Feature/4752 file validators pipe

packages/common/pipes/file/file-type.validator.ts

@@ -0,0 +1,30 @@
+import { FileValidator } from './file-validator.interface';
+
+export type FileTypeValidatorOptions = {
+  fileType: string;
+};
+
+/**
+ * Defines the built-in FileType File Validator
+ *
+ * @see [File Validators](https://docs.nestjs.com/techniques/file-upload#validators)
+ *
+ * @publicApi
+ */
+export class FileTypeValidator extends FileValidator<FileTypeValidatorOptions> {
+  buildErrorMessage(): string {
+    return `Validation failed (expected type is ${this.validationOptions.fileType})`;
+  }
+
+  isValid(file: any): boolean {
+    if (!this.validationOptions) {
+      return true;
+    }
+
+    if (!file.mimetype) {
+      return false;
+    }
+
+    return (file.mimetype as string).endsWith(this.validationOptions.fileType);
+  }
+}

packages/common/pipes/file/file-validator.interface.ts

@@ -0,0 +1,18 @@
+/**
+ * Interface describing FileValidators, which can be added to a {@link ParseFilePipe}.
+ */
+export abstract class FileValidator<TValidationOptions = Record<string, any>> {
+  constructor(protected readonly validationOptions: TValidationOptions) {}
+
+  /**
+   * Indicates if this file should be considered valid, according to the options passed in the constructor.
+   * @param file the file from the request object
+   */
+  abstract isValid(file?: any): boolean | Promise<boolean>;
+
+  /**
+   * Builds an error message in case the validation fails.
+   * @param file the file from the request object
+   */
+  abstract buildErrorMessage(file: any): string;
+}

packages/common/pipes/file/index.ts

@@ -0,0 +1,6 @@
+export * from './file-type.validator';
+export * from './file-validator.interface';
+export * from './max-file-size.validator';
+export * from './parse-file-options.interface';
+export * from './parse-file.pipe';
+export * from './parse-file-pipe.builder';

packages/common/pipes/file/max-file-size.validator.ts

@@ -0,0 +1,26 @@
+import { FileValidator } from './file-validator.interface';
+
+export type MaxFileSizeValidatorOptions = {
+  maxSize: number;
+};
+
+/**
+ * Defines the built-in MaxSize File Validator
+ *
+ * @see [File Validators](https://docs.nestjs.com/techniques/file-upload#validators)
+ *
+ * @publicApi
+ */
+export class MaxFileSizeValidator extends FileValidator<MaxFileSizeValidatorOptions> {
+  buildErrorMessage(): string {
+    return `Validation failed (expected size is less than ${this.validationOptions.maxSize})`;
+  }
+
+  public isValid(file: any): boolean {
+    if (!this.validationOptions) {
+      return true;
+    }
+
+    return file.size < this.validationOptions.maxSize;
+  }
+}

packages/common/pipes/file/parse-file-options.interface.ts

@@ -0,0 +1,8 @@
+import { ErrorHttpStatusCode } from '../../utils/http-error-by-code.util';
+import { FileValidator } from './file-validator.interface';
+
+export interface ParseFileOptions {
+  validators?: FileValidator[];
+  errorHttpStatusCode?: ErrorHttpStatusCode;
+  exceptionFactory?: (error: string) => any;
+}

packages/common/pipes/file/parse-file-pipe.builder.ts

@@ -0,0 +1,37 @@
+import {
+  FileTypeValidator,
+  FileTypeValidatorOptions,
+} from './file-type.validator';
+import { FileValidator } from './file-validator.interface';
+import {
+  MaxFileSizeValidator,
+  MaxFileSizeValidatorOptions,
+} from './max-file-size.validator';
+import { ParseFileOptions } from './parse-file-options.interface';
+import { ParseFilePipe } from './parse-file.pipe';
+
+export class ParseFilePipeBuilder {
+  private validators: FileValidator[] = [];
+
+  addMaxSizeValidator(options: MaxFileSizeValidatorOptions) {
+    this.validators.push(new MaxFileSizeValidator(options));
+    return this;
+  }
+
+  addFileTypeValidator(options: FileTypeValidatorOptions) {
+    this.validators.push(new FileTypeValidator(options));
+    return this;
+  }
+
+  build(
+    additionalOptions?: Omit<ParseFileOptions, 'validators'>,
+  ): ParseFilePipe {
+    const parseFilePipe = new ParseFilePipe({
+      ...additionalOptions,
+      validators: this.validators,
+    });
+
+    this.validators = [];
+    return parseFilePipe;
+  }
+}

