Trin Ffeiliau yn PHP

Sesiynau a chwcis yn PHP

Because it allows you to read, write, and change files on the server, file management in PHP is a critical part of web development. In this post, we will go over the fundamentals of file handling in PHP as well as the most often used file-handling methods.

Opening and Closing Files

PHP has various file-related functions, including fopen(), fread(), fwrite(), and fclose() (). The fopen() function is used to open a file and accepts two parameters: the file name and the mode in which the file should be opened. The most prevalent modes of operation are “r” for reading and “w” for writing.

Once a file is open, you can use the fread() function to read its contents and the fwrite() function to write to it. The fread() function takes two parameters: the file handle and the number of bytes to read, whereas the fwrite() function takes three: the file handle, the data to be written, and the number of bytes to write.

When you have finished working with a file, use the fclose() function to close it. As an input, this function only accepts the file handle.

Additional File Handling Functions in PHP

In addition to these fundamental file handling procedures, PHP includes various more file-related functions, such as file get contents(), file put contents(), and file exists() (). These functions make it easier to read, write, and check the presence of files in PHP.

Importance of File Permissions in PHP

It is crucial to note that while working with files, it is critical to ensure that the necessary caniatadau are established to prevent illegal mynediad neu newid.

file_exists ()

When working with files, errors and warnings are common. It is possible that the provided file does not bodoli. This may result in problems or warnings. To avoid such problems and rhybuddion, defnyddiwch y file_exists() function before using fopen() to determine whether or not the file exists.

<?php

// check if the file exists

if (file_exists("demo.txt"))
{
  // open the file in read mode
  $file = fopen("demo.txt","r");
  // close the file
  fclose($file);
} else {
    echo "file does not exist";
}

?>

Yn y cod uchod, mae'r file_exists () defnyddir swyddogaeth gyda'r datganiad os i wirio a yw “demo.txt” yn bodoli ai peidio. 

fread ()

A file can be rather large in size. As a result, we may select to read only a portion of a file rather than the entire file. We have the fread() method for situations like these. It permits us to read only ten characters, for example.

Mae practis meddygol fread () swyddogaeth yn gofyn am ddau baramedr - ffeil a hyd mewn beit.

<?php

// check if the file exists

if (file_exists("demo.txt"))
{
  // open the file in read mode
  $file = fopen("demo.txt","r");
  // use fread() function
  $data = fread($file, "10");
  echo $data

  // close the file
  fclose($file);
} else {
    echo "file does not exist";
}
?>

Yn y cod uchod, mae'r fread () defnyddir swyddogaeth i ddarllen 10 beit o'r ffeil “demo.txt”. 

fwrite ()

Mae practis meddygol fwrite () defnyddir swyddogaeth i ysgrifennu data mewn ffeil. Mae angen dau baramedr - ffeil a llinyn.

<?php
//checking the existence of the file

if(file_exists("demo.txt"))
{
  //opening the file in “w” mode
  $file = fopen("demo.txt", "w");
   fwrite($file, "This is a string");
}
else{
  echo "file does not exist";
}
?>

Mae dau senario yn y cod uchod. 

  • Os nad yw “demo.txt” yn bodoli mae'r fwrite () Bydd y swyddogaeth yn creu ffeil newydd a bydd yn allbwn “This is a string”. 
  • Os oes “demo.txt” yn bodoli, bydd y fwrite () bydd swyddogaeth yn trosysgrifo cynnwys y ffeil.
    Nodyn: Rhag ofn eich bod am atodi (ychwanegu) i'r cynnwys gallwch ddefnyddio'r modd “a” yn lle'r modd “w”.

math ffeil()

PHP includes the math ffeil() method for determining the file type. The filetype() method can dychwelyd the values listed below.

dolen gyswllt ()

Mae practis meddygol dolen gyswllt () function is used to delete a file or directory. If the file or directory is destroyed, it returns true; otherwise, it returns false.



