PHP - tutorial - 10 - network functions

revision:

Network functions let you manipulate information sent to the browser by the Web server.

checkdnsrr() - checks DNS records for type corresponding to host.

Syntax: checkdnsrr(host, type)

Parameter values:

host : required. Specifies an IP address or host name to check.

type : optional. Specifies the type. Can be one of the following: A, MX (default), NS, SOA, PTR, CNAME, AAAA, A6, SRV, NAPTR,TXT, ANY

example: check DNS records

Passed
code: 
                <?php
                    $domain="w3schools.com";
                    if(checkdnsrr($domain,"MX")) {
                    echo "Passed";
                    } else {
                    echo "Failed";
                    }
                ?>

closelog() - closes the connection of system logger.

Syntax: closelog()

example:

code: 
                <?php
                    function _log($text) {
                        openlog("phperrors", LOG_PID | LOG_PERROR);
                        syslog(LOG_ERR, $text);
                        closelog();
                        
                    }
                ?>

define_syslog_variables() - deprecated and removed in PHP 5.4. Initializes the variables used in syslog functions.

deprecated and removed in PHP 5.4

dns_check_record() - alias of checkdnsrr().

Syntax: dns_check_record(host, type)

Parameter values:

host : required. Specifies an IP address or host name to check.

type : optional. Specifies the type. Can be one of the following: A, MX (default), NS, SOA, PTR, CNAME, AAAA, A6, SRV, NAPTR,TXT, ANY

example:

Passed
code: 
                <?php
                    $domain="w3schools.com";
                    if(dns_check_record($domain,"MX")) {
                    echo "Passed";
                    } else {
                    echo "Failed";
                    }
                ?>

dns_get_mx() - alias of getmxrr().

Syntax: dns_get_mx(host, mxhosts, weight)

Parameter values:

host : required. Specifies the host name

mxhosts : required. An array that specifies a list of MX records found

weight : optional. An array that specifies the weight information gathered

example:

0 => alt1.aspmx.l.google.com
1 => alt2.aspmx.l.google.com
2 => aspmx.l.google.com
3 => alt3.aspmx.l.google.com
4 => alt4.aspmx.l.google.com
5 => feedback-smtp.eu-west-1.amazonses.com
code: 
                <?php
                    $domain="w3schools.com";
                    if(dns_get_mx($domain,$mx_details)){
                        foreach($mx_details as $key=>$value){
                            echo "$key => $value <br>";
                        }
                    }
                ?>

dns_get_record() - gets the DNS resource records associated with the specified hostname.

Syntax: dns_get_record(hostname, type, authns, addtl, raw)

Parameter values:

hostname : required. Specifies a hostname (like "www.w3schools.com")

type : optional. Specifies the resource record type to search for. Can be one of the following: DNS_A, DNS_CNAME, DNS_HINFO,DNS_CAA, DNS_MX, DNS_NS, DNS_PTR, DNS_SOA, DNS_TXT, DNS_AAAA, DNS_SRV, DNS_NAPTR, DNS_A6, DNS_ALL, DNS_ANY (default)

authns : optional. Passed by reference and, if set, it will be populated with Resource Records for the Authoritative Name Servers

addtl : optional. Passed by reference and, if set, it will be populated with any Additional Records

: optional. A Boolean value. If set to TRUE, it queries only the requested type instead of looping type-by-type before getting the info stuff. Default is FALSE

example:

Array ( [0] => Array ( [host] => w3schools.com [class] => IN [ttl] => 60 [type] => MX [pri] => 10 [target] => alt4.aspmx.l.google.com ) [1] => Array ( [host] => w3schools.com [class] => IN [ttl] => 60 [type] => MX [pri] => 10 [target] => feedback-smtp.eu-west-1.amazonses.com ) [2] => Array ( [host] => w3schools.com [class] => IN [ttl] => 60 [type] => MX [pri] => 5 [target] => alt1.aspmx.l.google.com ) [3] => Array ( [host] => w3schools.com [class] => IN [ttl] => 60 [type] => MX [pri] => 5 [target] => alt2.aspmx.l.google.com ) [4] => Array ( [host] => w3schools.com [class] => IN [ttl] => 60 [type] => MX [pri] => 1 [target] => aspmx.l.google.com ) [5] => Array ( [host] => w3schools.com [class] => IN [ttl] => 60 [type] => MX [pri] => 10 [target] => alt3.aspmx.l.google.com ) )
code: 
                <?php
                    print_r(dns_get_record("w3schools.com", DNS_MX));
                ?>

fsockopen() - opens an Internet or Unix domain socket connection.

