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  • What are functions in PHP, and how do I define them?
    What are functions in PHP, and how do I define them?
    PHP functions are blocks of code that perform specific tasks and can be reused in scripts. They are defined by the function keyword, including function names, parameters and code blocks. When creating a function, you need to use the function keyword, name the function, define parameters (optional), and write logical code. For example, functiongreet($name){echo"Hello,$name!";}, call greet("Alice") to output "Hello,Alice!". Function names are case-insensitive, but are recommended to maintain consistency. Functions can have zero or more parameters and pass a return statement
    PHP Tutorial . Backend Development 446 2025-06-21 00:40:01
  • How do I use HTTP methods (GET, POST, PUT, DELETE) in PHP?
    How do I use HTTP methods (GET, POST, PUT, DELETE) in PHP?
    The method of judging and processing HTTP requests in PHP can be implemented through $_SERVER['REQUEST_METHOD']. The specific steps are as follows: 1. Use $method=$_SERVER['REQUEST_METHOD'] to obtain the current request method; 2. Use if/elseif to judge GET, POST, PUT or DELETE requests and process them separately; 3. The GET data obtains URL query parameters through $_GET, and the POST data obtains the form submission content through $_POST; 4. PUT and DELETE requests need to read data from the php://input input stream, and you can use parse_str() or json_d
    PHP Tutorial . Backend Development 477 2025-06-21 00:37:10
  • How do I delete data from a database using PHP?
    How do I delete data from a database using PHP?
    TodeletedatafromadatabaseusingPHP,usetheSQLDELETEstatementwithsecurePHPdatabasehandling.1.SetupasecureconnectionusingPDOorMySQLi;PDOispreferredforflexibilityandsupportspreparedstatements.2.ConstructaDELETEquery,ideallyusingplaceholderstosafelyhandleu
    PHP Tutorial . Backend Development 170 2025-06-21 00:27:51
  • How do I secure PHP applications against common web vulnerabilities?
    How do I secure PHP applications against common web vulnerabilities?
    PHP application security can be improved through five key measures. 1. Use preprocessing statements to prevent SQL injection, such as PDO or MySQLi; 2. Verify and filter user input, such as filter_var and htmlspecialchars; 3. Implement CSRF token protection and verify form requests; 4. Secure management sessions, including ID regeneration and secure cookie parameters; 5. Force HTTPS and set HTTP security headers, such as Content-Security-Policy and X-Frame-Options, to comprehensively enhance application protection capabilities.
    PHP Tutorial . Backend Development 833 2025-06-21 00:27:01
  • How do I use version control systems (e.g., Git) to manage PHP code?
    How do I use version control systems (e.g., Git) to manage PHP code?
    UsingGitforPHPprojectsisessentialfortrackingchanges,collaboration,androllbackcapabilities.1.StartbyconfiguringGitgloballywithyourusernameandemailandinitializingtherepositoryearly.2.Usea.gitignorefiletoexcludeunnecessaryfileslikevendor/,.env,andlogs,a
    PHP Tutorial . Backend Development 737 2025-06-21 00:03:30
  • What are default argument values in PHP functions?
    What are default argument values in PHP functions?
    PHP allows setting default values ??for function parameters, making functions more flexible and easy to use. When defining a function, you can set the default value by using the = operator assigning a value, such as functiongreet($name="Guest"). If the parameter is not passed during the call, the default value will be automatically used. It can also be used in multiple parameters, and the default parameters should be placed after the required parameters. The default value must be a constant expression (PHP8.1 can use callable), or null can be used to represent dynamic processing or skip parameters. This feature simplifies the code structure, reduces redundant functions, and improves backward compatibility.
    PHP Tutorial . Backend Development 808 2025-06-20 08:29:10
  • How do I use Xdebug to set breakpoints and step through code?
    How do I use Xdebug to set breakpoints and step through code?
    TouseXdebugfordebuggingPHPcode,firstinstallandenableitbycheckingphp.inisettingslikezend_extension=xdebug.so,xdebug.mode=debug,andensuringyourIDElistensfordebugconnections.Next,setbreakpointseitherinyourIDEbyclickingthegutterorusingxdebug_break()incod
    PHP Tutorial . Backend Development 493 2025-06-20 08:21:10
  • What are strings in PHP, and how do I manipulate them?
    What are strings in PHP, and how do I manipulate them?
