A love story starring Symfony and Domain-Driven Design

This is the story of how I discovered Domain-Driven Design, what happened when I tried to apply it to a Symfony framework project, and what are the key takeaways.

Talk given at SymfonyCon Amsterdam 2019, unconference

Transcript

1. A love story
   starring Symfony
   and Domain-Driven Design
   Romaric Drigon @ SymfonyCon Amsterdam, 22/11/2019
   

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2. @romaricdrigon
   So,ware engineer @ ASIT VD
   !
   

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3. How it started
   

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5. Let's code...
   

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6. Let's try to code...
   

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7. What went wrong?
   2 pre-requisite for DDD:
   • an itera)ve process is in place
   • domain experts are available and coopera)ve
   

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8. Hard fact #1: Most us can't do DDD
   

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9. Hard fact #2: Most us don't need DDD
   

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10. S"ll, we can learn a lot from DDD
    

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11. Ubiquitous language
    

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12. Write a glossary
    

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13. Automa'c glossary
    $metadatas = $this->doctrine->getMetadataFactory()->getAllMetadata();
    foreach ($metadatas as $metadata) {
    $fields = [];
    foreach ($metadata->getFieldNames() as $fieldName) {
    $property = $metadata->getReflectionClass()->hasProperty($fieldName) ? $metadata->getReflectionClass()->getProperty($fieldName) : null;
    $fields[$fieldName] = [
    'doc' => $property ? $this->cleanPhpDoc($property->getDocComment()) : null,
    'isIdentifier' => $metadata->isIdentifier($fieldName),
    'name' => $fieldName,
    'isNullable' => $metadata->isNullable($fieldName),
    'type' => $metadata->getTypeOfField($fieldName),
    ];
    }
    $entities[] = [
    'doc' => $this->cleanPhpDoc($metadata->getReflectionClass()->getDocComment()),
    'name' => $metadata->getReflectionClass()->getShortName(),
    'properties' => $fields,
    ];
    }
    $doc = $this->twig->render('doc.html.twig', ['entities' => $entities]);
    

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14. Anemic model vs Rich domain model
    

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15. Does Symfony love DDD?
    Doctrine ORM
    ❤
    Messenger
    ❤
    Workflow
    ❤
    App structure
    ⁉
    Validator
    ⁉
    Forms
    !
    

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16. Tac$cal pa$erns
    

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18. “A pa&ern is not a cookbook.
    It lets you start from a base of experience to
    develop your solu;on, and it gives you some
    language to talk about what you are doing.”
    — Eric Evans, Domain-Driven Design
    

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19. Final word
    Read books!
    You can improve a lot quality of your so4ware by improving
    processes and communica9on around
    Do not be a DDD groupie
    

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20. Thank you for your a,en.on
    h"ps:/
    /romaricdrigon.github.io/
    

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