I'm a fairly experienced programmer getting my head around PHP and Ajax for the first time, and I'm having a bit of trouble figuring out how to incorporate object-oriented PHP into my ajax webapp.
I have an admin page (admin.php) that will load and write information (info.xml) from an XML file depending on the users selection of a form on the admin page. I have decided to use an object (ContentManager.php) to manage the loading and writing of the XML file to disk, i.e :
class ContentManager{
var $xml_attribute_1
...
function __construct(){
//load the xml file from disk and save its contents into variables
$xml_attribute = simplexml_load_file(/path/to/xml)
}
function get_xml_contents(){
return xml_attribute;
}
function write_xml($contents_{
}
function print_xml(){
}
}
I create the ContentManager object in admin.php like so
<?php
include '../includes/CompetitionManager.php';
$cm = new CompetitionManager()
?>
<script>
...all my jquery
</script>
<html>
... all my form elements
</html>
So now I want to use AJAX to allow the user to retrieve information from the XML file via the ContentManger app using an interface (ajax_handler.php) like so
<?php
if(_POST[]=="get_a"){
}else if()
}
...
?>
I understand how this would work if I wasn't using objects, i.e. the hander php file would do a certain action depending on a variable in the .post request, but with my setup, I can't see how I can get a reference to the ContentManager object I have created in admin.php in the ajax_handler.php file? Maybe my understanding of php object scope is flawed.
Anyway, if anyone can make sense of what I'm trying to do, I would appreciate some help!
think of each ajax call as a separate request. if in the life cycle of a particular request you have not instantiated your ContentManager, the object doesn't exist. If you'd like to use a single object between multiple requests, serialize it to session and deserialize it early in the request life cycle.
I dont know if this is what you need, well, here goes. Have a single PHP file to handle all the form submissions. For eg: proc.php or something like that in the ACTION="proc.php". Inside the proc.php, depending upon the parameters submitted, make function calls. One other thing you should likely do is to create an instance of the class (the object) at the end of the class file itself avoiding the need to check everytime if the object was instantiated or not.
Use global $objectname before you make calls to the object functions, if necessary.
Related
I have a function that creates an array that contains the return value from the HTML DOM method : window.document.getElementById()
function makearray1(){
var array1=[1,window.document.getElementById('divID'),['a','b'],[1,2]];
}
then I pass the array into another function
use(array1)
function use(xxx){
xxx[1].innerHTML=xxx[2][0];
}
and 'a' is written in the appropriate div
later I decided to put the array in a form and post it to a txt file on the server using php and:
JSON.stringify(array)
So now I use AJAX to call the data from the txt file after the rest of the page has loaded etc... and the original function used to make the array is not included at all.
so my php is basically this:
$a1='use(';
$data1 =file_get_contents("text_file.txt") ;
$a2=')';
echo $a1.$data1.$a2;
and the response text:
var n= XMLHttpRequestObject.responseText;
eval(n);
which pretty much means this:
use(text_file)
function use(xxx){
xxx[1].innerHTML=xxx[2][0];
}
the problem is that the array in the text file looks like this:
[1,null,['a','b'],[1,2]]
instead of:
[1,window.document.getElementById('divID'),['a','b'],[1,2]]
My question: Is there any way that I can do the equivalent of what I'm trying to do here, which is immediately replicate the return value of the HTML/DOM method in an array using AJAX/php?
To clarify: this is a simple example. I actually have a huge, multidimensional array that already has established pointers, or prefetched DOM nodes in it. Now I'm trying to replicate the array when a text version is loaded using ajax. I'm looking for a recursive approach to changing all of the null assignments with something that will immediately fetch the appropriate DOM node. Most likely I will need to do it with the response text, but was hoping I could do it with the php portion.
You're trying to stringify a reference to a javascript object in the memory of whatever computer is evaluating getElementById first, and that has no chance to represent something on the end client's computer.
Send the id instead:
function makearray1(){
array1=[1,'divID',['a','b'],[1,2]];
}
then, in the client:
function use(xxx){
window.document.getElementById(xxx[1]).innerHTML=xxx[2][0];
}
If you really want to eval it at the end, you can use this, I guess
function makearray1(){
array1=[1,"window.document.getElementById(\"divID\")",['a','b'],[1,2]];
}
I've no idea why you would want to do that though
Assuming the dom element exists in the second page, it should look something like this.
