);
+	TRMNL* get_device_by_friendly(const std::string& friendly);
+
+	void clear();
+
+	friend void to_json(nlohmann::json& j, const TRMNLContainer& cont);
+};
+
+#endif // TRMNL_H_

config_example.json

@@ -2,9 +2,11 @@
 	// Required
 	"host": "localhost",
 	"port": 0,
+	"base_url": "https://trmnl.com/",
 
 	// Optional
 	"devices_filename": "devices.json",
+	"folder_images": "images",
 	"cert_file": "path/to/file",
 	"key_file": "path/to/file"
 }

devices_example.json

@@ -0,0 +1,11 @@
+[
+	{
+		// Required
+		"ID": "MAC ADDRESS",
+
+		// Auto managed
+		"api_key": "api key",
+		"friendly_id": "917F0B",
+		"refresh_rate": 600
+	}
+]

helpers.cpp

@@ -6,32 +6,33 @@ using nlohmann::json;
 
 using std::endl;
 using std::ifstream;
+using std::ofstream;
 using std::istream;
 using std::ostream;
 using std::string;
 
-bool read_config_json(json& cfg, const string& filename, ostream* log)
+bool read_file_json(json& j, const string& filename, ostream* log)
 {
-	ifstream cfg_file(filename);
+	ifstream file(filename);
 
-	if (!cfg_file.is_open())
+	if (!file.is_open())
 	{
 		if (nullptr != log)
 		{
-			*log << "Could not open config file" << endl;
+			*log << "Could not open file to read - " << filename << endl;
 		}
 		return false;
 	}
 
-	return read_config_json(cfg, cfg_file, log);
+	return read_stream_json(j, file, log);
 }
 
-bool read_config_json(json& cfg, istream& in, ostream* log)
+bool read_stream_json(json& j, istream& in, ostream* log)
 {
 	// Parse with comments
 	try
 	{
-		cfg = json::parse(in, nullptr, true, true);
+		j = json::parse(in, nullptr, true, true);
 	}
 	catch (const std::exception &e)
 	{
@@ -45,6 +46,24 @@ bool read_config_json(json& cfg, istream& in, ostream* log)
 	return true;
 }
 
+bool write_file_json(const json& j, const string& filename, ostream* log)
+{
+	ofstream file(filename);
+
+	if (!file.is_open())
+	{
+		if (nullptr != log)
+		{
+			*log << "Could not open file to write - " << filename << endl;
+		}
+		return false;
+	}
+
+	file << j.dump(4) << endl;
+
+	return true;
+}
+
 bool json_extract(const json& j, const string& key, string& out)
 {
 	bool result = false;

helpers.h

@@ -9,19 +9,26 @@
 #include "json.hpp"
 
 
-// Reads configuration json from supplied filename
-// cfg - output json
+// Reads json from supplied filename
+// j - 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);
+bool read_file_json(nlohmann::json& j, const std::string& filename, std::ostream* log);
 
 // Reads configuration json from supplied istream
-// cfg - output json
+// j - 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);
+bool read_stream_json(nlohmann::json& j, std::istream& in, std::ostream* log);
+
+// Writes json to supplied filename
+// j - input json
+// filename - filepath to which to write json
+// log - ostream to log human readable errors to - can be nullptr
+// Returns - true if write is successful
+bool write_file_json(const nlohmann::json& j, const std::string& filename, std::ostream* log);
 
 // JSON Extraction Helpers
 // out value is modified only if an extraction happened

main.cpp

@@ -1,45 +1,221 @@
+// Start using chrono when C++20 becomes available
+// #include <chrono>
+#include <filesystem>
 #include <iostream>
+#include <list>
+#include <map>
 #include <memory>
+#include <random>
+#include <set>
 #include <string>
+#include <utility>
+#include <vector>
 
+#include <stdio.h>
 #include <stdint.h>
+#include <time.h>
+
+// Stop using these when C++20 becomes available
+#include <fcntl.h>
+#include <sys/stat.h>
 
