Co

Asynchronous cURL executor simply based on resource and Generator

PHP	❓	Feature Restriction
7.0~	😄	Full Support
5.5~5.6	😧	Generator is not so cool
~5.4	💥	Incompatible

function curl_init_with(string $url, array $options = [])
{
    $ch = curl_init();
    $options = array_replace([
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
    ], $options);
    curl_setopt_array($ch, $options);
    return $ch;
}
function get_xpath_async(string $url) : \Generator
{
    $dom = new \DOMDocument;
    @$dom->loadHTML(yield curl_init_with($url));
    return new \DOMXPath($dom);
}

var_dump(Co::wait([

    'Delay 5 secs' => function () {
        echo "[Delay] I start to have a pseudo-sleep in this coroutine for about 5 secs\n";
        for ($i = 0; $i < 5; ++$i) {
            yield Co::DELAY => 1;
            if ($i < 4) {
                printf("[Delay] %s\n", str_repeat('.', $i + 1));
            }
        }
        echo "[Delay] Done!\n";
    },

    "google.com HTML" => curl_init_with("https://google.com"),

    "Content-Length of github.com" => function () {
        echo "[GitHub] I start to request for github.com to calculate Content-Length\n";
        $content = yield curl_init_with("https://github.com");
        echo "[GitHub] Done! Now I calculate length of contents\n";
        return strlen($content);
    },

    "Save mpyw's Gravatar Image URL to local" => function () {
        echo "[Gravatar] I start to request for github.com to get Gravatar URL\n";
        $src = (yield get_xpath_async('https://github.com/mpyw'))
                 ->evaluate('string(//img[contains(@class,"avatar")]/@src)');
        echo "[Gravatar] Done! Now I download its data\n";
        yield curl_init_with($src, [CURLOPT_FILE => fopen('/tmp/mpyw.png', 'wb')]);
        echo "[Gravatar] Done! Saved as /tmp/mpyw.png\n";
    }

]));

The requests are executed as parallelly as possible 😄
Note that there is only 1 process and 1 thread.

[Delay] I start to have a pseudo-sleep in this coroutine for about 5 secs
[GitHub] I start to request for github.com to calculate Content-Length
[Gravatar] I start to request for github.com to get Gravatar URL
[Delay] .
[Delay] ..
[GitHub] Done! Now I calculate length of contents
[Gravatar] Done! Now I download its data
[Delay] ...
[Gravatar] Done! Saved as /tmp/mpyw.png
[Delay] ....
[Delay] Done!
array(4) {
  ["Delay 5 secs"]=>
  NULL
  ["google.com HTML"]=>
  string(262) "<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="https://www.google.co.jp/?gfe_rd=cr&amp;ei=XXXXXX">here</A>.
</BODY></HTML>
"
  ["Content-Length of github.com"]=>
  int(25534)
  ["Save mpyw's Gravatar Image URL to local"]=>
  NULL
}

Installing

Install via Composer.

composer require mpyw/co:^1.5

And require Composer autoloader in your scripts.

require __DIR__ . '/vendor/autoload.php';

use mpyw\Co\Co;
use mpyw\Co\CURLException;

API

Co::wait()

Wait for all the cURL requests to complete.
The options will override static defaults.

static Co::wait(mixed $value, array $options = []) : mixed

Arguments

(mixed) $value
Any values to be parallelly resolved.
(array<string, mixed>) $options
Associative array of options.

Key	Default	Description
`throw`	`true`	Whether to throw or capture `CURLException` or `RuntimeException` on top-level.
`pipeline`	`false`	Whether to use HTTP/1.1 pipelining. At most 5 requests for the same destination are bundled into single TCP connection.
`multiplex`	`true`	Whether to use HTTP/2 multiplexing. All requests for the same destination are bundled into single TCP connection.
`autoschedule`	`false`	Whether to use automatic scheduling by `CURLMOPT_MAX_TOTAL_CONNECTIONS`.
`interval`	`0.002`	`curl_multi_select()` timeout seconds. `0` means real-time observation.
`concurrency`	`6`	Limit of concurrent TCP connections. `0` means unlimited. The value should be within `10` at most.

Throwable which are not extended from RuntimeException, such as Error Exception LogicException are not captured. If you need to capture them, you have to write your own try-catch blocks in your functions.
HTTP/1.1 pipelining can be used only if the TCP connection is already established and verified that uses keep-alive session. It means that the first bundle of HTTP/1.1 requests CANNOT be pipelined. You can use it from second yield in Co::wait() call.
To use HTTP/2 multiplexing, you have to build PHP with libcurl 7.43.0+ and --with-nghttp2.
To use autoschedule, PHP 7.0.7 or later is required.

