mdns.h File Reference

mDNS service discovery UI with terminal_screen rendering More...

Go to the source code of this file.

Data Structures
struct	ui_mdns_server_t
	Discovered server information from mDNS. More...
struct	ui_mdns_config_t
	Configuration for TUI discovery. More...

Functions
void	ui_mdns_log_init (void)
	Initialize log buffer for mDNS discovery UI.
void	ui_mdns_log_destroy (void)
	Destroy mDNS discovery log buffer.
void	ui_mdns_log_clear (void)
	Clear mDNS discovery log buffer.
void	ui_mdns_log_append (const char *message)
	Append message to mDNS discovery log buffer.
ui_mdns_server_t *	ui_mdns_query (const ui_mdns_config_t *config, int *out_count)
	Discover ascii-chat servers on the local network via mDNS.
void	ui_mdns_free_results (ui_mdns_server_t *servers)
	Free results from TUI discovery query.
int	ui_mdns_prompt_selection (const ui_mdns_server_t *servers, int count)
	Display discovered servers to user and prompt for selection.
int	ui_mdns_select (const ui_mdns_server_t *servers, int count)
	TUI-based server selection with formatted display.
const char *	ui_mdns_get_best_address (const ui_mdns_server_t *server)
	Get best address representation for a discovered server.

Detailed Description

mDNS service discovery UI with terminal_screen rendering

Implements interactive mDNS-based discovery of ascii-chat servers on the local network. Uses the shared terminal_screen infrastructure for consistent UI rendering with other modules.

Definition in file ui/mdns.h.

Function Documentation

ui_mdns_free_results()

void ui_mdns_free_results

(

ui_mdns_server_t *

servers

)

Free results from TUI discovery query.

Releases memory allocated by ui_mdns_query().

Parameters

servers

Pointer to server array (safe to pass NULL)

Note

Safe to call multiple times or with NULL pointer

Free results from TUI discovery query.

Definition at line 77 of file ui/mdns.c.

                                                     {
  discovery_mdns_destroy(servers);
}

References discovery_mdns_destroy().

ui_mdns_get_best_address()

const char * ui_mdns_get_best_address

(

const ui_mdns_server_t *

server

)

Get best address representation for a discovered server.

Returns the most suitable address representation (IPv4 > hostname > IPv6) for connecting to a discovered server.

Selection Priority:

1. IPv4 address (most universal)
2. Service name (if IPv4 not available)
3. IPv6 address (last resort)

Parameters

server

Discovered server

Returns

Pointer to best address string (points to field in server struct)

Get best address representation for a discovered server.

Definition at line 233 of file ui/mdns.c.

                                                                     {
  if (!server) {
    return "";
  }
 
  // Prefer IPv4 > name > IPv6
  if (server->ipv4[0] != '\0') {
    return server->ipv4;
  }
  if (server->name[0] != '\0') {
    return server->name;
  }
  if (server->ipv6[0] != '\0') {
    return server->ipv6;
  }
 
  return server->address; // Fallback to address field
}

References ui_mdns_server_t::address, ui_mdns_server_t::ipv4, ui_mdns_server_t::ipv6, and ui_mdns_server_t::name.

Referenced by ui_mdns_prompt_selection(), and ui_mdns_select().

ui_mdns_log_append()

void ui_mdns_log_append

(

const char *

message

)

Append message to mDNS discovery log buffer.

Delegates to the logging system which automatically captures to session log buffer.

Parameters

message

Log message to append

Definition at line 46 of file ui/mdns.c.

                                             {
  if (message) {
    log_info("%s", message);
  }
}

References log_info.

ui_mdns_log_clear()

void ui_mdns_log_clear

(

void

)

Clear mDNS discovery log buffer.

Delegates to terminal_screen log clear. Useful when starting fresh mDNS discovery screen.

Definition at line 42 of file ui/mdns.c.

                             {
  terminal_screen_log_clear();
}

References terminal_screen_log_clear().

ui_mdns_log_destroy()

void ui_mdns_log_destroy

(

void

)

Destroy mDNS discovery log buffer.

Delegates to terminal_screen log cleanup.

Definition at line 37 of file ui/mdns.c.

                               {
  log_clear_session_log_buffer();
  terminal_screen_log_destroy();
}

References log_clear_session_log_buffer(), and terminal_screen_log_destroy().

ui_mdns_log_init()

void ui_mdns_log_init

(

void

)

Initialize log buffer for mDNS discovery UI.

Delegates to terminal_screen log initialization. Call once at startup before rendering mDNS discovery screen.

Definition at line 30 of file ui/mdns.c.

                            {
  session_log_buffer_t *buf = terminal_screen_log_init();
  if (buf) {
    log_set_session_log_buffer(buf);
  }
}

References log_set_session_log_buffer(), and terminal_screen_log_init().

ui_mdns_prompt_selection()

int ui_mdns_prompt_selection	(	const ui_mdns_server_t *	servers,
		int	count
	)

Display discovered servers to user and prompt for selection.

Shows a numbered list of discovered servers and prompts user to select one. Handles invalid input with re-prompting.

User Experience:

Available ascii-chat servers on LAN:
  1. swift-river-canyon (192.168.1.100:27224)
  2. quiet-mountain-lake (192.168.1.101:27224)
  3. gentle-forest-breeze (192.168.1.102:27224)
 
Select server (1-3) or press Enter to cancel: _

Behavior:

• Displays each server with instance name and best-guess address
• Shows IPv4 address if available, falls back to IPv6 or hostname
• Handles non-numeric input with error message and re-prompt
• Returns -1 if user presses Enter/Ctrl+C to cancel
• Returns 0-based index of selected server

Parameters

servers	Array of discovered servers
count	Number of servers in array

Returns

Index of selected server (0 to count-1), or -1 to cancel

Note

This function performs interactive I/O - may not be suitable for automated contexts

For automated selection, use servers[0] directly instead

Display discovered servers to user and prompt for selection.

Definition at line 84 of file ui/mdns.c.

                                                                         {
  if (!servers || count <= 0) {
    return -1;
  }
 
  // Display available servers
  printf("\nAvailable ascii-chat servers on LAN:\n");
  for (int i = 0; i < count; i++) {
    const ui_mdns_server_t *srv = &servers[i];
    const char *addr = ui_mdns_get_best_address(srv);
    printf("  %d. %s (%s:%u)\n", i + 1, srv->name, addr, srv->port);
  }
 
  // Prompt for selection
  printf("\nSelect server (1-%d) or press Enter to cancel: ", count);
  fflush(stdout);
 
  // Read user input
  char input[32];
  if (fgets(input, sizeof(input), stdin) == NULL) {
    printf("\n");
    return -1; // EOF or error
  }
 
  // Check for empty input (Enter pressed)
  if (input[0] == '\n' || input[0] == '\r' || input[0] == '\0') {
    return -1; // User cancelled
  }
 
  // Parse input as number
  char *endptr;
  long selection = strtol(input, &endptr, 10);
 
  // Validate input
  if (selection < 1 || selection > count) {
    printf("⚠️  Invalid selection. Please enter a number between 1 and %d\n", count);
    return ui_mdns_prompt_selection(servers, count); // Re-prompt
  }
 
  return (int)(selection - 1); // Convert to 0-based index
}

References ui_mdns_server_t::name, ui_mdns_server_t::port, ui_mdns_get_best_address(), and ui_mdns_prompt_selection().

Referenced by ui_mdns_prompt_selection().

ui_mdns_query()

ui_mdns_server_t * ui_mdns_query	(	const ui_mdns_config_t *	config,
		int *	out_count
	)

Discover ascii-chat servers on the local network via mDNS.

Performs an mDNS query for _ascii-chat._tcp services on the local network. Collects responses and returns discovered servers to the caller.

