feat: add validation for email attachments (#62)

apps/api/src/jobs/consumers/notifications/mailgun-notifications.job.consumer.ts

@@ -28,7 +28,12 @@ export class MailgunNotificationConsumer {
 
     try {
       this.logger.log(`Sending notification with id: ${id}`);
-      const result = await this.mailgunService.sendEmail(notification.data as MailgunMessageData);
+      const formattedNotificationData = await this.mailgunService.formatNotificationData(
+        notification.data,
+      );
+      const result = await this.mailgunService.sendEmail(
+        formattedNotificationData as MailgunMessageData,
+      );
       notification.deliveryStatus = DeliveryStatus.SUCCESS;
       notification.result = { result };
     } catch (error) {

apps/api/src/modules/notifications/dtos/create-notification-attachment.dto.ts

@@ -0,0 +1,70 @@
+import {
+  IsNotEmpty,
+  ValidateIf,
+  registerDecorator,
+  ValidationOptions,
+  ValidationArguments,
+} from 'class-validator';
+import { Stream } from 'stream';
+
+export class CreateNotificationAttachmentDto {
+  @IsNotEmpty({ message: 'Filename cannot be empty' })
+  filename: string;
+
+  @IsNotEmpty({ message: 'Content or path must be provided' })
+  @ValidateIf((obj) => !obj.path, { message: 'Content or path must be provided' })
+  content: string | Buffer | Stream;
+
+  @IsNotEmpty({ message: 'Content or path must be provided' })
+  @ValidateIf((obj) => !obj.content, { message: 'Content or path must be provided' })
+  path: string;
+}
+
+// TODO: Custom Validator added for the bug
+// https://github.com/OsmosysSoftware/osmo-notify/pull/62
+export function AttachmentValidation(validationOptions?: ValidationOptions) {
+  return function (object: unknown, propertyName: string) {
+    registerDecorator({
+      name: 'attachmentValidation',
+      target: object.constructor,
+      propertyName: propertyName,
+      options: validationOptions,
+      validator: {
+        validate(value: unknown[]) {
+          if (!value || value.length === 0) {
+            return false;
+          }
+
+          for (const attachment of value) {
+            const path = attachment['path'];
+            const content = attachment['content'];
+            const filename = attachment['filename'];
+
+            if ((!path && !content) || !filename?.length) {
+              return false;
+            }
+          }
+
+          return true;
+        },
+        defaultMessage(args: ValidationArguments) {
+          if (!args.value || args.value.length === 0) {
+            return 'Attachments must be provided';
+          }
+
+          for (const attachment of args.value) {
+            if (!attachment['filename']?.length) {
+              return 'Filename cannot be empty';
+            }
+
+            if (!attachment['content'] && !attachment['path']) {
+              return 'Content or path must be provided for each attachment';
+            }
+          }
+
+          return 'Invalid attachments';
+        },
+      },
+    });
+  };
+}

apps/api/src/modules/notifications/dtos/providers/mailgun-data.dto.ts

@@ -1,4 +1,9 @@
 import { IsString, IsNotEmpty, IsOptional } from 'class-validator';
+import {
+  AttachmentValidation,
+  CreateNotificationAttachmentDto,
+} from '../create-notification-attachment.dto';
+import { Type } from 'class-transformer';
 
 export class MailgunDataDto {
   @IsNotEmpty()
@@ -24,4 +29,9 @@ export class MailgunDataDto {
   @IsNotEmpty()
   @IsString()
   html: string;
+
+  @IsOptional()
+  @Type(() => CreateNotificationAttachmentDto)
+  @AttachmentValidation()
+  attachments: CreateNotificationAttachmentDto[];
 }

apps/api/src/modules/notifications/dtos/providers/smtp-data.dto.ts

@@ -1,4 +1,9 @@
 import { IsString, IsNotEmpty, IsOptional } from 'class-validator';
+import {
+  AttachmentValidation,
+  CreateNotificationAttachmentDto,
+} from '../create-notification-attachment.dto';
+import { Type } from 'class-transformer';
 
 export class SMTPDataDto {
   @IsNotEmpty()
@@ -24,4 +29,9 @@ export class SMTPDataDto {
   @IsNotEmpty()
   @IsString()
   html: string;
+
+  @IsOptional()
+  @Type(() => CreateNotificationAttachmentDto)
+  @AttachmentValidation()
+  attachments: CreateNotificationAttachmentDto[];
 }

apps/api/src/modules/providers/mailgun/mailgun.service.ts

@@ -2,6 +2,9 @@ import { Injectable } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import * as FormData from 'form-data';
 import Mailgun, { MailgunClientOptions, MailgunMessageData, MessagesSendResult } from 'mailgun.js';
+import * as path from 'path';
+import * as fs from 'node:fs/promises';
+import { CreateNotificationAttachmentDto } from 'src/modules/notifications/dtos/create-notification-attachment.dto';
 
 @Injectable()
 export class MailgunService {
@@ -22,4 +25,33 @@ export class MailgunService {
   sendEmail(mailgunNotificationData: MailgunMessageData): Promise<MessagesSendResult> {
     return this.mailgunClient.messages.create(this.mailgunDomain, mailgunNotificationData);
   }
+
+  async formatNotificationData(notificationData: Record<string, unknown>): Promise<object> {
+    const formattedNotificationData = notificationData;
+    formattedNotificationData.attachment = await this.formatAttachments(
+      notificationData.attachments as CreateNotificationAttachmentDto[],
+    );
+    delete formattedNotificationData.attachments;
+    return formattedNotificationData;
+  }
+
+  async formatAttachments(attachments: CreateNotificationAttachmentDto[]): Promise<object[]> {
+    const formattedAttachments = [];
+
+    for (const attachment of attachments) {
+      let data = attachment.content;
+
+      if (attachment.path) {
+        const filepath = path.resolve(attachment.path);
+        data = await fs.readFile(filepath);
+      }
+
+      formattedAttachments.push({
+        filename: attachment.filename,
+        data,
+      });
+    }
+
+    return formattedAttachments;
+  }
 }