Defensive Programming - Fear Driven Development

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Defensive Programming The Best Defense is a good Offense Tuesday, February 26, 13

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little about me Product, technology and development consultant RoR, Python/Django, Performance is my passion Development methodologies, agile and effective patterns @liorsion, about.me/liorsion Tuesday, February 26, 13

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defensive dev It’s mostly about psychology Ruby code as example For every rule there’s an exception Tuesday, February 26, 13

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defensive dev It’s mostly about psychology Ruby code as example For every rule there’s an exception Tuesday, February 26, 13

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defensive dev It’s mostly about psychology Ruby code as example For every rule there’s an exception Tuesday, February 26, 13

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defensive dev It’s mostly about psychology Ruby code as example For every rule there’s an exception Tuesday, February 26, 13

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Best practices Always validate your input - everywhere! Tuesday, February 26, 13

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Validate input Tuesday, February 26, 13

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dangerous exceptions Always safeguard from exceptions Tuesday, February 26, 13

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naming Naming is not that important Tuesday, February 26, 13

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Multi threading When in doubt - lock it! Tuesday, February 26, 13

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Multi threading When in doubt - lock it! Tuesday, February 26, 13

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More refactoring Don’t refactor if you don’t know the code Tuesday, February 26, 13

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More refactoring W r o n g ! Don’t refactor if you don’t know the code Tuesday, February 26, 13

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More refactoring W r o n g ! Tuesday, February 26, 13

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Best practices Always validate your input - everywhere! Tuesday, February 26, 13

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Validate input Tuesday, February 26, 13

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dangerous exceptions Always safeguard from exceptions Tuesday, February 26, 13

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naming Naming is not that important Tuesday, February 26, 13

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naming Naming is not that important Tuesday, February 26, 13

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Multi threading When in doubt - lock it! Tuesday, February 26, 13

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Multi threading When in doubt - lock it! Tuesday, February 26, 13

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Multi threading When in doubt - lock it! Tuesday, February 26, 13

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More refactoring Don’t refactor if you don’t know the code Tuesday, February 26, 13

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More refactoring Tuesday, February 26, 13

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why do that? Don’t know better Can’t be bothered Tuesday, February 26, 13

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why do that? Don’t know better Can’t be bothered Afraid of production meltdown Tuesday, February 26, 13

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why do that? Don’t know better Can’t be bothered Afraid of production meltdown Need to teach Tuesday, February 26, 13

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why do that? Don’t know better Can’t be bothered Afraid of production meltdown Need to ﬁre Need to teach Tuesday, February 26, 13

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why do that? Don’t know better Can’t be bothered Afraid of production meltdown Need to ﬁre Why? Need to teach Tuesday, February 26, 13

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Most popular reasons We’re in a hurry The code is too complicated I don’t know what is going on there There’s code smell in this area There are no tests Tuesday, February 26, 13

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But really.. Fear is a bitch, and is near sighted Tuesday, February 26, 13

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space time theories There’s never enough time But spending the time saves time, always Tuesday, February 26, 13

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space time theories There’s never enough time But spending the time saves time, always On Quality Tuesday, February 26, 13

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Fear Fear is an emotion induced by a perceived threat which causes entities to quickly pull away from it and usually hide People develop speciﬁc fears as a result of learning. Fear is paralyzing Paralyze is spiral, technical debt is collecting => startup death Tuesday, February 26, 13

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Knowing your code Tuesday, February 26, 13

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refactor huge code http://thejoysofcode.com/post/35328929865/when-it-is-announced-i-must- refactor-5000-lines-of-code When I see huge methods.. Tuesday, February 26, 13

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Refactor Small Fast Ongoing Tuesday, February 26, 13

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defense Be aware, always Tuesday, February 26, 13

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Patterns, really? Tuesday, February 26, 13

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psychology Don’t punish mistakes Don’t punish a task that spirals FOR GOOD REASONS In short - don’t punish Tuesday, February 26, 13

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Why should we care? Tuesday, February 26, 13

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My work here is done Find me: @liorsion Find funny images: http://thejoysofcode.com Tuesday, February 26, 13

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Thank you our sponsors Tuesday, February 26, 13