Behavior:

• Sends multicast mDNS query for _ascii-chat._tcp.local services
• Waits for responses for the specified timeout period
• Collects all discovered servers with their addresses and ports
• Returns array of discovered servers

Memory Management:

• Caller is responsible for freeing the returned array with ui_mdns_free_results()
• Returned servers are valid until ui_mdns_free_results() is called

Error Handling:

• Returns NULL and sets errno on initialization failure
• Partial results returned if mDNS init fails but discovery was attempted
• Network errors logged but don't prevent continuation

Threading:

• Blocking operation - waits for full timeout period
• Safe to call from main thread
• Does not spawn background threads

Parameters

config	Discovery configuration (NULL uses defaults)
out_count	Output parameter: number of discovered servers

Returns

Array of discovered servers, or NULL on error Must be freed with ui_mdns_free_results()

Note

Timeout includes network round-trip time, so 2000ms allows ~1.5s of actual waiting

Returns empty array (non-NULL with count=0) if no servers found, not NULL

Example:

ui_mdns_config_t config = {.timeout_ms = 2000, .max_servers = 20};
int count = 0;
ui_mdns_server_t *servers = ui_mdns_query(&config, &count);
 
if (servers && count > 0) {
    for (int i = 0; i < count; i++) {
        printf("%d: %s (%s:%d)\n", i+1, servers[i].name, servers[i].address, servers[i].port);
    }
    // User selects server...
    ui_mdns_free_results(servers);
}

Discover ascii-chat servers on the local network via mDNS.

Calls discovery_mdns_query() from discovery.c with TUI-friendly configuration.

Definition at line 57 of file ui/mdns.c.

                                                                                {
  if (!out_count) {
    SET_ERRNO(ERROR_INVALID_PARAM, "out_count pointer is NULL");
    return NULL;
  }
 
  *out_count = 0;
 
  // Apply defaults if needed
  int timeout_ms = (config && config->timeout_ms > 0) ? config->timeout_ms : 2000;
  int max_servers = (config && config->max_servers > 0) ? config->max_servers : 20;
  bool quiet = (config && config->quiet);
 
  // Call the core mDNS discovery function from discovery.c
  return discovery_mdns_query(timeout_ms, max_servers, quiet, out_count);
}

References discovery_mdns_query(), ERROR_INVALID_PARAM, ui_mdns_config_t::max_servers, ui_mdns_config_t::quiet, SET_ERRNO, and ui_mdns_config_t::timeout_ms.

ui_mdns_select()

int ui_mdns_select	(	const ui_mdns_server_t *	servers,
		int	count
	)

TUI-based server selection with formatted display.

Displays discovered servers in a formatted terminal UI with:

• Clear screen and boxed display
• Server list with numbering and addresses
• "No results" message if no servers available
• Interactive numeric selection prompt

Display Example (3 servers):

╭─ 🔍 ascii-chat Server Discovery ────────────╮
│
│ Found 3 servers on your local network:
│
│   [1] swift-river-canyon     192.168.1.100:27224
│   [2] quiet-mountain-lake    192.168.1.101:27224
│   [3] gentle-forest-breeze   192.168.1.102:27224
│
╰────────────────────────────────────────────╯
 
Enter server number (1-3) or press Enter to cancel:

No Results Display:

╭─ 🔍 ascii-chat Server Discovery ─╮
│
│   No servers found on local network
│
│   Make sure an ascii-chat server is running on your LAN
│   Or provide a server address manually: ascii-chat client <address>
│
╰─────────────────────────────────────────╯

Parameters

servers	Array of discovered servers
count	Number of servers (0 for "no results")

Returns

0-based index of selected server, or -1 to cancel

Displays discovered servers in a terminal UI with the following features:

• Clears terminal and displays formatted server list
• Shows "No results" message if no servers available
• Allows numeric input for selection
• Shows helpful prompts and icons

Parameters

servers	Array of discovered servers
count	Number of servers

Returns

0-based index of selected server, or -1 to cancel

Definition at line 149 of file misc.c.

                                                               {
  (void)servers;
  (void)count;
  return -1;
}

References colored_string(), LOG_COLOR_DEBUG, LOG_COLOR_INFO, LOG_COLOR_WARN, log_lock_terminal(), log_plain, log_unlock_terminal(), ui_mdns_server_t::name, platform_sleep_ms(), ui_mdns_server_t::port, ui_mdns_get_best_address(), and ui_mdns_select().

Referenced by client_main(), and ui_mdns_select().