Added helper functions

Author: Kolappan N

CHANGELOG.md

@@ -5,6 +5,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+
+## [0.0.1] - 2019-01-02
 ### Added
 - Added changelog.
-- Added core library.
+- Added core library.
+- Added API Helper functions
+
+### Changed
+- Format of model validation errors

src/WebApiBolierplate/API/Helpers/Notification.cs

@@ -0,0 +1,37 @@
+using Core.Constants;
+using System;
+using System.Collections.Generic;
+using System.Net;
+
+namespace API.Helpers
+{
+    public static class Notification
+    {
+        /// <summary>
+        /// Contains mapping for error codes to the Error messages and status
+        /// </summary>
+        private static readonly Dictionary<int, Tuple<string, HttpStatusCode>> notifications = new Dictionary<int, Tuple<string, HttpStatusCode>>()
+        {
+            { -1,  Tuple.Create(Errors.InternalServerError, HttpStatusCode.InternalServerError) },
+            { -102,  Tuple.Create(Errors.AccountNotFound, HttpStatusCode.Unauthorized) },
+            { -103,  Tuple.Create(Errors.InvalidCredentials, HttpStatusCode.Unauthorized) },
+            { -104,  Tuple.Create(Errors.AccountDeleted, HttpStatusCode.Unauthorized) }
+        };
+
+        /// <summary>
+        /// Returns the error message, and <see cref="HttpStatusCode"/> for the specified error code
+        /// </summary>
+        /// <param name="code">The error code obtained from business layer or other functions</param>
+        /// <returns></returns>
+        public static Tuple<string, HttpStatusCode> GetNotification(int code)
+        {
+            Tuple<string, HttpStatusCode> value;
+            bool hasValue = notifications.TryGetValue(code, out value);
+            if (!hasValue)
+            {
+                value = Tuple.Create(Errors.InternalServerError, HttpStatusCode.InternalServerError);
+            }
+            return value;
+        }
+    }
+}

src/WebApiBolierplate/API/Helpers/ValidationHelper.cs

@@ -0,0 +1,29 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+
+namespace API.Helpers
+{
+    public class ValidationHelper
+    {
+        private WebAPIHelper webAPIHelper;
+
+        public ValidationHelper()
+        {
+            webAPIHelper = new WebAPIHelper();
+        }
+
+        public BadRequestObjectResult GetDataValidationError(ModelStateDictionary model)
+        {
+            var errorText = string.Empty;
+            foreach (var value in model.Values)
+            {
+                for (var i = 0; i < value.Errors.Count; i++)
+                {
+                    errorText = errorText + ", " + value.Errors[i].ErrorMessage;
+                }
+            }
+            errorText = errorText.Substring(1, errorText.Length - 1);
+            return webAPIHelper.CreateBadRequest(errorText);
+        }
+    }
+}

src/WebApiBolierplate/API/Helpers/WebAPIHelper.cs

@@ -0,0 +1,82 @@
+using Core.Constants;
+using Microsoft.AspNetCore.Mvc;
+using Model;
+using System;
+using System.Net;
+
+namespace API.Helpers
+{
+    public class WebAPIHelper
+    {
+        #region [Declarations]
+
+        private APIResponse apiResponse;
+
+        #endregion [Declarations]
+
+        /// <summary>
+        /// Creates a error or successful response based on the data to be sent
+        /// </summary>
+        /// <param name="data"></param>
+        /// <returns></returns>
+        public JsonResult CreateResponse(object data)
+        {
+            if (data == null || (data is bool && Convert.ToBoolean(data) == false))
+            {
+                apiResponse = new APIResponse(string.Empty, Errors.InternalServerError, true);
+                return new JsonResult(apiResponse)
+                {
+                    StatusCode = (int)HttpStatusCode.InternalServerError
+                };
+            }
+            else if (data is int && Convert.ToInt32(data) < 0)
+            {
+                Tuple<string, HttpStatusCode> resData = Notification.GetNotification(Convert.ToInt32(data));
+                apiResponse = new APIResponse(string.Empty, resData.Item1, true);
+                return new JsonResult(apiResponse)
+                {
+                    StatusCode = (int)resData.Item2
+                };
+            }
+            else if (data is APIResponse)
+            {
+                apiResponse = (APIResponse)data;
+                return new JsonResult(apiResponse)
+                {
+                    StatusCode = apiResponse.IsError ? (int)HttpStatusCode.InternalServerError : (int)HttpStatusCode.OK
+                };
+            }
+            else
+            {
+                apiResponse = new APIResponse(data, string.Empty, false);
+                return new JsonResult(apiResponse);
+            }
+        }
+
+        /// <summary>
+        /// Creates a Json response with 400 status code(Bad Request)
+        /// </summary>
+        /// <param name="errorText">Error message to be sent</param>
+        /// <returns>The http response</returns>
+        public BadRequestObjectResult CreateBadRequest(string errorText)
+        {
+            apiResponse = new APIResponse(string.Empty, errorText, true);
+            return new BadRequestObjectResult(apiResponse);
+        }
+
+        /// <summary>
+        /// Creates an error response with a 500 status code(Internal Server error)
+        /// </summary>
+        /// <param name="errorText">Error message to be sent</param>
+        /// <param name="data">Data to be sent</param>
+        /// <returns></returns>
+        public JsonResult CreateErrorResponse(string errorText, dynamic data = null)
+        {
+            apiResponse = new APIResponse(data, errorText, true);
+            return new JsonResult(apiResponse)
+            {
+                StatusCode = (int)HttpStatusCode.InternalServerError
+            };
+        }
+    }
+}

