The request signature we calculated does not match the signature you provided. Check your key and signing method. I get this error only when i use lambda function. Their is no issue in local server

Question

const { S3Client, DeleteObjectCommand, PutObjectCommand } = require("@aws-sdk/client-s3");
const dotenv = require('dotenv');

dotenv.config();

const bucketName = process.env.AWS_BUCKET_BLOG;
const region = process.env.AWS_BUCKET_REGION;
const accessKeyId = process.env.AWS_ACCESS_KEY;
const secretAccessKey = process.env.AWS_SECRET_ACCESS_KEY;
const domain = process.env.AWS_CD_URL_BLOG;

const s3Client = new S3Client({
    region,
    credentials: {
        accessKeyId,
        secretAccessKey
    },
    signatureVersion: 'v4',
});

function uploadPost(fileBuffer, fileName , mimetype) {
    const uploadParams = {
        Bucket: bucketName,
        Body: fileBuffer,
        Key: fileName,
        ContentType: mimetype,
    };

return s3Client.send(new PutObjectCommand(uploadParams));
}

function deletePost(fileName) {
    const deleteParams = {
        Bucket: bucketName,
        Key: fileName,
    };

return s3Client.send(new DeleteObjectCommand(deleteParams));
}

async function getObjectSignedUrlPost(key) {
    const url = domain + key;

return url;
}

module.exports = {
    uploadPost,
    deletePost,
    getObjectSignedUrlPost,
};

Didier_Durand · Accepted Answer

Hi,

Using AWS_ACCESS_KEY and AWS_SECRET_ACCESS_KEY within a Lambda is not the right way to go: you will get credential mismatches like the one you get because the request that you make is done under the Lambda execution role.

So, the right way is to use only the Lambda execution role after granting it the right credentials for the services that you need.

See https://docs.aws.amazon.com/lambda/latest/dg/lambda-intro-execution-role.html

```
You provide an execution role when you create a function. When you invoke your function, 
Lambda automatically provides your function with temporary credentials by assuming this role. 
You don't have to call sts:AssumeRole in your function code.
```
Best,

Didier

The request signature we calculated does not match the signature you provided. Check your key and signing method. I get this error only when i use lambda function. Their is no issue in local server

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