<?php
//check if the file exists
if(file_exists("demo.txt")) {
  //use unlink() function to delete demo.txt
  if(unlink("demo.text")){
    echo "file deleted";
  }
  else {
    echo "error while trying to delete the file";
  }
  else {
    echo "the file doesn't exist";
  }
}
?>

Yn y cod uchod, mae'r dolen gyswllt () swyddogaeth yn cael ei ddefnyddio i ddileu "demo.txt".

Holi ac Ateb

Q: What is file handling in PHP?
A: File handling in PHP is the process of reading, writing, and manipulating files on a server using built-in PHP functions. This allows developers to easily access and manipulate files as needed for their web applications.

Q: What are some of the most commonly used functions for file handling in PHP?
A: Some of the most commonly used functions for file handling in PHP include fopen(), fread(), fwrite(), and fclose(). These functions allow you to open, read, write, and close files, respectively.

Q: What is the purpose of the fopen() function in PHP?
A: The fopen() function in PHP is used to open a file. It takes two parameters: the name of the file and the mode in which you want to open the file. The most commonly used modes are “r” for reading and “w” for writing.

Q: What is the purpose of the fread() function in PHP?
A: The fread() function in PHP is used to read the contents of an open file. It takes two parameters: the file handle and the number of bytes you want to read.

Q: What is the purpose of the fwrite() function in PHP?
A: The fwrite() function in PHP is used to write data to an open file. It takes three parameters: the file handle, the data you want to write, and the number of bytes you want to write.

Q: What is the purpose of the fclose() function in PHP?
A: The fclose() function in PHP is used to close an open file. It takes the file handle as its only parameter.

Q: What are some other file handling functions provided by PHP?
A: Some other file handling functions provided by PHP include file_get_contents(), file_put_contents(), and file_exists(). These functions provide a more convenient way to read, write and check the existence of a file in PHP.

Q: Why is it important to ensure that files have the correct permissions set when working with them in PHP?
A: Ensuring that files have the correct permissions set is important because it prevents unauthorized access or modifications to the files. If the permissions are not set correctly, it could result in security vulnerabilities in your web application.

Ymarferion:

  1. How do you open a file in PHP?
  2. How do you read the contents of a file in PHP?
  3. How do you write to a file in PHP?
  4. How do you append to a file in PHP?
  5. How do you close a file in PHP?
  6. How do you delete a file in PHP?
  7. How do you check if a file exists in PHP?
  8. How do you get the size of a file in PHP?

Atebion:

  1. A file can be opened in PHP using the fopen() function. For example: $file = fopen(“example.txt”, “r”);
  2. The contents of a file can be read in PHP using the fread() or fgets() function. For example: $contents = fread($file, filesize(“example.txt”));
  3. Data can be written to a file in PHP using the fwrite() function. For example: fwrite($file, “Hello World!”);
  4. Data can be appended to a file in PHP by opening the file with the “a” flag. For example: $file = fopen(“example.txt”, “a”);
  5. A file can be closed in PHP using the fclose() function. For example: fclose($file);
  6. A file can be deleted in PHP using the unlink() function. For example: unlink(“example.txt”);
  7. A file can be checked if it exists in PHP using the file_exists() function. For example: file_exists(“example.txt”);
  8. The size of a file can be obtained in PHP using the filesize() function. For example: filesize(“example.txt”);

Crynodeb

  • Mae practis meddygol fopen () swyddogaeth yn cael ei ddefnyddio i agor ffeil. 
  • Mae yna wahanol ddulliau i agor ffeil gan ddefnyddio'r fopen () swyddogaeth.
  • Mae practis meddygol fclose () swyddogaeth yn cael ei ddefnyddio i gau ffeil.
  • Mae PHP yn darparu sawl swyddogaeth fewnol i weithio gyda ffeiliau.
  • Mae rhai o'r swyddogaethau mewnol a ddefnyddir yn gyffredin yn file_exists (), fread (), fwrite (), math ffeil(), a datgysylltu().

Casgliad

Finally, PHP file handling is a strong tool for interacting with files on the server. You may quickly read, write, and modify files and add new functionality to your web applications by utilizing PHP’s built-in functions and methods.

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Sesiynau a chwcis yn PHP
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