docs::a...:Bucket(3)

📦 version 2.0.13, in nixos 26.05, nixpkgs unstable

✨ NAME ✨

okay so welcome to docs::a...:Bucket(3), bestie — this is a User Contributed Perl Documentation page, and it's all about APR::Bucket, aka the Perl API for manipulating APR Buckets. 💅 Literally the bucket manual, and yes, we are gonna get into it. 🎀

🌟 Synopsis 🌟

Here's the whole vibe check at a glance, with every line exactly as it appears:

use APR::Bucket ();
my $ba = $c->bucket_alloc;

$b1 = APR::Bucket->new($ba, "aaa");
$b2 = APR::Bucket::eos_create($ba);
$b3 = APR::Bucket::flush_create($ba);

$b2->is_eos;
$b3->is_flush;

$len = $b1->length;
$len = $b1->read($data);
$type = $b1->type;

$b1->insert_after($b2);
$b1->insert_before($b3);
$b1->remove;
$b1->destroy;

$b2->delete; # remove+destroy

$b4 = APR::Bucket->new($ba, "to be setaside");
$b4->setaside($pool);

🦋 Description 🦋

APR::Bucket lets you create, manipulate and delete APR buckets. That's the whole assignment. 😌

The various insert methods? yeah, you will probably find them confusing at first — that's normal. The tip is iconic: read the function right to left. 🫶 The following code sample helps to visualize the operations, so keep an eye on the little head/tail comments:

         my $bb = APR::Brigade->new($r->pool, $ba);
         my $d1 = APR::Bucket->new($ba, "d1");
         my $d2 = APR::Bucket->new($ba, "d2");
         my $f1 = APR::Bucket::flush_create($ba);
         my $f2 = APR::Bucket::flush_create($ba);
         my $e1 = APR::Bucket::eos_create($ba);
                                  # head->tail
         $bb->insert_head(  $d1); # head->d1->tail
         $d1->insert_after( $d2); # head->d1->d2->tail
         $d2->insert_before($f1); # head->d1->f1->d2->tail
         $d2->insert_after( $f2); # head->d1->f1->d2->f2->tail
         $bb->insert_tail(  $e1); # head->d1->f1->d2->f2->e1->tail

that chain is the visual, and it's gonna make the next parts make so much more sense. 🧚 keep it in your head, bestie — this chain is lowkey the key to the insert-method chaos. 🌈

✨ API ✨

okay bestie, this is where APR::Bucket shows you all its little tricks 💅 every method, every arg, every code block, all of it — no skipping, no cap.

🗑️ `delete`

Tell the bucket to remove itself from the bucket brigade it belongs to, and then destroy itself. It's giving "I'm leaving the group chat and deleting the app" energy 😭

$bucket->delete();

obj: $bucket ("APR::Bucket object")
ret: no return value
since: 2.0.00

If the bucket isn't attached to any bucket brigade, this operation just destroys the bucket. Simple.

delete is a convenience wrapper that internally does this:

$b->remove;
$b->destroy;

Examples:

Assuming $bb already exists and is filled with buckets, replace the existing data buckets with new buckets with upcased data:

for (my $b = $bb->first; $b; $b = $bb->next($b)) {
   if ($b->read(my $data)) {
        my $nb = APR::Bucket->new($bb->bucket_alloc, uc $data);
        $b->insert_before($nb);
        $b->delete;
        $b = $nb;
    }
}

💀 `destroy`

Free the resources used by a bucket. If multiple buckets refer to the same resource, it gets freed when the last one goes away. last one out, lights off 🕯️

$bucket->destroy();

obj: $bucket ("APR::Bucket object")
ret: no return value
since: 2.0.00

A bucket needs to be destroyed if it was removed from a bucket brigade, to avoid a memory leak. do not skip this, bestie 😭

If a bucket is linked to a bucket brigade, it needs to be removed from it before it can be destroyed.

Usually instead of calling:

$b->remove;
$b->destroy;

it's better to call delete, which does exactly that. Iconic shortcut behavior 💅

🌊 `eos_create`

Create an EndOfStream bucket — the "that's all, folks" of the filter stack 🎬

$b = APR::Bucket::eos_create($ba);

arg1: $ba ("APR::BucketAlloc object") — the freelist from which this bucket should be allocated
ret: $b ("APR::Bucket object") — the new bucket
since: 2.0.00

This bucket type indicates that there is no more data coming from down the filter stack. All filters should flush any buffered data at this point. flush it, queen 💖

Example:

use APR::Bucket ();
use Apache2::Connection ();
my $ba = $c->bucket_alloc;
my $eos_b = APR::Bucket::eos_create($ba);

🚿 `flush_create`

Create a flush bucket. It's literally the "go ahead, flush" button 🫧

$b = APR::Bucket::flush_create($ba);

arg1: $ba ("APR::BucketAlloc object") — the freelist from which this bucket should be allocated
ret: $b ("APR::Bucket object") — the new bucket
since: 2.0.00

This bucket type indicates that filters should flush their data. There is no guarantee that they will flush it, but this is the best we can do. Lowkey humble, but okay 😭

