I make use of an external XML file I can get from a certain URL. Now there is a problem regarding the getting of the XML file, because if you try too much times to get the file, you don't get anything at all, presumably to limit the amount of requests.
Is there a possibility to download via PHP the XML file every day to limit the requests to the external server.
I have checked what options I have and I saw that CRON is the most found solution to this problem. But I want to do this via PHP if that is possible, because I don't have the access to the server to setup CRON.
Does anyone have any experience with downloading an XML file to your own server and use that, and download that XML file daily to limit the requests?
I have this code to get the actual XML file:
$xml = file_get_contents("my-xml-file-url-external");
file_put_contents("my-path-to-save-xml-file", $xml);
But how can I make sure this gets called every day?
You can check the last modified time (see filemtime() documentation) of the file you write to, and if it's more than a day old (or non-existant) overwrite it:
$cacheFile = "file.xml";
if (!file_exists($cacheFile) || filemtime($cacheFile) < time() - 86400)
{
$xml = file_get_contents("my-xml-file-url-external");
file_put_contents($cacheFile, $xml);
} else {
$xml = file_get_contents($cacheFile);
}
Related
I have a case,
I have a remote server that contains so many generated transaction files (.txt) from 2015 until now. I must download it everyday real time. For now, i use PHP to download it all, but the method i think is not effectifely. First, I list all files, and then I read the component of the files such as the date modified, but this method is annoying. Make my program run slowly and take a very much time.
This is my code (I've used PHP Yii2),
public function actionDownloadfile(){
$contents=Yii::$app->ftpFs->listContents('/backup', ['timestamp','path','basename']); --> Much time needed while executing this line
var_dump($contents);
foreach ($contents as $value) {
if (date('Y-m-d',$value['timestamp']) == date('Y-m-d')){
echo "[".date('Y-m-d H:i:s')."] : Downloading file ".$value['basename']."\n";
$isi = Yii::$app->ftpFs->read($value['path']);
$dirOut = Yii::$app->params['out'];
$fileoutgoing = $dirOut."/".$value['basename'];
$file = fopen($fileoutgoing,"w");
fwrite($file,$isi);
}
}
}
i have a question,
Is that possible to list and download some files in ftp server just only on this current date without listing them all first?
Any solution either using PHP or Shell Script is OK.
Thank you so much (y)
Some background information
The files I would like to download is kept at the external server for a week, and a new XML file(10-50mb large) is created there every hour with a different name. I would like the large file to be downloaded to my server chunk by chunk in the background each time my website is loaded, perhaps 0.5mb each time, and then resume the download the next time someone else loads the website. This would require my site to have atleast 100 pageloads each hour to stay updated, so perhaps abit more of the file each time if possible. I have researched simpleXML, XMLreader, SAX parsing, but whatever I do, it seems it takes too long to parse the file directly, therefore I would like a different approach, namely downloading it like described above.
If I download a 30mb large XML file, I can parse it locally with XMLreader in 3 seconds(250k iterations) only, but when I try to do the same from the external server limiting it to 50k iterations, it uses 15secs to read that small part, so it would not be possible to parse it directly from that server it seems.
Possible solutions
I think it's best to use cURL. But then again, perhaps fopen(), fsockopen(), copy() or file_get_contents() are the way to go. I'm looking for advice on what functions to use to make this happen, or different solutions on how I can parse a 50mb external XML file into a mySQL database.
I suspect a Cron job every hour would be the best solution, but I am not sure how well that would be supported by webhosting companies, and I have no clue how to do something like that. But if thats the best solution, and the majority thinks so, I will have to do my research in that area too.
If a java applet/javascript running in the background would be a better solution, please point me in the right direction when it comes to functions/methods/libraries there aswell.
Summary
What's the best solution to downloading parts of a file in the
background, and resume the download each time my website is loaded
until its completed?
If the above solution would be moronic to even try, what
language/software would you use to achieve the same thing(download a large file every hour)?
Thanks in advance for all answers, and sorry for the long story/question.
Edit: I ended up using this solution to get the files with cron job scheduling a php script. It checks my folder for what files I already have, generates a list of the possible downloads for the last four days, then downloads the next XMLfile in line.
