Convert string to resource php

Содержание

Creating streams from strings in PHP
Update June 23th, 2013
Web mentions
Comments
strval
Parameters
Return Values
Examples
See Also
User Contributed Notes 9 notes

Creating streams from strings in PHP

I’m in the process of writing an API that relies on (file-)streams to be passed around.

There are situations where a string instead needs to be used, and for these purposes the data: stream wrapper is used. Initially I thought it was only possible to encode the actual string in base64, which I didn’t like because of the added footprint.

 $string = "I should have really done some laundry tonight."; $stream = fopen('data://text/plain;base64,' . base64_encode($string),'r'); echo stream_get_contents($stream); ?>

Quickly checking out the rfc, it turns out that ‘;base64’ can be omitted to just pass along the raw data, which makes a lot more sense in the context of PHP.

Thankfully, PHP gladly supports it:

 $string = "I tried, honestly!"; $stream = fopen('data://text/plain,' . $string,'r'); echo stream_get_contents($stream); ?>

Update June 23th, 2013

Just in case anyone stumbles upon this, I would no longer recommend using the data uri for this purpose.

Since PHP 5.1 we have php://memory and php://temp . The former keeps the entire string into memory, and the latter automatically writes to a file as soon as the stream exceeds a certain amount of memory.

 $string = 'Some bad-ass string'; $stream = fopen('php://memory','r+'); fwrite($stream, $string); rewind($stream); echo stream_get_contents($stream);

A bit more info can be found on php.net.

Looking for a CTO or senior developer for your next project? I’m looking for contracts or full-time gigs! Check out my resume or drop me a line! —>

Web mentions

Comments

Josh • Jan 30, 2009 My favorite usage of the data: wrapper is for raw uploaded csv data. If you let user’s cut-n-paste a csv for upload you can use the data: wrapper to fopen the POST data then fgetcsv() on it to save yourself from parsing it manually.

Michael Gauthier • Jan 30, 2009 Great tip, thanks! I might use this to simplify some code I have that works with either IPC pipes or strings.

aparimana • Jun 23, 2013 remember to urlencode() your $string before passing it to fopen — PHP will always urldecode(), to serve the data up, which will cause problems if your input data happens to contain sequences that look like URL encoded characters ( eg input string ‘this%26that’ will be output ‘this&that’)

Evert • Jun 23, 2013 I should really update this post, but I would _not_ recommend using the data:// url. Use php://memory and php://temp instead!

Nicholas Ruunu • Apr 23, 2017 Is it possible to write initial data to a read only stream with php://temp?

Markus • Nov 25, 2013 instead of base64_encode() in php which consumes a lot of php memory you should use stream_filter_append($fh, ‘convert.base64-encode’);
which is not limited by php-memory limits AFAIK

Jasmine Hegman • Jul 28, 2015 Thank you for this fine article w/ update! I know this is old and sort of minor but in your last code example you open the php://memory string with ‘r+’ and then write to it — I think that should be ‘w+’ :o)

Evert • Jul 28, 2015 r+ actually works too. Judging from the documentation is looks like the only difference is that w+ creates a new file if it doesn’t already exist, but that’s not really relevant here.

Jasmine Hegman • Jul 30, 2015 Oh you are so right, I don’t know what I was thinking! I guess my brain decided to pretend the + symbol was meaningless. :3

linoge • Jun 04, 2016 Thank you very much for the article, I was looking exactly for this, and it’s such a nice thing that you added the update c;

Hugo Franco de Campos • Nov 30, 2016 Is there any concern about keep large strings in memory using fopen? I’m sending a large csv string to a file storage and I have no idea if I should use memory, temp or anything else.

rinogo • Sep 02, 2017 Thanks for your short examples on this, especially for the 2013 update! Exactly what I was looking for.

Источник

strval

Get the string value of a variable. See the documentation on string for more information on converting to string.

This function performs no formatting on the returned value. If you are looking for a way to format a numeric value as a string, please see sprintf() or number_format() .

Parameters

The variable that is being converted to a string .

value may be any scalar type, null , or an object that implements the __toString() method. You cannot use strval() on arrays or on objects that do not implement the __toString() method.

