Helpful GIT Commands

 Some helpful GIT Commands:

How to check if your machine supports SSL or TLS 1.1, 1.2 or 1.3

Open the following link in the browser: https://clienttest.ssllabs.com:8443/ssltest/viewMyClient.html

Scroll down to section: Protocol Features

Avoid CORS issues in Chrome, Firefox, Safari and Edge for local JavaScript development

Setup a simple proxy using nodejs and npm to bypass CORS issues. 

This will solve the following issue in the web browsers:

No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disable

Install the following npm package globally:

npm install -g local-cors-proxy

Now you are ready to setup a local proxy. Let's say the URL that's throwing the CORS issue is: 

https://www.example.com/v1/api

To start the proxy, execute the following command:

lcp --proxyUrl https://www.example.com

You will get the following output:

Note: Do not close this window as long as you need the proxy.

Now, in the JavaScript code, API endpoint will be:

http://localhost:8010/proxy/v1/api

This will make a request to URL: https://www.example.com/v1/api without any issues.

Additional options to setup the proxy: 

Option	Example	Default
--proxyUrl	https://www.google.ie
--proxyPartial	foo	proxy
--port	8010	8010
--credentials	(no value needed)	false
--origin	http://localhost:4200	*

Original article can be viewed here.

Creating an angular service to share data between components using session storage

Create the session storage service as:


To store and retrieve the session storage data, use the service as:

Creating an angular service to share data between components

Create a Data store to save data as key and values. E.g:


Note: It uses build in Map data structure and it already has function to add, remove, delete and check objects.

Now let's create a service.


To store and save data call the service as:

Using C# to read an update excel files

Create a new solution and add the DocumentFormat.OpenXml Nuget packages to this solution.

Add a new class ExcelManager.cs with the following code:

using System;
using System.Collections.Generic;
using System.Linq;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using System.IO;
using Logger;
using DocumentFormat.OpenXml;

namespace Demo
{
    class ExcelManager : IDisposable
    {
        #region Private Variables
        SpreadsheetDocument _document;
        Sheet _sheet;
        Worksheet _worksheet;
        #endregion

        #region Public Properties
        public IEnumerable<Row> Rows { get; private set; }
        #endregion

        #region Constructor
        public ExcelManager(string filePath)
        {
            if(!File.Exists(filePath))
            {
                Logger.log.Error($"Error in DataManager(). File with the following path does not exists:{filePath}");
                return;
            }
            else
            {
                Logger.log.Info($"Processing file at path: {filePath}");
                //Open the Excel file in Edit Mode using OpenXml.
                _document = SpreadsheetDocument.Open(filePath, true);
                _sheet = _document.WorkbookPart.Workbook.Sheets.GetFirstChild<Sheet>();
                _worksheet = (_document.WorkbookPart.GetPartById(_sheet.Id.Value) as WorksheetPart).Worksheet;
                Rows = _worksheet.GetFirstChild<SheetData>().Descendants<Row>();
            }
        }
        #endregion

        public void Dispose()
        {
            _document.Dispose();
            _document = null;
            _sheet = null;
            _worksheet = null;
        }

        #region Public Excel Functions
        public string GetCellValue(Cell cell)
        {
            return _document.WorkbookPart.SharedStringTablePart.SharedStringTable.Elements<SharedStringItem>().ElementAt(Convert.ToInt32(cell.InnerText)).InnerText;
        }

        public string GetCellValueByReference(string cellReference)
        {
            var cell = _worksheet.Descendants<Cell>().Where(c => c.CellReference == cellReference).FirstOrDefault();

            if (cell != null)
            {
                return GetCellValue(cell);
            }
            else
            {
                return null;
            }
        }

        public void UpdateCell(string columnName, uint rowIndex, string value)
        {
            try
            {
                Cell cell = GetCellByColumnName(columnName, rowIndex);
                if (cell != null)
                {
                    cell.CellValue = new CellValue(value);
                    cell.DataType = new EnumValue<CellValues>(CellValues.SharedString);

                    // Save the worksheet.
                    _worksheet.Save();
                }
                else
                {
                    Logger.log.Warn($"Error in DataManager.UpdateCell(). Error: Cell is null");
                }
            }
            catch (Exception ex)
            {
                Logger.log.Error($"Error in DataManager.UpdateCell().Error: {ex.Message} StackTrace:{ex.StackTrace}");
            }
        }
        #endregion

        #region Private Excel functions
        private Cell GetCellByColumnName(string columnName, uint rowIndex)
        {
            Row row = GetRow(rowIndex);

            if (row == null)
                return null;

            string cellReference = GetColumnReference(columnName).FirstOrDefault().ToString();

            if (cellReference == null)
            { 
                Logger.log.Warn($"Error in DataManager.GetCellByColumnName(). Error: Cell Reference is null");
                return null;
            }
            else
                return row.Elements<Cell>().Where(c => string.Compare(c.CellReference.Value, cellReference + (rowIndex + 1), true) == 0).First();
        }

        private string GetColumnReference(string columnName)
        {
            var cell = GetRow(0).Elements<Cell>().FirstOrDefault(c => GetCellValue(c) == columnName);

            if (cell == null)
            {
                Logger.log.Warn($"Error in DataManager.GetColumnReference(). Error: Cannot retrieve cell with column name: {columnName}");
                return null;
            }
            else
                return cell.CellReference.Value;
        }

        private Row GetRow(uint rowIndex)
        {
            return Rows.ElementAt(int.Parse(rowIndex.ToString()));
        }
        #endregion
    }
}

This provides the basic items like rows of excel data and functions to save text based on column header names and retrieve cell values.

To add logging, refer to my blog here.