Using the fgets() function (or any other way) in PHP is there a way to read the LAST line of a file then work backwards?
What I am doing: (as per request) I am appending to a .txt file lines from an input (don't worry about that) and of course append adds to the END of a file so I need to display the contents of a file with one line being one entry to be displayed
So if the contents of the file are:
Hello, World!
Foo likes Bar!
then it needs to display as
1. Foo likes Bar!
2. Hello, World!
As far as I know PHP does not know the gets() function. But..
If you use 'file()' and inverse the array you can work it through from bottom to top. That should do the trick for you!
If it is a really big file, it might be better to use the following...
exec("tail -1 input_file > output_file") ;
$string = file_get_contents("output_file") ;
unlink("output_file") ;
This is based on UNIX/Linux system commands, but I'm sure Windows has a command similar to tail.
Related
What is the best way to overwrite a specific line in a file? I basically want to search a file for the string '#parsethis' and overwrite the rest of that line with something else.
If the file is really big (log files or something like this) and you are willing to sacrifice speed for memory consumption you could open two files and essentially do the trick Jeremy Ruten proposed by using files instead of system memory.
$source='in.txt';
$target='out.txt';
// copy operation
$sh=fopen($source, 'r');
$th=fopen($target, 'w');
while (!feof($sh)) {
$line=fgets($sh);
if (strpos($line, '#parsethis')!==false) {
$line='new line to be inserted' . PHP_EOL;
}
fwrite($th, $line);
}
fclose($sh);
fclose($th);
// delete old source file
unlink($source);
// rename target file to source file
rename($target, $source);
If the file isn't too big, the best way would probably be to read the file into an array of lines with file(), search through the array of lines for your string and edit that line, then implode() the array back together and fwrite() it back to the file.
Your main problem is the fact that the new line may not be the same length as the old line. If you need to change the length of the line, there is no way out of rewriting at least all of the file after the changed line. The easiest way is to create a new, modified file and then move it over the original. This way there is a complete file available at all times for readers. Use locking to make sure that only one script is modifying the file at once, and since you are going to replace the file, do the locking on a different file. Check out flock().
If you are certain that the new line will be the same length as the old line, you can open the file in read/write mode (use r+ as the second argument to fopen()) and call ftell() to save the position the line starts at each time before you call fgets() to read a line. Once you find the line that you want to overwrite, you can use fseek() to go back to the beginning of the line and fwrite() the new data. One way to force the line to always be the same length is to space pad it out to the maximum possible length.
This is a solution that works for rewriting only one line of a file in place with sed from PHP. My file contains only style vars and is formatted:
$styleVarName: styleVarProperty;\n
For this I first add the ":" to the ends of myStyleVarName, and sed replaces the rest of that line with the new property and adds a semicolon.
Make sure characters are properly escaped in myStyleVarProp.
$command = "pathToShellScript folder1Name folder2Name myStyleVarName myStyleVarProp";
shell_exec($command);
/* shellScript */
#!/bin/bash
file=/var/www/vhosts/mydomain.com/$1/$2/scss/_variables.scss
str=$3"$4"
sed -i "s/^$3.*/$str;/" $file
or if your file isn't too big:
$sample = file_get_contents('sample');
$parsed =preg_replace('##parsethis.*#', 'REPLACE TO END OF LINE', $sample);
You'll have to choose delimiters '#' that aren't present in the file though.
If you want to completely replace the contents of one file with the contents of another file you can use this:
rename("./some_path/data.txt", "./some_path/data_backup.txt");
rename("./some_path/new_data.txt", "./some_path/data.txt");
So in the first line you backup the file and in the second line you replace the file with the contents of a new file.
As far as I can tell the rename returns a boolean. True if the rename is successful and false if it fails. One could, therefore, only run the second step if the first step is successful to prevent overwriting the file unless a backup has been made successfully. Check out:
https://www.php.net/manual/en/function.rename.php
Hope that is useful to someone.
Cheers
Adrian
I'd most likely do what Jeremy suggested, but just for an alternate way to do it here is another solution. This has not been tested or used and is for *nix systems.
$cmd = "grep '#parsethis' " . $filename;
$output = system($cmd, $result);
$lines = explode("\n", $result);
// Read the entire file as a string
// Do a str_repalce for each item in $lines with ""
Quick update: The reason I need this solution is that this one php file is used to expand the flat file for about hundred users (that all use the same php file, but have their own flat files)
SOLUTION:
I worked with this one more day, rephrased the question and got a really great answer. I add it here for future help for others:
$content = file_get_contents("newstest.db");
$content = preg_replace('/(^ID:.*\S)/im', '$1value4:::', $content);
$content = preg_replace('/(^\d+.*\S)/im', '$1:::', $content);
file_put_contents("newstest.db", $content);
The original content of the flat file used when testing the code was:
ID:::value1:::value2:::value3:::
1:::My:::first:::line:::
2:::My:::second:::line:::
3:::Your:::third:::line:::
ORIGINAL QUESTION:
I have a PHP script I am trying to modify. Being a PHP newbie, and have searched both here and on Google without finding a solution, I ask here.
I need to add more values (columns) in the flat file, automatically if the "column" does not exist from before.
Because this one PHP file is shared with many users (each with their own flat file), I need a way to automatically add new "columns" in their flat files if the column does not exist. Doing it manually is very time consuming, and I bet there is an easy way.
INFO:
The flat file is named "newstest.db"
The flat file has this layout:
id:::title:::short:::long:::author:::email:::value1:::value2:::value3:::
So the divider is :::
I understand the basics, that I need to add for instance "value4:::" after "value3:::" in the first line of the news.db, then add ::: to the other existing lines to update all lines and prepare for the new "value4"
Today the php uses this to connect to the flat file:
($filesource is the path to the flat file including it's name. Unique for each user.)
