Home Backend Development PHP Problem What is the usage of php fopen function

What is the usage of php fopen function

Feb 25, 2021 pm 05:02 PM
fopen function php

php Usage of fopen function: [fopen()] function opens a file or URL. If the opening fails, this function returns FALSE, and the syntax is [fopen(filename, mode, include_path, context)].

What is the usage of php fopen function

The operating environment of this tutorial: Windows 7 system, PHP version 5.6, DELL G3 computer. This method is suitable for all brands of computers.

php fopen function usage:

<strong>fopen()</strong> function opens a file or URL.

If the opening fails, this function returns FALSE.

Syntax:

fopen(filename,mode,include_path,context)

What is the usage of php fopen function

Possible values ​​for the mode parameter

What is the usage of php fopen function

Description

fopen() Binds the name resource specified by filename to a stream. If filename is of the form "scheme://...", it is treated as a URL and PHP will search for a protocol handler (also called a wrapper protocol) to handle the scheme. If the wrapper protocol has not been registered for the protocol, PHP will emit a message to help check for potential problems in the script and continue execution of filename as if it were a normal filename.

If PHP thinks that filename specifies a local file, it will try to open a stream on the file. The file must be accessible to PHP, so you need to confirm that the file access permissions allow this access. If safe mode or open_basedir is activated further restrictions apply.

If PHP believes that filename specifies a registered protocol, and the protocol is registered as a network URL, PHP will check and confirm that allow_url_fopen has been activated. If it is closed, PHP will issue a warning and the call to fopen will fail.

Support for context was added in PHP 5.0.0.

Tips and Notes

Note: Different operating system families have different line ending conventions. When writing to a text file and want to insert a new line, you need to use operating system-compliant line endings. Unix-based systems use \n as the line-ending character, Windows-based systems use \r\n as the line-ending character, and Macintosh-based systems use \r as the line-ending character. If files are written with incorrect line endings, other applications may behave strangely when opening the files.

Windows provides a text conversion tag ("t") that can transparently convert \n to \r\n. Alternatively, "b" can be used to force binary mode so that the data is not converted. To use these flags, use either "b" or "t" as the last character of the mode argument.

The default conversion mode depends on the SAPI and PHP version used, so for portability it is encouraged to always specify the appropriate tags. If you are working with plain text files and use \n as the line terminator in your script, but you also want the files to be readable by other applications such as Notepad, use "t" in mode. Use "b" in all other cases.

If you do not specify the "b" flag when operating binary files, you may encounter some strange problems, including corrupted image files and strange problems with \r\n characters.

Note: For portability reasons, it is strongly recommended to always use the "b" flag when opening a file with fopen().

Comments: Once again, for portability reasons, it is strongly recommended that you rewrite code that relies on "t" mode to use the correct line terminator and change it to "b" model.

Example

<?php
$file = fopen("test.txt","r");
$file = fopen("/home/test/test.txt","r");
$file = fopen("/home/test/test.gif","wb");
$file = fopen("http://www.example.com/","r");
$file = fopen("ftp://user:password@example.com/test.txt","w");
?>

Related video recommendations: PHP programming from entry to proficiency

The above is the detailed content of What is the usage of php fopen function. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

A Simple Guide to PHP Setup A Simple Guide to PHP Setup Jul 18, 2025 am 04:25 AM

The key to setting up PHP is to clarify the installation method, configure php.ini, connect to the web server and enable necessary extensions. 1. Install PHP: Use apt for Linux, Homebrew for Mac, and XAMPP recommended for Windows; 2. Configure php.ini: Adjust error reports, upload restrictions, etc. and restart the server; 3. Use web server: Apache uses mod_php, Nginx uses PHP-FPM; 4. Install commonly used extensions: such as mysqli, json, mbstring, etc. to support full functions.

Quick PHP Installation Tutorial Quick PHP Installation Tutorial Jul 18, 2025 am 04:52 AM

ToinstallPHPquickly,useXAMPPonWindowsorHomebrewonmacOS.1.OnWindows,downloadandinstallXAMPP,selectcomponents,startApache,andplacefilesinhtdocs.2.Alternatively,manuallyinstallPHPfromphp.netandsetupaserverlikeApache.3.OnmacOS,installHomebrew,thenrun'bre

Learning PHP: A Beginner's Guide Learning PHP: A Beginner's Guide Jul 18, 2025 am 04:54 AM

TolearnPHPeffectively,startbysettingupalocalserverenvironmentusingtoolslikeXAMPPandacodeeditorlikeVSCode.1)InstallXAMPPforApache,MySQL,andPHP.2)Useacodeeditorforsyntaxsupport.3)TestyoursetupwithasimplePHPfile.Next,learnPHPbasicsincludingvariables,ech

Tips for Writing PHP Comments Tips for Writing PHP Comments Jul 18, 2025 am 04:51 AM

The key to writing PHP comments is to clarify the purpose and specifications. Comments should explain "why" rather than "what was done", avoiding redundancy or too simplicity. 1. Use a unified format, such as docblock (/*/) for class and method descriptions to improve readability and tool compatibility; 2. Emphasize the reasons behind the logic, such as why JS jumps need to be output manually; 3. Add an overview description before complex code, describe the process in steps, and help understand the overall idea; 4. Use TODO and FIXME rationally to mark to-do items and problems to facilitate subsequent tracking and collaboration. Good annotations can reduce communication costs and improve code maintenance efficiency.

Commenting Out Code in PHP Commenting Out Code in PHP Jul 18, 2025 am 04:57 AM

There are three common methods for PHP comment code: 1. Use // or # to block one line of code, and it is recommended to use //; 2. Use /.../ to wrap code blocks with multiple lines, which cannot be nested but can be crossed; 3. Combination skills comments such as using /if(){}/ to control logic blocks, or to improve efficiency with editor shortcut keys, you should pay attention to closing symbols and avoid nesting when using them.

Mastering PHP Block Comments Mastering PHP Block Comments Jul 18, 2025 am 04:35 AM

PHPblockcommentsareusefulforwritingmulti-lineexplanations,temporarilydisablingcode,andgeneratingdocumentation.Theyshouldnotbenestedorleftunclosed.BlockcommentshelpindocumentingfunctionswithPHPDoc,whichtoolslikePhpStormuseforauto-completionanderrorche

Writing Effective PHP Comments Writing Effective PHP Comments Jul 18, 2025 am 04:44 AM

Comments cannot be careless because they want to explain the reasons for the existence of the code rather than the functions, such as compatibility with old interfaces or third-party restrictions, otherwise people who read the code can only rely on guessing. The areas that must be commented include complex conditional judgments, special error handling logic, and temporary bypass restrictions. A more practical way to write comments is to select single-line comments or block comments based on the scene. Use document block comments to explain parameters and return values at the beginning of functions, classes, and files, and keep comments updated. For complex logic, you can add a line to the previous one to summarize the overall intention. At the same time, do not use comments to seal code, but use version control tools.

Improving Readability with Comments Improving Readability with Comments Jul 18, 2025 am 04:46 AM

The key to writing good comments is to explain "why" rather than just "what was done" to improve the readability of the code. 1. Comments should explain logical reasons, such as considerations behind value selection or processing; 2. Use paragraph annotations for complex logic to summarize the overall idea of functions or algorithms; 3. Regularly maintain comments to ensure consistency with the code, avoid misleading, and delete outdated content if necessary; 4. Synchronously check comments when reviewing the code, and record public logic through documents to reduce the burden of code comments.

See all articles