backend.php

<?php
/*
 * to use any function in this module first call connect()
 * at the end of a page call disconnect()
 */

$LINK = NULL;

// get db connection
function connect() {
  global $LINK;

  // Try localhost connection first
//  $conn = mysql_connect("localhost","root","") or die ("dbconnect failed");
//  if ($conn) {
//    mysql_select_db("db_final") or die ("dbconnect failed");
//    $LINK = $conn;
//    return $conn;
//  }

  // Try server connections
  $url=parse_url(getenv("CLEARDB_DATABASE_URL"));

  $server = $url["host"];
  $username = $url["user"];
  $password = $url["pass"];
  $db = substr($url["path"],1);
  // echo "Server: " . $server;
  // echo "Username: " . $username;
  // echo "Password: " . $password;
  $conn = mysql_connect($server, $username, $password);
  if ($conn) {
    mysql_select_db($db);
    $LINK = $conn;

    return $conn;
  }

}

// unget db connection
function disconnect() {
  mysql_close($LINK);
}

/*
 * Creating
 */

// String [[Arrayof Int] = array()] ->
function create_user($name, $groups = array()){
  global $LINK;
  $result = mysql_query("INSERT INTO users (name) VALUES (\"$name\");",$LINK);
  if (!$result) {
    die('Invalid query: ' . mysql_error());
  }
  $id = get_user_id($name);
  add_user_to_groups($id,$groups);
}

// String [[Arrayof int] = array()] [[Arrayof int] = array()] ->
function create_group($name,$users = array(), $groups = array()) {
  global $LINK;

  $result = mysql_query("INSERT INTO groups (name) VALUES (\"$name\");",$LINK);
  $id = get_group_id($name);
  foreach($users as $user) {
    add_user_to_groups($user,array($id));
  }

  foreach($groups as $group) {
    add_group_to_groups($group,array($id));
  }
}

// String ->
function create_resource($uri) {
  global $LINK;
  mysql_query("INSERT INTO resources VALUES (\"$uri\")",$LINK);
}

// Int String String [Boolean = true] ->
function create_permission_set($group,$uri,$action,$access = True) {
  global $LINK;
  $query = "INSERT INTO permission_sets (is_allowed, group_id,resource_uri,action_name) VALUES ($access,$group,\"$uri\",\"$action\")";
  $result = mysql_query($query,$LINK);
  if (!$result) {
    echo "ERROR: " . mysql_error();
  }

}

/*
 * Modifying
 */

// Int [Arrayof Int] ->
function add_user_to_groups($id,$groups) {
  global $LINK;
  foreach($groups as $gid) {
    mysql_query("INSERT INTO user_group_mapping (user_id,group_id) VALUES (\"$id\",\"$gid\")",$LINK);
  }
}

// Int [Arrayof Int] ->
function add_group_to_groups($id,$groups) {
  global $LINK;
  foreach($groups as $group) {
    mysql_query("INSERT INTO group_group_mapping (contained_id,container_id) VALUES (\"$id\",\"$group\")",$LINK);
  }
}

// Int ->
function delete_user($id) {
  global $LINK;
  $result = mysql_query("DELETE FROM users WHERE id = \"$id\"",$LINK);
  if (!$result) {
    echo mysql_error();
  }
}
function delete_group($id) {
  global $LINK;
  $result = mysql_query("DELETE FROM groups WHERE id = \"$id\"",$LINK);
  if (!$result) {
    echo mysql_error();
  }
}
function delete_resource($id) {
  global $LINK;
  $result = mysql_query("DELETE FROM resources WHERE uri = \"$id\"",$LINK);
  if (!$result) {
    echo mysql_error();
  }
}

// Int Int ->
function delete_group_from_group($contained,$container) {
  global $LINK;
  $query = "DELETE FROM group_group_mapping WHERE container_id = $container AND contained_id = $contained";
  $result = mysql_query($query, $LINK);
  if (!$result) {
    echo mysql_error();
  }
}
function delete_user_from_group($user_id,$group_id) {
  global $LINK;
  $query = "DELETE FROM user_group_mapping WHERE user_id = $user_id AND group_id = $group_id";
  $result = mysql_query($query, $LINK);
  if (!$result) {
    echo mysql_error();
  }
}
/*
 * querying
 */

