dirname/basename expansions; template fiddling

[disorder] / server / actions.c

/*
 * This file is part of DisOrder.
 * Copyright (C) 2004-2008 Richard Kettlewell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */
/** @file server/actions.c
 * @brief DisOrder web actions
 *
 * Actions are anything that the web interface does beyond passive template
 * expansion and inspection of state recieved from the server.  This means
 * playing tracks, editing prefs etc but also setting extra headers e.g. to
 * auto-refresh the playing list.
 */

#include "disorder-cgi.h"

/** @brief Redirect to some other action or URL */
static void redirect(const char *url) {
  /* By default use the 'back' argument */
  if(!url)
    url = cgi_get("back");
  if(url) {
    if(!strncmp(url, "http", 4))
      /* If the target is not a full URL assume it's the action */
      url = cgi_makeurl(config->url, "action", url, (char *)0);
  } else {
    /* If back= is not set just go back to the front page */
    url = config->url;
  }
  if(printf("Location: %s\n"
            "%s\n"
            "\n", url, dcgi_cookie_header()) < 0)
    fatal(errno, "error writing to stdout");
}

/* 'playing' and 'manage' just add a Refresh: header */
static void act_playing(void) {
  long refresh = config->refresh;
  long length;
  time_t now, fin;
  char *url;
  const char *action;

  dcgi_lookup(DCGI_PLAYING|DCGI_QUEUE|DCGI_ENABLED|DCGI_RANDOM_ENABLED);
  if(dcgi_playing
     && dcgi_playing->state == playing_started /* i.e. not paused */
     && !disorder_length(dcgi_client, dcgi_playing->track, &length)
     && length
     && dcgi_playing->sofar >= 0) {
    /* Try to put the next refresh at the start of the next track. */
    time(&now);
    fin = now + length - dcgi_playing->sofar + config->gap;
    if(now + refresh > fin)
      refresh = fin - now;
  }
  if(dcgi_queue && dcgi_queue->state == playing_isscratch) {
    /* next track is a scratch, don't leave more than the inter-track gap */
    if(refresh > config->gap)
      refresh = config->gap;
  }
  if(!dcgi_playing
     && ((dcgi_queue
          && dcgi_queue->state != playing_random)
         || dcgi_random_enabled)
     && dcgi_enabled) {
    /* no track playing but playing is enabled and there is something coming
     * up, must be in a gap */
    if(refresh > config->gap)
      refresh = config->gap;
  }
  if((action = cgi_get("action")))
    url = cgi_makeurl(config->url, "action", action, (char *)0);
  else
    url = config->url;
  if(printf("Content-Type: text/html\n"
            "Refresh: %ld;url=%s\n"
            "%s\n"
            "\n",
            refresh, url, dcgi_cookie_header()) < 0)
    fatal(errno, "error writing to stdout");
  dcgi_expand("playing");
}

static void act_disable(void) {
  if(dcgi_client)
    disorder_disable(dcgi_client);
  redirect(0);
}

static void act_enable(void) {
  if(dcgi_client)
    disorder_enable(dcgi_client);
  redirect(0);
}

static void act_random_disable(void) {
  if(dcgi_client)
    disorder_random_disable(dcgi_client);
  redirect(0);
}

static void act_random_enable(void) {
  if(dcgi_client)
    disorder_random_enable(dcgi_client);
  redirect(0);
}

/** @brief Table of actions */
static const struct action {
  /** @brief Action name */
  const char *name;
  /** @brief Action handler */
  void (*handler)(void);
} actions[] = {
  { "disable", act_disable },
  { "enable", act_enable },
  { "manage", act_playing },
  { "playing", act_playing },
  { "random-disable", act_random_disable },
  { "random-enable", act_random_enable },
};

/** @brief Expand a template
 * @param name Base name of template, or NULL to consult CGI args
 */
void dcgi_expand(const char *name) {
  const char *p;
  
  /* For unknown actions check that they aren't evil */
  for(p = name; *p && isalnum((unsigned char)*p); ++p)
    ;
  if(*p)
    fatal(0, "invalid action name '%s'", name);
  byte_xasprintf((char **)&p, "%s.tmpl", name);
  if(mx_expand_file(p, sink_stdio("stdout", stdout), 0) == -1
     || fflush(stdout) < 0)
    fatal(errno, "error writing to stdout");
}

/** @brief Execute a web action
 * @param action Action to perform, or NULL to consult CGI args
 *
 * If no recognized action is specified then 'playing' is assumed.
 */
void dcgi_action(const char *action) {
  int n;

  /* Consult CGI args if caller had no view */
  if(!action)
    action = cgi_get("action");
  /* Pick a default if nobody cares at all */
  if(!action) {
    /* We allow URLs which are just c=... in order to keep confirmation URLs,
     * which are user-facing, as short as possible.  Actually we could lose the
     * c= for this... */
    if(cgi_get("c"))
      action = "confirm";
    else
      action = "playing";
    /* Make sure 'action' is always set */
    cgi_set("action", action);
  }
  if((n = TABLE_FIND(actions, struct action, name, action)) >= 0)
    /* Its a known action */
    actions[n].handler();
  else {
    /* Just expand the template */
    if(printf("Content-Type: text/html\n"
              "%s\n"
              "\n", dcgi_cookie_header()) < 0)
      fatal(errno, "error writing to stdout");
    dcgi_expand(action);
  }
}

/** @brief Generate an error page */
void dcgi_error(const char *msg, ...) {
  va_list ap;

  va_start(ap, msg);
  byte_xvasprintf(&dcgi_error_string, msg, ap);
  va_end(ap);
  dcgi_expand("error");
}

/*
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indent-tabs-mode:nil
End:
*/