🪄 `insert_after`

Insert a list of buckets after a specified bucket. It's giving "you go after them, bestie" ✨

$after_bucket->insert_after($add_bucket);

obj: $after_bucket ("APR::Bucket object") — the bucket to insert after
arg1: $add_bucket ("APR::Bucket object") — the buckets to insert. It says buckets, since $add_bucket may have more buckets attached after itself.
ret: no return value
since: 2.0.00

🫶 `insert_before`

Insert a list of buckets before a specified bucket. Main character energy, but make it earlier in the brigade 💅

$before_bucket->insert_before($add_bucket);

obj: $before_bucket ("APR::Bucket object") — the bucket to insert before
arg1: $add_bucket ("APR::Bucket object") — the buckets to insert. It says buckets, since $add_bucket may have more buckets attached after itself.
ret: no return value
since: 2.0.00

🏁 `is_eos`

Determine if a bucket is an EOS bucket. A little vibe check for "is this the end?" 👀

$ret = $bucket->is_eos();

obj: $bucket ("APR::Bucket object")
ret: $ret (boolean)
since: 2.0.00

🫧 `is_flush`

Determine if a bucket is a FLUSH bucket. Another tiny vibe check, but make it bubbly 🫧

$ret = $bucket->is_flush();

obj: $bucket ("APR::Bucket object")
ret: $ret (boolean)
since: 2.0.00

📏 `length`

Get the length of the data in the bucket. It's the "how much data are we talking about" check 🍓

$len = $b->length;

obj: $b ("APR::Bucket object")
ret: $len (integer) — if the length is unknown, $len value will be -1.
since: 2.0.00

🌱 `new`

Create a new bucket and initialize it with data. New bucket, new me, same exact behavior ✨

$nb = APR::Bucket->new($ba, $data);
$nb =          $b->new($ba, $data);
$nb = APR::Bucket->new($ba, $data, $offset);
$nb = APR::Bucket->new($ba, $data, $offset, $len);

obj: $b ("APR::Bucket object or class")
arg1: $ba ("APR::BucketAlloc object")
arg2: $data (string) — the data to initialize with.

Important: in order to avoid unnecessary data copying, the variable is stored in the bucket object. That means if you modify $data after passing it to new() you will modify the data in the bucket as well. To avoid that, pass to new() a copy which you won't modify. fr fr, do not skip this warning 😭

opt arg3: $offset (number) — optional offset inside $data. Default: 0.
opt arg4: $len (number) — optional partial length to read.

If $offset is specified, then:

length $buffer - $offset;

will be used. Otherwise the default is to use:

length $buffer;

ret: $nb ("APR::Bucket object") — a newly created bucket object
since: 2.0.00

Examples:

Create a new bucket using a whole string:

use APR::Bucket ();
my $data = "my data";
my $b = APR::Bucket->new($ba, $data);

now the bucket contains the string 'my data'.

Create a new bucket using a sub-string:

use APR::Bucket ();
my $data   = "my data";
my $offset = 3;
my $b = APR::Bucket->new($ba, $data, $offset);

now the bucket contains the string 'data'.

Create a new bucket not using the whole length and starting from an offset:

use APR::Bucket ();
my $data   = "my data";
my $offset = 3;
my $len    = 3;
my $b = APR::Bucket->new($ba, $data, $offset, $len);

now the bucket contains the string 'dat'.

📖 `read`

Read the data from the bucket. It's giving "give me the tea" but, like, actual bytes 🍵

$len = $b->read($buffer);
$len = $b->read($buffer, $block);

obj: $b ("APR::Bucket object") — the bucket to read from
arg1: $buffer (SCALAR) — the buffer to fill. All previous data will be lost.
opt arg2: $block ("APR::Const :read_type constant") — optional reading mode constant.

By default the read is blocking, via APR::Const::BLOCK_READ constant.

ret: $len (number) — how many bytes were actually read.

$buffer gets populated with the string that is read. It will contain an empty string if there was nothing to read.

since: 2.0.00
excpt: APR::Error

It's important to know that certain bucket types (e.g. file bucket), may perform a split and insert extra buckets following the current one. Therefore never call $b->remove before calling $b->read, or you may lose data. Like, genuinely, do not do it 😭

Examples:

Blocking read:

my $len = $b->read(my $buffer);

Non-blocking read:

use APR::Const -compile 'NONBLOCK_READ';
my $len = $b->read(my $buffer, APR::Const::NONBLOCK_READ);

🚪 `remove`

Tell the bucket to remove itself from the bucket brigade it belongs to. It's the "I'm stepping out, don't wait up" of bucket methods 🚪💅

$bucket->remove();

obj: $bucket ("APR::Bucket object")
ret: no return value
since: 2.0.00

If the bucket is not attached to any bucket brigade, then this operation doesn't do anything.