Return Values

The string value of value .

Examples

Example #1 strval() example using PHP magic __toString() method.

class StrValTest
public function __toString ()
return __CLASS__ ;
>
>

// Prints ‘StrValTest’
echo strval (new StrValTest );
?>

User Contributed Notes 9 notes

As of PHP 5.2, strval() will return the string value of an object, calling its __toString() method to determine what that value is.

Some notes about how this function has changed over time, with regards the following statement:

> You cannot use strval() on arrays or on objects that
> do not implement the __toString() method.

In PHP 5.3 and below, strval(array(1, 2, 3)) would return the string «Array» without any sort of error occurring.

From 5.4 and above, the return value is unchanged but you will now get a notice-level error: «Array to string conversion».

For objects that do not implement __toString(), the behaviour has varied:

PHP 4: «Object»
PHP 5 < 5.2: "Object id #1" (number obviously varies)
PHP >= 5.2: Catchable fatal error: Object of class X could not be converted to string

If you want to convert an integer into an English word string, eg. 29 -> twenty-nine, then here’s a function to do it.

Note on use of fmod()
I used the floating point fmod() in preference to the % operator, because % converts the operands to int, corrupting values outside of the range [-2147483648, 2147483647]

I haven’t bothered with «billion» because the word means 10e9 or 10e12 depending who you ask.

The function returns ‘#’ if the argument does not represent a whole number.

$nwords = array( «zero» , «one» , «two» , «three» , «four» , «five» , «six» , «seven» ,
«eight» , «nine» , «ten» , «eleven» , «twelve» , «thirteen» ,
«fourteen» , «fifteen» , «sixteen» , «seventeen» , «eighteen» ,
«nineteen» , «twenty» , 30 => «thirty» , 40 => «forty» ,
50 => «fifty» , 60 => «sixty» , 70 => «seventy» , 80 => «eighty» ,
90 => «ninety» );

function int_to_words ( $x ) global $nwords ;

if(! is_numeric ( $x ))
$w = ‘#’ ;
else if( fmod ( $x , 1 ) != 0 )
$w = ‘#’ ;
else if( $x < 0 ) $w = 'minus ' ;
$x = — $x ;
> else
$w = » ;
// . now $x is a non-negative integer.

if( $x < 21 ) // 0 to 20
$w .= $nwords [ $x ];
else if( $x < 100 ) < // 21 to 99
$w .= $nwords [ 10 * floor ( $x / 10 )];
$r = fmod ( $x , 10 );
if( $r > 0 )
$w .= ‘-‘ . $nwords [ $r ];
> else if( $x < 1000 ) < // 100 to 999
$w .= $nwords [ floor ( $x / 100 )] . ‘ hundred’ ;
$r = fmod ( $x , 100 );
if( $r > 0 )
$w .= ‘ and ‘ . int_to_words ( $r );
> else if( $x < 1000000 ) < // 1000 to 999999
$w .= int_to_words ( floor ( $x / 1000 )) . ‘ thousand’ ;
$r = fmod ( $x , 1000 );
if( $r > 0 ) $w .= ‘ ‘ ;
if( $r < 100 )
$w .= ‘and ‘ ;
$w .= int_to_words ( $r );
>
> else < // millions
$w .= int_to_words ( floor ( $x / 1000000 )) . ‘ million’ ;
$r = fmod ( $x , 1000000 );
if( $r > 0 ) $w .= ‘ ‘ ;
if( $r < 100 )
$word .= ‘and ‘ ;
$w .= int_to_words ( $r );
>
>
>
return $w ;
>

Usage:
echo ‘There are currently ‘ . int_to_words ( $count ) . ‘ members logged on.’ ;
?>

I can’t help being surprised that

evaluates to true. It’s the same with strval and single quotes.
=== avoids it.

Why does it matter? One of my suppliers, unbelievably, uses 0 to mean standard discount and 0.00 to mean no discount in their stock files.

The only way to convert a large float to a string is to use printf(‘%0.0f’,$float); instead of strval($float); (php 5.1.4).