Syntax: fsockopen(hostname, port, errno, errstr, timeout)

Parameter values:

hostname : required. Specifies a hostname (like "www.w3schools.com"). ssl:// or tls:// works over TCP/IP to connect to the remote host

port : optional. Specifies the port number. Use -1 for transports that do not use ports, like unix://

errno : optional. Specifies the system level error number

errstr : optional. Specifies the error message as a string

timeout : optional. Specifies the connection timeout (in seconds)

example:

HTTP/1.1 409 Conflict Date: Sat, 18 Jan 2025 05:12:01 GMT Content-Type: text/plain; charset=UTF-8 Content-Length: 16 Connection: close X-Frame-Options: SAMEORIGIN Referrer-Policy: same-origin Cache-Control: private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Expires: Thu, 01 Jan 1970 00:00:01 GMT Server: cloudflare CF-RAY: 903c1670edded5db-DFW error code: 1001
code: 
                <?php
                    $fp = fsockopen("www.lwitters.com", 80, $errno, $errstr, 20);
                    if (!$fp) {
                        echo "$errstr ($errno)<br>";
                    } else {
                        $out = "GET / HTTP/1.1\r\n";
                        $out .= "Host: www.w3schools.com\r\n";
                        $out .= "Connection: Close\r\n\r\n";
                        fwrite($fp, $out);
                        while (!feof($fp)) {
                            echo fgets($fp, 128);
                        }
                        fclose($fp);
                    }
                ?>

gethostbyaddr() - returns the domain name for a given IP address.

Syntax: gethostbyaddr(ipaddress)

Parameter values:

ipaddress : required. Specifies an IP address

example:

web-dal.anuson.com
code: 
                <?php
                    $host = gethostbyaddr($_SERVER["REMOTE_ADDR"]);
                    echo $host;
                ?>

gethostbyname() - returns the IPv4 address for a given domain/host name.

Syntax: gethostbyname(hostname)

Parameter values:

hostname : required. Specifies a hostname (like "www.w3schools.com")

example:

23.47.48.43
code: 
                <?php
                    $ip = gethostbyname("www.w3schools.com");
                    echo $ip;
                ?>

gethostbynamel() - returns a list of IPv4 address for a given domain/host name.

Syntax: gethostbynamel(hostname)

Parameter values:

hostname : required. Specifies a hostname (like "www.w3schools.com")

example:

Array ( [0] => 23.47.48.58 [1] => 23.47.48.43 )
code: 
                <?php
                    $hostlist = gethostbynamel("www.w3schools.com");
                    print_r($hostlist);
                ?>

gethostname() - returns the host name.

Syntax: gethostname()

example:

web-dal.anuson.com
code: 
                <?php
                    echo gethostname(); 
                ?>

getmxrr() - returns the MX records for the specified internet host name.

Syntax: getmxrr(host, mxhosts, weight)

Parameter values:

host : required. Specifies the host name

mxhosts : required. An array that specifies a list of MX records found

weight : otional. An array that specifies the weight information gathered

example:

0 => alt4.aspmx.l.google.com
1 => feedback-smtp.eu-west-1.amazonses.com
2 => alt1.aspmx.l.google.com
3 => alt2.aspmx.l.google.com
4 => aspmx.l.google.com
5 => alt3.aspmx.l.google.com
code: 
                <?php
                    $domain="w3schools.com";
                    if(getmxrr($domain,$mx_details)){
                    foreach($mx_details as $key=>$value){
                        echo "$key => $value <br>";
                    }
                    }
                ?>

getprotobyname() - returns the protocol number for a given protocol name.

Syntax: getprotobyname(protocolname)

Parameter values:

protocolname : required. Specifies a protocol name (like "tcp")

example:

6
code: 
                <?php
                    $protocolnum = getprotobyname("tcp");
                    echo $protocolnum;
                ?>

getprotobynumber() - returns the protocol name for a given protocol number.

Syntax: getprotobynumber(protocolnumber)

Parameter values:

protocolnumber : required. Specifies a protocol number (like 17)

example:

tcp
code: 
                <?php
                    $protocolname = getprotobynumber(6);
                    echo $protocolname;
                ?>

getservbyname() - returns the port number for a given Internet service and protocol.

Syntax: getservbyname(service, protocol)

Parameter values:

service : required. Specifies the Internet service name (like "http")

protocol : required. Specifies a protocol name (like "tcp" or "udp")

example:

80
code: 
                <?php
                    $portnum = getservbyname("http", "tcp");
                    echo $portnum;
                ?>

getservbyport() - returns the Internet service for a given port and protocol.

