write to file /coding problem

saeed99

Hi
the following xml fragment is generated by the php code below

<?xml version="1.0"?>
<result rest_id="an1">
<answer_text>answer</answer_text>
<desc-result>descriptions</desc-result>
<result>

for one session the code updates the file every time the user adds new data , and the current data will be deleted , so the file will always contains one node set as the above

how can i make this code to append the new data to the old one in this file(the file will take the session id name so for each session the file will be unique)

thanks in advance

session_start(); 
//variable for this visite to the page 
$new= $GET['new']; 
//build a dom tree to get the attribute , and the children of the the 
//answer node whose attribute an_id equal to the variable $new 
$dom1 = new DOMDocument; 
$dom1->Load('test.xml'); 
$xpath = new DOMXPath($dom1); 
$query = "//answer[@an_id = '$new']"; 
$entries = $xpath->query($query); 


foreach ($entries as $entry) { 
  $attrt=$entry->getAttribute('an_id'); 
  $answer_text=$entry->childNodes->item(0)->nodeValue; 
  $desc_result=$entry->childNodes->item(1)->nodeValue; 

  } 


//build a dom tree to create a nodeset for the data from the dom1 
$dom2 = new DomDocument; 
$parent_node = $dom2->createElement('result'); 
$attr = $parent_node->setAttributeNode(new DOMAttr('rest_id',$attrt)); 
$parent_node->appendChild($dom2->createElement('answer_text',$answer_text)); 
$parent_node->appendChild($dom2->createElement('desc-result',$desc_result)); 

$dom2->appendChild($parent_node); 


//create a file with the session id name 
$dom2->save(session_id().'.xml');

sneakyimp

this code refers to some php classes that are defined in another file. the code that actually writes the file is in those class definitions. search for either createElement or appendChild functions. in there you will probably find a line containing fopen and/or fwrite statements.

show us that code and maybe we can help.

saeed99

i used to use the following code to write to the file but becouse the file will be named dinamicly i could not use it becouse would make the file not well formated :
but if you have any idea on how to make working , that will be perfect , pear in maind that the file has to start with the lines :
<?xml version="1.0"?><results>

//$file_handle = fopen(session_id().'.xml','a+');

//$file_handle = fopen('Result.xml','r+');
//fseek($file_handle,-10,SEEK_END);
//fwrite($file_handle,$contents.'</results>');
//fclose($file_handle);

thanks for your help

saeed99

sorry
please replace the following line (typing mistake from last post )

//$file_handle = fopen($session_id_file.'.xml','r+');

sneakyimp

i need more code to help. i'll need to see the whole process of opening the file and writing to it. the code you posted doesn't have any fwrite statement so we don't know how the file gets written.

perhaps you can post the entire function?

saeed99

i made some progress to the code and the problem 99% solved
the only thing is to solve is the following :
as you know fopen() with

r+

works if the file exists but in my case i need to write to a file which will take the session id name in onther word the file dose not exixts yet , i tried with

a+

but the code dose not work for some reasone

if we can find the problem for that would be fab

and thanks

<?php
session_start();

$new= $HTTP_GET_VARS['new'];

$doc = new DOMDocument;

$doc->Load('Test.xml');
$xpath = new DOMXPath($doc);
$query = "//answer[@an_id = '$new']";
$entries = $xpath->query($query);

foreach ($entries as $entry) {
  $attrt=$entry->getAttribute('an_id');
  $answer_text=$entry->childNodes->item(0)->nodeValue;
  $desc_result=$entry->childNodes->item(1)->nodeValue;


}

$dom = new DomDocument;

$parent_node = $dom ->createElement('result');

$attr = $parent_node->setAttributeNode(new DOMAttr('rest_id',$attrt));
$parent_node->appendChild($dom->createElement('answer_text',$answer_text));
$parent_node->appendChild($dom->createElement('desc-result',$desc_result));
$dom->appendChild($parent_node);
$contents= $dom->saveXML($parent_node);


//   the problem 
$file_handle = fopen(session_id().'.xml','r+');
fseek($file_handle,-10,SEEK_END);
fwrite($file_handle,$contents.'</results>');
fclose($file_handle);


 ?>

sneakyimp

RTFM! 😉

it sounds like there is some unexpected behavior when opening with 'a'....not sure at all...maybe read the notes here:
http://www.php.net/manual/en/function.fseek.php

I'm not sure if that's going to help at all.

it occurred to me that if you use 'a' and then try to seek to the end of the file minus 10 bytes, then you might get an error because the file has length zero. what are those last 10 bytes anyway?

Another approach would be to explicitly check for the existence of the file first using file_exists() and then deciding whether to open with w or whatever.