Question

我正在努力寻找将两个文件上传到s3的解决方案。我可以使用multer上载一个文件，并且我已经学会了如何做。但是，当我尝试在formdata中的所有文件中进行映射并上载每个文件时，我将每个位置URL放入数组中，这是我保存的位置URL我的数据库。然后，我尝试打印每个URL，但令我惊讶的是，它们在if语句中打印，但是当我将其保存在if之外的数据库中时，却没有打印。可能是异步问题吗？谢谢。

tournamentsCtrl.createTournament = async (req, res) => {
    var files_upload = []
    if (req.files) {
        aws.config.setPromisesDependency();
        aws.config.update({
            accessKeyId: process.env.AWS_ACCESS_KEY_ID,
            secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
            //region: process.env.REGION
        });
        const s3 = new aws.S3();
        req.files.map((item) => {
            var params = {
                ACL: 'public-read',
                Bucket: process.env.AWS_BUCKET_NAME,
                Body: fs.createReadStream(item.path),
                Key: `tournament_img/${uuidv4()/* +req.file.originalname */}`
            };

            await s3.upload(params, (err, data) => {
                if (err) {
                    console.log('Error occured while trying to upload to S3 bucket', err);
                }
                if (data) {
                    fs.unlinkSync(item.path); // Empty temp folder
                    const locationUrl = data.Location;
                    files_upload.push(locationUrl);
                    console.log(files_upload)
                }
            });
        });
    }
    console.log(files_upload)
    const new_data = { ...JSON.parse(req.body.values), img_source: files_upload[0], info_url: files_upload[1] }
    console.log(new_data)
    const newUser = new Tournaments(new_data);
    newUser
        .save()
        .then(user => {
            res.json({ message: 'User created successfully', user });
        })
        .catch(err => {
            console.log('Error occured while trying to save to DB');
        });
};

Answer 1

如果您查看upload的文档，它不会返回promise，因此您不应对其调用await。默认的映射方法与此格式的异步代码不兼容。您需要使用async.map或将异步代码包装在Prom中，例如

return await new Promise((resolve, reject) => {
...
    if (data) {
      fs.unlinkSync(item.path);
      resolve(data.location);
    }

}

您的其他代码也有一些问题。映射函数应返回一个值。如果您不想返回任何内容，则应使用foreach。

Answer 2

我已尝试解决此问题，但我无法做到这一点:( 这是我的新代码。

tournamentsCtrl.createTournament = async (req, res) => {
    aws.config.setPromisesDependency();
    aws.config.update({
        accessKeyId: process.env.AWS_ACCESS_KEY_ID,
        secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
        //region: process.env.REGION
    });
    const s3 = new aws.S3();
    var files_upload = {};
    let promiseList = new Promise(function (resolve, reject) {
        req.files.forEach(element => {
            if (element.fieldname.includes('img')) {
                var folder = 'club_images'
            } else if (element.fieldname.inlcudes('poster')) {
                var folder = 'poster_tournament'
            } else {
                var folder = 'info_tournament'
            }
            var params = {
                ACL: 'public-read',
                Bucket: process.env.AWS_BUCKET_NAME,
                Body: fs.createReadStream(element.path),
                Key: `${folder + '/' + uuidv4() + element.fieldname}`
            };
            s3.upload(params, (err, data) => {
                if (err) {
                    console.log('Error occured while trying to upload to S3 bucket', err);
                }
                if (data) {
                    fs.unlinkSync(element.path); // Empty temp folder
                    const locationUrl = data.Location;
                    files_upload[element.fieldname] = locationUrl;
                    console.log(files_upload);
                }
            });
        });
        resolve(files_upload)
    })
    Promise.all([promiseList]).then(() => {
        console.log(Object.assign(JSON.parse(req.body.values), files_upload));
        const newUser = new Tournaments(Object.assign(JSON.parse(req.body.values), files_upload));
        console.log(newUser)
        newUser
            .save()
            .then(user => {
                res.json({ message: 'User created successfully', user });
            })
            .catch(err => {
                console.log('Error occured while trying to save to DB');
            });
    })
};

Answer 3

这是一个寻求代码建议的好地方，但类似以下内容

function uploadFile(s3, element) {
    return new Promise((resolve, reject) => {
        let folder;
        if (element.fieldname.includes('img')) {
            folder = 'club_images'
        } else if (element.fieldname.inlcudes('poster')) {
            folder = 'poster_tournament'
        } else {
            folder = 'info_tournament'
        }
        const params = {
            ACL: 'public-read',
            Bucket: process.env.AWS_BUCKET_NAME,
            Body: fs.createReadStream(element.path),
            Key: `${folder + '/' + uuidv4() + element.fieldname}`
        };
        s3.upload(params, (err, data) => {
            if (err) {
                return reject(err);
            }

            if (data) {
                return fs.unlink(element.path, err=> {
                    if(err) {
                        console.error("Failed to unlink file", element.path);
                    }
                    return resolve({[element.fieldname]: data.Location});
                }); // Empty temp folder
            }
            return resolve();

        });
    })
}

tournamentsCtrl.createTournament = async (req, res) => {
    aws.config.setPromisesDependency();
    aws.config.update({
        accessKeyId: process.env.AWS_ACCESS_KEY_ID,
        secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
        //region: process.env.REGION
    });
    const s3 = new aws.S3();

    try {
        const uploadData = await Promise.all(req.files.map(element => uploadFile(s3, element)));
        const returnData = Object.assign({}, ...uploadData);
        console.log(Object.assign(JSON.parse(req.body.values), returnData));
    } catch(e) {
        console.error('Failed to upload file', e);
        return res.sendStatus(500);
    }

    const newUser = new Tournaments(Object.assign(JSON.parse(req.body.values), files_upload));
    console.log(newUser)
    try {
        const user = await newUser.save()
        res.json({message: 'User created successfully', user});
    } catch(e) {
        console.error('Error occured while trying to save to DB');
        return res.sendStatus(500);
    }
};

在s3地图问题中使用节点上传多张图片

3 个答案: