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xyph

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Posts posted by xyph

    Help code registration+login+members area

    in Miscellaneous

    Posted

    I'm not sure what you're asking for. The concept is pretty straightforward.

     

    Use sessions to track a user between requests. If the session has no record of a successful login stored within it, redirect users to a login page.

     

    For information on how to properly handle passwords with PHP and store/recall them with a database, check out the article in my signature.

    collaberative filtering - post 'likes' and 'dislikes'

    in MySQL Help

    Posted

    You can always use sub-queries to filter your results.

     

    Step 1 - Straightforward

    SELECT entryid FROM votes
WHERE userid = 1 AND value = 1

     

    Step 2 - The JOIN is the query above. The main query selects DISTINCT userids that have a matching entryid to the ones within the JOIN

    SELECT DISTINCT userid
FROM votes
JOIN (
  SELECT entryid FROM votes
  WHERE userid = 1 AND value = 1
) as sub USING(entryid)
WHERE userid <> 1

     

    Step 3-4 - Take our previous query, and use it as another join. The innermost JOIN grabs the entries that match the given userid, the other one uses that list to get a list of userids that also have the entryids, and the final, outer query uses that list to grab entryids by those userids, grouping, counting and ordering them.

    SELECT entryid, COUNT(entryid) as total
FROM votes
JOIN (
  SELECT DISTINCT userid
  FROM votes
  JOIN (
    SELECT entryid FROM votes
    WHERE userid = 1 AND value = 1
  ) as sub1 USING(entryid)
  WHERE userid <> 1
) as sub2 USING(userid)
GROUP BY entryid
ORDER BY total DESC

     

    I'm using the following structure/data.

    CREATE TABLE IF NOT EXISTS `entries` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `userid` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=18 ;

INSERT INTO `entries` (`id`, `userid`) VALUES
(1, 1),
(2, 1),
(3, 2),
(4, 2),
(5, 3),
(6, 4),
(7, 4),
(8, 4),
(9, 5),
(10, 5),
(11, 6),
(12, 7),
(13, 7),
(14, 7),
(15, 7),
(16, 7),
(17, ;

CREATE TABLE IF NOT EXISTS `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(10) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=9 ;

INSERT INTO `users` (`id`, `name`) VALUES
(1, 'matt'),
(2, 'bob'),
(3, 'joe'),
(4, 'tim'),
(5, 'carl'),
(6, 'john'),
(7, 'foo'),
(8, 'bar');

CREATE TABLE IF NOT EXISTS `votes` (
  `userid` int(11) NOT NULL,
  `entryid` int(11) NOT NULL,
  `value` tinyint(1) NOT NULL DEFAULT '1',
  UNIQUE KEY `userid` (`userid`,`entryid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `votes` (`userid`, `entryid`, `value`) VALUES
(1, 3, 1),
(1, 7, 1),
(1, 10, 1),
(1, 14, 1),
(1, 16, 1),
(2, 5, 1),
(2, 7, 1),
(2, 9, 1),
(2, 14, 1),
(2, 15, 1),
(3, 13, 1),
(4, 2, 1),
(4, 3, 1),
(4, 9, 1),
(4, 10, 1),
(4, 13, 1),
(4, 14, 1),
(5, 3, 1),
(5, 4, 1),
(5, 5, 1),
(5, 7, 1),
(5, 11, 1),
(6, 9, 1),
(7, 1, 1),
(7, 2, 1),
(7, 5, 1),
(7, 7, 1),
(7, 9, 1),
(7, 10, 1),
(8, 1, 1),
(8, 4, 1),
(8, 16, 1);

    PHP captcha without graphics ?

    in PHP Coding Help

    Posted

    How it displays could vary from system to system, because it relies on client-side rendering to be visible.

     

    If you don't have Lucida Console, Terminal or Courier fonts installed, it will flat out break. Using <pre> tags might help with this, but it still depends on the font the browser decides to use for that tag.

    XML Parsing Assistance

    in PHP Coding Help

    Posted

    Your array contains the same data as your object. What was the point of turning it into an array?

     

    If you want to access individual values

    <?php

$xml = new SimpleXMLElement('http://www.amecim.com/metronashvillewater/metronashvilleraingaugeservice.asmx/getAllGaugesAllIntervals', 0, true);
header('content-type: text/plain');

echo $xml->BntCrk->FifteenMinute->SampleDate;

echo "\n";

if( isset($xml->BntCrk->TwoHour->SampleValueAccumulation) )
echo $xml->BntCrk->TwoHour->SampleValueAccumulation;
else
echo 'value does not exist';


?>

     

    Turning that into an array will not make anything easier, you'll just have the same data in memory twice.

    XML Parsing Assistance

    in PHP Coding Help

    Posted

    The concept is still the same.

