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PHP - Most Efficient Random String Method
currently using
function gen_chars($length = 6) { // Available characters $chars = '0123456789abcdefghjkmnoprstvwxyz'; $Code = ''; // Generate code for ($i = 0; $i < $length; ++$i) { $Code .= substr($chars, (((int) mt_rand(0,strlen($chars))) - 1),1); } return $Code; } // Usage $var = gen_chars(12); echo $var; However ide like to know if theres a more efficient way of generating this since this is going to be using a lot. Thanks Similar Tutorialshttp://www.phpfreaks.com/forums/index.php/topic,308549.0.html The above link is a problem relating to CSS. The way route i've choosen thanks to haku is to determine the users browser then let php give one css or another. What is the best way to determine the users browser. At the moment i can only find a problem with css fixed in ie6 and below. Therefore i only really need to find if the user is running on ie6. I've come accross the http://php.net/manual/en/function.get-browser.php but requires http://browsers.garykeith.com/downloads.asp. Is there a simpler way? I am looking to generate a random number for every user contribution as a title of the contribution. I could simply check the database each time with a query and generate a number which does not equal to any of the entries of the database. But I imagine this as inefficient and it could become slow if the database is big in my opinion. Also I'd have to contain all the numbers of the database somewhere to manage the "not equals to", in an array or something similar but that can end up as a giant one. Excuse the layman's speech I am new to this. Any suggestions how this can be solved efficiently without straining the resources too much? You can explain it linguistically and do not have to provide me any scripts, I will figure it out. Hello everyone, I am trying to select and return any rows that have a specific string in it. Let's say I have a column name "item_id" and in every row of that column I have values like so: row A: (11,22,44,34) row B: (12,56,78,98) If the user picks the number '22', I use the following SQL line to get the row in which the number '22' is contained. SELECT * FROM Persons WHERE City LIKE '%22%' and row A gets returned, just like it is suppose to. The problem is, if the user selects a single digit number like '2', both row A and row B gets returned because they both have values that contain the number '2' in it. Instance, row A has the number '22' and row B has the number '12' so both rows get returned when the number '2' is requested. I don't want that, I only want the row that has the exact number '2' or '34' or whatever number I request, to be returned. So to get around this problem, I am wrapping my numbers in letters like so: row A: (a11a,a22a,a44a,a34a) row B: (a12a,a56a,a78a,a98a,a2a) and requesting it like so: SELECT * FROM Persons WHERE City LIKE '%a22a%' My question is: Is there a better way to work out this logic? Hi, I'm having trouble generating random string with 8 characters, when I refresh I sometimes get 6 characters and sometimes 8. "-" not included as character. Wrong: 6JW-F7W Correct: (should always generate random like this) DVMF-F36V I know I'm trying to achieve this in wrong methods but it's the only way I know. Hope someone can help. function getReference() { $length = 8; $characters = "0123456789abcdefghijklmnopqrstuvwxyz"; for ($p = 0; $p < $length; $p++) { $string .= $characters[mt_rand(0, strlen($characters))]; } return strtoupper(substr($string, 0, -$length/2)."-".substr($string, $length/2-1, -1)); } i have to tables... forums & subscription i would like to insert a random character string into 'forums' to be used as a subscription id. and then have the same random string to be inserted into 'subscription' In the PHP script I'm using, in the Upload Form the user selects an image to Upload, the Form renames it like so:
$allowedExts = array("gif", "jpeg", "jpg", "pdf", "png");
$temp = explode(".", $_FILES["file"]["name"]);
$extension = strtolower( end($temp) );
if (!in_array($extension,$allowedExts))
{
echo ("Error - Invalid File Name");
}
$length = 20;
$randomString = (time());
$thumbnail = $randomString . "." . $extension;
The random string works successfully, but I'd like to add the user_id to the beginning of it and a dash, like this:
user_id -
So, the new file name would be something like: user_id-randomString.extension
Can you please help me add that?