JS:
function packDomData(){
return {
"MySpecificYetBriefProperty0":1,
"DomID":"divID",
"MySpecificYetBriefProperty1":['a','b'],
"MySpecificYetBriefProperty2":[1,2]
};
}
function useDomData(domData){
document.getElementByID(domData.DomID).innerHTML=domData.MySpecificYetBriefProperty1[0];
}
PHP:
//Make sure the contents of this file is the json from packDomData. use json_encode in php or JSON.stringify in js
echo file_get_contents("text_file.txt");
var myData = JSON.parse(XMLHttpRequestObject.responseText);
useDomData(myData);
I used to code like you. Here are some tips that have helped turn my coding horror into a fun job:
Use objects with descriptive properties instead of arrays whenever you aren't actually looping through the array - I promise it will save you and others headache! "DomID" is much more flexible than 1, and if you change the order in the array, javascript gods help you that array is everywhere - including however many random text files on your server!
Also use descriptive names for functions
Always return a value from a function instead of using globals whenever possible, even where the result is then used as a nasty global. Trust me.
Never put javascript function names in an ajax call. Use JSON instead and keep the functions and other script in the javascript file where it belongs.
Mysql will save your life!!
Disclaimer - I didn't run this code but it should basically work when you get everything hooked up right.
I am trying to do the following:
Open a file, say "myfile.json" from a php- let's call it "utils.php"; Use it in other php pages; close it from another php.
I have tried to include "utils.php" in the other files and write in the utils file, but it does not seem to work. I suppose this happens because utils.php is never actually executed, only included, but if I should execute it, how can I do it without having to refresh any page, preferably right when the user gets on the main page? This should not be seen by the user, what he sees should remain the main page.
Thanks in advance, I am quite new to php, and am trying to learn.
When you include a file, you are running all code inside it. The functions and classes will not be evaluated but will be defined for future use. If you open your file as this example:
util.php
<?php
$file_hand = fopen('/tmp/file.txt','r');
You will have a handle if the operation is completed. However, the variable $file_hand is global. If you need to use a function to close it, you will need the following code to do it:
other.php
function close_file(){
global $file_hand;
fclose($file_hand)
}
or you can pass the handle as parameter like:
function close_file($file_hand){
fclose($file_hand)
}
Doesn't matter how you will close the file. You have to make sure the variable you are using is the same created in utils.php. If you close like this:
function close_file(){
fclose($file_hand)
}
The variable you've created in until.php file is different of this one.
My first contact with Ajax is happening right now, and I'm kind a confused. I've read many of questions asked, but I'm not able to read the answer, that is most likely here somewhere.
Situation is, I'm using OOP PHP approach, and all I do go through index.php with parameters. So I do not call any other .php file in form posts, button clicks..
I've created an HTML listbox (which I'd like to remove vertical scrollbar, but that's just a bonus to resolve), which feeds my categories in it.
Now, by clicking each category I'd like to call certain function that would then generate output for the other div.
function swapContent(){
$("#myPresentDiv").html('<img src="../../imgs/ajax-loader-big.gif"/>').show();
var cat = $('#listbox').val();
$("#action").change(alert(cat));
var url = "&s=".cat;
$.post(url, {contentVar: cat} ,function(data) {
$("#myPresentDiv").html(data).show();
});
}
So, my JQuery script picks up correct Category, I alert it to alert dialog, so I'm sure that's fine, and then with code as it is at the moment, I reload my whole page so I get, page in page in page in page...
I'm trying to figure out how to write JQ ajax call, that would return only the results, not the whole page.
can I put URL "index.php&s="cat, and then somehow tell to ajax "go through index, call function displayresults ($cat); ?
Hope everything I wrote make sense to you :)
Tnx.
The url's your ajax function call, must return only the page parts and not the whole html document.
If you have
$.post('ajax.php',data,function(d){
$('#responsediv').html(d).show();
});
The file ajax.php must only return the page parts,like
<div>This is the new content</div>
so you will not have page inside page.
If you look at the frameworks or cms out there, they basically have routes that map calls to your index.php function to methods of the controller.
