create password pdf file in lambda nodejs - node.js

Question

here is a problem in aws lambda using node.js for creating password in copied pdf file.
const aws = require("aws-sdk");
const fs = require("fs");
const QPDF = require("node-qpdf");
const s3 = new aws.S3();
exports.handler = async (event) => {
const params = {
Bucket: "BucketName",
Key: "key"
};
const s3Object = await s3.getObject(params).promise();
fs.writeFileSync('/tmp/test.pdf', s3Object.Body.toString('base64'),{'encoding':'base64'});
var options = {
keyLength: 128,
password: 'abc123',
restrictions: {
print: 'low',
useAes: 'y'
}
}
QPDF.encrypt('/tmp/test.pdf',options,(err)=>{
if(err)console.log(err,err.stack);
});
fs.exists ( '/tmp/test.pdf', function (exists) {
console.log (exists);
const file = fs.readFileSync('/tmp/test.pdf');
console.log(file);
const params = {
Bucket: "BucketName",
Key: "test.pdf",
Body: file
};
s3.upload(params, (err,data) => {
if (err) console.log(err);
console.log(data);
});
});
};
this is my code!
i could copy my pdf file in S3 and successed upload the copy pdf file in S3.
So next step, i wanted to create a password in that copy pdf file.
So i used code here,
var options = {
keyLength: 128,
password: 'abc123',
restrictions: {
print: 'low',
useAes: 'y'
}
}
QPDF.encrypt('/tmp/test.pdf',options,(err)=>{
if(err)console.log(err,err.stack);
});
but there is an error.
Response:
{
"errorType": "Error",
"errorMessage": "/bin/sh: qpdf: command not found\n",
"trace": [
"Error: /bin/sh: qpdf: command not found",
"",
" at Socket.<anonymous> (/opt/nodejs/node_modules/node-qpdf/index.js:124:17)",
" at Object.onceWrapper (events.js:300:26)",
" at Socket.emit (events.js:210:5)",
" at Socket.EventEmitter.emit (domain.js:476:20)",
" at addChunk (_stream_readable.js:308:12)",
" at readableAddChunk (_stream_readable.js:289:11)",
" at Socket.Readable.push (_stream_readable.js:223:10)",
" at Pipe.onStreamRead (internal/stream_base_commons.js:182:23)"
]
}
i installed npm qpdf and node-qpdf and checked the installed npms.
what is the problem?

Answer 1

QPDF is a command-line program, you'll need to have it installed (system-wise) before using it.
I tested your code on Ubuntu after installing QPDF and it worked. You can refer to the repository link above for other systems.
sudo apt-get install qpdf

Answer 2

You need to build a standalone package and add it to the zip, you upload to AWS Lambda. Here is more information what needs to be done in order to generate the package: https://github.com/qpdf/qpdf/issues/352

Answer 3

You need to have the QPDF command line program in the run time. AWS Lambda has concept of AWS Layers which gives ability to solve these kind of issues. You can basically upload your program as zip on AWS Layer and then while creating the Lambda function you can give the reference of the layer created.
You can read more about it here -
https://docs.aws.amazon.com/lambda/latest/dg/configuration-layers.html
Good things is you can keep your code separate and your command line program separate.
Layers can also be shared across different lambda functions.
Hope this helps.