Added image filename implementation

config_example.json

@@ -2,6 +2,7 @@
 	// Required
 	"host": "localhost",
 	"port": 0,
+	"base_url": "https://trmnl.com/",
 
 	// Optional
 	"devices_filename": "devices.json",

main.cpp

@@ -1,12 +1,23 @@
+// 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"
@@ -17,8 +28,11 @@
 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)
 {
@@ -68,13 +82,13 @@ string generate_api_key(int len = API_KEY_LENGHT)
 	return result;
 }
 
-void reload_container(TRMNLContainer& container, const string& filename)
+bool reload_container(TRMNLContainer& container, const string& filename)
 {
 	json j;
 	bool ok = read_file_json(j, filename, &cout);
 	if (!ok)
 	{
-		return;
+		return false;
 	}
 	container.clear();
 	if (j.is_array())
@@ -84,17 +98,98 @@ void reload_container(TRMNLContainer& container, const string& filename)
 			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 host = "";
 	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;
@@ -113,10 +208,14 @@ int main(int argc, char **argv)
 		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);
 
@@ -132,12 +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
@@ -147,14 +258,13 @@ int main(int argc, char **argv)
 		server = make_shared<httplib::Server>();
 	}
 
-	ok = read_file_json(devs, devices_filename, &cout);
+	ok = reload_container(container, devices_filename);
 	if (!ok)
 	{
+		cout << "Could not read devices file" << endl;
 		return -1;
 	}
 
-	reload_container(container, devices_filename);
-
 	auto setup_handler = [&container, &devices_filename](const httplib::Request& req, httplib::Response& res)
 	{
 		json response;
@@ -213,9 +323,8 @@ int main(int argc, char **argv)
 		response["status"] = 200;
 		response["api_key"] = trmnl->api_key();
 		response["friendly_id"] = trmnl->friendly_id();
-		// TODO: Check for image in folder
-		response["image_url"] = "https://trmnl.com/images/setup/setup-logo.bmp";
-		response["filename"] = "welcome";
+		response["image_url"] = DEFAULT_IMAGE_URL;
+		response["filename"] = DEFAULT_IMAGE_FNAME;
 
 		res.set_header("Content-Type", "application/json");
 		res.body = response.dump();
@@ -226,7 +335,8 @@ int main(int argc, char **argv)
 		}
 	};
 
-	auto display_handler = [&container, &devices_filename](const httplib::Request& req, httplib::Response& res)
+	auto display_handler = [&container, &devices_filename, &folder_images, &base_url]
+		(const httplib::Request& req, httplib::Response& res)
 	{
 		json response;
 
@@ -277,19 +387,35 @@ int main(int argc, char **argv)
 			return;
 		}
 
-		// TODO: Check for image in folder
-		// string image;
+		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;
-		response["image_url"] = "https://trmnl.com/images/setup/setup-logo.bmp";
-		response["filename"] = "2024-09-20T00:00:00";
+
+		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["refresh_rate"] = to_string(trmnl->refresh_rate());
 		response["reset_firmware"] = false;
 
 		res.set_header("Content-Type", "application/json");