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nestjs-form-data is aNestJS middleware for handling multipart/form-data, which is primarily used for uploading files.

• Process files and strings, serialize form-data to object
• Process files in nested objects
• Integration withclass-validator, validate files with validator decorator

nestjs-form-data serializes the form-data request into an object and places it in the body of the request.The files in the request are transformed into objects.
Standard file storage types:

• Memory storage
• File system storage

Changelog

# npmnpm install nestjs-form-data# yarnyarn add nestjs-form-data

This module hasclass-validator andclass-transformer as arequired peed dependencies.
Read more about validation pipe in theofficial docs page.
Make sure that you already have these and enable global validation pipe:

# npmnpm install class-validator class-transformer# yarnyarn add class-validator class-transformer

Register a global validation pipe inmain.ts file insidebootstrap function:

//main.tsapp.useGlobalPipes(newValidationPipe({transform:true// Transform is recomended configuration for avoind issues with arrays of files transformations}));

Add the module to your application

@Module({imports:[NestjsFormDataModule,],})exportclassAppModule{}

Apply@FormDataRequest() decorator to your controller method

@Controller()exportclassNestjsFormDataController{  @Post('load')  @FormDataRequest()getHello(@Body()testDto:FormDataTestDto):void{console.log(testDto);}}

If you are using class-validator describe dto and specify validation rules

exportclassFormDataTestDto{  @IsFile()  @MaxFileSize(1e6)  @HasMimeType(['image/jpeg','image/png'])avatar:MemoryStoredFile;}

Need to install@fastify/multipart.

// main.tsimport{NestFactory}from'@nestjs/core';import{FastifyAdapter,NestFastifyApplication,}from'@nestjs/platform-fastify';importmultipartfrom'@fastify/multipart'asyncfunctionbootstrap(){constapp=awaitNestFactory.create<NestFastifyApplication>(AppModule,newFastifyAdapter());app.register(multipart);awaitapp.listen(3000);}

You can set the global configuration when connecting the module using theNestjsFormDataModule.config method:

@Module({imports:[NestjsFormDataModule.config({storage:MemoryStoredFile}),],controllers:[],providers:[],})exportclassAppModule{}

Quite often you might want to asynchronously pass your module options instead of passing them beforehand.In such case, useconfigAsync() method, that provides a couple of various ways to deal with async data.

NestjsFormDataModule.configAsync({useFactory:()=>({storage:MemoryStoredFile})});

Our factory behaves like every other one (might be async and is able to inject dependencies through inject).

NestjsFormDataModule.configAsync({imports:[ConfigModule],useFactory:async(configService:ConfigService)=>({storage:MemoryStoredFile,limits:{files:configService.get<number>('files'),}}),inject:[ConfigService],});

NestjsFormDataModule.configAsync({useClass:MyNestJsFormDataConfigService});

Above construction will instantiateMyNestJsFormDataConfigService insideNestjsFormDataModule and will leverage itto create options object.

exportclassMyNestJsFormDataConfigServiceimplementsNestjsFormDataConfigFactory{configAsync():Promise<FormDataInterceptorConfig>|FormDataInterceptorConfig{return{storage:FileSystemStoredFile,fileSystemStoragePath:'/tmp/nestjs-fd',};}}

NestjsFormDataModule.configAsync({imports:[MyNestJsFormDataConfigModule],useExisting:MyNestJsFormDataConfigService});

It works the same as useClass with one critical difference -NestjsFormDataModule will lookup imported modules toreuse already createdMyNestJsFormDataConfigService, instead of instantiating it on its own.

Or pass the config object while using the decorator on the method

@Controller()exportclassNestjsFormDataController{  @Post('load')  @FormDataRequest({storage:MemoryStoredFile})getHello(@Body()testDto:FormDataTestDto):void{console.log(testDto);}}

• isGlobal - If you want the module to be available globally. Once you import the module and configure it, it will be available globally
• storage - The type of storage logic for the uploaded file (Default MemoryStoredFile)
• fileSystemStoragePath - The path to the directory for storing temporary files, used only forstorage: FileSystemStoredFile (Default: /tmp/nestjs-tmp-storage)
• cleanupAfterSuccessHandle - If set to true, all processed and uploaded files will be deleted after successful processing by the final method. This means that thedelete method will be called on all files (StoredFile)
• cleanupAfterFailedHandle - If set to true, all processed and uploaded files will be deleted after unsuccessful processing by the final method. This means that thedelete method will be called on all files (StoredFile)
• limits -busboy limits configuration. Constraints in this declaration are handled at the serialization stage, so using these parameters is preferable for performance.