src/WebApiBolierplate/API/Startup.cs

@@ -1,15 +1,9 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
+using API.Helpers;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.AspNetCore.HttpsPolicy;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Logging;
-using Microsoft.Extensions.Options;
 
 namespace API
 {
@@ -26,6 +20,15 @@ public Startup(IConfiguration configuration)
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
+
+            var validationHelper = new ValidationHelper();
+
+            // To handle model validation errors and change it to 
+            // Ref: https://stackoverflow.com/a/51159755/5407188
+            services.Configure<ApiBehaviorOptions>(o =>
+            {
+                o.InvalidModelStateResponseFactory = actionContext => validationHelper.GetDataValidationError(actionContext.ModelState);
+            });
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.

src/WebApiBolierplate/Core.Constants/Core.Constants.csproj

@@ -0,0 +1,7 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>

src/WebApiBolierplate/Core.Constants/Errors.cs

@@ -0,0 +1,20 @@
+namespace Core.Constants
+{
+    /// <summary>
+    /// Constains all the error messages across the application
+    /// </summary>
+    public class Errors
+    {
+        public const string InternalServerError = "Oops! An Internal Error Occured.";
+        public const string DatabaseSaveFailed = "Failed to save to the database";
+
+        #region [Authorization]
+
+        public const string InvalidCredentials = "The credentials are invalid.";
+        public const string UnauthorizedRequest = "The request is unauthorised.";
+        public const string AccountNotFound = "No acount exists for the specified email. Are you trying to Signup?";
+        public const string AccountDeleted = "The user account has been deleted. Contact administrator.";
+
+        #endregion [Authorization]
+    }
+}

src/WebApiBolierplate/WebApiBolierplate.sln

@@ -3,13 +3,15 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
 VisualStudioVersion = 15.0.28307.168
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "API", "API\API.csproj", "{63F1C3A8-3F0D-47F1-8BC9-2E2645C6ABF3}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "API", "API\API.csproj", "{63F1C3A8-3F0D-47F1-8BC9-2E2645C6ABF3}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Core", "Core", "{DF265B0E-249D-4395-BCE8-03B031708DB5}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Core.Lib", "Core.Lib\Core.Lib.csproj", "{3C9B3915-9D3D-4D3B-ADB4-1F976DF2B60B}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Core.Lib", "Core.Lib\Core.Lib.csproj", "{3C9B3915-9D3D-4D3B-ADB4-1F976DF2B60B}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Model", "Model\Model.csproj", "{45F145EE-EB8D-401E-A1EA-1743F5A06C49}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Model", "Model\Model.csproj", "{45F145EE-EB8D-401E-A1EA-1743F5A06C49}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Core.Constants", "Core.Constants\Core.Constants.csproj", "{B97C8E88-5711-44D9-A362-43F91A6F2C0C}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -29,12 +31,17 @@ Global
 		{45F145EE-EB8D-401E-A1EA-1743F5A06C49}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{45F145EE-EB8D-401E-A1EA-1743F5A06C49}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{45F145EE-EB8D-401E-A1EA-1743F5A06C49}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B97C8E88-5711-44D9-A362-43F91A6F2C0C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B97C8E88-5711-44D9-A362-43F91A6F2C0C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B97C8E88-5711-44D9-A362-43F91A6F2C0C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B97C8E88-5711-44D9-A362-43F91A6F2C0C}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{3C9B3915-9D3D-4D3B-ADB4-1F976DF2B60B} = {DF265B0E-249D-4395-BCE8-03B031708DB5}
+		{B97C8E88-5711-44D9-A362-43F91A6F2C0C} = {DF265B0E-249D-4395-BCE8-03B031708DB5}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {5E2BFE0C-9475-430E-95F1-3D76F7FD2BBE}