I have a nestjs project that is mostly in RESTful structure. Everything works fine, but my concern is that some of the routes check for the presence of some query parameters to fetch data.
for instance
#Get('/some-resources')
async getSomeResource(
#Query() query: any
): Promise<HTTPResponseDTO>{
const startDate = query.startDate ? DateTime.fromISO(query.startDate).startOf('day').toISO(): null;
const endDate = query.endDate ? DateTime.fromISO(query.endDate).endOf('day').toISO() : null;
.
.
.
const result = await this.someResourceService.findAll(startDate, endDate,...)
}
Now my question is, is there a cleaner approach to this? Because this can get become a pain to maintain when we have many resources.
As mentioned by Micael Levi, you should be able to do this by creating your own custom pipe. Assuming that what you posted works, you should be able to do something along the lines of:
#Get('/some-resources')
async getSomeResource(
#Query('startDate', ParseDateIsoPipe) startDate?: string,
#Query('endDate', ParseDateIsoPipe) endDate?: string
): Promise<HTTPResponseDTO>{
<code>
}
With your ParseDateIsoPipe as follows (Note that you will still need to import DateTime from the package you are using):
import { PipeTransform, Injectable, ArgumentMetadata } from '#nestjs/common';
#Injectable()
export class ParseDateIsoPipe implements PipeTransform {
transform(value: any, metadata: ArgumentMetadata) {
return value ? DateTime.fromISO(value).startOf('day').toISO(): null;
}
}
You can use the built-in validation pipe: https://docs.nestjs.com/techniques/validation with the auto validation feature.
Related
In Laravel (php) has route /article/:article, and in controller method I get the model:
function getArticle(ArticleModel $article) {...}
How to make this in NestJS?
My controller:
#Controller('/articles')
export class ArticlesController {
#Get('/:article/edit')
editArticle(#Param('article') articleId: number) {...}
}
How to transform #Param('article') to custom decorator #ArticleParam() which will return my Article entity by id in request?
You can implement a custom pipe that injects a TypeORM repository and returns the database entity when prompted with an ID, something like this:
#Injectable()
export class ArticlePipe implements PipeTransform {
constructor(#InjectRepository(Article) private repository: Repository<Article>) {}
transform(value: id, metadata: ArgumentsMetadata): Promise<Article|null> {
return this.repository.findOneBy({ id });
}
}
Then use it like
#Get('/article/:id')
getArticle(#Param('id', ArticlePipe) article: Article) { ... }
You just need to make sure to use the pipe only on modules that provide the Article EntityRepository.
Then, if you need the specific #ArticleParam, it should be like this:
export function ArticleParam = () => applyDecorators(
Param(ArticlePipe)
)
I am new to nestjs and tring to apply Get and Post simultaneously on a method in my controller.
For simplicity, I just post the core logic code snippet:
Customized Decorator
import { Get, Post } from "#nestjs/common";
import { RenderReact } from 'my-personal-package';
export function Page(path: string, view?: React.ComponentType, methodDecorators?: ((path?: string | string[]) => MethodDecorator)[]): MethodDecorator {
return (target: any, key: string, desc: PropertyDescriptor) => {
const decorators = [
Get(path), // Add Get first.
Post(path) // Add Post then.
];
if (view) {
decorators.push(RenderReact(view)); // RenderReact will return a MethodDecorator as well.
}
decorators.forEach(decorate => decorate(target, key, desc));
return desc;
};
}
Controller method:
#Page("my-path", ThisIsMyPageFunctionalComponent, [Post]) // Post was from #nestjs/common
async return() {
// method logic
}
The array "decorators" at the very beginning in the Page function,
Add Get, then Post, Only Post works.
Add Post, then Get, Only Get works.
How can we apply Get/Post simultaneously here?
As #Micael Levi mentioned above, as the machanism of how decorator factory works, we can not apply both Get and Post in this way. I have tried it for a long time.
Please refer to the question here, like #Kim Kern posted
We extracted common logic into a method.
Separate the method Get and Post which will call the common logic.
I think I might be misunderstanding Nest.js's IoC container, or maybe DI as a whole.
I have a class, JSONDatabase, that I want to instantiate myself based on some config value (can either be JSON or SQL).
My DatabaseService provider:
constructor(common: CommonService, logger: LoggerService) {
// eslint-disable-next-line prettier/prettier
const databaseType: DatabaseType = common.serverConfig.dbType as DatabaseType;
if (databaseType === DatabaseType.JSON) {
this.loadDatabase<JSONDatabase>(new JSONDatabase());
} else if (databaseType === DatabaseType.SQL) {
this.loadDatabase<SQLDatabase>(new SQLDatabase());
} else {
logger.error('Unknown database type.');
}
}
My JSONDatabase class:
export class JSONDatabase implements IDatabase {
dbType = DatabaseType.JSON;
constructor(logger: LoggerService, io: IOService) {
logger.log(`Doing something...`)
}
}
However, the problem with this is that if I want my JSONDatabase to take advantage of injection, ie. it requires both IOService and LoggerService, I need to add the parameters from the DatabaseService constructor rather than inject them through Nest's IoC containers.
Expected 2 arguments, but got 0 [ts(2554)]
json.database.ts(7, 15): An argument for 'logger' was not provided.
Is this the proper way to do this? I feel like manually passing these references through is incorrect, and I should use Nest's custom providers, however, I don't really understand the Nest docs on this subject. I essentially want to be able to new JSONDatabase() without having to pass in references into the constructor and have the Nest.js IoC container inject the existing singletons already (runtime dependency injection?).
I might be completely off base with my thinking here, but I haven't used Nest all that much, so I'm mostly working off of instinct. Any help is appreciated.