MemoryStoredFile The file is loaded into RAM, files with this storage type are very fast but not suitable for processing large files.

FileSystemStoredFile The file is loaded into a temporary directory (see configuration) and is available during the processing of the request. The file is automatically deleted after the request finishes

You can define a custom type of file storage, for this, inherit your class fromStoredFile, see examples in the storage directory

By default, several validators are available with which you can check the file
Note: If you need to validate an array of files for size or otherwise, useeach: true property fromValidationOptions

Checks if the value is an uploaded file

@IsFile(validationOptions?:ValidationOptions)

Checks an array of files, the same as@IsFile({ each: true })
For convenience

@IsFiles(validationOptions?:ValidationOptions)

Maximum allowed file size

@MaxFileSize(maxSizeBytes: number,validationOptions?:ValidationOptions)

Minimum allowed file size

@MinFileSize(minSizeBytes: number,validationOptions?:ValidationOptions)

Check the mime type of the file
The library uses two sources to get the mime type for the file:

• file-type library gets mime-type: gets the mime-type from themagic number directly from the binary data, it is a reliable source because it checks the file itself but may not return values for some files
• content type header from [busboy](https://www.npmjs.com/package/busboy: is a less trusted source because it can be tampered with

Priority of receiving mime-type corresponds to the list

The default is simple mode, which does not check the data source, but you can pass a second argument to strictly check the mime-type and data source.
You can also get the mime type and data source via theget mimeTypeWithSource():MetaFieldSource getter on theStoredFile

typeAllowedMimeTypes=Array<AllowedMimeType>typeAllowedMimeType=string|RegExp;@HasMimeType(allowedMimeTypes:AllowedMimeTypes|AllowedMimeType,strictSource?:MetaSource|ValidationOptions,validationOptions?:ValidationOptions)

You can also use partial matching, just pass the unimportant parameter as*, for example:

@HasMimeType('image/*')

also as array:

@HasMimeType(['image/*','text/*'])

Check the extension type of the fileThe library uses two sources to get the extension for the file:

• file-type library gets mime-type: gets the extension from themagic number directly from the binary data, it is a reliable source because it checks the file itself but may not return values for some files
• value after the last dot in file name: is a less trusted source because it can be tampered with

Priority of receiving extension corresponds to the list

The default is simple mode, which does not check the data source, but you can pass a second argument to strictly check the extension and data source.
You can also get the extension and data source via theget extensionWithSource():MetaFieldSource getter on theStoredFile

@HasExtension(allowedMimeTypes: string[]|string,strictSource?:MetaSource|ValidationOptions,validationOptions?:ValidationOptions)

Controller

import{FileSystemStoredFile,FormDataRequest}from'nestjs-form-data';@Controller()exportclassNestjsFormDataController{  @Post('load')  @FormDataRequest({storage:FileSystemStoredFile})getHello(@Body()testDto:FormDataTestDto):void{console.log(testDto);}}

DTO

import{FileSystemStoredFile,HasMimeType,IsFile,MaxFileSize}from'nestjs-form-data';exportclassFormDataTestDto{  @IsFile()  @MaxFileSize(1e6)  @HasMimeType(['image/jpeg','image/png'])avatar:FileSystemStoredFile;}

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DTO

import{FileSystemStoredFile,HasMimeType,IsFiles,MaxFileSize}from'nestjs-form-data';exportclassFormDataTestDto{  @IsFiles()  @MaxFileSize(1e6,{each:true})  @HasMimeType(['image/jpeg','image/png'],{each:true})avatars:FileSystemStoredFile[];}

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MIT