ApacheReferenceManual12_PHP教程
UseCanonicalName directive Syntax: UseCanonicalName on|off|dns Default: UseCanonicalName on Context: server config, virtual host, directory Override: Options Compatibility: UseCanonicalName is only available in Apache 1.3 and later In many situations Apache has to construct a self-referential URL. That is, a URL which refers back to the same server. With UseCanonicalName on (and in all versions prior to 1.3) Apache will use the ServerName and Port directives to construct a canonical name for the server. This name is used in all self-referential URLs, and for the values of SERVER_NAME and SERVER_PORT in CGIs. With UseCanonicalName off Apache will form self-referential URLs using the hostname and port supplied by the client if any are supplied (otherwise it will use the canonical name). These values are the same that are used to implement name based virtual hosts, and are available with the same clients. The CGI variables SERVER_NAME and SERVER_PORT will be constructed from the client supplied values as well. An example where this may be useful is on an intranet server where you have users connecting to the machine using short names such as www. Youll notice that if the users type a shortname, and a URL which is a directory, such as http://www/splat, without the trailing slash then Apache will redirect them to http://www.domain.com/splat/. If you have authentication enabled, this will cause the user to have to reauthenticate twice (once for www and once again for www.domain.com). But if UseCanonicalName is set off, then Apache will redirect to http://www/splat/. There is a third option, UseCanonicalName DNS, which is intended for use with mass IP-based virtual hosting to support ancient clients that do not provide a Host: header. With this option Apache does a reverse DNS lookup on the server IP address that the client connected to in order to work out self-referential URLs. Warning: if CGIs make assumptions about the values of SERVER_NAME they may be broken by this option. The client is essentially free to give whatever value they want as a hostname. But if the CGI is only using SERVER_NAME to construct self-referential URLs then it should be just fine. See also: ServerName, Port -------------------------------------------------------------------------------- User directive Syntax: User unix-userid Default: User #-1 Context: server config, virtual host Status: core The User directive sets the userid as which the server will answer requests. In order to use this directive, the standalone server must be run initially as root. Unix-userid is one of: A username Refers to the given user by name. # followed by a user number. Refers to a user by their number. The user should have no privileges which result in it being able to access files which are not intended to be visible to the outside world, and similarly, the user should not be able to execute code which is not meant for httpd requests. It is recommended that you set up a new user and group specifically for running the server. Some admins use user nobody, but this is not always possible or desirable. For example mod_proxys cache, when enabled, must be accessible to this user (see the CacheRoot directive). Notes: If you start the server as a non-root user, it will fail to change to the lesser privileged user, and will instead continue to run as that original user. If you do start the server as root, then it is normal for the parent process to remain running as root. Special note: Use of this directive in

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There are four main error types in PHP: 1.Notice: the slightest, will not interrupt the program, such as accessing undefined variables; 2. Warning: serious than Notice, will not terminate the program, such as containing no files; 3. FatalError: the most serious, will terminate the program, such as calling no function; 4. ParseError: syntax error, will prevent the program from being executed, such as forgetting to add the end tag.

PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.

In PHP, password_hash and password_verify functions should be used to implement secure password hashing, and MD5 or SHA1 should not be used. 1) password_hash generates a hash containing salt values to enhance security. 2) Password_verify verify password and ensure security by comparing hash values. 3) MD5 and SHA1 are vulnerable and lack salt values, and are not suitable for modern password security.

PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.

HTTP request methods include GET, POST, PUT and DELETE, which are used to obtain, submit, update and delete resources respectively. 1. The GET method is used to obtain resources and is suitable for read operations. 2. The POST method is used to submit data and is often used to create new resources. 3. The PUT method is used to update resources and is suitable for complete updates. 4. The DELETE method is used to delete resources and is suitable for deletion operations.

PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7

PHP handles file uploads through the $\_FILES variable. The methods to ensure security include: 1. Check upload errors, 2. Verify file type and size, 3. Prevent file overwriting, 4. Move files to a permanent storage location.

In PHPOOP, self:: refers to the current class, parent:: refers to the parent class, static:: is used for late static binding. 1.self:: is used for static method and constant calls, but does not support late static binding. 2.parent:: is used for subclasses to call parent class methods, and private methods cannot be accessed. 3.static:: supports late static binding, suitable for inheritance and polymorphism, but may affect the readability of the code.
