Sometimes it is not posible to create a recipe without some knowledge about application. For example, Flex does not know how application stores and operates with its data. Only the developer has this knowledge! So, Flex could ask developer about application and store all answers in composer.json somewhere under extra key.

With this knowledge, Flex could replace some placeholders in configuration files or copy different files for different user input.

Examples:

• User could choose db_driver for friendsofsymfony/user-bundle. A recipe could be created with replacing some placeholder with user choice (orm, mongodb, couchdb or custom);
• User could choose database layer for sonata-project/media-bundle (orm, phpcr or mongodb) and copy some classes only into Entity/, Document/ or PHPCR/ directory.

What do you think?