What does -> do?

[Manfred Kooistra]

I have these pieces of example code that I am trying to figure out:

(a) $a = $b->c();
(b) $d->e();

What does "->" do?
Where is there a reference/explanation in the PHP manual (or anywhere
else)?

(Unfortunately Google et al. don't search for these characters, so I
don't know how to look for an explanation on this.)

[raghuanandy]

Manfred Kooistra wrote:

I have these pieces of example code that I am trying to figure out:

(a) $a = $b->c();
(b) $d->e();

What does "->" do?

Basically, "->" use to reference variables or functions (or more
precisely members and methods) within a class.
eg:
class Something {
public $a = 'Hello';
function __construct($a)
{ $this->a = $a; }
function SetA($a);
{ $this->a = $a; }
function GetA()
{ return $this->a; }
} //end class

Now the member "a" and methods SetA , GetA can be accessed via the "->"
operator
$obj = new Something('World');

//Access method "GetA" of object "obj" using ->
print $obj->GetA();

//accessing member "a" of object "obj" using ->
$obj->a = 'Hello';
print $obj->a;

Where is there a reference/explanation in the PHP manual (or anywhere
else)?

(Unfortunately Google et al. don't search for these characters, so I
don't know how to look for an explanation on this.)

For more information visit:
http://www.php.net/manual/en/language.oop.php
&
http://www.php.net/manual/en/language.oop5.basic.php

[Manfred Kooistra]

Okay, understood: classes and objects
(http://de.php.net/manual/en/language.oop.php).

So why does this work:

require('Class_definition.php');
$object = new Class;
$object->function_defined_in_class($something);
other_function_defined_in_class($object);

but not this:

require('Class_definition.php');
$object = new Class;
while($something) {
$object->function_defined_in_class($something);
}
other_function_defined_in_class($object);

?

[Rik]

Manfred Kooistra wrote:

Okay, understood: classes and objects
(http://de.php.net/manual/en/language.oop.php).

So why does this work:

require('Class_definition.php');
$object = new Class;
$object->function_defined_in_class($something);
other_function_defined_in_class($object);

but not this:

require('Class_definition.php');
$object = new Class;
while($something) {
$object->function_defined_in_class($something);
}
other_function_defined_in_class($object);

It highly depends on the specific class offcourse. Normally it would work,
unless there's something else going on inside the class. Offcourse, it
would only work when $something is altered by the
function_defined_in_class, else it'd be an infinite loop....
--
Rik Wasmus

[Manfred Kooistra]

Thank you so far.

To make this more concrete:
I am trying to send a variable number of attachments with PEAR::Mail.

With a fixed number of attachments (example with 1 file), the relevant
part of the code was this:

$mime->addAttachment($file, "image/$type_of_file",
$_FILES['upfile_0']['name']);

Now, with an unknown number of files, I changed that part of the code
to (exactly as in my script):

$i = 0;
foreach($_POST_DATA as $key =$value){
if(preg_match("/^upfile_/i", $key)){
$uploaded_file_name = $value;
$uploaded_file_path = $_POST_DATA['upload_dir'] .
$uploaded_file_name;

if(is_file($uploaded_file_path)){
preg_match('/(\.\w+)$/', $uploaded_file_name, $match);
$typ = substr($match[1], 1);

$handle = fopen($uploaded_file_path, 'r');
$file = fread($handle, filesize($uploaded_file_path));
$mime->addAttachment($file, "image/$typ", $uploaded_file_name);
fclose($handle);

$i++;
}
}
}

$_POST_DATA is stuff processed through a Perl script. Files are named
upfile_0, upfile_1 etc. The data is all there, I checked it. I can even
output $file to the screen, but $mime->addAttachment seems not do do
anything, because the emails arrive without attachment (all other
content is okay, since the rest of the [rather very long, so not posted
here] script is unchanged).

It seems to me that somehow the foreach and the -don't work well
together, because I have the same foreach loop for the email content,
where $text .= $sometextfragment; works fine.

[Rik]

Manfred Kooistra wrote:

Thank you so far.

To make this more concrete:
I am trying to send a variable number of attachments with PEAR::Mail.

With a fixed number of attachments (example with 1 file), the relevant
part of the code was this:

$mime->addAttachment($file, "image/$type_of_file",
$_FILES['upfile_0']['name']);

Now, with an unknown number of files, I changed that part of the code
to (exactly as in my script):

<SNIP>

$_POST_DATA is stuff processed through a Perl script. Files are named
upfile_0, upfile_1 etc. The data is all there, I checked it. I can
even output $file to the screen, but $mime->addAttachment seems not
do do anything, because the emails arrive without attachment (all
other content is okay, since the rest of the [rather very long, so
not posted here] script is unchanged).

It seems to me that somehow the foreach and the -don't work well
together, because I have the same foreach loop for the email content,
where $text .= $sometextfragment; works fine.

There is absolutely no problem in using objects within a loop. It's the
logic that is faulty. I do not use the PEAR::Mail class, but I suspect this
will solve your problem (untested, might be one or two typos):

function return_mime($filename,$fallback){
if(function_exists('finfo_file')){
$finfo = finfo_open(FILEINFO_MIME);
return finfo_file($finfo, $filename);
}
$mime_magic = mime_content_type($filename);
return ($mime_magic==false) ? $fallback : $mime_magic;
}
foreach($_FILES as $file){
if($file['error'] == UPLOAD_ERR_OK){
$mime->addAttachment($file['tmp_name'],
return_mime($file['name'],$file['type']),$file['tmp_name']);
} else {
trigger_error("{$file['name'] is not uploaded correctly.");
}
}

I do not know how your PERL script works, or what it does, so I have not
used that. You should be able te get it to work using this example though.
--
Rik Wasmus

[Manfred Kooistra]

Thank you, Rik.
Alas, that wasn't it.

I found out that the problem was trying to attach the file after
fopening and freading it. On debug, I got an error message telling me:
"File is not readable." I was wondering about that, because that files
permissions and path are alright. So I simply attached it without
fopening it - and that did the trick!

Not working:

$handle = fopen($uploaded_file_path, 'r');
$file = fread($handle, filesize($uploaded_file_path));
$mime->addAttachment($file, "image/$typ", $uploaded_file_name);
fclose($handle);

Working:

$mime->addAttachment($uploaded_file_path, "image/$typ",
$uploaded_file_name);

(with $typ preg_match/substr-ed from the file name)

I wonder about this, because I found hundreds of
mail-attachment-examples with fopen/fread, but I'm happy that my script
is running and I get mailed the uploaded files.

Thank you to all of you!

[Rik]

Manfred Kooistra wrote:

Thank you, Rik.
Alas, that wasn't it.

I found out that the problem was trying to attach the file after
fopening and freading it. On debug, I got an error message telling me:
"File is not readable." I was wondering about that, because that files
permissions and path are alright. So I simply attached it without
fopening it - and that did the trick!

Not working:

$handle = fopen($uploaded_file_path, 'r');
$file = fread($handle, filesize($uploaded_file_path));
$mime->addAttachment($file, "image/$typ", $uploaded_file_name);
fclose($handle);

Working:

$mime->addAttachment($uploaded_file_path, "image/$typ",
$uploaded_file_name);

(with $typ preg_match/substr-ed from the file name)

I wonder about this, because I found hundreds of
mail-attachment-examples with fopen/fread, but I'm happy that my
script is running and I get mailed the uploaded files.

Well, it always pays to read up on the functions. Does it take the data of
a file, or the filename, that's the only difference.
--
Rik Wasmus