    InPHP,stringsarecreatedusingsingleordoublequotes,withvariableparsingonlyoccurringindoublequotes.1.Useechotoprintstrings.2.Manipulatestringswithconcatenation(.),strlen(),substr(),andstr_replace().3.Cleanandformatstringsusingtrim(),strtolower()/strtoup
    PHP Tutorial . Backend Development 903 2025-06-20 08:13:10
  • How do I use the $_FILES superglobal to access uploaded file information?
    How do I use the $_FILES superglobal to access uploaded file information?
    To effectively handle file uploads in PHP, you need to perform the following steps in turn: First, check whether the file is uploaded successfully, and determine whether $_FILES['fileToUpload']['error'] is equal to UPLOAD_ERR_OK; second, understand the file information contained in the $_FILES array, such as name, type, tmp_name, error and size; then, use the move_uploaded_file() function to move the file from the temporary path to the specified directory, and ensure that the target directory is writable and the file name is safe; finally, if you need to support multiple file uploads, you should set the name attribute to an array form in HTML, and traverse each process in PHP.
    PHP Tutorial . Backend Development 208 2025-06-20 01:07:01
  • How do I destroy a session in PHP using session_destroy()?
    How do I destroy a session in PHP using session_destroy()?
    To completely destroy a session in PHP, you must first call session_start() to start the session, and then call session_destroy() to delete all session data. 1. First use session_start() to ensure that the session has started; 2. Then call session_destroy() to clear the session data; 3. Optional but recommended: manually unset$_SESSION array to clear global variables; 4. At the same time, delete session cookies to prevent the user from retaining the session state; 5. Finally, pay attention to redirecting the user after destruction, and avoid reusing the session variables immediately, otherwise the session needs to be restarted. Doing this will ensure that the user completely exits the system without leaving any residual information.
    PHP Tutorial . Backend Development 329 2025-06-20 01:06:21
  • How do I access form data submitted via POST using the $_POST superglobal?
    How do I access form data submitted via POST using the $_POST superglobal?
    To obtain form data through $_POST in PHP, you must ensure that the field name matches, check the submission method and pay attention to safe processing. Use the $_POST hyperglobal variable to directly obtain the corresponding value based on the name attribute of the form field; 1. Ensure that the key name in the PHP code is consistent with the name attribute of the HTML form; 2. Use $_SERVER['REQUEST_METHOD'] or isset function to determine whether the data has been submitted; 3. Use functions such as htmlspecialchars or filter_input to filter and verify user input to prevent security risks; 4. For array data such as check boxes, the HTML field name should be written in hobbies[] format for PHP to correct
    PHP Tutorial . Backend Development 918 2025-06-20 01:05:20
  • How do I use the set_error_handler() function to define a custom error handler?
    How do I use the set_error_handler() function to define a custom error handler?
    set_error_handler() is used in PHP for custom error handling and can catch non-fatal errors such as E_WARNING, E_NOTICE, etc., but cannot handle fatal errors such as E_ERROR. 1. Its functions include replacing default error handling, formatting messages, logging and blocking production environment specific errors; 2. Custom functions must receive at least error level and message parameters, and can prevent the execution of the built-in processor by returning true; 3. Fatal errors such as E_ERROR and E_PARSE are not captured by default, and they need to be processed in combination with register_shutdown_function() and error_get_last(); 4. Practical recommendations include logs
    PHP Tutorial . Backend Development 745 2025-06-20 01:05:00
  • What are nullable types in PHP 7.1?
    What are nullable types in PHP 7.1?
    PHP7.1 introduces nullable types to improve type safety and code clarity. 1. Usage method: add a question mark (?) before the type, such as ?string means returning a string or null; 2. Parameters are also applicable, such as ?int means integer or null; 3. The advantage is to make it clear that null is a legal value to reduce runtime errors; 4. Pay attention to avoid abuse, keeping the return type consistent, and can be used in PHP8.0 in combination with joint types. The nullable type is suitable for scenarios such as API, optional fields or database results, making the code more concise and safe.
    PHP Tutorial . Backend Development 411 2025-06-20 01:04:40
  • How do I upload files to a server using PHP?
    How do I upload files to a server using PHP?
    TouploadfilesusingPHP,createanHTMLformwithmethod="post"andenctype="multipart/form-data",thenhandletheuploadsecurelyinPHP.1.CreateanHTMLformwithanelementpointingtothePHPscript.2.Inupload.php,usemove\_uploaded\_file()tomovethefileaf
    PHP Tutorial . Backend Development 994 2025-06-20 01:03:51

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