 #include "httplib.h"
 #include "json.hpp"
 
 #include "helpers.h"
+#include "TRMNL.h"
 
 using nlohmann::json;
 
 using namespace std;
+namespace fs = std::filesystem;
+
+constexpr int API_KEY_LENGHT = 16;
+constexpr char DEFAULT_IMAGE_URL[] = "https://trmnl.com/images/setup/setup-logo.bmp";
+constexpr char DEFAULT_IMAGE_FNAME[] = "2024-09-20T00:00:00";
+
+string generate_api_key(int len = API_KEY_LENGHT)
+{
+	string result = "";
+	std::random_device rand;
+	std::uniform_int_distribution distribution(0, 63);
+	int single;
+	char symbol;
+
+	if (len < 0)
+	{
+		len = API_KEY_LENGHT;
+	}
+
+	for (int i = 0; i < len; ++i)
+	{
+		single = distribution(rand);
+		if (single <= 9)
+		{
+			symbol = '0' + single;
+		}
+		else if ((single >= 10) && (single <= 35))
+		{
+			symbol = 'A' + single - 10;
+		}
+		else if ((single >= 36) && (single <= 61))
+		{
+			symbol = 'a' + single - 36;
+		}
+		else if (62 == single)
+		{
+			symbol = '+';
+		}
+		else if (63 == single)
+		{
+			symbol = '/';
+		}
+		// This should never happen
+		else
+		{
+			symbol = '?';
+		}
+
+		result += symbol;
+	}
+
+	return result;
+}
+
+bool reload_container(TRMNLContainer& container, const string& filename)
+{
+	json j;
+	bool ok = read_file_json(j, filename, &cout);
+	if (!ok)
+	{
+		return false;
+	}
+	container.clear();
+	if (j.is_array())
+	{
+		for (int i = 0; i < j.size(); ++i)
+		{
+			container.add_device(j[i]);
+		}
+	}
+
+	return true;
+}
+
+string get_timestamp_from_filename(const string& filepath)
+{
+	char result[128] = "";
+
+	struct stat status;
+	stat(filepath.c_str(), &status);
+
+	// Time of last modification
+	time_t file_time = status.st_mtim.tv_sec;
+
+	tm* file_tm;
+	file_tm = gmtime(&file_time);
+
+	snprintf(result, sizeof(result) - 1, "%04d-%02d-%02dT%02d:%02d:%02d",
+		file_tm->tm_year + 1900,
+		file_tm->tm_mon + 1,
+		file_tm->tm_mday,
+		file_tm->tm_hour,
+		file_tm->tm_min,
+		file_tm->tm_sec
+	);
+
+	return result;
+}
+
+// Use this when C++20 becomes available
+#if 0
+string get_timestamp_from_file_time(const fs::file_time_type& ftime)
+{
+	char result[128] = "";
+	time_t file_time = std::chrono::system_clock::to_time_t(std::chrono::file_clock::to_sys(ftime));
+
+	tm* file_tm;
+	file_tm = gmtime(&file_time);
+
+	snprintf(result, sizeof(result) - 1, "%04d-%02d-%02dT%02d:%02d:%02d",
+		file_tm->tm_year + 1900,
+		file_tm->tm_mon + 1,
+		file_tm->tm_mday,
+		file_tm->tm_hour,
+		file_tm->tm_min,
+		file_tm->tm_sec
+	);
+
+	return result;
+}
+#endif
+
+// First string is image filename for URL
+// Second string is timestamp for TRMNL filename
+pair<string, string> find_image_for_friendly(const string& folder_images, const string& friendly_id)
+{
+	pair<string, string> result = {"", ""};
+	set<string> permitted_extensions = { ".bmp", ".png" };
+
+	if (!fs::is_directory(folder_images))
+	{
+		return result;
+	}
+
+	for (const fs::directory_entry& entry : fs::directory_iterator(folder_images))
+	{
+		if ((entry.path().stem() == friendly_id) &&
+			(0 != permitted_extensions.count(entry.path().extension())))
+		{
+			result.first = entry.path().filename();
+			result.second = get_timestamp_from_filename(entry.path());
+			// Change to this when C++20 becomes available
+			// result.second = get_timestamp_from_file_time(entry.last_write_time());
+		}
+	}
+
+	return result;
+}
 
