Using ImageMagick to optimize and resize

Author: arivera-tiempodev

.gitignore

@@ -0,0 +1,26 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+*/node_modules
+*/.pnp
+*.pnp.js
+
+# testing
+*/coverage
+
+# production
+*/build
+
+# misc
+.DS_Store
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Bundle
+*.zip

function/event.json

@@ -0,0 +1,38 @@
+{
+  "Records": [
+    {
+      "eventVersion": "2.1",
+      "eventSource": "aws:s3",
+      "awsRegion": "us-east-1",
+      "eventTime": "2019-08-07T20:02:00.791Z",
+      "eventName": "ObjectCreated:Put",
+      "userIdentity": {
+        "principalId": "AWS:SOMEID"
+      },
+      "requestParameters": {
+        "sourceIPAddress": "192.168.0.1"
+      },
+      "responseElements": {
+        "x-amz-request-id": "REQUESTID",
+        "x-amz-id-2": "AMAZONID2="
+      },
+      "s3": {
+        "s3SchemaVersion": "1.0",
+        "configurationId": "a34d5c09-019b-4a6a-ba09-2fca03412e81",
+        "bucket": {
+          "name": "rtalexk-gallery",
+          "ownerIdentity": {
+            "principalId": "SOMEID"
+          },
+          "arn": "arn:aws:s3:::rtalexk-gallery"
+        },
+        "object": {
+          "key": "original/cat.jpg",
+          "size": 3513370,
+          "eTag": "TAGID",
+          "sequencer": "SEQUENCERID"
+        }
+      }
+    }
+  ]
+}

function/index.js

@@ -0,0 +1,82 @@
+const gm = require('gm').subClass({ imageMagick: false });
+const AWS = require('aws-sdk');
+
+const s3 = new AWS.S3();
+
+exports.handler = async (event, context, cb) => {
+  const validExtensions = ['jpg', 'jpeg', 'png'];
+
+  const { bucket, object } = event.Records[0].s3;
+
+  // Where images are uploaded
+  const origin = 'original/';
+
+  // Where optimized images will be saved
+  const dest = 'thumbs/';
+
+  // Object key may have spaces or unicode non-ASCII characters. Remove prefix
+  const fullFileName = decodeURIComponent(object.key.replace(/\+/g, ' '))
+    .split('/').pop();
+
+  const [fileName, fileExt] = fullFileName.split('.');
+
+  if (!validExtensions.includes(fileExt)) {
+    return cb(null, `Image not processed due to .${fileExt} file extension`);
+  }
+
+  // Download image from S3
+  const s3Image = await s3.
+    getObject({
+      Bucket: bucket.name,
+      Key: `${origin}${fullFileName}`
+    })
+    .promise();
+
+  function gmToBuffer(data) {
+    return new Promise((resolve, reject) => {
+      data.stream((err, stdout, stderr) => {
+        if (err) { return reject(err) }
+        const chunks = []
+        stdout.on('data', (chunk) => { chunks.push(chunk) })
+        stdout.once('end', () => { resolve(Buffer.concat(chunks)) })
+        stderr.once('data', (data) => { reject(String(data)) })
+      })
+    })
+  }
+
+  function getBuffer(body, size, quality) {
+    const data = gm(body)
+      .resize(size)
+      .quality(quality);
+
+    return gmToBuffer(data);
+  }
+
+  // use null to optimize image without resizing
+  const sizes = [null, 1200, 640, 420];
+
+  // Uploades all images to S3
+  const uploadPromises = sizes.map(async size => {
+    // Optimize image with current size
+    const imgBuffer = await getBuffer(s3Image.Body, size, 60);
+    const key = size
+      ? `${dest}${fileName}_thumb_${size}.${fileExt}`
+      : `${dest}${fileName}_original.${fileExt}`;
+
+    return s3.putObject({
+      Bucket: bucket.name,
+      Key: key,
+      Body: imgBuffer,
+    }).promise();
+  });
+
+  await Promise.all(uploadPromises);
+
+  cb(null, 'finished');
+};
+
+if (process.env.LOCAL === 'true') {
+  exports.handler(require('./event.json'), null, (err, res) => {
+    console.log(res);
+  });
+}