I'm writing a chat application for joomla (apache server) and use this construction to emulate long-polling (server side):
function get_messages($last_id) {
$time = time();
while((time() - $time) < 25) {
$sql = 'SELECT * FROM #__messages WHERE `id` >'.intval($last_id);
$db->setQuery($sql);
$rows = $db->loadAssocList();
if (count($rows)>0) {
echo 'JSON STRING HERE';
} else {
flush();
}
usleep(5000000);
}
}
How Can I optimize this part of code.
Should I use infinite looping or should I avoid while construction?
P/S: I know Apache is not best choice to write chat app for and node.js is better.
Thanks!
Infinite loops are never a good idea because they hammer your server resources. You are better off having JS providing the intermittent polling to your get_messages function. Use a timeout and embed the script on any page that shows the messages.
I'm going to answer based on the limited information I've got to help you in the broadest way possible following industry standards. You need to not code in the way you currently are because it is very inefficient and quite frankly dangerous.
Here is the mootools code required to run an intervaled polling (I've used Mootools as you said you're using Joomla, I've assumed you're using 1.6+ as 1.5 is EOL this month):
//this sets how often you want to update (in milliseconds).
setInterval('chatPoll()',2000);
//this function essentially just grabs the raw data
//from the specified url and dumps it into the specified div
function chatPoll()
{
var unixTimestamp Math.round(new Date().getTime() / 1000)
var req = new Request({
method: 'get',
url: $('ajax-alert').get('http://www.yoururltoupdate.com/file.php?last=' + (unixTimestamp-2),
data: { 'do' : '1' },
onComplete: function(response) { response.inject($('my-chat-wrapper')); }
}).send();
}
Your PHP file should look something look like this:
get_messages($_GET['last']);
function get_messages($last_id) {
$sql = 'SELECT * FROM #__messages WHERE `id` >'.intval($last_id);
$db->setQuery($sql);
$rows = $db->loadAssocList();
if (count($rows)>0) {
echo json_encode($rows);
}
}
I haven't fully tested this code but it should work and if not will definitely help answer your query as to how what you're trying to do should be achieved rather than the way you originally posted. If you really wanted to get fancy you could check out node.js as well. There is also tons of extensions for Joomla which work as chat mediums for support purposes if that's what you were after.
Related
I've been working on a script that makes close to a thousand async requests using getAsync and Promise\Settle. Each page requested it then parsed using Symphony crawler filter method (Also slow but a separate issue.)
My code looks something like this:
$requestArray = [];
$request = new Client($url);
foreach ($thousandItemArray as $item) {
$requestArray[] = $request->getAsync(null, $query);
}
$results = Promise\settle($request)->wait(true);
foreach ($results as $item) {
$item->crawl();
}
Is there a way I can crawl the requested pages as they come in rather than waiting for them all and then crawling. Am i right in thinking this would speed things up if possible?
Thanks for your help in advance.
You can. getAsync() returns a promise, so you can assign an action to it using ->then().
$promisesList[] = $request->getAsync(/* ... */)->then(
function (Response $resp) {
// Do whatever you want right after the response is available.
}
);
$results = Promise\settle($request)->wait(true);
P.S.
Probably you want to limit the concurrency level to some number of requests (not to start all the requests at once). If yes, use each_limit() function instead of settle. And vote for my PR to be able to use settle_limit() ;)
I've been searching for a suitable PHP caching method for MSSQL results.
Most of the examples I can find suggest storing the results in an array, which would then get included to page. This seems great unless a request for the content was made at the same time as it being updated/rebuilt.
I was hoping to find something similar to ASP's application level variables, but far as I'm aware, PHP doesn't offer this functionality?
The problem I'm facing is I need to perform 6 queries on page to populate dropdown boxes. This happens on the vast majority of pages. It's also not an option to combine the queries. The cached data will also need to be rebuilt sporadically, when the system changes. This could be once a day, once a week or a month. Any advice will be greatly received, thanks!
You can use Redis server and phpredis PHP extension to cache results fetched from database:
$redis = new Redis();
$redis->connect('/tmp/redis.sock');
$sql = "SELECT something FROM sometable WHERE condition";
$sql_hash = md5($sql);
$redis_key = "dbcache:${sql_hash}";
$ttl = 3600; // values expire in 1 hour
if ($result = $redis->get($redis_key)) {
$result = json_decode($result, true);
} else {
$result = Db::fetchArray($sql);
$redis->setex($redis_key, $ttl, json_encode($result));
}
(Error checks skipped for clarity)
I have an ordinary html table in which each cell contains a name. I've added a function to each of these cells, which turns the cells background color green, if it's white and the other way around. However, I would also like to update an mySql datebase, when a cell is clicked, but I can't seem to figure out a good way to do this, without reloading the page (which I would prefer not to do) or using javascript to connect to the server (which seems like a very bad practice). The page has already been loaded at this point. Does anybody have any good suggestions?