 int main(int argc, char **argv)
 {
 	string config_filename = "config.json";
 	string devices_filename = "devices.json";
+	string folder_images = "images";
+
 	string host = "";
+	uint16_t port = 0;
+	string base_url = "";
+
 	string cert_file = "";
 	string key_file = "";
-	uint16_t port = 0;
+
 	shared_ptr<httplib::Server> server = nullptr;
 
 	bool ok;
 	json cfg;
+	json devs;
+	TRMNLContainer container;
 
 	if (argc > 2)
 	{
 		config_filename = argv[1];
 	}
 
-	ok = read_config_json(cfg, config_filename, &cout);
+	ok = read_file_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, "base_url", base_url);
+
+	json_extract(cfg, "devices_filename", devices_filename);
+	json_extract(cfg, "folder_images", folder_images);
+
+	// TODO: Extract when SSL is ready
 	// json_extract(cfg, "cert_file", cert_file);
 	// json_extract(cfg, "key_file", cert_file);
 
@@ -55,6 +231,24 @@ int main(int argc, char **argv)
 		return -1;
 	}
 
+	if (base_url.empty())
+	{
+		cout << "base url not provided" << endl;
+		return -1;
+	}
+
+	if (folder_images.empty())
+	{
+		cout << "folder for images is empty" << endl;
+		return -1;
+	}
+
+	if (!fs::is_directory(folder_images))
+	{
+		cout << "filepath for images is not a folder" << endl;
+		return -1;
+	}
+
 	if (!cert_file.empty() && !key_file.empty())
 	{
 		// TODO: Implement SSL Server Properly
@@ -64,22 +258,197 @@ int main(int argc, char **argv)
 		server = make_shared<httplib::Server>();
 	}
 
-	server->Get("/api/setup/", [](const httplib::Request& req, httplib::Response& res)
+	ok = reload_container(container, devices_filename);
+	if (!ok)
 	{
-		cout << req.headers.size() << endl;
-		for (auto header : req.headers)
-		{
-			cout << header.first << ": " << header.second << endl;
+		cout << "Could not read devices file" << endl;
+		return -1;
 	}
-		res.status = 400;
-	});
 
