使用NestJS上传图片至Cloudinary时遇"buf"参数错误求助

问题描述 #

使用NestJS将图片上传至Cloudinary时触发错误：

ERROR [RpcExceptionsHandler] "buf" argument must be a string or an instance of Buffer
TypeError: "buf" argument must be a string or an instance of Buffer

已确认file.buffer类型为Buffer，但上传仍失败，相关代码如下：

service.ts #

import { Injectable } from '@nestjs/common';
import { UploadApiErrorResponse, UploadApiResponse, v2 } from 'cloudinary';
import toStream = require('buffer-to-stream');
@Injectable()
export class CloudinaryService {
  async uploadImage(file: Express.Multer.File): Promise<UploadApiResponse | UploadApiErrorResponse> {
    return new Promise((resolve, reject) => {
      const upload = v2.uploader.upload_stream((error, result) => {
        if (error) return reject(error);
        resolve(result);
      });
      toStream(file.buffer).pipe(upload);
    });
  }
}

module.ts #

import { Module } from '@nestjs/common';
import { CloudinaryServiceController } from './cloudinary-service.controller';
import { CloudinaryService } from './cloudinary-service.service';
import { CloudinaryProvider } from './cloudinary-service.provider';

@Module({
  imports: [],
  controllers: [CloudinaryServiceController],
  providers: [CloudinaryProvider, CloudinaryService],
  exports: [CloudinaryProvider, CloudinaryService],
})
export class CloudinaryServiceModule {}

解决方案 #

1. 替换buffer-to-stream为原生Buffer流 #

buffer-to-stream可能存在版本兼容问题，改用Node.js原生Readable流处理：

import { Injectable } from '@nestjs/common';
import { UploadApiErrorResponse, UploadApiResponse, v2 } from 'cloudinary';
import { Readable } from 'stream';

@Injectable()
export class CloudinaryService {
  async uploadImage(file: Express.Multer.File): Promise<UploadApiResponse | UploadApiErrorResponse> {
    return new Promise((resolve, reject) => {
      const upload = v2.uploader.upload_stream((error, result) => {
        if (error) return reject(error);
        resolve(result);
      });
      Readable.from(file.buffer).pipe(upload);
    });
  }
}

2. 直接上传Base64格式 #

绕开流处理问题，将Buffer转为Base64字符串后上传：

import { Injectable } from '@nestjs/common';
import { UploadApiErrorResponse, UploadApiResponse, v2 } from 'cloudinary';

@Injectable()
export class CloudinaryService {
  async uploadImage(file: Express.Multer.File): Promise<UploadApiResponse | UploadApiErrorResponse> {
    const base64Image = `data:${file.mimetype};base64,${file.buffer.toString('base64')}`;
    return v2.uploader.upload(base64Image, { resource_type: 'auto' });
  }
}

3. 校验Multer控制器配置 #

确保控制器中正确配置Multer，接收完整的Express.Multer.File对象：

import { Controller, Post, UploadedFile, UseInterceptors } from '@nestjs/common';
import { FileInterceptor } from '@nestjs/platform-express';
import { CloudinaryService } from './cloudinary-service.service';

@Controller('upload')
export class CloudinaryServiceController {
  constructor(private readonly cloudinaryService: CloudinaryService) {}

  @Post()
  @UseInterceptors(FileInterceptor('image')) // 确保表单字段名与前端一致
  async uploadFile(@UploadedFile() file: Express.Multer.File) {
    return this.cloudinaryService.uploadImage(file);
  }
}

4. 更新Cloudinary依赖 #

确保cloudinary包为最新版本，执行命令：

npm update cloudinary

内容的提问来源于stack exchange，提问作者Antonio