<script type="text/javascript">
var tbl = document.getElementById("table");
if (tbl != null) {
for (var i = 1; i < tbl.rows.length; i++) {
for (var j = 0; j < tbl.rows[i].cells.length; j++)
tbl.rows[i].cells[j].onclick = function () { getval(this); };
}
}
function getval(cel) {
if(cel.style.backgroundColor == "green")
{
cel.style.backgroundColor = "white";
// Here I would like to update my datebase with mySql
// query(UPDATE team SET attended=0 WHERE name = cel.innterText)
// (name associated with the cell)
}
else
{
cel.style.backgroundColor = "green";
// Here I would like to update my datebase with mySql
// query(UPDATE team SET attended=1 WHERE name = cel.innterText)
// (name associated with the cell)
}
}
</script>
In broad terms, you need to turn part of your application into a service and have calls to it made by an asynchronous HTTP request from your page (this falls under the "AJAX" denomination).
That service can be written as an extra PHP script on your server, which may not necessarily return an HTML document, but possible XML or JSON (the latter is probably more popular these days), which will be handled by your JavaScript script in the browser for further actions if necessary (e.g. turning the background white only if this request has succeeded).
It is this PHP script that should handle the SQL queries.
As a general guideline, don't prepare or handle any SQL at all on the client side (in your JavaScript script), and make sure you use prepared statements when running your SQL queries. (I'm just saying that because you're obviously new to this and you'll inevitably find snippets of code here or on various blogs where people just put the variables they in into their SQL statements by using the variable in the query strings. This is extremely bad practice.)
EDIT:
I actually need to go no further than W3Schools to have a bad example of MySQL query that is vulnerable to SQL injection (the problem is in $sql="SELECT * FROM user WHERE id = '".$q."'";). DO NOT USE THIS EXAMPLE. I'd avoid W3Schools, see http://www.w3fools.com/
SQL is server side, not client side. You need to use AJAX to send data to your server and then the server will use SQL to save.
I am currently doing a tutorial which was found on TutsPlus.
This tutorial was to save information from AS3 to MySQL via PHP and then retrieve this information.
So far, it works. I Can enter a username and score, which saves to the database. There is one problem though, I would like to be able to display ALL the names and scores in a table, instead of having to search for a name and then finding the score for that specific user.
The code in which the information is saved (which works), is below.
package {
import flash.display.*;
import flash.events.*;
import flash.net.*;
public class register extends MovieClip {
public function register ():void {
register_button.buttonMode = true;
register_button.addEventListener(MouseEvent.MOUSE_DOWN, checkForm);
username_text.text = "";
userbio_text.text = "";
}
public function checkForm (e:MouseEvent):void {
if (username_text.text != "" && userbio_text.text != "") {
sendForm();
} else {
result_text.text = "PLEASE ENTER A NAME";
}
}
public function sendForm ():void {
/*
we use the URLVariables class to store our php variables
*/
var phpVars:URLVariables = new URLVariables();
phpVars.username = username_text.text;
phpVars.userbio = userbio_text.text;
/*
we use the URLRequest method to get the address of our php file and attach the php vars.
*/
var urlRequest:URLRequest = new URLRequest("localhost/php/register.php");
/*
the POST method is used here so we can use php's $_POST function in order to recieve our php variables.