The issue you have right now is because you are instantiating JSONDatabase manually when you call new JSONDatabase() not leveraging the DI provided by NestJS. Since the constructor expects 2 arguments (LoggerService, and IOService) and you are providing none, it fails with the message
Expected 2 arguments, but got 0 [ts(2554)]
I think depending on your use case you can try a couple of different options
If you fetch your configuration on startup and set the database once in the application lifetime you can use use a Custom provider with the useFactory syntax.
const providers = [
{
provide: DatabaseService,
useFactory: (logger: LoggerService, io: IOService, config: YourConfigService): IDatabase => {
if (config.databaseType === DatabaseType.JSON) {
return new JSONDatabase(logger, io);
} else if (databaseType === DatabaseType.SQL) {
return new SQLDatabase(logger, io);
} else {
logger.error('Unknown database type.');
}
},
inject: [LoggerService, IOService, YourConfigService]
},
];
#Module({
providers,
exports: providers
})
export class YourModule {}
If you have LoggerService, IOService and YourConfigurationService annotated with #Injectable() NestJS will inject them in the useFactory context. There you can check the databaseType and manually instantiate the correct IDatabase implementation. The drawback with this approach is that you can't easily change the database in runtime. (This might work just fine for your use case)
You can use strategy/factory pattern to get the correct implementation based on a type. Let say you have a method that saves to different databases based on an specific parameter.
#Injectable()
export class SomeService {
constructor(private readonly databaseFactory: DatabaseFactory){}
method(objectToSave: Object, type: DatabaseType) {
databaseFactory.getService(type).save(objectToSave);
}
}
#Injectable()
export class DatabaseFactory {
constructor(private readonly moduleRef: ModuleRef) {}
getService(type: DatabaseType): IDatabase {
this.moduleRef.get(`${type}Database`);
}
}
The idea of the code above is, based on the database type, get the correct singleton from NestJS scope. This way it's easy to add a new database if you want - just add a new type and it's implementation. (and your code can handle multiple databases at the same time!)
I also believe you can simply pass the already injected LoggerService and IOService to the DatabasesService you create manually (You would need to add IOService as a dependency of DatabaseServce
#Injectable()
export class DatabaseService {
constructor(common: CommonService, logger: LoggerService, ioService: IOService) {
// eslint-disable-next-line prettier/prettier
const databaseType: DatabaseType = common.serverConfig.dbType as DatabaseType;
if (databaseType === DatabaseType.JSON) {
this.loadDatabase<JSONDatabase>(new JSONDatabase(logger, ioService));
} else if (databaseType === DatabaseType.SQL) {
this.loadDatabase<SQLDatabase>(new SQLDatabase(logger, ioService));
} else {
logger.error('Unknown database type.');
}
}
}
Whilst studying NestJS I encountered an issue, I have the following DTO:
export default class SearchNotesDto {
query: string;
createdAfter: Date;
createdBefore: Date;
}
Which I wish to get when a GET request is made to an endpoint, which is handled by the following function in my controller:
#Get()
getNotes(#Query() searchNotesDto: SearchNotesDto): Note[] {
if (Object.keys(searchNotesDto).length) {
return this.notesService.searchNotes(searchNotesDto);
}
return this.notesService.getAllNotes();
}
My problem is that createdAfter and createdBefore are strings in searchNotesDto, and I wish to work with the Date object, is there a way to implicitly convert those fields to a Date?
#Query will serialize all properties to type string because that's how query string works in terms of HTTP Request. You will need to utilize a Pipe to transform your query to the right shape of data.
https://docs.nestjs.com/pipes
export class SearchNotePipe implements PipeTransform {
transform(value: any, metadata: ArgumentMetadata) {
// value will be your `searchNotesDto`
const notesDto = new SearchNotesDto();
// do your transformation here
return notesDto;
}
}
I am writing a NestJS application. Some of the endpoints support sorting e.g. http://127.0.0.1:3000/api/v1/members?sort=-id&take=100 Which means sort by id descending.
This parameter arrives as a #Query parameter and is passed to my service. This service transforms it into an object which is used by TypeORM:
{
id: 'DESC'
}
I don't want to call this conversion method manually every time I need sorting.
I've tried an intercepter but this one could not easily change the request parameters into the desired object.
A pipe worked but then I still need to add #Query(new SortPipe()) for every endpoint definition.
Another option is in the repository itself. The NestJS documentation is very well written, but misses guidance in where to put what.
Is there someone who had a similar issue with converting Query parameters before they are used in NestJS, and can explain what approach is the best within NestJS?
This question might look like an opinion based question, however I am looking for the way it is supposed to be done with the NestJS philosophy in mind.
Pipes are probably the easiest way to accomplish this. Instead of adding your pipe for every endpoint definition you can add a global pipe that will be called on every endpoint. In your main.ts:
async function bootstrap() {
...
app.useGlobalPipes(new SortPipe());
...
}
You can then create a pipe like this:
import { PipeTransform, Injectable, ArgumentMetadata } from '#nestjs/common';
#Injectable()
export class SortPipe implements PipeTransform {
transform(value: any, metadata: ArgumentMetadata) {
const { type } = metadata;
// Make sure to only run your logic on queries
if (type === 'query') return this.transformQuery(value);
return value;
}
transformQuery(query: any) {
if (typeof query !== 'object' || !value) return query;
const { sort } = query;
if (sort) query.sort = convertForTypeOrm(sort);
return query;
}
}
If you do not want sort value on ALL endpoints to be automatically converted, you can pass custom parameter to #Query(), for example #Query('sort'). And then:
transform(value: any, metadata: ArgumentMetadata) {
const { type, data } = metadata;
// Make sure to only run your logic on queries when 'sort' is supplied
if (type === 'query' && data === 'sort') return this.transformQuery(value);
return value;
}