Lambda image resizer

index.js

const AWS = require('aws-sdk');
const sharp = require('sharp');

const s3 = new AWS.S3();

exports.handler = async (event) => {
    try {
        const bucket = event.Records[0].s3.bucket.name;
        const key = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, ' '));
        const outputKey = `resized/${key}`;
        const resizeWidth = 800; // Width to resize the image to

        // Fetch the original image from S3
        const originalImage = await s3.getObject({
            Bucket: bucket,
            Key: key
        }).promise();

        // Resize the image using sharp
        const resizedImage = await sharp(originalImage.Body)
            .resize({ width: resizeWidth })
            .toBuffer();

        // Save the resized image back to S3
        await s3.putObject({
            Bucket: bucket,
            Key: outputKey,
            Body: resizedImage,
            ContentType: 'image/jpeg' // Update based on your file type
        }).promise();

        console.log(`Image resized and uploaded to ${outputKey}`);

        return {
            statusCode: 200,
            body: JSON.stringify({
                message: 'Image resized successfully',
                resizedKey: outputKey
            })
        };
    } catch (error) {
        console.error('Error processing image:', error);

        return {
            statusCode: 500,
            body: JSON.stringify({
                message: 'Error resizing image',
                error: error.message
            })
        };
    }
};