*/
urlRequest.method = URLRequestMethod.POST;
/*
this attaches our php variables to the url request
*/
urlRequest.data = phpVars;
/*
we use the URLLoader class to send the request URLVariables to the php file
*/
var urlLoader:URLLoader = new URLLoader();
urlLoader.dataFormat = URLLoaderDataFormat.VARIABLES;
/*
runs the function once the php file has spoken to flash
*/
urlLoader.addEventListener(Event.COMPLETE, showResult);
/*
we send the request to the php file
*/
urlLoader.load(urlRequest);
}
/*
function to show result
*/
public function showResult (e:Event):void {
result_text.text = "" + e.target.data.result_message;
}
}
}
From here, I can go to another application and search the users name, and then displays that users score. Code below:
package actions {
import flash.display.MovieClip;
import flash.events.*;
import flash.net.*;
import flash.text.*;
public class main extends MovieClip {
public function main ():void {
submit_button.buttonMode = true;
submit_button.addEventListener(MouseEvent.MOUSE_DOWN, checkLogin);
username.text = "";
}
public function checkLogin (e:MouseEvent):void {
if (username.text == "") {
username.text = "Enter your username";
}
else {
processLogin();
}
}
public function processLogin ():void {
var phpVars:URLVariables = new URLVariables();
var phpFileRequest:URLRequest = new URLRequest("http://xx.xx.xx.uk/~bf93fv/Source%202/php/controlpanel.php");
phpFileRequest.method = URLRequestMethod.POST;
phpFileRequest.data = phpVars;
var phpLoader:URLLoader = new URLLoader();
phpLoader.dataFormat = URLLoaderDataFormat.VARIABLES;
phpLoader.addEventListener(Event.COMPLETE, showResult);
phpVars.systemCall = "checkLogin";
phpVars.username = username.text;
phpLoader.load(phpFileRequest);
}
public function showResult (event:Event):void {
result_text.autoSize = TextFieldAutoSize.LEFT;
result_text.text = "" + event.target.data.systemResult;
}
}
}
The controlpanel.php file, which displays the username and score individually is below:
<?php
include_once "connect.php";
$username = $_POST['username'];
if ($_POST['systemCall'] == "checkLogin") {
$sql = "SELECT * FROM users WHERE username='$username'";
$query = mysql_query($sql);
$login_counter = mysql_num_rows($query);
if ($login_counter > 0) {
while ($data = mysql_fetch_array($query)) {
$userbio = $data["user_bio"];
print "systemResult=$username Scored $userbio";
}
}
else {
print "systemResult=The login details dont match our records.";
}
}
?>
Does anybody know any easy way in order to view ALL the information from the database into a table?
There are few things you might want to improve in your PHP code (your AS3 is better).
Use PDO instead of the functions that work with particular DBMS. The reason to this is that it is portable (to an extend). Say, if you wanted to ever move the database from MySQL to Postgres, you'd had to rewrite less of your code, then you would have to otherwise. PDO also provides some means of sanitizing the input. It's not bullet proof - still better then nothing. PDO is considered the "good practice", so you would learn to write the good code right away instead of making that journey from writing newby-style code at first and then discovering how to actually do it properly. It might be just a little bit more verbose if you are thinking about a very primitive task such as a single select, but as soon as your task becomes just a little bit more complex it becomes all worth the time.
In your SQL queries make a general rule never to use select *, unless for testing / debugging. That's sort of laziness that in the end will cost you a lot of problems. By doing so you will make it very difficult to maintain your code later, effectively transforming it into "write once - run away" kind of thing. Again, as a simple proof of concept it is OK, - long-term solution - bad. If you are still blur on what I'm trying to say: list all column names explicitly.
Using include / require and their _once family is a bad idea as a long-term solution. Again, OK for a simple test - bad in the long run. Good programs are written in functions / classes and use __autoload() or a framework that uses the ability to load classes automatically. This makes larger applications more manageable, easier to navigate and understand then the web of includes.
You must sanitize input from the user of your web application, that is don't do $_POST['key']. At least write the function that will both check that the key exists and that it is of an expected format.
Now, your actual problem, sending the data.
You can just send the raw SQL output you get in PHP - will spare your server the problem of re-encoding all of it. Works in the very simple cases, but it becomes more complex with more complex tasks. This is also uncommon to do, so you will find that people will not know how to handle that. (No technical restriction, it is just really a historical artefact).
There are a bunch of popular formats that can be digested by variety of applications, not necessary Flash. Those include XML, JSON, Protobuf. There are also some more particular to PHP like the one produced from serialize(). I'd urge you to stick to JSON if you go down this route. XML might be a more mature technology, but JSON has a benefit of the basic type system built in (while in XML it is yet another layer on top of it, which is, beside other things is not implemented in Flash - I'm talking about XSL).
There's AMF (ActionScript Message Format) - it is ideal for Flash. PHP also knows very well how to produce it (there are several popular implementations out there). This format is a lot more compact compared to JSON or XML. It has more expressive power (can describe circular dependencies, many-to-many relationships, has a procedure for introducing custom types, custom [de]serialization routines). It is also self-describing, unless you used custom serialization routine. This is the best option if you aren't planning on moving your application to JavaScript later, because JavaScript has problems consuming binary data. Parsing this format would not be possible there.
Protobuf is a viable option too. This is a data exchange format designed by Google. It is similar in spirit to AMF, however it may not be self-describing. It relies on the application to know how to produced custom objects from it. It has, however, a form, that can be parsed in JavaScript (although you'd lose the the compactness benefit).
Your ActionScript code: If you opt for AMF, you'd need to look into NetConnection class. I'd advise you to take a look in AMFPHP project - it also has examples. Alternatively, Zend Framework has Zend_Amf library to be used for that purpose. But using the entire framework may be overwhelming at start.
If you go with XML - then there's a built-in XML class, there are millions of examples on the web on how to use it.
If you go with JSON, then since not so long ago there's a built-in class for that too. But before there was one, there were several libraries to parse it.
