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Decode JWT Token

Abhith Rajan — Mon, 29 Aug 2022 09:26:00 GMT

Method

function decodeJwt(token) {
  var base64Payload = token.split(".")[1];
  var payloadBuffer = Buffer.from(base64Payload, "base64");
  return JSON.parse(payloadBuffer.toString());
}

Usage

var payload = decodeJwt(
  "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c"
);
console.log(payload);

Output Environment Variable

Abhith Rajan — Mon, 25 Jul 2022 09:26:00 GMT

If you want to print the value of an environment variable, you can use the $env:variable_name syntax.

$env:MY_VARIABLE

Replace MY_VARIABLE with the name of the environment variable you want to print.

Delete All Local/Remote Git Tags

Abhith Rajan — Thu, 02 Jun 2022 09:26:00 GMT

On rare occasions, you may want to remove all local and remote git tags from your repository. For that, you can follow the below Recommended Steps.

In short, first, we are replacing the local tags with the remote tags, then removing all remote tags with reference to the local tags, and finally, removing all local tags.

Recommended Steps

1. Delete all local tags

git tag -d $(git tag -l)

2. Fetch all remote tags

git fetch

Retrieves all remote tags giving you a complete list of remote tags.

3. Delete All remote tags

git push origin --delete $(git tag -l)

Deletes the remote tags with reference to the local list.

4. Delete All local tags

git tag -d $(git tag -l)

Once again, deletes all local tags.

Unnecessary Details

One of the rare occasions to delete all tags in my case was, that we were maintaining a monorepo in Azure DevOps, and wanted to migrate it to GitHub, but in a repo per component manner. So,

First I did import the monorepo by following 👉 Code Migration From Azure DevOps to GitHub,
Then removed all other component’s code from the repo (git history is still dirty with other component’s old commits)
Re-configured the existing Azure pipeline triggers, i.e switched to a tag-based trigger. So, on each new release in GitHub, the connected Azure pipelines will run.

Now, the monorepo had so many tags including the tags of the other components. So, I wanted to remove all the tags from the repo before proceeding with the GitHub releases, and I did use the Recommended Steps above.

Create New Database Level User

Abhith Rajan — Sun, 23 Jan 2022 09:26:00 GMT

Connect to your SQL-Server using privileged account credentials (eg. sa) in your favorite IDE. I still use SSMS together with Azure Data Studio.

Set the query target database, In most IDE, right click on the DB, then new query.

CREATE USER [username]
WITH PASSWORD = 'password'
-- add user to role(s) in db
ALTER ROLE [db_datareader] ADD MEMBER [username];
ALTER ROLE [db_datawriter] ADD MEMBER [username];
ALTER ROLE [db_ddladmin] ADD MEMBER [username];
GRANT EXECUTE TO [username]

Execute the above statement after replacing the username and password according to your choice. You can also manage the roles as per your needs.

Some of the Fixed-database roles are,

Fixed-Database role name	Description
db_owner	Members of the db_owner fixed database role can perform all configuration and maintenance activities on the database, and can also drop the database in SQL Server. (In SQL Database and Azure Synapse, some maintenance activities require server-level permissions and cannot be performed by db_owners.)
db_ddladmin	Members of the db_ddladmin fixed database role can run any Data Definition Language (DDL) command in a database.
db_datawriter	Members of the db_datawriter fixed database role can add, delete, or change data in all user tables.
db_datareader	Members of the db_datareader fixed database role can read all data from all user tables and views. User objects can exist in any schema except sys and INFORMATION_SCHEMA.

Note: In order to connect to the DB using the new credentials, you need to specify the database name in the advanced options from your IDE since the above credentials don’t have the privilege to list the DB’s in the server.

Additional Resources

UTC to UAE Time (Arabian Standard Time)

Abhith Rajan — Tue, 07 Sep 2021 09:26:00 GMT

SELECT CONVERT(datetime, SWITCHOFFSET(GETUTCDATE(), DATEPART(TZOFFSET,
GETUTCDATE() AT TIME ZONE 'Arabian Standard Time'))) AS CreationTime

Replace GETUTCDATE() with your table column that has the UTC time.

DNS Lookup

Abhith Rajan — Wed, 23 Sep 2020 09:26:00 GMT

for i in {1..10}; do curl -k -o /dev/null -s -w "DNS-Lookup [%{time_namelookup}] Time-Connect [%{time_connect}] Time-PreTransfer [%{time_pretransfer}] Time-StartTransfer [%{time_starttransfer}] Total-Time [%{time_total}] Response-Code [%{http_code}]\n" https://www.abhith.net; done