This is a complex argument, you could try to start out reading this article
Yeah, that makes sense. Your question is basically: when you get a result of an AJAX op and insert it into your page, it inserts the whole layout again, rather than the template.
OK, so the solution is to make a call to a PHP script that is "unstyled" i.e. has no template data. Your PHP script should therefore just output a short HTML snippet rather than a page (you might have a 'header' and 'footer' that can be removed for this page). What action you need to take depends what you're using on the server side - framework? CMS? Custom PHP app?
I did the exact thing for a internal app quite some time ago....What happened was i was passing the class name, function name and the function parameters via ajax variables and reading the same in php at the backend and then call the appropriate function in the class with those paraeters.
The PHP code:
$option = trim($_GET['v']);
switch ( $option ) {
case 1:
$sid = trim($_GET['q']);
$page = trim($_GET['p']);
$method = trim($_GET['m']);
$class = new $page( $link );
echo $class->$method( $sid );
break;
case 2:
$page = trim($_GET['p']);
$method = trim($_GET['m']);
$class = new $page( $link );
echo $class->$method();
break;
default:
echo '';
break;
}
But this was an internal app, so there was no injection attacks, xss,xsrf,session hijack issues....things might differ for you
Hope this helps.
I think you are searching for a GENERAL strategy to handle ajax requests its upto you
for example Server Side Ajax
unless you are using a specific framework (CI , yii etc)
You might want to look into some frameworks, as they can make this for you infinitely easier to implement:
http://demo.atk4.com/demo.html?t=20
I render the page corretly, display images etc. But when the user changes the album selection I want to use ajax to refresh the div.
My problem is that when I send the call to the server it gets an exception since the facebook objects are dead/no-reference, I don't know.
I tried to save them with session_start. I can pass strings like this but if I pass the objects like this than calling them still fails:
$albumID = $_GET['album'];
$facebook = $_SESSION['fb'];
$albums = $_SESSION['albums'];
$tester = $_SESSION['tester']; //works fine
echo get_pictures_from_album($facebook, $albums, $albumID);
I would also reallt appriciate it if someone can refer me to good documentation. It seems that facebook only have examples for the simple, trivial issues but no complicated apps.
If you are storing an object in the session, you need to make sure you require the file containing the class definition before you call session_start. Otherwise PHP won't be able to deserialize the objects from the session correctly.
I render a page using YUI. and depending on the user I need to change how it is rendered. This change is not something that can be parametrized, it is drastic and different for each user.
Please tell me how can I generate Javascript dynamically?
I personally use a PHP file to pass a JavaScript object made up of some basic session and internal settings, nothing mission-critical as passing information to the client isn't overly secure, but I believe it might follow the same principles as what you are looking for.
Similarly, I use this to display certain elements once the client is logged in, although all the authorization is still done on the server-side. If my session handler gives the PHP file the ok, it outputs a JavaScript object using a PHP heredoc string, otherwise, it doesn't output anything. You can use attributes of this object to compare against, or you could output only the JavaScript for how a certain page should be rendered, based on settings in your PHP file.
HTML:
<script src="common/javascript/php_feeder.php" type="text/javascript"></script>
PHP:
//my session handler authorisation check has been removed
//although you could place your own up here.
//assuming session was authorised
//set content type header
header("content-type: application/x-javascript");
$js_object = <<<EOT
var my_object = {
my_attr: '{$my_attr}',
my_attr2: '{$my_arrt2}',
etc: '{$etc}'
}
EOT;
print($js_object);
You can probably create two separate Java script files, and include the required file, depending upon the user type.
Pseudocode
If user_type is One
<Script src='one.js' type='javascript'></script>
else
<Script src='other.js' type='javascript'></script>
End If
JavaScript has an eval function, so I think (I haven't tried it) that you can generate JavaScript by writing it into a string variable (and then calling eval on that string variable).
A little bit of elaboration here would most certainly help in getting you a more descript and helpful answer. That in mind, though, you could easily just use functions declared inside an if statement to provide distinctly varied experiences for different users.
A very basic example:
<script>
function do_something(userType)
{
if (userType == 'A')
{
// everything you need to do for userType A
}
if (userType == 'B')
{
// everything you need to do for userType B
}
}
</script>