When the bucket is removed, it's not destroyed. Usually this is done in order to move the bucket to another bucket brigade. Or to copy the data way before destroying the bucket. If the bucket wasn't moved to another bucket brigade, it must be destroyed. don't leave it orphaned, bestie 😭

Examples:

Assuming that $bb1 already exists and is filled with buckets, move every odd bucket number to $bb2 and every even to $bb3:

my $bb2 = APR::Brigade->new($c->pool, $c->bucket_alloc);
my $bb3 = APR::Brigade->new($c->pool, $c->bucket_alloc);
my $count = 0;
while (my $bucket = $bb->first) {
    $count++;
    $bucket->remove;
    $count % 2
        ? $bb2->insert_tail($bucket)
        : $bb3->insert_tail($bucket);
}

🛟 `setaside`

Ensure the bucket's data lasts at least as long as the given pool. It's the "bestie, stay a little longer" of bucket methods 🫶

my $status = $b->setaside($pool);

obj: $b ("APR::Bucket object")
arg1: $pool ("APR::Pool object")
ret: ("APR::Const status constant") — on success, APR::Const::SUCCESS is returned. Otherwise a failure code is returned.
excpt: APR::Error

When your code deals only with mod_perl buckets, you don't have to ask for the return value. If this method is called in the VOID context, i.e.:

$b->setaside($pool);

mod_perl will do the error checking on your behalf, and if the return code is not APR::Const::SUCCESS, an APR::Error exception will be thrown.

However, if your code doesn't know which bucket types it may need to setaside, you may want to check the return code and deal with any errors. For example one of the possible error codes is APR::Const::ENOTIMPL. As of this writing the pipe and socket buckets can't setaside(), in which case you may want to look at the ap_save_brigade() implementation. iykyk 👀

since: 2.0.00

Usually setaside is called by certain output filters, in order to buffer socket writes of smaller buckets into a single write. This method works on all bucket types (not only the mod_perl bucket type), but as explained in the exceptions section, not all bucket types implement this method.

When a mod_perl bucket is setaside, its data is detached from the original perl scalar and copied into a pool bucket. That allows downstream filters to deal with the data originally owned by a Perl interpreter, making it possible for that interpreter to go away and do other things, or be destroyed. literally detaching with love 💖

🏷️ `type`

Get the type of the data in the bucket. It's the "what are you, bestie?" check 🧐

$type = $b->type;

obj: $b ("APR::Bucket object")
ret: $type ("APR::BucketType object")
since: 2.0.00

You need to invoke APR::BucketType methods to access the data.

Example:

Create a flush bucket and read its type's name:

use APR::Bucket ();
use APR::BucketType ();
my $b = APR::Bucket::flush_create($ba);
my $type = $b->type;
my $type_name =  $type->name; # FLUSH

The type name will be 'FLUSH' in this example. Slay 🫧💅

✨ Unsupported API ✨

Okay so <pink>APR::Socket</pink> also gives you an auto-generated Perl interface for a few other methods — and bestie, these cuties aren't tested at the moment, so their API is lowkey subject to change 😭. They'll be finalized later whenever a need arises. If you're thinking about relying on any of these methods, please contact the mod_perl development mailing list so we can help each other take the steps necessary to shift the method to an officially supported API. Teamwork, periodt 🫶

🧸 `data`

$data = $b->data;

This one hands you a C pointer to the address of the data in the bucket. And ngl? It's giving “what would you even do with this in Perl?” 💀

obj: $b ( APR::Bucket object )
ret: $data ( C pointer )
since: subject to change

🌸 `start`

$start = $b->start;

It gives you the offset for when a new bucket is created with a non-zero offset value:

my $b = APR::Bucket->new($ba, $data, $offset, $len);

So yeah — if the offset was 3, $start will be 3 too. Iconic. I fail to see what it can be useful for to the end user (it's mainly used internally) 🙈

obj: $b ( APR::Bucket object )
ret: $start ( offset number )
since: subject to change

👀 See Also 👀

mod_perl 2.0 documentation.

📜 Copyright 📜

mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0.

👑 Authors 👑

The mod_perl development team and numerous contributors.

That's the whole page, bestie 🫶 — sourced as docs::a...:Bucket(3), perl v5.42.3, dated 2023-10-21. Mwah 💋

📦 where this page comes from

nixos 26.05: mod_perl 2.0.13
nixpkgs unstable: mod_perl 2.0.13
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms

docs::a...:Bucket(3)

✨ NAME ✨

🌟 Synopsis 🌟

🦋 Description 🦋

✨ API ✨

🗑️ delete

💀 destroy

🌊 eos_create

🚿 flush_create

🪄 insert_after

🫶 insert_before

🏁 is_eos

🫧 is_flush

📏 length

🌱 new

📖 read

🚪 remove

🛟 setaside

🏷️ type

✨ Unsupported API ✨

🧸 data

🌸 start

👀 See Also 👀

📜 Copyright 📜

👑 Authors 👑

🗑️ `delete`

💀 `destroy`

🌊 `eos_create`

🚿 `flush_create`

🪄 `insert_after`

🫶 `insert_before`

🏁 `is_eos`

🫧 `is_flush`

📏 `length`

🌱 `new`

📖 `read`

🚪 `remove`

🛟 `setaside`

🏷️ `type`

🧸 `data`

🌸 `start`