Syntax: getservbyport(port, protocol)

Parameter values:

port : required. Specifies the port number (like 80)

protocol : required. Specifies a protocol name (like "tcp" or "udp")

example:

http
code: 
                <?php
                    $intservname = getservbyport(80, "tcp");
                    echo $intservname;
                ?>

header_register_callback() - calls a header function.

Syntax: header_register_callback(callback)

Parameter values:

callback : required. Specifies a callback function

example:

header_remove() - removes an HTTP header previously set with the header() function.

Syntax: header_remove(headername)

Parameter values:

headername : optional. Specifies a header name to be removed. If omitted, all previously set headers are removed

example:

code: 
                <?php
                    header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
                    header("Cache-Control: no-cache");
                    header("Pragma: no-cache");

                    header_remove("Pragma");
                ?>

header() - sends a raw HTTP header to a client.

Syntax: header(header, replace, http_response_code)

Parameter values:

header : required. Specifies the header string to send

replace : optional. Indicates whether the header should replace a previous similar header or add a new header of the same type. Default is TRUE (will replace). FALSE allows multiple headers of the same type

http_response_code : optional. Forces the HTTP response code to the specified value

It is important to notice that the header() function must be called before any actual output is sent!

example:

code: 
                <?php
                    // Date in the past
                    header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
                    header("Cache-Control: no-cache");
                    header("Pragma: no-cache");
                ?>

headers_list() - returns a list of response headers to be sent to the browser.

example:

code: 
                <?php
                    setcookie("TestCookie","SomeValue");
                    header("X-Sample-Test: foo");
                    header("Content-type: text/plain");
                ?>
                <?php
                    var_dump(headers_list());
                ?>

headers_sent() - checks if/where headers have been sent.

Syntax: headers_sent(file,line)

Parameter values:

file : optional. If the file and line parameters are set, headers_sent() will put the PHP source file name and line number where output started in the file and line variables

line : optional. Specifies the line number where the output started

example:

code: 
                <?php
                    if (!headers_sent()) {
                        header("Location: https://www.w3schools.com/");
                        exit;
                    }   
                ?>

http_response_code() - sets or returns the HTTP response status code.

Syntax: http_response_code(code)

Parameter values:

code : optional. Specifies a response code (like 404)

example:

code: 
                <?php
                    http_response_code(404);
                ?>

inet_ntop() - converts a 32bit IPv4 or 128bit IPv6 address into a readable format.

Syntax: inet_ntop(address)

Parameter values:

address : required. Specifies a 32bit IPv4 or 128bit IPv6 address

example:

127.0.1.1
code: 
                <?php
                    $addr = chr(127) . chr(0) . chr(1) . chr(1);
                    $exp = inet_ntop($addr);
                    echo $exp; 
                ?>

inet_pton() - converts a readable IP address into a packed 32bit IPv4 or 128bit IPv6 format.

Syntax: inet_pton(address)

Parameter values:

address : required. Specifies a readable IP address

example:


code: 
                <?php
                    $addr = inet_pton("127.0.1.1");
                    echo $addr;
                ?>

ip2long() - converts an IPv4 address into a long integer.

Syntax: ip2long(address)

Parameter values:

address : required. Specifies a readable IP address

example:

The following URLs are equivalent:
https://www.w3schools.com/, https://23.47.48.43/, and https://388968491/
code: 
                <?php
                    $ip = gethostbyname("www.w3schools.com");
                    $out = "The following URLs are equivalent:<br>";
                    $out .= "https://www.w3schools.com/, https://" . $ip . "/, and https://" . sprintf("%u", ip2long($ip)) . "/";
                    echo $out;
                ?>

long2ip() - converts a long integer address into a string in IPv4 format.

Syntax: long2ip(address)

Parameter values:

address : required. Specifies a long integer that represents an IP address

example:

41.148.72.0
code: 
                <?php
                    echo(long2ip(344294967296));
                ?>

openlog() - opens the connection of system logger.

Syntax: openlog(ident, option, facility)

Parameter values:

ident : required. Specifies a string ident that is added to each message

option : required. Specifies what logging options will be used when generating a log message. Can be one or more of the following options (separated with |): LOG_CONS, LOG_NDELAY, LOG_ODELAY, LOG_PERROR, LOG_PID

facility : required. Specifies what type of program is logging the message:LOG_AUTH, LOG_AUTHPRIV, LOG_CRON, LOG_DAEMON, LOG_KERN, LOG_LOCAL0...LOG_LOCAL7, LOG_LPR, LOG_MAIL, LOG_NEWS, LOG_SYSLOG, LOG_USER - (is the only valid log type for Windows OS), LOG_UUCP

example:

code: 
                <?php
                    function _log($text) {
                        openlog("phperrors", LOG_PID | LOG_PERROR);
                        syslog(LOG_ERR, $text);
                        closelog();
                    }
                ?>

pfsockopen() - opens a persistent Internet or Unix domain socket connection.