Sample Output

root@pod-name-69d96c5494-bd97v:/app# for i in {1..10}; do curl -k -o /dev/null -s -w "DNS-Lookup [%{time_namelookup}] Time-Connect [%{time_connect}] Time-PreTransfer [%{time_pretransfer}] Time-StartTransfer [%{time_s
tarttransfer}] Total-Time [%{time_total}] Response-Code [%{http_code}]\n" https://www.abhith.net; done
DNS-Lookup [5.465393] Time-Connect [5.542967] Time-PreTransfer [5.626041] Time-StartTransfer [6.024135] Total-Time [6.261565] Response-Code [200]
DNS-Lookup [0.458571] Time-Connect [0.536812] Time-PreTransfer [0.619370] Time-StartTransfer [0.960386] Total-Time [1.199219] Response-Code [200]
DNS-Lookup [0.005218] Time-Connect [0.083305] Time-PreTransfer [0.167227] Time-StartTransfer [0.505865] Total-Time [0.745717] Response-Code [200]
DNS-Lookup [5.066491] Time-Connect [5.144106] Time-PreTransfer [5.227078] Time-StartTransfer [5.585845] Total-Time [5.825170] Response-Code [200]
DNS-Lookup [0.004125] Time-Connect [0.081587] Time-PreTransfer [0.165687] Time-StartTransfer [0.246201] Total-Time [0.481887] Response-Code [200]
DNS-Lookup [0.005214] Time-Connect [0.083619] Time-PreTransfer [0.168375] Time-StartTransfer [0.510846] Total-Time [0.823167] Response-Code [200]
DNS-Lookup [0.016983] Time-Connect [0.094932] Time-PreTransfer [0.177621] Time-StartTransfer [0.522677] Total-Time [0.758300] Response-Code [200]
DNS-Lookup [0.005210] Time-Connect [0.083526] Time-PreTransfer [0.166203] Time-StartTransfer [0.246943] Total-Time [0.481547] Response-Code [200]
DNS-Lookup [0.010488] Time-Connect [0.088643] Time-PreTransfer [0.172099] Time-StartTransfer [0.517206] Total-Time [0.829188] Response-Code [200]
DNS-Lookup [0.005282] Time-Connect [0.083156] Time-PreTransfer [0.167259] Time-StartTransfer [0.499211] Total-Time [0.734148] Response-Code [200]
root@pod-name-69d96c5494-bd97v:/app#

Noticed the 5sec+ responses above? Explore more about the intermittent delay in Kubernetes in these articles,

Truncate String Without Word Break

Abhith Rajan — Mon, 14 Sep 2020 09:26:00 GMT

/// <summary>
/// Truncate string at a word near to the limit specified. Avoid word split.
/// </summary>
/// <param name="input">string</param>
/// <param name="length"></param>
/// <param name="appendDots"></param>
/// <returns></returns>
public static string TruncateAtWord(this string input, int length, bool appendDots = false)
{
    if (input == null || input.Length < length)
        return input;
    var iNextSpace = input.LastIndexOf(" ", length, StringComparison.Ordinal);
    var trimmedInput = string.Format("{0}", input.Substring(0, (iNextSpace > 0) ? iNextSpace : length).Trim());

    if (appendDots)
    {
        return trimmedInput + "...";
    }
    return trimmedInput;
}

Tests

[Fact]
public void TruncateAtWordTests()
{
    "This is a long sentence".TruncateAtWord(6).Should().Be("This");
    "This is a long sentence".TruncateAtWord(7).Should().Be("This is");
}

Reference

Code.Library

Domain Name From URL

Abhith Rajan — Sun, 13 Sep 2020 09:26:00 GMT

export const domainFromURL = (url) => {
  return url
    .replace("http://", "")
    .replace("https://", "")
    .replace("www.", "")
    .split(/[/?#]/)[0];
};

Mask String

Abhith Rajan — Sat, 12 Sep 2020 09:26:00 GMT

/// <summary>
/// Mask the string.
/// </summary>
/// <param name="value">String that need to be masked</param>
/// <param name="startIndex">zero index indicating mask start position</param>
/// <param name="mask">mask that need to be applied, eg. ***</param>
/// <returns>Usage: "123456789".Mask(3, "****") => "123****89"</returns>
public static string Mask(this string value, int startIndex, string mask)
{
    if (string.IsNullOrEmpty(value))
        return string.Empty;

    var result = value;
    var starLength = mask.Length;

    if (value.Length < startIndex) return result;

    result = value.Insert(startIndex, mask);

    result = result.Length >= (startIndex + (starLength * 2)) ? result.Remove(startIndex + starLength, starLength) : result.Remove(startIndex + starLength, result.Length - (startIndex + starLength));

    return result;
}

Tests

"123456789".Mask(3, "****").Should().Be("123****89");
"123456789".Mask(3, "****---").Should().Be("123****---");

Reference

Mask Mobile Number Using C# - JIN Weijie

Snippets RSS Feed

Decode JWT Token

Method#

Usage#

Output Environment Variable

Delete All Local/Remote Git Tags

Recommended Steps#

1. Delete all local tags#

2. Fetch all remote tags#

3. Delete All remote tags#

4. Delete All local tags#

Unnecessary Details#

Create New Database Level User

Additional Resources#

UTC to UAE Time (Arabian Standard Time)

DNS Lookup

Sample Output#

Truncate String Without Word Break

Tests#

Reference#

Domain Name From URL

Mask String

Tests#

Reference#

Method

Usage

Recommended Steps

1. Delete all local tags

2. Fetch all remote tags

3. Delete All remote tags

4. Delete All local tags

Unnecessary Details

Additional Resources

Sample Output

Tests

Reference

Tests

Reference