When autoschedule Disabled:

curl_multi_add_handle() call can be delayed.
concurrency controlling with pipeline / multiplex CANNOT be correctly driven. You should set higher concurrency in those cases.

When autoschedule Enabled:

curl_multi_add_handle() is always immediately called.
CURLINFO_TOTAL_TIME CANNOT be correctly calculated. "Total Time" includes the time waiting for other requests are finished.

The details of CURLIFNO_*_TIME timing charts are described at the bottom of this page.

Return Value

(mixed)
Resolved values; in exception-safe context, it may contain...

CURLException which has been raised internally.
RuntimeException which has been raised by user.

Exception

Throws CURLException or RuntimeException in exception-unsafe context.

Co::async()

Execute cURL requests along with Co::wait() call, without waiting resolved values.
The options are inherited from Co::wait().

This method is mainly expected to be used ...

When you are not interested in responses.
In CURLOPT_WRITEFUNCTION or CURLOPT_HEADERFUNCTION callbacks.

static Co::async(mixed $value, mixed $throw = null) : null

Arguments

(mixed) $value
Any values to be parallelly resolved.
(mixed) $throw
Overrides throw in Co::wait() options when you passed true or false.

Return Value

(null)

Exception

CURLException or RuntimeException can be thrown in exception-unsafe context.
Note that you CANNOT capture top-level exceptions unless you catch outside of Co::wait() call.

Co::isRunning()

Return if Co::wait() is running().
With this check, you can safely call Co::wait() or Co::async().

static Co::isRunning() : bool

Co::any()
Co::race()
Co::all()

Return a Generator that resolves with specific value.

static Co::any(array $value) : \Generator<mixed>
static Co::race(array $value) : \Generator<mixed>
static Co::all(array $value) : \Generator<mixed>

Family	Return Value	Exception
`Co::any()`	First Success	`AllFailedException`
`Co::race()`	First Success	First Failure

Jobs CANNOT be canceled.
Incomplete jobs remain even if Co::any() or Co::race() is resolved.
Co::all(...) is just a wrapper of (function () { return yield ...; })().
It should be only used with Co::race() or Co::any().

Co::wait(function () {
    $group1 = Co::all([$ch1, $ch2, $ch3]);
    $group2 = Co::all([$ch4, $ch5, $ch6]);
    $group1or2 = Co::any([$group1, $group2]);
    var_dump(yield $group1or2);
});

Co::setDefaultOptions()
Co::getDefaultOptions()

Overrides/gets static default settings.

static Co::setDefaultOptions(array $options) : null
static Co::getDefaultOptions() : array

Rules

Conversion on Resolving

The all yielded/returned values are resolved by the following rules.
Yielded values are also resent to the Generator.
The rules will be applied recursively.

Before	After
cURL resource	`curl_multi_getconent()` result or `CURLException`
Array	Array (with resolved children) or `RuntimeException`
Generator Closure Generator	Return value (after all yields done) or `RuntimeException`

"Generator Closure" means Closure that contains yield keywords.

Exception-safe or Exception-unsafe Priority

Context in Generator

Exception-unsafe context by default.
The following yield statement specifies exception-safe context.

$results = yield Co::SAFE => [$ch1, $ch2];

This is equivalent to:

$results = yield [
    function () use ($ch1) {
        try {
            return yield $ch1;
        } catch (\RuntimeException $e) {
            return $e;
        }
    },
    function () use ($ch2) {
        try {
            return yield $ch2;
        } catch (\RuntimeException $e) {
            return $e;
        }
    },
];

Context on `Co::wait()`

Exception-unsafe context by default.
The following setting specifies exception-safe context.

$result = Co::wait([$ch1, $ch2], ['throw' => false]);

This is equivalent to:

$results = Co::wait([
    function () use ($ch1) {
        try {
            return yield $ch1;
        } catch (\RuntimeException $e) {
            return $e;
        }
    },
    function () use ($ch2) {
        try {
            return yield $ch2;
        } catch (\RuntimeException $e) {
            return $e;
        }
    },
]);

Context on `Co::async()`

Contexts are inherited from Co::wait().
The following setting overrides parent context as exception-safe.

Co::async($value, false);

The following setting overrides parent context as exception-unsafe.