Hey all, I'm looking to produce a random 10 character string like: abcABC0123 when the below method is called: <?php function randomize(){ $chars = explode(' ',(range("a","z"))) . explode(' ',(range("A","Z"))) . explode(' ',(range("0","9"))); $pass = ""; for($i = 0; $i < $len; $i += 1){ array_push($pass,$chars[rand(count($chars)-1)]); } return $pass; } var_dump(randomize(10)); ?> But the randomize method is not returning desired result. Any idea what I'm doing wrong? Thanks for response. So I found this code from someone else on here who posted about creating a random string. I've copied the code for myself but when I upload php page to my server and view source... there is no php code. Essentially, i see no randomly generated text. what am i missing? Code: [Select] <?php function genRandomString() { $length = 5; $characters = array_merge(range(0,9),range('a','z'),range('A','Z')); $string = ""; for ($p = 0; $p < $length; $p++) { $string .= $characters[mt_rand(0, count($characters)-1)]; } return $string; } ?> I'm looking for a function that creates a random string that contains random letters, numbers and symbols. Also it needs to generate it in a way that there are no repeating characters. Any ideas? Hi everyone Well I've started learning php yesterday and now I encountered my first problem, I looked around but I don't really know what to search for if I want my answer so here I come Code: [Select] <html> <body> <?php $names = array('Peter','Quagmire','Joe'); $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34); $who = rand(0,2); $who2 = $names[$who]; echo "$names[$who] is $ages[$who2] years old"; ?> </body> </html> This is the script I have, and there is the kind of script I expected: Code: [Select] <html> <body> <?php $names = array('Peter','Quagmire','Joe'); $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34); $who = rand('Peter','Quagmire','Joe'); echo "$who is $ages[$who] years old"; ?> </body> </html> But after some search I concluded that rand is only used for random numbers So, my question is, which function should I use to achieve my goal? Is there any randstring('string1','string2',etc) command? Tnx for your time Hello everyone, I have this very short script I wrote with help from a book using arrays and the rand function. Basically it changes the images randomly on browser load or refresh. However, I am trying to add an additional, not sure what to call it, a string or another caption for each images. Instead of this being a caption, it will be a link, so a link will appear under each caption that goes to another page when it is clicked on. I tried adding another caption and adding a like to it but getting syntax error. Thanks everyone! Here is the code: Code: [Select] <?php $images = array( array('file' => 'image1', 'caption' => 'Caption 1'), array('file' => 'image2', 'caption' => 'Caption 2'), ); $i = rand(0, count($images)-1); $selectedImage = "graphics/{$images[$i]['file']}.png"; $caption = $images[$i]['caption']; ?> And here is where the images are written to the page: Code: [Select] <div id="stage"> <img src="<?php echo $selectedImage; ?>" alt="Random image" /> <p id="caption"><?php echo $caption; ?></p> </div> IC
My script has 3 classes (that are relevant to this discussion): DB, User and Validate. They are all in independent files and loaded automatically, when required, by an autoloader.
The error messages I am getting a Any pointers as to what I am doing wrong, or what I should be doing, would be most welcome. I have some code which i think is really inefficient especially as there will be more more conditions to be met. I was thinking about using s switch but don't know if this is possible or if it's best leaving as it is. Any ideas? if($parts[($i-1)]=="forum") { //do some code } else if($parts[($i-2)]=="forum") { //do code } else if (($parts[($i-1)]=="list-messages") && (isset($parts[($i+1)]))) { //do code } else { // do some code } Code: [Select] <?php $IPaddress = $_SERVER['REMOTE_ADDR']; if(stristr($IPaddress, "123.456.58.451") || stristr($IPaddress, "123.126.456.10") || stristr($IPaddress, "123.126.456.10")) { echo "<center><b><i>CWB permits you to views this page...</i></b></center></br>"; echo '<center><b><font size="5">'.$IPaddress.'</font></b></center>'; } else { echo "<center><b>CWB DOES NOT PERMIT YOU TO VIEW THIS PAGE</b></center>"; } exit; ?> how do I make it to where I dont have to keep adding on to Code: [Select] if(stristr($IPaddress, "123.456.58.451") || stristr($IPaddress, "123.126.456.10") || stristr($IPaddress, "123.126.456.10")) this xml_parse_into_struct($iP=xml_parser_create(), curl_exec($ch), $bR, $bJ);xml_parser_free($iP); echo "::: ".strip_tags(str_replace("<br>","\n",$bR[$bJ['MESSAGE'][0]]['value']))."\n"; or... $xml = simplexml_load_string(curl_exec($ch)); foreach($xml->xml as $message){ echo strip_tags($message->message)."\n";} Just want to know which of these two would execute faster and if there was a better way that would be faster than both of these options? Thanks Hi all! I'm a real noob and this is my first time making a website and I haven't hosted it yet. I'm trying to make a website that is fast and secure. My pages look something like this. Code: [Select] <?php include("header.php");include("sidebar.php"); ?> HTML CODES <?php include("footer.php"); ?> 1. Are these php files cached after their first load? When I go to another page, those parts seem to stay still. 2. Is this code secure? And now I'm starting to make product pages which will be around 40 pages. So I'm considering something like this... Code: [Select] <?php include("header.php");include("sidebar.php"); ?> <a href="index.php?page=a">Page A</a> <?php $page = $_GET['page']; if (file_exists('pages/'.