packages/common/pipes/file/parse-file.pipe.ts

@@ -0,0 +1,68 @@
+import { Injectable, Optional } from '../../decorators/core';
+import { HttpStatus } from '../../enums';
+import { HttpErrorByCode } from '../../utils/http-error-by-code.util';
+import { PipeTransform } from '../../interfaces/features/pipe-transform.interface';
+import { ParseFileOptions } from './parse-file-options.interface';
+import { FileValidator } from './file-validator.interface';
+import { throws } from 'assert';
+
+/**
+ * Defines the built-in ParseFile Pipe. This pipe can be used to validate incoming files
+ * with `@UploadedFile()` decorator. You can use either other specific built-in validators
+ * or provide one of your own, simply implementing it through {@link FileValidator}
+ * interface and adding it to ParseFilePipe's constructor.
+ *
+ * @see [Built-in Pipes](https://docs.nestjs.com/pipes#built-in-pipes)
+ *
+ * @publicApi
+ */
+@Injectable()
+export class ParseFilePipe implements PipeTransform<any> {
+  protected exceptionFactory: (error: string) => any;
+  private readonly validators: FileValidator[];
+
+  constructor(@Optional() options: ParseFileOptions = {}) {
+    const {
+      exceptionFactory,
+      errorHttpStatusCode = HttpStatus.BAD_REQUEST,
+      validators = [],
+    } = options;
+
+    this.exceptionFactory =
+      exceptionFactory ||
+      (error => new HttpErrorByCode[errorHttpStatusCode](error));
+
+    this.validators = validators;
+  }
+
+  async transform(value: any): Promise<any> {
+    if (this.validators.length) {
+      await this.validate(value);
+    }
+    return value;
+  }
+
+  protected async validate(file: any): Promise<any> {
+    for (const validator of this.validators) {
+      await this.validateOrThrow(file, validator);
+    }
+
+    return file;
+  }
+
+  private async validateOrThrow(file: any, validator: FileValidator) {
+    const isValid = await validator.isValid(file);
+
+    if (!isValid) {
+      const errorMessage = validator.buildErrorMessage(file);
+      throw this.exceptionFactory(errorMessage);
+    }
+  }
+
+  /**
+   * @returns list of validators used in this pipe.
+   */
+  getValidators() {
+    return this.validators;
+  }
+}

packages/common/pipes/index.ts

@@ -6,3 +6,4 @@ export * from './parse-float.pipe';
 export * from './parse-enum.pipe';
 export * from './parse-uuid.pipe';
 export * from './validation.pipe';
+export * from './file';

packages/common/test/pipes/file/file-type.validator.spec.ts

@@ -0,0 +1,65 @@
+import { FileTypeValidator } from '../../../pipes';
+import { expect } from 'chai';
+
+describe('FileTypeValidator', () => {
+  describe('isValid', () => {
+    it('should return true when the file mimetype is the same as the specified', () => {
+      const fileTypeValidator = new FileTypeValidator({
+        fileType: 'image/jpeg',
+      });
+
+      const requestFile = {
+        mimetype: 'image/jpeg',
+      };
+
+      expect(fileTypeValidator.isValid(requestFile)).to.equal(true);
+    });
+
+    it('should return true when the file mimetype ends with the specified option type', () => {
+      const fileTypeValidator = new FileTypeValidator({
+        fileType: 'jpeg',
+      });
+
+      const requestFile = {
+        mimetype: 'image/jpeg',
+      };
+
+      expect(fileTypeValidator.isValid(requestFile)).to.equal(true);
+    });
+
+    it('should return false when the file mimetype is different from the specified', () => {
+      const fileTypeValidator = new FileTypeValidator({
+        fileType: 'image/jpeg',
+      });
+
+      const requestFile = {
+        mimetype: 'image/png',
+      };
+
+      expect(fileTypeValidator.isValid(requestFile)).to.equal(false);
+    });
+
+    it('should return false when the file mimetype was not provided', () => {
+      const fileTypeValidator = new FileTypeValidator({
+        fileType: 'image/jpeg',
+      });
+
+      const requestFile = {};
+
+      expect(fileTypeValidator.isValid(requestFile)).to.equal(false);
+    });
+  });
+
+  describe('buildErrorMessage', () => {
+    it('should return a string with the format "Validation failed (expected type is #fileType)"', () => {
+      const fileType = 'image/jpeg';
+      const fileTypeValidator = new FileTypeValidator({
+        fileType,
+      });
+
+      expect(fileTypeValidator.buildErrorMessage()).to.equal(
+        `Validation failed (expected type is ${fileType})`,
+      );
+    });
+  });
+});

packages/common/test/pipes/file/max-file-size.validator.spec.ts

@@ -0,0 +1,56 @@
+import { expect } from 'chai';
+import { MaxFileSizeValidator } from '../../../pipes';
+
+describe('MaxFileSizeValidator', () => {
+  const oneKb = 1024;
+
+  describe('isValid', () => {
+    it('should return true when the file size is less than the maximum size', () => {
+      const maxFileSizeValidator = new MaxFileSizeValidator({
+        maxSize: oneKb,
+      });
+
+      const requestFile = {
+        size: 100,
+      };
+
+      expect(maxFileSizeValidator.isValid(requestFile)).to.equal(true);
+    });
+
+    it('should return false when the file size is greater than the maximum size', () => {
+      const maxFileSizeValidator = new MaxFileSizeValidator({
+        maxSize: oneKb,
+      });
+
+      const requestFile = {
+        size: oneKb + 1,
+      };
+
+      expect(maxFileSizeValidator.isValid(requestFile)).to.equal(false);
+    });
+
+    it('should return false when the file size is equal to the maximum size', () => {
+      const maxFileSizeValidator = new MaxFileSizeValidator({
+        maxSize: oneKb,
+      });
+
+      const requestFile = {
+        size: oneKb,
+      };
+
+      expect(maxFileSizeValidator.isValid(requestFile)).to.equal(false);
+    });
+  });
+
+  describe('buildErrorMessage', () => {
+    it('should return a string with the format "Validation failed (expected size is less than #maxSize")', () => {
+      const maxFileSizeValidator = new MaxFileSizeValidator({
+        maxSize: oneKb,
+      });
+
+      expect(maxFileSizeValidator.buildErrorMessage()).to.equal(
+        `Validation failed (expected size is less than ${oneKb})`,
+      );
+    });
+  });
+});