Yaya kuke sarrafa sakandare a cikin NestJS?

Question

IT Interview Practice · Accepted Answer

NestJS yana da **sarrafa sakandare da aka gina ciki** wacce ta kama jiya-jiya klaaje wajen karya kuma ta canza su zuwa amsa HTTP da kyau. Kina isowar muni ta **jefar da sakandare** (galibi azuzuwan sarrafa sakandare HTTP da aka gina), kuma Nest ya tsara su zuwa amsa JSON da yake jujjuyawa tare da lambar yanayin daidai.

## Jefar da sakandare HTTP da aka gina

```ts
import { NotFoundException, BadRequestException, UnauthorizedException } from "@nestjs/common";

@Get(":id")
findOne(@Param("id") id: string) {
  const user = this.usersService.findOne(id);
  if (!user) {
    throw new NotFoundException("User not found");   // → 404 with a JSON error body
  }
  return user;
}
```

NestJS yana yin azuzuwan sakandare wajen kwatanto da lambar yanayin HTTP, kuma jefar da ɗaya yana haifar da amsa madaidaici, wajen jujjuyawa ta atomatik:

```json
{ "statusCode": 404, "message": "User not found", "error": "Not Found" }
```

## Sakandare HTTP da aka gina gabatarwa

```text
BadRequestException        → 400
UnauthorizedException      → 401
ForbiddenException         → 403
NotFoundException          → 404
ConflictException          → 409
UnprocessableEntityException → 422
InternalServerErrorException → 500
```

Akwai ajin kwa kowane kuskure na HTTP - yi amfani da daidaicin ɗaya don sanar yanayin daidai.

## Sakunan mahangar ikirari da HttpException na jujjuyawa

```ts
// custom status + body via the base HttpException
throw new HttpException(
  { status: HttpStatus.FORBIDDEN, error: "custom message" },
  HttpStatus.FORBIDDEN,
);
```

## Azuzuwan sakandare na mahangar

```ts
export class UserNotFoundException extends NotFoundException {
  constructor(id: string) {
    super(`User with id ${id} not found`);   // domain-specific, reusable
  }
}
throw new UserNotFoundException(id);
```

## Karbye wajen karya suna zama 500s

```text
If code throws a non-HttpException error (e.g. a plain Error or an unexpected
exception), NestJS's default exception filter catches it and returns a generic
500 Internal Server Error (without leaking internal details to the client).
```

## Tacce sakandare don gyara duniya

```ts
// a custom exception filter customizes how errors are formatted/logged globally
@Catch()
export class AllExceptionsFilter implements ExceptionFilter {
  catch(exception: unknown, host: ArgumentsHost) {
    // log, format the response, etc.
  }
}
app.useGlobalFilters(new AllExceptionsFilter());   // apply app-wide
```

Don tsara kula daidai, rubuta, ko sarrafa karbye wajen karya ne ba HTTP ba, kina amfani da **tacce sakandare** (sanannen ban, ƙarin cikakkun fasali).

## Yaya ya dace

Sarrafa sakandare ta gida ta ilmantar rayuwa daidai ta gida, kuma sarrafa sakandare ta NestJS ta gina ciki ta sanya ta tsabta da daidai.

Jibewar yadda za a jefa sakandare HTTP (`NotFoundException`, `BadRequestException`, da sauransu) ilmi na kwanar-kwana ne - hanya ta ubangiji ce ta isowar muni tare da lambar yanayin daidai da amsohin JSON da jiya-jiya, ba tare da tsarata amsa sakandare da jiya a kowa sanin aiki ba.

Firgi yana kama su ta atomatik kuma ya tsara su, kuma ya canza cikakkun karbye wajen karya ta amfani zuwa gajiya 500s ba tare da bayar shedar ciki ba (mahimme ne don tsaro).

Jibewar azuzuwan sakandare da aka kasuwa, yadda za a jefa ikirari/sakandare na mahangar, kuma cewa **tacce sakandare** akwai don gyara duniya (tsara daidai, rubuta) mahimman ilmi ne don gina NestJS APIs wajen karya, na jiya-jiya.

Sarrafa sakandare tsabta, daidai mahimman sanannen lamiri ne na amfani na yau da gida, na takaita shi mahimman, gida wajen amfani fakondarin NestJS.

Jefar da sakandare HTTP da aka gina

Sakandare HTTP da aka gina gabatarwa

Sakunan mahangar ikirari da HttpException na jujjuyawa

Azuzuwan sakandare na mahangar

Karbye wajen karya suna zama 500s

Tacce sakandare don gyara duniya

Yaya ya dace

Tambayoyi masu alaƙa