Syntax: pfsockopen(hostname, port, errno, errstr, timeout)

Parameter values:

hostname : required. Specifies a hostname (like "www.w3schools.com"). ssl:// or tls:// works over TCP/IP to connect to the remote host

port : optional. Specifies the port number. Use -1 for transports that do not use ports, like unix://

errno : optional. Specifies the system level error number

errstr : optional. Specifies the error message as a string

timeout : optional. Specifies the connection timeout (in seconds)

example:

HTTP/1.1 200 OK Date: Sat, 18 Jan 2025 05:12:01 GMT Content-Type: text/html; charset=UTF-8 Transfer-Encoding: chunked Connection: close Vary: Accept-Encoding cf-cache-status: DYNAMIC Report-To: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v4?s=TR4hBvfJaLlEKP2MZnmK5S56HFjlhsFpMT3KNQ8Bjq4lQ8m21A0J%2FDj9ZsnFvqm%2BSKj5%2F9%2FgHViK48OrKYILyT5GaXmB5AQgrhRFs7cHr6y2tq%2FbBtV%2BQYnjCp4x1DH38FOZGLpdH4FSfzuiz%2F8g"}],"group":"cf-nel","max_age":604800} NEL: {"success_fraction":0,"report_to":"cf-nel","max_age":604800} Server: cloudflare CF-RAY: 903c16722f6c4612-DFW alt-svc: h3=":443"; ma=86400 server-timing: cfL4;desc="?proto=TCP&rtt=2862&min_rtt=2862&rtt_var=1431&sent=1&recv=3&lost=0&retrans=0&sent_bytes=0&recv_bytes=61&delivery_rate=0&cwnd=249&unsent_bytes=0&cid=0000000000000000&ts=0&x=0" 7248 a picture is worth a 1000 words

"A picture is worth a thousand words"

"Een beeld zegt meer dan duizend woorden"

"一幅画值千言万语"

is an English language adage meaning that complex and sometimes multiple ideas can be conveyed by a single "still image", which expresses its meaning or essence more effectively than a mere verbal description. Norwegian playwright Henrik Ibsen first said: "a thousand words leave not the same deep impression as does a single deed." After his death in 1906 this quote was plagiarized and para-phrased into what we know now.
What concerns this website, this means that the focus will be more on visuals and less on words.

Karl Lagerfeld:“What I like about photographs is that they capture a moment that's gone forever, impossible to reproduce.”

Abraham Lincoln:“There are no bad pictures; that is just how your face looks sometimes.”

Lewis Hine: "If I could tell the story in words, I wouldn't need to lug around a camera."

Susan Sontag: "The painter constructs, the photographer discloses."

P.S. mouse over the pictures here below to go to webpages.

Photography

Antwerpen

Photography is the art of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. Many fields of science, manufacturing and business use photography for research, product development and product promotion, amongst others. It is also more directly used for art, film and video production, recreational purposes, hobby, and mass communication.

Artificial intelligence (AI) image generation is one of the most dramatic developments the creative fields have seen for some time, and 2022 was the year that it truly exploded. In a space of a few months, a new technology seemed to appear out of nowhere and evolve at lightning speed, allowing anyone to create an image of practically anything they want merely by typing a description.

Countries

Bali island

A collection of photos of the countries that were visited during travels and trips.

cameras
China - Beijing

A collection of photos from various provinces and cities in China.

cameras
Shanghai

A collection of photos from different districts and areas in Shanghai.

cameras

Food & dishes

Spanish rice

Photos of menus, dishes, and specialties.

cameras
flower

Pictures of flowers and plants planted at home.

cameras

A series of photos related to social, political and striking events.

cameras

Short video clips created to keep memories alive.

cameras

Coding

Coding picture

Documents, examples, and texts related to web development and related techniques.

Digital art

dig_art picture

Techniques to make digital art as well as a number of trials.

Streetart has transformed the urban landscape into a vibrant tapestry of expression and dialogue. Once considered a form of vandalism, it has evolved into a legitimate and powerful art form, resonating deeply with culture and identity. Graffiti, the early precursor to streetart, etched its marks on city walls as an act of visibility, a claim to existence in a rapidly changing urban reality. These visual declarations ranged from personal taggings to elaborate pieces, setting the stage for an urban art revolution.
The essence of street art lies in its ability to converse with the public without the barriers of traditional art venues. It invites passersby to pause and reflect, engaging with themes of social commentary and giving a voice to the voiceless. This art is often temporary, weathering over time or being covered by new layers of paint, adding to its transient beauty and immediacy.