     

    <?php

$xml = new SimpleXMLElement('http://www.amecim.com/metronashvillewater/metronashvilleraingaugeservice.asmx/getAllGaugesAllIntervals', 0, true);
header('content-type: text/plain');

foreach( $xml as $location => $data ) {
echo "$location\n";
foreach( $data as $time => $subdata ) {
	echo "\t$time\n";
	foreach( $subdata as $key => $value ) {
		echo "\t\t$key -> $value\n";
	}
}
}

?>

    XML Parsing Assistance

    in PHP Coding Help

    Posted

    Well the desire is to iterate over the entire xml document and for each place name pull out the child elements of the intervals in a form that can be:

     

    a) directly echoed to the page

    b) stored in a database

     

    The issue is if you have a variable number of child elements under each time interval you can't access the values directly (because you may not know what they are).

     

    So what is the best method of extracting the values from the time interval child elements in a form that can be used as outlined above?

     

    Sorry I don't mean to sound deliberately obtuse (or to be awkward), its just that using get_object_vars appears to do the above but you suggest it's incorrect. So I genuinely want to understand how it's possible to achieve the above without using get_object_vars or type casting if you don't know the end precise end element name.

     

    SimpleXML provides iteration through the class. There's no reason to convert it to an array only to iterate through it.

     

    Unknown values can be looped through.

     

    <?php

$xml = new SimpleXMLElement('http://www.amecim.com/metronashvillewater/metronashvilleraingaugeservice.asmx/getAllGauges15m', 0, true);

header('content-type: text/plain');

foreach( $xml as $location => $data ) {
echo "$location\n";
foreach( $data->clsRainGaugeReading as $subdata ) {
	foreach( $subdata as $key => $value ) {
		echo "\t$key -> $value\n";
	}
}
}

?>

    0-9 and A, B, C, D...Z Query

    in PHP Coding Help

    Posted

    Do it separately. You're not accomplishing anything by grabbing them all in a single query.

     

    It can be done on a single page as well, simply use a GET variable. getData.php?letter=a

     

    If you must get them all in a single query, use ORDER BY instead. Parse the resulting data with PHP, keeping track of the first letter in the previous row. When the current first letter differs from the last, you know you need to make a new 'group'

     

    If you want to run a query to find out if any values exist that start with a given letter (so you aren't linking to empty lists) use something like

     

    SELECT DISTINCT IF(

    LOWER(SUBSTR(yourColumn FROM 1 FOR 1)) REGEXP '[^a-z]',

            '#',

                    LOWER(SUBSTR(yourColumn FROM 1 FOR 1))

            ) as letter

    FROM yourTable

    ORDER BY letter

    multiple submit button handling

    in PHP Coding Help

    Posted

    I wouldn't rely upon the button pressed at all, but rather compare the submitted values against the existing ones. Easiest way to do this, is to include the old value in a session variable, or something similar. Then you just loop through the values posted, compare them to what you have saved, and you'll know instantly what's been changed and what haven't.

    As an added benefit this will allow your users to update several rows at the same time, without having to send a POST request for every single one of them.

     

    Sessions aren't meant to hold mutable data, and if it must, you have to be very careful to isolate them to the current line of requests using some sort of unique token passed in the form itself.

     

    If a user browses to the same form in multiple tabs, your session has no way to differentiate between the two otherwise. It's a stateless protocol, so trying to enforce state that could possibly change in a per-request manner should be done so with care.

     

    The correct way to do this is use a different form for each submit button. It's more mark-up, but it won't harm your page visibly at all, and with PHP behind it, there's not much extra effort involved.

     

    Avoid using hacky solutions for the sole purpose of saving your website from a little bit of extra mark-up. You'll find your application will play better universally if you stick to the spec.

    weed and programming

    in Miscellaneous

    Posted

    I don't see how it couldn't be regulated any differently than drinking.

     

    The big issue is 'proving' you're stoned while driving, since your body doesn't flush out THC like it does alcohol (naturally occurring chemical vs a poison). Roadside sobriety tests would be the ideal solution I suppose. It's an awkward argument though, as the cannabinoids don't affect motor skills like booze. The bigger issue is those who suffer minor visuals, paranoia, and the lowering of reaction time as potential and fairly common side-effects. I'm not trying to support smoking and driving - I'm very much against it, but it's something that would be hard to enforce.

    PHP a "fractal of bad design"? Hardly

    in Miscellaneous

    Posted

    Half point at most. A JSON string parsing as null should always mean garbage-in/out. If you need more specific reporting, it's easy enough to code in and return. If it's an external JSON and there's a potential of it returning NULL as well as badly formed data, then I think you've got a bigger issue on your plate.

    I still gave him a full point because you can't argue with the basic statement: The error condition is also valid output.  The fact that the programmer should know better doesn't change the validity of his statement. 

     

    Well, json_decode can also return FALSE on a successful parse, so beyond throwing an error/exception, what can it do? The behaviour is documented, and since NULL is the least likely 'correct' return value, I think it makes sense on failure.

    Stripslashes as a back up?

    in PHP Coding Help

    Posted

    I think if I ever ran into a system that disabled active, working, safe core functionality I would suggest that the owners fire their admins.

     

    I can understand why they included that ability through the INI though, though black-listing is generally much more difficult than white.

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