// Int -> [Arrayof Int]
function users_in_group($id) {
  global $LINK;
  $query = "SELECT user_id FROM user_group_mapping WHERE group_id = \"$id\"";
  $result = mysql_query($query, $LINK);
  if (!$result) {
    echo "ERROR: " . mysql_error();
  }
  return single_results_to_array($result);
}

function user_group_direct($id) {
  global $LINK;
  $query = "SELECT group_id FROM user_group_mapping WHERE user_id = $id";
  $groups_id = mysql_query($query,$LINK);
  return single_results_to_array($groups_id);
}

// Int String String -> Boolean
function does_user_has_access($uid,$uri,$action){
  $user_groups = get_user_groups($uid);
  $permission_sets = get_permission_sets($uri, $action);
  $permission_set_groups = get_permission_set_groups($permission_sets);

  foreach($user_groups as $id) {

    if(in_array($id,$permission_set_groups)) {
      return true;
    }
  }
  return false;
}

// [Array Ints] -> [Arrayof Ints]
function get_permission_set_groups($ids){
  global $LINK;
  $query = "SELECT group_id FROM permission_sets WHERE group_id in (" . implode("\", \"",$ids) . ")";
  $results =  single_results_to_array(mysql_query($query,$LINK));
  return $results;
}

// String String -> [Arrayof Ints]
function get_permission_sets($uri,$action){
  global $LINK;
  return single_results_to_array(mysql_query("SELECT group_id FROM permission_sets WHERE resource_uri = \"$uri\" AND action_name = \"$action\"",$LINK));
}

// Int -> Arrayof Int
function get_group_groups($id) {
  return get_groups_groups(array($id));
}

// [Arrayof Int] -> [Arrayof Int]
function get_groups_groups($ids) {
  global $LINK;
  $todos = $ids;
  $acc = array();
  $results = $todos;
  while(!empty($todos)) {
    foreach($todos as $id) {
      $query = "SELECT contained_id FROM group_group_mapping WHERE container_id = $id";
      $news = single_results_to_array(mysql_query($query, $LINK));
      foreach($news as $new) {
        if(!in_array($new,$results)){
          array_push($results,$new);
          array_push($acc,$new);
        }
      }
      $todos = $acc;
      $acc = array();
    }
  }
  return $results;
}

// Int -> String
function get_group_name($id) {
  global $LINK;
  $query = "SELECT name FROM groups WHERE id = $id";
  $result = mysql_query($query);
  $result = mysql_result($result, 0);
  return $result;
}

function get_user_name($id) {
  global $LINK;
  $query = "SELECT name FROM users WHERE id = $id";
  $result = mysql_query($query);
  $result = mysql_result($result, 0);
  return $result;
}

// Int -> [Arrayof Int]
function get_user_groups($id) {
    $groups = user_group_direct($id);
    return get_groups_groups($groups);
}

// String -> Int
function get_user_id($user) {
  global $LINK;
  $res =  mysql_fetch_array(mysql_query("SELECT id FROM users WHERE name = \"$user\"",$LINK));
  return $res[0];
}

// String -> Int
function get_group_id($group){
  global $LINK;
  $res =  single_results_to_array(mysql_query("SELECT id FROM groups WHERE name = \"$group\"",$LINK));
  return $res[0];
}

// -> Arrayof Strings
function get_all_users() {
  global $LINK;
  return single_results_to_array(mysql_query("SELECT name FROM users",$LINK));
}
function get_all_groups(){
  global $LINK;
  return single_results_to_array(mysql_query("SELECT name FROM groups",$LINK));
}
function get_all_resources(){
  global $LINK;
  return single_results_to_array(mysql_query("SELECT uri FROM resources",$LINK));
}
function get_all_actions(){
  global $LINK;
  return single_results_to_array(mysql_query("SELECT name FROM actions",$LINK));
}


function single_results_to_array($result) {
  $res = array();
  while ($next = mysql_fetch_array($result)) {
    array_push($res,$next[0]);
  }
  return $res;
}