// strval() will lose digits around pow(2,45);
echo pow(2,50); // 1.1258999068426E+015
echo (string)pow(2,50); // 1.1258999068426E+015
echo strval(pow(2,50)); // 1.1258999068426E+015

// full conversion
printf(‘%0.0f’,pow(2,50)); // 112589906846624
echo sprintf(‘%0.0f’,pow(2,50)); // 112589906846624

It seems that one is being treated as an unsigned large int (32 bit), and the other as a signed large int (which has rolled over/under).

2326201276 — (-1968766020) = 4294967296.

As of PHP 5.1.4 (I have not tested it in later versions), the strval function does not attempt to invoke the __toString method when it encounters an object. This simple wrapper function will handle this circumstance for you:

/**
* Returns the string value of a variable
*
* This differs from strval in that it invokes __toString if an object is given
* and the object has that method
*/
function stringVal ($value)
// We use get_class_methods instead of method_exists to ensure that __toString is a public method
if (is_object($value) && in_array(«__toString», get_class_methods($value)))
return strval($value->__toString());
else
return strval($value);
>

In complement to Tom Nicholson’s contribution, here is the french version (actually it’s possible to change the language, but you should check the syntax 😉 )

function int_to_words($x) global $nwords;

if(!is_numeric($x))
$w = ‘#’;
else if(fmod($x, 1) != 0)
$w = ‘#’;
else if($x < 0) $w = $nwords['minus'].' ';
$x = -$x;
> else
$w = »;
// . now $x is a non-negative integer.

if($x < 21) // 0 to 20
$w .= $nwords[$x];
else if($x < 100) < // 21 to 99
$w .= $nwords[10 * floor($x/10)];
$r = fmod($x, 10);
if($r > 0)
$w .= ‘-‘. $nwords[$r];
> else if($x < 1000) < // 100 to 999
$w .= $nwords[floor($x/100)] .’ ‘.$nwords[‘hundred’];
$r = fmod($x, 100);
if($r > 0)
$w .= ‘ ‘.$nwords[‘separator’].’ ‘. int_to_words($r);
> else if($x < 1000000) < // 1000 to 999999
$w .= int_to_words(floor($x/1000)) .’ ‘.$nwords[‘thousand’];
$r = fmod($x, 1000);
if($r > 0) $w .= ‘ ‘;
if($r < 100)
$w .= $nwords[‘separator’].’ ‘;
$w .= int_to_words($r);

>
> else < // millions
$w .= int_to_words(floor($x/1000000)) .’ ‘.$nwords[‘million’];
$r = fmod($x, 1000000);
if($r > 0) $w .= ‘ ‘;
if($r < 100)
$word .= $nwords[‘separator’].’ ‘;
$w .= int_to_words($r);
>
>
>
return $w;
>

// Usage in English
$nwords = array( «zero», «one», «two», «three», «four», «five», «six», «seven»,
«eight», «nine», «ten», «eleven», «twelve», «thirteen»,
«fourteen», «fifteen», «sixteen», «seventeen», «eighteen»,
«nineteen», «twenty», 30 => «thirty», 40 => «forty»,
50 => «fifty», 60 => «sixty», 70 => «seventy», 80 => «eighty»,
90 => «ninety» , «hundred» => «hundred», «thousand»=> «thousand», «million»=>»million»,
«separator»=>»and», «minus»=>»minus»);

echo ‘There are currently ‘. int_to_words(-120223456) . ‘ members logged on.
‘;

//Utilisation en Francais
$nwords = array( «zéro», «un», «deux», «trois», «quatre», «cinq», «six», «sept»,
«huit», «neuf», «dix», «onze», «douze», «treize»,
«quatorze», «quinze», «seize», «dix-sept», «dix-huit»,
«dix-neuf», «vingt», 30 => «trente», 40 => «quarante»,
50 => «cinquante», 60 => «soixante», 70 => «soixante-dix», 80 => «quatre-vingt»,
90 => «quatre-vingt-dix» , «hundred» => «cent», «thousand»=> «mille», «million»=>»million»,
«separator»=>»», «minus»=>»moins»);

echo ‘Il y a actuellement ‘. int_to_words(-120223456) . ‘ membres connectés.
‘;