<?php
$date = new DateTime();
$current_time = $date->getTimestamp();
$four_days_ago = $current_time-345600;
echo 'Downloading: '."\n";
for ($i=$four_days_ago; $i<=$current_time; ) {
$date->setTimestamp($i);
if($date->format('H') !== '00') {
$temp_filename = $date->format('Y_m_d_H') ."_full.xml";
if(!glob($temp_filename)) {
$temp_url = 'http://www.external-site-example.com/'.$date->format('Y/m/d/H') .".xml";
echo $temp_filename.' --- '.$temp_url.'<br>'."\n";
break; // with a break here, this loop will only return the next file you should download
}
}
$i += 3600;
}
set_time_limit(300);
$Start = getTime();
$objInputStream = fopen($temp_url, "rb");
$objTempStream = fopen($temp_filename, "w+b");
stream_copy_to_stream($objInputStream, $objTempStream, (1024*200000));
$End = getTime();
echo '<br>It took '.number_format(($End - $Start),2).' secs to download "'.$temp_filename.'".';
function getTime() {
$a = explode (' ',microtime());
return(double) $a[0] + $a[1];
}
?>
edit2: I just wanted to inform you that there is a way to do what I asked, only it would'nt work in my case. With the amount of data I need the website would have to have 400+ visitors an hour for it to work properly. But with smaller amounts of data there are some options; http://www.google.no/search?q=poormanscron
You need to have a scheduled, offline task (e.g., cronjob). The solution you are pursuing is just plain wrong.
The simplest thing that could possibly work is a php script you run every hour (scheduled via cron, most likely) that downloads the file and processes it.
You could try fopen:
<?php
$handle = fopen("http://www.example.com/test.xml", "rb");
$contents = stream_get_contents($handle);
fclose($handle);
?>
Is there any way to check id a file is being accessed or modified by another process from a php script. i have attempted to use the filemtime(), fileatime() and filectime() functions but i have the script in a loop which is checking continuously but it seems once the script has been executed it will only take the time from the first time the file was checked.. an example would be uploading files to a FTP or SMB share i attempted this below
while(1==1)
{
$LastMod = filemtime("file");
if(($LastMod +60) > time())
{
echo "file in use please wait... last modified : $LastMod";
sleep(10);
}else{
process file
}
}
I know the file is constantly changing but the $LastMod variable is not updating but end process and execute again will pick up a new $LastMod from the file but dosnt seem to update each time the file is checked in the loop
I have also attempted this with looking at filesize() but get the same symptoms i also looked into flock() but as the file is created or modified outside PHP I don't see how this would work.
If anyone has any solutions please let me know
thanks Vip32
PS. using PHP to process the files as requires interaction with mysql and querying external websites
The file metadata functions all work off stat() output, which caches its data, as a stat() call is a relatively expensive function. You can empty that cache to force stat() to fetch fresh data with clearstatcache()
There are other mechanisms that allow you to monitor for file changes. Instead of doing a loop in PHP and repeatedly stat()ing, consider using an external monitoring app/script which can hook into the OS-provided mechanism and call your PHP script on-demand when the file truly does change.
Add clearstatcache(); to your loop:
while(true)
{
$LastMod = filemtime("file");
clearstatcache();
if(($LastMod +60) > time())
{
echo "file in use please wait... last modified : $LastMod";
sleep(10);
}else{
process file
}
}
I experimenting with twitter streaming API,
I use Phirehose to connect to twitter and fetch the data but having problems storing it in files for further processing.
Basically what I want to do is to create a file named
date("YmdH")."."txt"
for every hour of connection.
Here is how my code looks like right now (not handling the hourly change of files)
public function enqueueStatus($status)
$data = json_decode($status,true);
if(isset($data['text'])/*more conditions here*/) {
$fp = fopen("/tmp/$time.txt");
fwirte ($status,$fp);
fclose($fp);
}
Help is as always much appreciated :)
You want the 'append' mode in fopen - this will either append to a file or create it.
if(isset($data['text'])/*more conditions here*/) {
$fp = fopen("/tmp/" . date("YmdH") . ".txt", "a");
fwrite ($status,$fp);
fclose($fp);
}
From the Phirehose googlecode wiki:
As of Phirehose version 0.2.2 there is
an example of a simple "ghetto queue"
included in the tarball (see file:
ghetto-queue-collect.php and
ghetto-queue-consume.php) that shows
how statuses could be easily collected
on to the filesystem for processing
and then picked up by a separate
process (consume).
This is a complete working sample of doing what you want to do. The rotation time interval is configurable too. Additionally there's another script to consume and process the written files too.
