Free SSL certificate for shared hosting using certbot

Nery Córdova — Sun, 25 Apr 2021 05:59:22 +0000

Depending on your hosting plan, it is possible that you have limited access to the machine were you app is running, which makes it difficult to generate a free SSL certificate (i.e. installing certbot) on the web server.

Fortunately, certbot makes it possible to generate an SSL certificate on a machine other than the one where certificate is going to be installed. For example, you could generate a certificate from your own computer and push it to your web server using good-old cpanel or FTP. To do that, follow these steps:

Step 1. Install certbot on your computer. If you are using a Debian-based OS, do something like this:

sudo apt-get install certbot

For further instructions about installing certbot, click here.

Step 2. To get a certificate, run the following command (you will need admin permission to run this command)

certbot certonly --manual --preferred-challenges http

Step 3. Next, enter domain name(s) to be included in your certificate, for example:

Plugins selected: Authenticator manual, Installer None
Please enter in your domain name(s) (comma and/or space separated)  (Enter 'c'
to cancel): 

www.my-super-project.com

Step 4. Now, certbot will start the validation process. Following message will appear, asking you to create a file and place it in .well-known/acme-challenge/ directory in your web server:

Create a file containing just this data:

GXyDY4mNeg46oX55-...

And make it available on your web server at this URL:

http://www.my-super-project.com/.well-known/acme-challenge/GXyDY4m...

Step 5. Once validation is completed, you'll see a message from certbot showing where certificates have been saved, for example:

Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/www.my-super-project.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/www.my-super-project.com/privkey.pem
   Your cert will expire on [3 months from now]. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot
   again. To non-interactively renew *all* of your certificates, run
   "certbot renew"

That's it! You now have a valid certificate that can be installed in your web application.

Unzip large files in AWS S3 using Lambda and Node.js

Nery Córdova — Tue, 02 Mar 2021 07:06:10 +0000

Extracting files from large (i.e. > 1Gb) .zip files can be a challenging task specially when resources are limited or when you are billed based on the amount of memory used and execution time (as it is the case with Lambdas).

Most Node.js packages that are used for this task work as follows: load the entire file in memory and then extract its contents. This results in a huge memory footprint (as big as the file itself) and long execution times.

Unzipper package, on the other hand, works based on Node.js streams. In short, streams allow us to process (read/write) data in chunks, keeping memory footprint as well as execution time very low.

The following snippet shows an example of the usage of this package.

const AWS = require("aws-sdk");
const s3 = new AWS.S3({ apiVersion: "2006-03-01" });
const unzipper = require("unzipper");

exports.handler = async (event) => {

  //...initialize bucket, filename and target_filename here
  try {
    /**
     * Step 1: Get stream of the file to be extracted from the zip
     */
    const file_stream = s3
      .getObject({ Bucket: bucket, Key: filename })
      .createReadStream()
      .on("error", (e) => console.log(`Error extracting file: `, e))
      .pipe(
        unzipper.ParseOne("file_name_inside_zip.ext", {
          forceStream: true,
        })
      );

    /**
     * Step 2: upload extracted stream back to S3: this method supports a readable stream in the Body param as per
     *  https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/S3.html#upload-property
     */
    await s3
      .upload({ Bucket: bucket, Key: target_filename, Body: file_stream })
      .promise();

  } catch (error) {
    console.log("Error: ", error.message, error.stack);
  }

};

Hope this helps!

DEV Community: Nery Córdova

Free SSL certificate for shared hosting using certbot

Unzip large files in AWS S3 using Lambda and Node.js