There used to be a project on GoogleCode for Protobuf support in Flash, but it required quite a bit of acquittance and manual labour to get going.
Finally, index of things mentioned here:
http://php.net/manual/en/book.pdo.php - PDO
http://php.net/manual/en/function.json-encode.php - JSON in PHP
http://php.net/manual/en/book.dom.php - XML in PHP (There is no agreement on which XML library is better if PHP is considered. I'd probably stick to this, but ymmv).
http://www.silexlabs.org/amfphp/ - AMF in PHP
http://framework.zend.com/manual/1.12/en/zend.amf.html Zend_Amf library
http://code.google.com/p/protobuf-actionscript3/ Protobuf in ActionScript
https://github.com/drslump/Protobuf-PHP PHP Protobuf (sorry, never used this one, but looks fine)
http://www.blooddy.by/en/crypto/ for older versions of Flash player - this library has the best JSON decoder I know of.
The best way is (I think) to use XML.
On the PHP side, the script output an XML document with all the users :
$sql = "SELECT * FROM users "; // add order statement if needed
$query = mysql_query($sql);
$login_counter = mysql_num_rows($query);
$xml = array('<?xml version="1.0" encoding="UTF-8"?><users>');
if ($login_counter > 0) {
while ($data = mysql_fetch_array($query)) {
$xml[] = '<user name="'.$data['username'].'" bio="'.$data["user_bio"].'" />';
}
}
else {
// do nothing
// you will handle it on the flash side by checking the length of user nodes list
}
$xml[] = '</users>';
header('Content-Type:text/xml');
die(implode('', $xml));
This will output an XML document :
<?xml version="1.0" encoding="UTF-8"?>
<users>
<user name="..." bio="..." />
<user name="..." bio="..." />
[...]
</users>
(There are class on PHP like SimpleXML to deal with XML in a cleaner way)
AS Side :
You can easily browse / display the data on the flash side with the help of the XML / XMLList class
Just adapt the URLLoaderDataFormat to TEXT and convert the data to XML in the complete event handler :
var xml:XML = new XML(event.target.data);
Then iterate the user elements to display them :
var users:XMLList = xml.user;
var user:XML;
for (user in users) {
trace('name->' + user.attribute('name') );
trace('bio->' + user.attribute('bio') );
}
need some advice on how to fix an ugly situation. our forum has resided on a couple of different domains over the years. we lost one domain that was in use 5-6 yrs ago and apparently some posts on our forum still have links in the threads that point to the old domain. what would be the most efficient way to change all links that point to
http://www.olddomain.com/stuff
point to
http://www.newdomain.com/stuff
the only part that has changed is the domain name, all thread variables in the url remain the same. is this something that is best done client side with javascript/jquery or should it be handled on a server level with a PHP function (dont know where to begin here..)? some pseudocode that doesn't seem to do what I need it to on the client side...
$('a').each(function() {
var domanin = 'newdomain';
if(href.search('olddomain.com') != -1) {
$(this).attr('href', newdomain);
}
});
thank you
I think it will make more sense if you handle this in the back end. Search engines will not notice the change you make through JavaScript.
So I advise you search for those domains in your database and replace them there.
Well you should probably do this on the server side, as it was said before, but if you can't for whatever reason, here is what you could do on the javascript side of things.
$('a').each(function() {
this.host = 'www.newdomain.com';
});
Note that this example uses jQuery, but you could do the same in plain javascript with getElementsByTagName.
To do this in JavaScript (w/ jQuery):
$('a').each(function() {
var link = this.href;
if(link.search('olddomain.com') != -1) {
this.href = link.replace('olddomain.com', 'newdomain.com');
}
});
Here is a jsfiddle: http://jsfiddle.net/tHXxK/
However I would suggest changing the links in the database, just get rid of all the old references. To do this create a script that searches for the old URLs and replaces them, something like:
$query = mysql_query("SELECT [id], [link] FROM [table] WHERE [link] LIKE '%//olddomain.com/%' OR [link] LIKE '%//www.olddomain.com/%'", $db) or trigger_erroR(mysql_error());
while ($row = mysql_query($query)) {
$iQuery = mysql_query("UPDATE [table] SET [link]='" . mysql_real_escape_string(str_replace(array('//olddomain.com/', '//www.olddomain.com/'), array('//newdomain.com/', '//www.newdomain.com/'), $row['link']) . "' WHERE [id]=" . $row['id']), $db) or trigger_error(mysql_error());
}
If it'd be me, I would have used a server side script to replace all instances of the old domain with the new one and be done with it once and for all.
I assume your forum DB is rather a large one. For the sake of system resources you can write a multi-step script and do the job in multiple steps.
This is a better approach as it can improve the data consistency for search engines as well.