-	server->Post("/api/log/", [](const httplib::Request& req, httplib::Response& res)
+	auto setup_handler = [&container, &devices_filename](const httplib::Request& req, httplib::Response& res)
+	{
+		json response;
+
+		if (!req.has_header("ID"))
+		{
+			// Bad Request - No ID header
+			res.status = 400;
+
+			response["status"] = 400;
+			response["error"] = "No ID header";
+
+			res.set_header("Content-Type", "application/json");
+			res.body = response.dump();
+
+			return;
+		}
+
+		// Refresh data from file
+		// Someone might have put a new device in
+		reload_container(container, devices_filename);
+
+		string id = req.get_header_value("ID");
+		TRMNL* trmnl = container.get_device_by_id(id);
+
+		if (nullptr == trmnl)
+		{
+			res.status = 404;
+
+			response["status"] = 404;
+			response["api_key"] = nullptr;
+			response["friendly_id"] = nullptr;
+			response["image_url"] = nullptr;
+			response["filename"] = nullptr;
+
+			res.set_header("Content-Type", "application/json");
+			res.body = response.dump();
+			return;
+		}
+
+		bool should_dump = false;
+
+		res.status = 200;
+		if (trmnl->friendly_id().empty())
+		{
+			should_dump = true;
+			trmnl->friendly_id(TRMNL::friendly_from_id(id));
+		}
+
+		if (trmnl->api_key().empty())
+		{
+			should_dump = true;
+			trmnl->api_key(generate_api_key());
+		}
+
+		response["status"] = 200;
+		response["api_key"] = trmnl->api_key();
+		response["friendly_id"] = trmnl->friendly_id();
+		response["image_url"] = DEFAULT_IMAGE_URL;
+		response["filename"] = DEFAULT_IMAGE_FNAME;
+
+		res.set_header("Content-Type", "application/json");
+		res.body = response.dump();
+
+		if (should_dump)
+		{
+			write_file_json(container, devices_filename, &cout);
+		}
+	};
+
+	auto display_handler = [&container, &devices_filename, &folder_images, &base_url]
+		(const httplib::Request& req, httplib::Response& res)
+	{
+		json response;
+
+		if (!req.has_header("ID") || !req.has_header("Access-Token"))
+		{
+			// Bad Request
+			res.status = 400;
+
+			response["status"] = 400;
+			response["error"] = "No ID and Access-Token headers set";
+
+			res.body = response.dump();
+			res.set_header("Content-Type", "application/json");
+			return;
+		}
+
+		// Refresh data from file
+		// Someone might have put a new device in
+		reload_container(container, devices_filename);
+
+		string id = req.get_header_value("ID");
+		string api_key = req.get_header_value("Access-Token");
+		TRMNL* trmnl = container.get_device_by_id(id);
+
+		if (nullptr == trmnl)
+		{
+			// Not Found
+			res.status = 404;
+
+			response["status"] = 404;
+			response["error"] = "Device not found";
+
+			res.set_header("Content-Type", "application/json");
+			res.body = response.dump();
+			return;
+		}
+
+		if (trmnl->api_key() != api_key)
+		{
+			// Forbidden
+			res.status = 403;
+
+			response["status"] = 403;
+			response["error"] = "Wrong credentials for this device";
+
+			res.set_header("Content-Type", "application/json");
+			res.body = response.dump();
+			return;
+		}
+
+		string image_fname;
+		string image_timestamp;
+		tie(image_fname, image_timestamp) = find_image_for_friendly(folder_images, trmnl->friendly_id());
+
+		// The ID and api_key match here
+		res.status = 200;
+
+		// From docs: will be 202 if no user_id is attached to device
+		response["status"] = 0;
+
+		if (image_fname.empty())
+		{
+			response["image_url"] = DEFAULT_IMAGE_URL;
+			response["filename"] = DEFAULT_IMAGE_FNAME;
+		}
+		else
+		{
+			string full_url = base_url;
+			full_url += "/images/";
+			full_url += image_fname;
+			response["image_url"] = full_url;
+			response["filename"] = image_timestamp;
+		}
+
+		response["refresh_rate"] = to_string(trmnl->refresh_rate());
+
+		// TODO: Handle firmware updating
+		response["update_firmware"] = false;
+		response["firmware_url"] = nullptr;
+		response["reset_firmware"] = false;
+
+		res.set_header("Content-Type", "application/json");
+		res.body = response.dump();
+	};
+
+	auto log_handler = [](const httplib::Request& req, httplib::Response& res)
+	{
+		try
+		{
+			json j = json::parse(req.body);
+			cout << j.dump(4) << endl;
+		}
+		catch (const exception& e)
 		{
 			cout << req.body << endl;
+		}
 		res.status = 200;
-	});
+	};
 
+
+	server->Get("/api/setup/*", setup_handler);
+	server->Get("/api/display/*", display_handler);
+	server->Post("/api/log/*", log_handler);
+
+	ok = server->set_mount_point("/images", folder_images);
+	if (!ok)
+	{
+		cout << "Could not mount images folder" << endl;
+		return -1;
+	}
+
+	cout << "Server listening on " << host << ":" << port << endl;
 	server->listen(host, port);
 
 	return 0;