imap_sort()

(PHP 4, PHP 5, PHP 7)

Gets and sort messages

说明

imap_sort(resource $imap_stream,int $criteria,int $reverse[,int $options= 0[,string $search_criteria= NULL[,string $charset= NULL]]]): array

Gets and sorts message numbers by the given parameters.

参数

$imap_stream

由imap_open()返回的 IMAP 流。

$criteria

Criteria can be one(and only one)of the following:

SORTDATE- message Date
SORTARRIVAL- arrival date
SORTFROM- mailbox in first From address
SORTSUBJECT- message subject
SORTTO- mailbox in first To address
SORTCC- mailbox in first cc address
SORTSIZE- size of message in octets

$reverse

Set this to 1 for reverse sorting

$options

The$optionsare a bitmask of one or more of the following:

SE_UID- Return UIDs instead of sequence numbers
SE_NOPREFETCH- Don't prefetch searched messages

$search_criteria

IMAP2-format search criteria string. For details see imap_search().

$charset

MIME character set to use when sorting strings.

返回值

Returns an array of message numbers sorted by the given parameters.

I worked a lot with IMAP functions since I wrote a complete webmail and I've got a little tip about the imap_sort function :
There is a big difference between :
<?php
 imap_sort($imap, SORTDATE, 1);
// and 
 imap_sort($imap, SORTARRIVAL, 1);
?>
The first command will issue a
 >> FETCH 1:last (UID ENVELOPE BODY.PEEK[HEADER.FIELDS (Newsgroups Content-MD5 Content-Disposition Content-Language Content-Location Followup-To References)] INTERNALDATE RFC822.SIZE FLAGS)
While the second resulted in
 >> FETCH 1:last (UID INTERNALDATE RFC822.SIZE FLAGS)
As a result, using SORTDATE took 3 seconds longer to complete on a 800-emails mailbox, while the results are quite the same (except if you have to deal with forged dates or timezones, but the arrival order is far more logical)
My advice if you sort your emails by arrival is to actually use SORTARRIVAL, or better don't use imap_sort and go straight with message numbers (not UIDs). On large mailboxes, if you display messages per page, you will have significant performance increases (by avoiding 5 seconds of sorting).

in reply to graham_NOSPAM at rdb-concepts dot NOSPAM dot co dot uk here is a more elegant way to achieve sorting of search results:
function order_search($searchresults, $sortresults) {
  return array_values(array_intersect($sortresults,$searchresults));
}
example of using function:
  $sortresults = imap_sort($stream, $sort, $sortorder);
  $searchresults = imap_search($stream, $query);
  $sorted_search_results = order_search($searchresults, $sortresults);
sorted version of search results will then be held in the array of $sorted_search_results.

Hello,
We used MIME and NLS libraries in our previous code(imap_locale_sort) that
are part of PEAR and Horde projects, and so our function
was so specific. Here is the general (pure php) code for this
function:
function imap_locale_sort($stream,$criteria,$reverse,$locale,$options)
{
    if ($criteria!=SORTSUBJECT)
        return (imap_sort($stream,$criteria,$reverse,$options));
    $unsorted = array();
    $sortresult = array();
    $MC=imap_check($stream);
    $MN=$MC->Nmsgs;
    $overview = imap_fetch_overview($stream,"1:$MN",0);
    $k=0;
    while( list($key,$val) = each($overview))
    {
        $unsorted[$k]["uid"]=$val->uid;
        $unsorted[$k]["subject"]=imap_utf8($val->subject);
        $k++;
    }
    usort ($unsorted, create_function('$a,$b','setlocale(LC_ALL,$locale);return strcoll($a["subject"],$b["subject"]);'));
    for ($m=0;$m<count($unsorted);$m++)
        array_push($sortresult,$unsorted[$m]["uid"]);
    if ($reverse)
        $sortresult = array_reverse($sortresult);
    return $sortresult;
}
Sample usage:
$mbox = imap_open("{localhost:143}INBOX.sent-mail","userid","password");
if ($mbox)
  echo ("Connection Successful!");
$sorted = imap_locale_sort($mbox,SORTSUBJECT,0,'fa_IR',0);
print_r($sorted);
print ("\n\n");
$sorted = imap_sort($mbox,SORTSUBJECT,SE_UID);
print_r($sorted);
imap_close($mbox);

imap_sort uses the c-client library to sort messages. This library currently does not 
support locale-based sort for foreign languages (Although it has charset option).
They are working on this(http://www.washington.edu/imap/IMAP-FAQs/#1.12),
but you can use the following function which uses strcoll() for locale-based sorting.
Pease note that this is required for SUBJECT field sorting, because most of 
other fields are sorted correctly by imap_sort in any locale:
function imap_locale_sort($stream,$criteria,$reverse,$locale,$options)
{
    if ($criteria!=SORTSUBJECT)
        return (imap_sort($stream,$criteria,$reverse,$options));
    $unsorted = array();
    $sortresult = array();
    $MC=imap_check($stream);
    $MN=$MC->Nmsgs;
    $overview = imap_fetch_overview($stream,"1:$MN",0);
    $k=0;
    while( list($key,$val) = each($overview))
    {
        $unsorted[$k]["uid"]=$val->uid;
        $unsorted[$k]["subject"]=MIME::decode($val->subject, NLS::getCharset());
        $k++;
    }
    usort ($unsorted, create_function('$a,$b','setlocale(LC_ALL,$locale);return strcoll($a["subject"],$b["subject"]);'));
    for ($m=0;$m<count($unsorted);$m++)
        array_push($sortresult,$unsorted[$m]["uid"]);
    if ($reverse)
        $sortresult = array_reverse($sortresult);
    return $sortresult;
}
Usage example:
$sorted = imap_locale_sort($stream,SORTSUBJECT,0,'fa_IR',0);

in response to fprado's problem, the solution would be to use array_multisort() function on imap_fetchheader(). sdavey at datalink dot net dot au wrote an excellent example under array_multisort. I have used it to sort POP3 by message size. Unfortunately, my code is much too convoluted to post it here.

I use imap_sort() to go through POP3 accounts. However, sometimes, when the mailbox is too large, the response is incredibly slow.
I tried sniffing the network to discover the source of the problem and found that when imap_sort() is called for a POP3 server, it downloads the full body & attachs of ALL the messages in the mailbox. Since my POP server and my Web server are on differente machines, this caused the considerably slow response.
I've been trying a work-around this issue and if I manage to do this I'll post it here.

for those of you with an old version of PHP that doesn't support the extra search paramater you may want to use this function:
function order_search($searchresults, $sortresults) {
  $searchhash = array();
  $returnresults = array();
  $count = 0;
  for ($i = 0; $i < sizeof($searchresults); $i++) {
    $searchhash[$searchresults[$i]] = true;
  }
  for ($i = 0; $i < sizeof($sortresults); $i++) {
    if (@$searchhash[$sortresults[$i]]) {
      $returnresults[$count] = $sortresults[$i];
      $count++;
    }
  }
  return $returnresults;
}
example of using function:
  $sortresults = imap_sort($stream, $sort, $sortdir, SE_UID);
  $searchresults = imap_search($stream, $search, SE_UID);
  $results = order_search($searchresults, $sortresults);
$results will then hold a sorted array of search results.