Now if only I could find a way to stop the whole sript, my log keeps filling up (the script continues execution) even if I close the browser tab :P
This first script gets called several times for each user via an AJAX request. It calls another script on a different server to get the last line of a text file. It works fine, but I think there is a lot of room for improvement but I am not a very good PHP coder, so I am hoping with the help of the community I can optimize this for speed and efficiency:
AJAX POST Request made to this script
<?php session_start();
$fileName = $_POST['textFile'];
$result = file_get_contents($_SESSION['serverURL']."fileReader.php?textFile=$fileName");
echo $result;
?>
It makes a GET request to this external script which reads a text file
<?php
$fileName = $_GET['textFile'];
if (file_exists('text/'.$fileName.'.txt')) {
$lines = file('text/'.$fileName.'.txt');
echo $lines[sizeof($lines)-1];
}
else{
echo 0;
}
?>
I would appreciate any help. I think there is more improvement that can be made in the first script. It makes an expensive function call (file_get_contents), well at least I think its expensive!
This script should limit the locations and file types that it's going to return.
Think of somebody trying this:
http://www.yoursite.com/yourscript.php?textFile=../../../etc/passwd (or something similar)
Try to find out where delays occur.. does the HTTP request take long, or is the file so large that reading it takes long.
If the request is slow, try caching results locally.
If the file is huge, then you could set up a cron job that extracts the last line of the file at regular intervals (or at every change), and save that to a file that your other script can access directly.
readfile is your friend here
it reads a file on disk and streams it to the client.
script 1:
<?php
session_start();
// added basic argument filtering
$fileName = preg_replace('/[^A-Za-z0-9_]/', '', $_POST['textFile']);
$fileName = $_SESSION['serverURL'].'text/'.$fileName.'.txt';
if (file_exists($fileName)) {
// script 2 could be pasted here
//for the entire file
//readfile($fileName);
//for just the last line
$lines = file($fileName);
echo $lines[count($lines)-1];
exit(0);
}
echo 0;
?>
This script could further be improved by adding caching to it. But that is more complicated.
The very basic caching could be.
script 2:
<?php
$lastModifiedTimeStamp filemtime($fileName);
if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
$browserCachedCopyTimestamp = strtotime(preg_replace('/;.*$/', '', $_SERVER['HTTP_IF_MODIFIED_SINCE']));
if ($browserCachedCopyTimestamp >= $lastModifiedTimeStamp) {
header("HTTP/1.0 304 Not Modified");
exit(0);
}
}
header('Content-Length: '.filesize($fileName));
header('Expires: '.gmdate('D, d M Y H:i:s \G\M\T', time() + 604800)); // (3600 * 24 * 7)
header('Last-Modified: '.date('D, d M Y H:i:s \G\M\T', $lastModifiedTimeStamp));
?>
First things first: Do you really need to optimize that? Is that the slowest part in your use case? Have you used xdebug to verify that? If you've done that, read on:
You cannot really optimize the first script usefully: If you need a http-request, you need a http-request. Skipping the http request could be a performance gain, though, if it is possible (i.e. if the first script can access the same files the second script would operate on).
As for the second script: Reading the whole file into memory does look like some overhead, but that is neglibable, if the files are small. The code looks very readable, I would leave it as is in that case.
If your files are big, however, you might want to use fopen() and its friends fseek() and fread()
# Do not forget to sanitize the file name here!
# An attacker could demand the last line of your password
# file or similar! ($fileName = '../../passwords.txt')
$filePointer = fopen($fileName, 'r');
$i = 1;
$chunkSize = 200;
# Read 200 byte chunks from the file and check if the chunk
# contains a newline
do {
fseek($filePointer, -($i * $chunkSize), SEEK_END);
$line = fread($filePointer, $i++ * $chunkSize);
} while (($pos = strrpos($line, "\n")) === false);
return substr($line, $pos + 1);
If the files are unchanging, you should cache the last line.
If the files are changing and you control the way they are produced, it might or might not be an improvement to reverse the order lines are written, depending on how often a line is read over its lifetime.
Edit:
Your server could figure out what it wants to write to its log, put it in memcache, and then write it to the log. The request for the last line could be fulfulled from memcache instead of file read.
The most probable source of delay is that cross-server HTTP request. If the files are small, the cost of fopen/fread/fclose is nothing compared to the whole HTTP request.
(Not long ago I used HTTP to retrieve images to dinamically generate image-based menus. Replacing the HTTP request by a local file read reduced the delay from seconds to tenths of a second.)
I assume that the obvious solution of accessing the file server filesystem directly is out of the question. If not, then it's the best and simplest option.
If not, you could use caching. Instead of getting the whole file, you just issue a HEAD request and compare the timestamp to a local copy.
Also, if you are ajax-updating a lot of clients based on the same files, you might consider looking at using comet (meteor, for example). It's used for things like chats, where a single change has to be broadcasted to several clients.