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One of the simplest ways to make functions asynchronous is to accept a callback function. This is what node.js does (at time of writing). This works, but has a number of issues.
- You lose the separation of inputs and outputs to a function since the callback must be passed as an input
- It is difficult to compose multiple serial or parallel operations
- You lose a lot of helpful debugging information and error handling ability relating to stack traces and the bubbling up of exceptions
- You can no longer use the built in control flow constructs and they must all be re-invented to work asynchronously.
Many APIs in the browser use some kind of event based model for control flow, which solves problem 1, but not problems 2 to 4.
Promises aim to solve issues 1 to 3 and can solve problem 4 in ES6 (with the use of generators).
There’s a lot of outdated information on the Web that leads new PHP users astray, propagating bad practices and insecure code. PHP: The Right Way is an easy-to-read, quick reference for PHP popular coding standards, links to authoritative tutorials around the Web and what the contributors consider to be best practices at the present time.
There is no canonical way to use PHP. This website aims to introduce new PHP developers to some topics which they may not discover until it is too late, and aims to give seasoned pros some fresh ideas on those topics they’ve been doing for years without ever reconsidering. This website will also not tell you which tools to use, but instead offer suggestions for multiple options, when possible explaining the differences in approach and use-case.
This is a living document and will continue to be updated with more helpful information and examples as they become available.