58 lines
1.2 KiB
Markdown
58 lines
1.2 KiB
Markdown
---
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title: >
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PHP types and assertions
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pubDate: 2023-08-20
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permalink: >-
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archive/2023/08/20/php-types-and-assertions
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tags:
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- php
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---
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Following yesterday's email about input validation, guard clauses and assertion libraries, these can be used to compliment PHP's native types and checking.
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For example:
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```php
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function createJourney(string $from, string $to, int $duration): void {
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var_dump($from, $to, $duration);
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}
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```
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In this code, each parameter has a type, but there's no validation on the values.
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If I run this:
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```plain
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createJourney('', '', -10);
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```
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I would get this output:
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```plain
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string(0) ""
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string(0) ""
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int(-10)
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```
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This is probably not what you want.
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I expect `$to` and `$from` to be not empty and the duration to be greater than zero.
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## Here's the thing
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I can use an assertion library or throw my own Exceptions if the values pass the type checks but aren't what I need.
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For example:
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```php
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function createJourney(string $from, string $to, int $duration): void {
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Assert::stringNotEmpty($from);
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Assert::stringNotEmpty($to);
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Assert::positiveInteger($duration);
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var_dump($from, $to, $duration);
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}
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```
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Now, if an empty string or negative duration is passed - in my implementation or test code - an Exception will be thrown.
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