$page.'.php')) { include('pages/'.$page.'.php'); } ?> <?php include("footer.php"); ?> 3. Is it better to make every page like this since it will load header, sidebar, footer only once? 4. How should I protect from the user input data, by making an array of allowed files or by prohibiting "." and "/" ? Thank you in advance. Need some feedback on this loop Tables: Table A Table B Loop Select all from A based on criteria a. Insert into table B using row data from table A b. Update record in table A to say that it has gone through loop to prevent future loop Thats three MySQL queries running over and over at the same time, how bad is that for performance, is there another way? Maybe instead of running b each time build an array with the record ids from Table A and after the loop runs to insert into Table B run another query with the IN command to loop through all of the IDs in the array and update? Hi all, I've been trying to improve the speed of my file download script and was wondering if anyone could advise me which of the following is more efficient (Don't worry its not the whole script, just one segment), in terms of speed and server load? The way I have the segment currently: //if file exists need to check authorision levels //set access to no $access = NULL; //retrieve current user levels $cpm = $_SESSION['MM_CPMGroup']; $cpmh = $_SESSION['MM_CPMHGroup']; $cm = $_SESSION['MM_CMGroup']; $cj200 = $_SESSION['MM_CJ200Group']; $cj = $_SESSION['MM_CJGroup']; //set file category type & set access if allowed if ($category == 'cpm') { if ($cpm == '1') { $access = 1; if ($subcategory == 'techdata') { $path = "files/techdata/cpm/"; } elseif ($subcategory == 'msds') { $path = "files/techdata/cpm/msds/"; } elseif ($subcategory == 'symbols') { $path = "files/symbols/cpm/"; } else { $path = "files/cpm/"; } } } elseif ($category == 'cpmh') { if ($cpmh == '1') { $access = 1; if ($subcategory == 'techdata') { $path = "files/techdata/cpmh/"; } elseif ($subcategory == 'msds') { $path = "files/techdata/cpmh/msds/"; } elseif ($subcategory == 'symbols') { $path = "files/symbols/cpmh/"; } else { $path = "files/cpmh/"; } } } elseif ($category == 'cm') { if ($cm == '1') { $access = 1; if ($subcategory == 'techdata') { $path = "files/techdata/cm/"; } elseif ($subcategory == 'msds') { $path = "files/techdata/cm/msds/"; } elseif ($subcategory == 'symbols') { $path = "files/symbols/cm/"; } else { $path = "files/cm/"; } } } elseif ($category == 'cj200') { if ($cj200 == '1') { $access = 1; if ($subcategory == 'techdata') { $path = "files/techdata/cj200/"; } elseif ($subcategory == 'msds') { $path = "files/techdata/cj200/msds/"; } elseif ($subcategory == 'symbols') { $path = "files/symbols/cj200/"; } else { $path = "files/cj200/"; } } } elseif ($category == 'cj') { if ($cj == '1') { $access = 1; if ($subcategory == 'techdata') { $path = "files/techdata/cj/"; } elseif ($subcategory == 'msds') { $path = "files/techdata/cj/msds/"; } elseif ($subcategory == 'symbols') { $path = "files/symbols/cj/"; } else { $path = "files/cj/"; } } } if ($access < 1) { // if user access not granted to file category return message if($logging > 0){ $status = "Wrong Permissions"; include('logit.php'); } if (! $_SESSION['PrevUrl']) { //header("Location: ". $loginpage ); exit; } $redirect = $_SESSION['PrevUrl']; header("Location: ". $redirect ); exit; } // if file exists and user access granted continue Obviously the above is a lot of lines of code... So I have rewritten the above to look like: //if file exists need to check authorision levels & retrieve current user levels if ($category == 'cpm' && $_SESSION['MM_CPMGroup'] == '1') { $access = 1; } elseif ($category == 'cpmh' && $cpmh = $_SESSION['MM_CPMHGroup'] == '1') { $access = 1; } elseif ($category == 'cm' && $cm = $_SESSION['MM_CMGroup'] == '1') { $access = 1; } elseif ($category == 'cj200' && $_SESSION['MM_CJ200Group'] == '1') { $access = 1; } elseif ($category == 'cj' && $_SESSION['MM_CJGroup'] == '1') { $access = 1; } else { $access = NULL; } if ($access == NULL) { // if user access not granted to file category return message $status = "Unauthorised"; include('logit.php'); header("Location: ".$_SESSION['PrevUrl']); exit; } // if file exists and user access granted continue switch($subcategory) { case "techdata":$path="files/techdata/".$category."/".$filename; break; case "msds": $path="files/techdata/".$category."/msds/".$filename; break; case "symbols": $path="files/symbols/".$category."/".$filename; break; default: $path="files/".$category."/".$filename; } The second version is a lot shorter, but is it better? And could I shorten the if statement further so its more like: //if file exists need to check authorision levels & retrieve current user levels if (($category == 'cpm' && $_SESSION['MM_CPMGroup'] == '1') || ($category == 'cpmh' && $cpmh = $_SESSION['MM_CPMHGroup'] == '1') || ($category == 'cm' && $cm = $_SESSION['MM_CMGroup'] == '1') || ($category == 'cj200' && $_SESSION['MM_CJ200Group'] == '1') || ($category == 'cj' && $_SESSION['MM_CJGroup'] == '1') { $access = 1; } else { $access = NULL; } if ($access == NULL) { // if user access not granted to file category return message $status = "Unauthorised"; include('logit.php'); header("Location: ".$_SESSION['PrevUrl']); exit; } // if file exists and user access granted continue switch($subcategory) { case "techdata":$path="files/techdata/".$category."/".$filename; break; case "msds": $path="files/techdata/".$category."/msds/".$filename; break; case "symbols": $path="files/symbols/".$category."/".$filename; break; default: $path="files/".$category."/".$filename; } Any advice would be appreciated! Thanks!! |
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