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@ergusto
Forked from jice-lavocat/imageSyncing.js
Created January 22, 2017 16:01
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AWS Lambda - S3 : Thumbnail creation
// dependencies
var async = require('async');
var path = require('path');
var AWS = require('aws-sdk');
var gm = require('gm').subClass({
imageMagick: true
});
var util = require('util');
// get reference to S3 client
var s3 = new AWS.S3();
exports.handler = function(event, context) {
// Read options from the event.
console.log("Reading options from event:\n", util.inspect(event, {
depth: 5
}));
var srcBucket = event.Records[0].s3.bucket.name;
// Object key may have spaces or unicode non-ASCII characters.
var srcKey = decodeURIComponent(event.Records[0].s3.object.key.replace(
/\+/g, " "));
var dstBucket = srcBucket + "-output";
// Sanity check: validate that source and destination are different buckets.
if (srcBucket == dstBucket) {
console.error("Destination bucket must not match source bucket.");
return;
}
var _800px = {
width: 800,
dstnKey: srcKey,
destinationPath: "large"
};
var _500px = {
width: 500,
dstnKey: srcKey,
destinationPath: "medium"
};
var _200px = {
width: 200,
dstnKey: srcKey,
destinationPath: "small"
};
var _45px = {
width: 45,
dstnKey: srcKey,
destinationPath: "thumbnail"
};
var _sizesArray = [_800px, _500px, _200px, _45px];
var len = _sizesArray.length;
console.log(len);
console.log(srcBucket);
console.log(srcKey);
// Infer the image type.
var typeMatch = srcKey.match(/\.([^.]*)$/);
var fileName = path.basename(srcKey);
if (!typeMatch) {
console.error('unable to infer image type for key ' + srcKey);
return;
}
var imageType = typeMatch[1].toLowerCase();
if (imageType != "jpg" && imageType != "gif" && imageType != "png" &&
imageType != "eps") {
console.log('skipping non-image ' + srcKey);
return;
}
// Transform, and upload to same S3 bucket but to a different S3 bucket.
async.forEachOf(_sizesArray, function(value, key, callback) {
async.waterfall([
function download(next) {
console.time("downloadImage");
console.log("download");
// Download the image from S3 into a buffer.
// sadly it downloads the image several times, but we couldn't place it outside
// the variable was not recognized
s3.getObject({
Bucket: srcBucket,
Key: srcKey
}, next);
console.timeEnd("downloadImage");
},
function convert(response, next) {
// convert eps images to png
console.time("convertImage");
console.log("Reponse content type : " +
response.ContentType);
console.log("Conversion");
gm(response.Body).antialias(true).density(
300).toBuffer('JPG', function(err,
buffer) {
if (err) {
//next(err);
next(err);
} else {
console.timeEnd(
"convertImage");
next(null, buffer);
//next(null, 'done');
}
});
},
function process(response, next) {
console.log("process image");
console.time("processImage");
// Transform the image buffer in memory.
//gm(response.Body).size(function(err, size) {
gm(response).size(function(err, size) {
//console.log("buf content type " + buf.ContentType);
// Infer the scaling factor to avoid stretching the image unnaturally.
console.log("run " + key +
" size array: " +
_sizesArray[key].width);
console.log("run " + key +
" size : " + size);
console.log(err);
var scalingFactor = Math.min(
_sizesArray[key].width /
size.width, _sizesArray[
key].width / size.height
);
console.log("run " + key +
" scalingFactor : " +
scalingFactor);
var width = scalingFactor *
size.width;
var height = scalingFactor *
size.height;
console.log("run " + key +
" width : " + width);
console.log("run " + key +
" height : " + height);
var index = key;
//this.resize({width: width, height: height, format: 'jpg',})
this.resize(width, height).toBuffer(
'JPG', function(err,
buffer) {
if (err) {
//next(err);
next(err);
} else {
console.timeEnd(
"processImage"
);
next(null,
buffer,
key);
//next(null, 'done');
}
});
});
},
function upload(data, index, next) {
console.time("uploadImage");
console.log("upload : " + index);
console.log("upload to path : /images/" +
_sizesArray[index].destinationPath +
"/" + fileName.slice(0, -4) +
".jpg");
// Stream the transformed image to a different folder.
s3.putObject({
Bucket: dstBucket,
Key: "images/" + _sizesArray[
index].destinationPath +
"/" + fileName.slice(0, -4) +
".jpg",
Body: data,
ContentType: 'JPG'
}, next);
console.timeEnd("uploadImage");
}
], function(err, result) {
if (err) {
console.error(err);
}
// result now equals 'done'
console.log("End of step " + key);
callback();
});
}, function(err) {
if (err) {
console.error('---->Unable to resize ' + srcBucket +
'/' + srcKey + ' and upload to ' + dstBucket +
'/images' + ' due to an error: ' + err);
} else {
console.log('---->Successfully resized ' + srcBucket +
' and uploaded to' + dstBucket + "/images");
}
context.done();
});
};
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