APIs, Return codes, C Programming Language, We've all been there.
TL;DR: Don't return codes to yourself. Raise Exceptions.
Problems
Code Polluting
Outdated documentation
Coupling to accidental codes.
Functional logic polluted.
Solutions
Change Ids and return Generic Exceptions.
Distinguish Happy Path from Exception Path.
Sample Code
Wrong
function createSomething(arguments) {
//Magic Creation
success = false; //we failed
//We failed to create
if (!success) {
return {
object: null,
errorCode: 403,
errorDescription: 'We didnt have permission to create...'
};
}
return {
object: createdObject,
errorCode: 400,
errorDescription: ''
};
}
var myObject = createSomething('argument');
if (myObject.errorCode != 400) {
console.log(myObject.errorCode + ' ' + myObject.errorDescription)
}
//but myObject does not hold My Object but an implementative
//and accidental array
//from now on me need to remember this
Right
function createSomething(arguments) {
//Magic Creation
success = false; //we failed
//We failed to create
if (!success) {
throw new Error('We didnt have permission to create...');
}
return createdObject;
}
try {
var myObject = createSomething('argument');
//no IFS, just happy path
} catch (exception) {
//deal with it!
console.log(exception.message);
}
// myObject holds my expected object
Detection
We can teach our linters to find patterns of integer and strings returns coupled with ifs and return checking.
Tags
- Exceptions
Conclusion
Ids and codes are external identifiers.
They are useful when you need to interact with an external system (for example an API Rest).
We should not use them on our own systems and our own internal APIs.
Create and raise generic exceptions.
Only create specific exceptions if you are ready to handle them, and they have specialized behavior.
Don't create anemic Exceptions.
Avoid immature and premature optimized languages favoring return codes.
Relations
More info
Credits
Error handling is important, but if it obscures logic, it’s wrong.
Robert Martin
This article is part of the CodeSmell Series.
Latest comments (4)
Tell the designers of Go programming language.
There's no exception.
Error checking everywhere.
That's exactly the same thing that occured to me, at first. Except, in Go they call "them" Errors and they are the mechanism that serves the same purpose, implemented different way. In the same manner you probably shouldn't return error codes in Go, but return Error objects as the second return value.
Yes. That is why I would chose a more mature language and not one based on the 60s.
But if performance is the ONLY concern I think we can tolerate lots of code smells . It is a price to pay
if you read this sentence on the article above you will find your own answer
Avoid immature and premature optimized languages favoring return codes