PHP Developer''''s Dictionary- P39 pptx

int is_stringmixed var Description The is_string function returns true if var is a string and returns false otherwise.. isset Syntax int issetmixed var Description The isset functio

int is_string(mixed var)

Description

The is_string() function returns true if var is a string and returns false otherwise

isset()

Syntax

int isset(mixed var)

Description

The isset() function returns true if var exists and returns false otherwise

$avar = 100;

echo isset($avar);//displays 1

print_r()

Syntax

void print_r(mixed expression);

Description

The print_r() function, which was added in PHP 4.0, displays human-readable information about the values of variables If expression is a string, integer, or

double, the value itself will be printed If expression is an array, the keys and

values will be displayed Similar notation is used for objects

$array1 = array (1,2,3);

print_r($array1);

//displays Array ( [0] => 1 [1] => 2 [2] => 3 )

settype()

IT-SC book 191

Syntax

int settype(string var, string type)

Description

The settype() function sets the type of var to that of type Possible values of type

are "integer", "double", "string", "array", and "object" The return value is true if the type could be set, and false otherwise

strval()

Syntax

string strval(mixed var)

Description

The strval() function returns the string representation of var var must be a

scalar type and not an array or object

unset()

Syntax

int unset(mixed var)

Description

The unset() function destroys the specified variable and returns true

var_dump()

Syntax

void var_dump(mixed expression)

Description

The var_dump() function, which was added in PHP 3.0.5 and PHP 4.0, displays structured information about an expression, including its type and value Arrays are processed recursively with values indented to show structure

$array1 = array (1,2,3);

var_dump($array1);

//displays array(3) { [0]=> int(1) [1]=> int(2) [2]=> int(3) }

IT-SC book 193

Chapter 6 Protocol Extensions

On the Internet, there are lots of methods, called protocols, of moving files and data

around from place to place These protocols are what enable us to move files, send and receive email, download Web pages, manage networks, and much more

Within the PHP programming language are several sets of functions that provide the ability to use these protocols They are the focus of this chapter and are as follows:

• FTP

• HTTP

• IMAP, POP3, and NNTP

• LDAP

• SNMP

FTP

The File Transfer Protocol (FTP) is a standard Internet protocol that is used to exchange files Generally speaking, FTP commands are issued either on a command-line interface or through an application You can read the Request For Comments (RFC) on FTP at http://www.ietf.org/rfc/rfc0959.txt

Note

For those of you using PHP 3, this library of functions was not added until 3.0.13

ftp_cdup()

Syntax

int ftp_cdup(int ftp_stream)

Description

The ftp_cdup() function instructs the connection to change to the parent directory

of the current working directory in ftp_stream, which is the name handle of a previously opened stream using ftp_connect() If successful, 1 is returned If the function fails, 0 is returned

The following short example moves up one directory on the system, whose connection is defined by $my_conn The result of the operation is stored in $status

If successful, this will contain 1; otherwise, it will contain an error message

$status = ftp_cdup($my_conn);

ftp_chdir()

Syntax

int ftp_chdir(int ftp_stream, string directory)

Description

The ftp_chdir() function changes the current working directory of ftp_stream, which is the name handle of a previously opened stream using ftp_connect(), to directory If successful, 1 is returned; otherwise 0 is returned on an error

ftp_connect()

Syntax

int ftp_connect(string host, int [port] )

Description

The ftp_connect() function opens an FTP connection to host when successful If the optional port is specified, the function attempts to open a connection to that specific port rather than to the default port 21 If the function fails, an error is returned

The following short example shows how you would connect to ftp.mcp.com and store the FTP stream reference in $my_conn The result of the operation is stored in

$status If successful, this will contain 1; otherwise, it will contain an error message

$status = ftp_connect('ftp.mcp.com');

ftp_delete()

Syntax