$connect_to_file = connect_pb ($filesource);
And to write to the file I use:
insert_pb($filesource,"$new_id:::$title:::$short:::$long:::$author:::$email:::$value1:::::::::");
(As you see in this case value 2 and 3 is not used in this case, but are in others.)
QUESTION:
Is there a quick/ existing php code to use to add a new column if it doesn't already exist? Or do I need to make the php code for this specific task?
I understand that the code must do something along:
If "value4" does not exist in line 0 in $filesource
then add "value4:::" at the end of line 0,
and for each of the other lines add ":::" at the end.
I don't know where to start, but I have tried for some hours.
I understand this:
update_pb(pathtofiletosaveto,"id","x == (ID of news)","value in first line","value to add");
But I don't know how to make an if statement as in 1) above, neither how to update the line 0 in the flat file to add "value4:::" at the end etc.
MY CODE (does not work as intended):
OR, may be I need to read only line 1 in the file (newstest.db), and then exchange that with a new line if "value4" is not in line 1?
A suggestion, but I don't know how do all:
(It's probably full of errors, as I have tried to read up and find examples and combining code.)
<?php
// specify the file
$file_source="newstest.db";
// get the content of the file
$newscontent = file($file_source, true);
$lines ='';
// handle the content, add "value4:::" and ":::" to the lines
foreach ($newscontent as $line_num => $linehere) {
// add "value4:::" at the end of first line only, and put it in memory
if($line_num[0]) {$lines .= $linehere.'value4:::';}
else {
// then add ":::" to the other lines and add them to memory
$lines .= $linehere.':::';
}
// echo results just to see what is going on
//echo 'Line nr'.$line_num.':<br />'.$lines.'<br /><br />';
}
// add
// to show the result
echo "Here is the result:<br /><br />".$lines."<br /><br />";
//Write new content to $file_source
$f = fopen($file_source, 'w');
fwrite($f,$lines);
fclose($f);
echo "done updating database flat file";
?>
This ALMOST works...
But it does NOT add "value4:::" to the end of the first line,
and it does not add ":::" to the end of the next lines, but to the beginning...
So a couple of questions remains:
1) How can I search in line 0 after "value4", and then write "value4:::" at the end of the line?
2) How can I add ":::" at the end of each line, and not in the beginning?
I kindly ask you to either help me with this.
Do you absolutely have to use PHP for this task? It seems like something you only need to do once, and is much easier to do in a different way.
For example, if you have a *nix shell with sed, sed -i 's/$/:::/' <file> will do that task for you.
Consider:
exec("php gmail-smtp.php >> basic-email-template/debug-mailer.log");
I want to log file messages to start on a new line. But I cannot find relevant information about Bash pipes.
I can't give you the right answer according the way you do it, but just do this:
file_put_contents('basic-email-template/debug-mailer.log', "\n", FILE_APPEND)
The problem could lie inside your log file. I.e., you're using >> correctly.
The single line in the result file could be because your logger gmail-smtp.php is writing log entries as a single line (without a line-break delimiter). Check that first.
I have big sql file, i need to change some lines there, now i have such data in my file
INSERT INTO `LINK_LA_TYP` VALUES
('1','8917181','1','24','2'),
('1','8934610','1','24','1'),
('1','9403766','1','30','1'),
('1','9422299','1','30','2'),
I done that, for example on $count line i write one more
INSERT INTO LINK_LA_TYP VALUES
but then my file looks like this:
INSERT INTO `LINK_LA_TYP` VALUES
('1','8917181','1','24','2'),
('1','8934610','1','24','1'),
('1','9403766','1','30','1'),
INSERT INTO `LINK_LA_TYP` VALUES
('1','9422299','1','30','2'),
But i need that previous line symbol , change to ; How i can do this in big file?
So i need to see file and write there line(done) and then change , to ; on previous line, and do this on every ~500 line (depends on counter) to the end of file
This is the simplest workflow:
Create a temporary file. Then:
Read one line at a time from the original file
Do your work on that line
Write the changed line to the temporary file
Repeat.
When you are done, simply rename the temp file to the correct filename, which will remove the old file.
If each line are going to be the exact same size as before, you may instead change the file inline. You can do this by aligning the file pointer correctly with fseek and then writing. This is a little bit trickier to achieve but may save you the space for the temp file (and possibly be a little bit faster as well). This is only possible if the resulting file size will be exactly the same as the original file size (e.g., if you only change certain bytes from one character to another).
If you read in the file stream (for example via fgets; see example there), you should count the lines and replace the comma with a semicolon on line X; and insert a new line at X + 1. No need to get a previous line.
Took some time to mock this together.
sed -i ':a;N;$!ba;s/,\n INSERT INTO/;\n INSERT INTO/g' your_file.sql
You can put this in exec() if you really want to run it from php script.
Sorry for my bad English.
I must to check 2 csv files, if strings with one id is different, must write to file.
If there is no string with id from 1st file in second file, must write this to file too.
it works, but with element (id=47) i have got a trouble. it into to files, but script sad, that there is only in one.
download script you can from here
http://sil-design.ru/uploads/script.zip
If you do a echo $str1[0].' - '.$str2[0].'<br />'; you will see that the two 47's are never compared. Also I am not sure what the t is in: $f2 = fopen($fileurl, 'rt');.
If you open your backup.csv in notepad and place your cursor after the 47;XL and hold delete to delete anything after it and save. Then try your script again, it should work. It seems that the backup.csv was created in a weird way, I am guessing PHP is getting an EOF before the file has even ended!