I need to save many variables in text file and later retrieve any one random data from the text document.
For Example ...i need to add 31231231 to the below text file
213123123
213123124
123412321
and i need to retrieve random value from above text file ..for example 213123124 from above text file
To write to the already existing file :
file_put_contents("file.txt","\n31231231",FILE_APPEND);
To get a random value from the file :
$file = file("file.txt")
$len = count($file);
$rand = rand ( 0, $len-1 );
echo $file[$rand];
Edit: While retrieving the PHP_EOL is included so do this:
echo intval($file[$rand]);
Edit: Seeing as intval() returns the max_int for numbers that exceed int specs, just use trim();
echo trim($file[$rand])
To save and access variables and information when stored as text, in db or flat files, create array of the data first, then use serialize() on the data before saving, and unserialize() after fetching again. This allows for easy handling of information.
And remember to save many smaller files , rather than a large one...
To write in to a file you can use :
file_put_contents("test.txt","31231231".PHP_EOL ,FILE_APPEND);
Here PHP_EOL outputs \r\n or \n depending on the OS.
To select a random value from the text file you can use:
$file = file("test.txt")
$file_length = count($file);
$random_value = rand ( 0, $file_length-1 );
echo $file[$random_value];
New Edit:
If you want to avoid new line at the retrieved output you can do :
echo intval($file[$random_value]);
Hope this helps
Related
I'm using php to perform read/write operation in a txt file. Currently I am using fseek($file,0) and if I am using "a" mode with fopen() it add the text at last and if I'm using "c" or "rw+" mode then it replace the string at the beginning of text file. If I increase the position number suppose to 10 then it leave the first 10 character and after that add string by replacing the existing text in file.
What I want to achieve is, not to overwrite the text in the file, just append at that position.
And is there any way in which, I append the text not by giving position number, just search the specific keyword in the file and append the text at that position.
abc.php
<?php
$val = "string";
echo $val;
$myfile = fopen("demo.txt", "c") or die("Unable to open file!");
fseek($myfile, 0);
fwrite($myfile, $val);
fclose($myfile);
?>
demo.txt
this is some text
this is some text
this is some text
$all = file_get_contents("file");
$find = strpos($all, "needle");
$write = substr($all, 0, $find) . "insert" . substr($all, $find);
file_put_contents("file", $all);
The way filesystems work is that you cannot insert bytes in the middle. You need to overwrite all the contents behind if you have to insert something in the middle.
If the performance impacts do not suit your needs, you might want to use a database format to save data.
Or if you don't want to learn to use a database, a "convenient" way is to adding padding bytes between units in the file so that you can overwrite those padding bytes without having to move the bytes behind. This is actually how most implementations of filesystems and databases prevent overhead when inserting in the middle is needed.
if(isset($_POST['submit']))
{
$file = $_FILES['file']['name'];
$fh = fopen($file,'r+');
// string to put username and passwords
$users = '';
while(!feof($fh)) {
$user = explode(' ',fgets($fh));
foreach ($user as $value)
{
$number= rand(1000,10000);
$final_number[] = $value .','. $number;
}
}
//print_r($final_number);
file_put_contents($_FILES['file']['name'], $final_number);
}
this is my code for appending a random text to a string with comma and save it in text file but when i am saving it it is not saving properly after comma it is going to next line which should not happen plzz.. help me
Your code starts with a very big issue: you try to open and read from a file that, most probably, doesn't exist.
$file = $_FILES['file']['name'];
$fh = fopen($file,'r+');
As you can read in the documentation, assuming that your form contains an input element of type file having the name file, $_FILES['file']['name'] is the original name of the uploaded file, on the user's computer. It is only the name and it is not the name of the file on the server. It is provided just as a hint for the file's content (check the filename extension) but you cannot rely on it.
The content of the file is temporarily stored on the webserver in a file whose path can be found in $_FILES['file']['tmp_name']. You should pass it to the PHP function is_uploaded_file() to be sure the file was uploaded and your script is not the victim of an injection attempt then, if you need to keep it, use move_uploaded_file() to move it where you need. If you don't move it, when your script ends the temporary file is deleted.
Another problem of your code is on the lines:
$user = explode(' ',fgets($fh));
foreach ($user as $value)
As explained in the documentation, the function fgets() called without a second argument reads a line from the input file, including the newline character that ends it. Since you split the line into words I think you don't need the newline character. You can remove it by using trim() with the string returned by fgets() before passing it to explode().
The last issue of the code is:
file_put_contents($_FILES['file']['name'], $final_number);
Because $final_number is an array1, file_put_contents() joins its elements to get a string and writes the string into file. This operation concatenates the random value generated for a $value with the next $value and there is no way to tell which is which after the data is stored in the file. You probably need to keep them on separate lines. Use function implode() on $final_number, with "\n" as its first argument and write the generated string into the file instead.
The last one: don't write the generated content to $_FILES['file']['name']. It is not safe! It contains a string received from the browser; a malicious user can put whatever path they want there and your script will overwrite a file that it shouldn't change.