If you would like to let us know your comments regarding this website, please send us an email.
Louis Witters - Belgium (Antwerp) - China (Shanghai)
📧:[email protected] ,📧: [email protected]
number of pictures in this page:
0
code: 
                <?php
                    $fp = pfsockopen("www.lwitters.com", 80, $errno, $errstr, 20);
                    if (!$fp) {
                        echo "$errstr ($errno)<br>";
                    } else {
                        $out = "GET / HTTP/1.1\r\n";
                        $out .= "Host: www.lwitters.com\r\n";
                        $out .= "Connection: Close\r\n\r\n";
                        fwrite($fp, $out);
                        while (!feof($fp)) {
                        echo fgets($fp, 128);
                        }
                        fclose($fp);
                    } 
                ?>

setcookie() - defines a cookie to be sent along with the rest of the HTTP headers.

Syntax: setcookie(name, value, expire, path, domain, secure, httponly);

Parameter values:

name : required. Specifies the name of the cookie

value : optional. Specifies the value of the cookie

expire : optional. Specifies when the cookie expires. The value: time()+86400*30, will set the cookie to expire in 30 days. If this parameter is omitted or set to 0, the cookie will expire at the end of the session (when the browser closes). Default is 0

path : optional. Specifies the server path of the cookie. If set to "/", the cookie will be available within the entire domain. If set to "/php/", the cookie will only be available within the php directory and all sub-directories of php. The default value is the current directory that the cookie is being set in

domain : optional. Specifies the domain name of the cookie. To make the cookie available on all subdomains of example.com, set domain to "example.com". Setting it to www.example.com will make the cookie only available in the www subdomain

secure : optional. Specifies whether or not the cookie should only be transmitted over a secure HTTPS connection. TRUE indicates that the cookie will only be set if a secure connection exists. Default is FALSE

httponly : optional. If set to TRUE the cookie will be accessible only through the HTTP protocol (the cookie will not be accessible by scripting languages). This setting can help to reduce identity theft through XSS attacks. Default is FALSE

example:

code: 
                <?php
                    $cookie_name = "user";
                    $cookie_value = "John Doe";
                    setcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/"); // 86400 = 1 day
                    ?>
                    <html>
                    <body>

                    <?php
                    if(!isset($_COOKIE[$cookie_name])) {
                        echo "Cookie named '" . $cookie_name . "' is not set!";
                    } else {
                        echo "Cookie '" . $cookie_name . "' is set!<br>";
                        echo "Value is: " . $_COOKIE[$cookie_name];
                    }
                
                ?>

setrawcookie() - defines a cookie (without URL encoding) to be sent along with the rest of the HTTP headers.

Syntax: setrawcookie(name, value, expire, path, domain, secure);

Parameter values:

name : required. Specifies the name of the cookie

value : optional. Specifies the value of the cookie

expire : optional. Specifies when the cookie expires. The value: time()+86400*30, will set the cookie to expire in 30 days. If this parameter is omitted or set to 0, the cookie will expire at the end of the session (when the browser closes). Default is 0

path : optional. Specifies the server path of the cookie. If set to "/", the cookie will be available within the entire domain. If set to "/php/", the cookie will only be available within the php directory and all sub-directories of php. The default value is the current directory that the cookie is being set in

domain : optional. Specifies the domain name of the cookie. To make the cookie available on all subdomains of example.com, set domain to "example.com". Setting it to www.example.com will make the cookie only available in the www subdomain

secure : optional. Specifies whether or not the cookie should only be transmitted over a secure HTTPS connection. TRUE indicates that the cookie will only be set if a secure connection exists. Default is FALSE

example:

code: 
                <?php
                $cookie_name = "user";
                $cookie_value = "John";
                setrawcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/");
                // 86400 = 1 day
                ?>
                <html>
                <body>

                <?php
                    echo "Cookie is set.";
                ?>

socket_get_status() - alias of stream_get_meta_data().

socket_set_blocking() - alias of stream_set_blocking().

socket_set_timeout() - alias of stream_set_timeout().

syslog() - generates a system log message.

Syntax: syslog(priority, message)

Parameter values:

priority : required. Specifies ... Can be one of the following options:LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG

message : required. Specifies the message to send

example:

code: 
                <?php
                    function _log($text) {
                        openlog("phperrors", LOG_PID | LOG_PERROR);
                        syslog(LOG_ERR, $text);
                        closelog(); 
                    }
                ?>