Laravel 5: Returning In-line Access to a Variable With with

The with is a useful utility function that can be used to simply return the provided values back to the caller. This can be used as an entry point for method chaining without the need to create temporary local variables.

It is also possible to supply a callback function that will accept the provided value as its first, and only argument.

#Signature

The signature of the with function is:

1function with(
2    $value,
3    callable $callback = null
4);

#Example Use

The with function can be used to simply return the supplied $value. This function can be used to invoke methods on new class instances that are passed as function arguments:

 1<?php
 2 
 3class ExampleClass {
 4 
 5    public function someMethod()
 6    {
 7        return 'some value';
 8    }
 9 
10    // Other methods.
11 
12}
13 
14$value = with(new ExampleClass)->someMethod();

In the above example, $value would be contain the value some value.

A>## Alternative to the with Function

Another useful way to interact with the with function is to take advantage of the $callback parameter. This allows you to perform additional actions, or mutate the value before it is returned.

In the following example, we will use this to get a weather forecast using the Yahoo weather API.

 1/**
 2 * Returns a weather forecast for a given place.
 3 *
 4 * @param string $place
 5 * @return \Illuminate\Support\Collection
 6 */
 7function getWeatherForecast($place) {
 8    return with($place, function ($place) {
 9        $apiUrl = 'https://query.yahooapis.com/v1/' .
10        'public/yql?q=select%20*%20from%20weather.' .
11        'forecast%20where%20woeid%20in%20(select'   .
12        '%20woeid%20from%20geo.places(1)%20where'   .
13        '%20text%3D%22<PLACE>%22)&format=json&env=' .
14        'store%3A%2F%2Fdatatables.org' .
15        '%2Falltableswithkeys';
16 
17        $apiUrl = str_replace(
18                    '<PLACE>',
19                    $place,
20                    $apiUrl
21                  );
22 
23        return with(
24            new GuzzleHttp\Client,
25            function ($client) use ($apiUrl) {
26                /** @var GuzzleHttp\Client $client */
27                $response     = $client->get($apiUrl);
28                $responseBody = $response->getBody();
29                $result       = json_decode(
30                                    $responseBody
31                                    ->getContents()
32                                );
33 
34                // Get the forecast.
35                return collect(
36                        $result->query->results
37                               ->channel->item
38                               ->forecast
39                        );
40        });
41    });
42}

We can now invoke our demo getWeatherForecast function like so to get the forecast for any provided location:

 1use Illuminate\Support\Str;
 2 
 3// Get the weather forecast for San Francisco, CA
 4$forecast = getWeatherForecast('San Francisco, CA');
 5 
 6// Get the cloudy days.
 7$cloudyDays = $forecast->filter(function ($forecast) {
 8   return Str::contains(
 9        $forecast->text,
10        'Cloudy'
11    );
12});

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