Create a directory dedicated to store files generated by your code and generate filenames based on an always incremented counter (the current time() or microtime() f.e.) for the files you store there. Never trust the data you receive from the browser.
1 $final_number is used as $final_number[] = ... and, because it is not defined when this line of code is executed for the first time, PHP creates an empty array for you and stores it in $final_number. Don't rely on this feature. Always initialize your variables before their first use. Put $final_number = array(); before the while().
I am going to use a different approach than you, let's say that the data you want to save to the file is stored in the variable $data.
So to append this data to the file with a comma at first, we can use just two lines of code:
$previousFileContent = file_get_contents("filename.txt");
file_put_contents("filename.txt", trim($previousFileContent . "," . $data));
I'm using the Sebastian Bergmann PHPUnit selenium webdriver.
Current I have:
$csv = file_get_contents('functions.csv', NULL,NULL,1);
var_dump($csv);
// select 1 random line here
This will load my CSV file and give me all possible data from the file.
It has multiple rows for example:
Xenoloog-FUNC/8_4980
Xylofonist-FUNC/8_4981
IJscoman-FUNC/8_4982
Question: How can I get that data randomly?
I just want to use 1 ( random) line of data.
Would it be easier to just grab 1 (random) line of the file instead of everything?
Split the string into an array, then grab a random index from that array:
$lines = explode("\n", $csv);
$item = $lines[array_rand($lines)];
You could use the offset and maxlen parameters to grab part of the file using file_get_contents. You could also use fseek after fopen to select part of a file. These functions both take numbers of bytes as arguments. This post has a little more information:
Get part of a file by byte number in php
It may require some hacking to translate a particular row-index of a CSV file to a byte offset. You might need to generate and load a small meta-data file which contains a list of bytes-occupancies for each row of of CSV data. That would probably help.
Can someone suggest a complex algorithm in php to name files that would be uploaded so that it never repeats? i wonder how youtube which has millions of videos does it??
Right now i use an random number and get its 16 character sha1 hash and name the file with that name but i'm pretty sure it will eventually repeat and generate an error as file will not be able to save in the file system.
something like:
$name = sha1(substr(sha1(md5($randomnumber)),0,10));
somebody once told me that its impossible to break the hash generated by this code or at least it'll take 100 years to break it.
you could do:
$uniq = md5(uniqid(rand(), true));
You could also apped user id of users uploading the file, like:
$uniq = $user_id_of_uploader."_".md5(uniqid(rand(), true));
Generate a GUID (sometimes called UUID) using a pre-existing implementation. GUIDs are unique per computer, timestamp, GUID generated during that timestamp and so on, so they will never repeat.
If making a GUID isn't available, using sha1 on the entire input and using the entire output of it is second best.
$name = 'filename'.$user_id(if_available).md5(microtime(true)).'extension';
Try to remove special characters and white spaces from the file name.
If you are saving name in database then a recursive function can be helpful.
Do below with proper methods.
First slice its extension and filename
Now Trim the filename
Change multiple Space into single space
Replace special character and whitespace into to _
Prefix with current timestamp using strtotime and salt using md5(uniqid(rand(), true)) separated by _ (Thanks to #Sudhir )
Suffix with a special signature using str_pad and limit the text length of a file
Now again add extension and formatted file name
hope it make sense.
Thanks
I usually just generate a string for the filename (implementation is not incredibly important), then check if a file already exists with that name. If so, append a counter to it. If you somehow have a lot of files with the same base filename, this could be inefficient, but assuming your string is unique enough, it shouldn't happen very often. There's also the overhead of checking that the file exists.
$base_name = generate_some_random_string(); // use whatever method you like
$extension = '.jpg'; // Change as necessary
$file_name = $base_name . $extension;
$i = 0;
while (file_exists($file_name)) {
$file_name = $base_name . $i++ . $extension;
}
/* insert code to save the file as $file_name */
I'm trying to write a php function that takes the $name and $time and write it to a txt file (no mySQL) and sort the file numerically.
For example:
10.2342 bob
11.3848 CandyBoy
11.3859 Minsi
12.2001 dj
just added Minsi under a faster time, for example.
If the $name already exists in the file, only rewrite it if the time is faster (smaller) than the previous one, and only write if the time fits within 300 entries to keep the file small.
My forte isn't file writing but I was guessing to go about using the file() to turn the whole file into an array, but to my avail, it didn't work quite like I wanted. Any help would be appreciated
If your data sets are small, you may consider using var_export()
function dump($filename, Array &$data){
return file_put_contents('<?php return ' . var_export($data, true) . ';');
}
// create a data set
$myData = array('alpha', 'beta', 'gamma');
// save a data set
dump('file.dat', $myData);
// load a data set
$myData = require('file.dat');
Perform your sorts using the PHP array_* functions, and dump when necessary. var_export() saves the data as PHP parsable text, which is why the dump() function prepends the string <?php return. Of course, this is really only a viable option when your data sets are going to be small enough that keeping their contents in memory is not unreasonable.
Try creating a multi dimensional array "$timeArray[key][time] = name" and then sort($timeArray)