Re: [development] AJAX return values

2 May 2006

      Dan Robinson schreef:
...
thanks for the quick response.  Is there some code you could point me at?
The Ajax autocompleter uses JSON to pass in the list of suggestions. 
It's quite simple.

For PHP to JS, you build a PHP variable/array/object and print it 
through drupal_to_js. On the JS side, you take the XMLHttpRequest data 
and pass it through parseJson().

For JS to PHP, we don't use JSON. JS and PHP already have a mechanism 
for passing data in: HTTP GET and POST. Simply use HTTPPost, and pass in 
a JS object. It will be parsed by PHP into a PHP object on the 
server-side. Or, you can pass in simpler requests through HTTP GET.

Either way, there is a transparent mechanism to pass data between PHP 
and JS without loss. It's not as hard as you might think, it all happens 
transparently.

Steven Wittens

Code from user.module:
------------------------------------

/**
 * Retrieve a pipe delimited string of autocomplete suggestions for 
existing users
 */
function user_autocomplete($string) {
  $matches = array();
  $result = db_query_range("SELECT name FROM {users} WHERE LOWER(name) 
LIKE LOWER('%s%%')", $string, 0, 10);
  while ($user = db_fetch_object($result)) {
    $matches[$user->name] = check_plain($user->name);
  }
  print drupal_to_js($matches);
  exit();
}

Code from autocomplete.js:
----------------------------------------

/**
 * Performs a cached and delayed search
 */
ACDB.prototype.search = function(searchString) {
   ....
  this.timer = setTimeout(function() {
    addClass(db.owner.input, 'throbbing');
    db.transport = HTTPGet(db.uri +'/'+ 
encodeURIComponent(searchString), db.receive, db);
  }, this.delay);
}

/**
 * HTTP callback function. Passes suggestions to the autocomplete object
 */
ACDB.prototype.receive = function(string, xmlhttp, acdb) {
 ...
 // Parse back result
  var matches = parseJson(string);
  if (typeof matches['status'] == 'undefined' || matches['status'] != 0) {
    acdb.cache[acdb.searchString] = matches;
    acdb.owner.found(matches);
  }
}