Co::async($value, true);

Pseudo-sleep for Each Coroutine

The following yield statements delay the coroutine processing:

yield Co::DELAY => $seconds
yield Co::SLEEP => $seconds  # Alias

Comparison with Generators of PHP7.0+ or PHP5.5~5.6

`return` Statements

PHP 7.0+:

yield $foo;
yield $bar;
return $baz;

PHP 5.5~5.6:

yield $foo;
yield $bar;
yield Co::RETURN_WITH => $baz;

Although experimental aliases Co::RETURN_ Co::RET Co::RTN are provided,
Co::RETURN_WITH is recommended in terms of readability.

`yield` Statements with Assignment

PHP 7.0+:

$a = yield $foo;
echo yield $bar;

PHP 5.5~5.6:

$a = (yield $foo);
echo (yield $bar);

`finally` Statements

Be careful that return triggers finally while yield Co::RETURN_WITH => does not.

try {
    return '...';
} finally {
    // Reachable
}

try {
    yield Co::RETURN_WITH => '...';
} finally {
    // Unreachable
}

Appendix

Timing Charts

Note that S is equal to Q when autoschedule is disabled.

Basic

ID	When
Q	`curl_multi_exec()` immediately after `curl_multi_add_handle()` called
S	Processing started actually
DNS	DNS resolution completed
TCP	TCP connection established
TLS	TLS/SSL session established
HS	All HTTP request headers sent
BS	Whole HTTP request body sent
HR	All HTTP response headers received
BR	Whole HTTP response body received

Constant	Time
CURLINFO_NAMELOOKUP_TIME	DNS - S
CURLINFO_CONNECT_TIME	TCP - S
CURLINFO_APPCONNECT_TIME	TLS - S
CURLINFO_PRETRANSFER_TIME	HS - S
CURLINFO_STARTTRANSFER_TIME	HR - S
CURLINFO_TOTAL_TIME	BR - Q

With Redirections by `CURLOPT_FOLLOWLOCATION`

ID	When
Q	`curl_multi_exec()` immediately after `curl_multi_add_handle()` called
S	Processing started actually
DNS(1)	DNS resolution completed
TCP(1)	TCP connection established
TLS(1)	TLS/SSL session established
HS(1)	All HTTP request headers sent
BS(1)	Whole HTTP request body sent
HR(1)	All HTTP response headers received
DNS(2)	DNS resolution completed
TCP(2)	TCP connection established
TLS(2)	TLS/SSL session established
HS(2)	All HTTP request headers sent
BS(2)	Whole HTTP request body sent
HR(2)	All HTTP response headers received
BR(2)	Whole HTTP response body received

Constant	Time
CURLINFO_REDIRECT_TIME	HR(1) - Q
CURLINFO_NAMELOOKUP_TIME	DNS(2) - HR(1)
CURLINFO_CONNECT_TIME	TCP(2) - HR(1)
CURLINFO_APPCONNECT_TIME	TLS(2) - HR(1)
CURLINFO_PRETRANSFER_TIME	HS(2) - HR(1)
CURLINFO_STARTTRANSFER_TIME	HR(2) - HR(1)
CURLINFO_TOTAL_TIME	BR(2) - Q

Name		Name	Last commit message	Last commit date
Latest commit History 274 Commits
examples		examples
src		src
tests		tests
.coveralls.yml		.coveralls.yml
.gitignore		.gitignore
.scrutinizer.yml		.scrutinizer.yml
.travis.yml		.travis.yml
CHANGELOG		CHANGELOG
LICENSE		LICENSE
README.md		README.md
codeception.yml		codeception.yml
composer.json		composer.json

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Co

Table of Contents

Installing

API

Co::wait()

Arguments

Return Value

Exception

Co::async()

Arguments

Return Value

Exception

Co::isRunning()

Co::any()Co::race()Co::all()

Co::setDefaultOptions()Co::getDefaultOptions()

Rules

Conversion on Resolving

Exception-safe or Exception-unsafe Priority

Context in Generator

Context on Co::wait()

Context on Co::async()

Pseudo-sleep for Each Coroutine

Comparison with Generators of PHP7.0+ or PHP5.5~5.6

return Statements

yield Statements with Assignment

finally Statements

Appendix

Timing Charts

Basic

With Redirections by CURLOPT_FOLLOWLOCATION

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Co::any()
Co::race()
Co::all()

Co::setDefaultOptions()
Co::getDefaultOptions()

Context on `Co::wait()`

Context on `Co::async()`

`return` Statements

`yield` Statements with Assignment

`finally` Statements

With Redirections by `CURLOPT_FOLLOWLOCATION`

Packages