Codebasis als Dateien ins Arbeitsrepo statt als Gitlink

QuellCode/CentronERP war nur als Gitlink (Submodul-Referenz auf 79c1142)
getrackt, ohne .gitmodules und ohne erreichbares Remote. Der
Untersuchungsgegenstand der Versuchsreihe war damit nicht reproduzierbar
gesichert: Ein Klon haette ein leeres Verzeichnis erhalten, und die Belege
der 3.287 Anforderungen waeren nicht ueberpruefbar gewesen.

Umstellung:
- Historie nach c:\DEV\CentronERP_git_snapshot_79c1142 ausgelagert
  (vollstaendig lesbar, enthaelt 79c1142 und Vorgaenger 89ccfd6)
- Gitlink aus dem Index entfernt
- Dateiinhalt aufgenommen: 24.557 Dateien, rund 333 MB

Die verschachtelte .gitignore der Codebasis gilt weiter, Build-Artefakte
bleiben ausgeschlossen. Details in Versuche/Versuch_01/_Codebasis-Nachweis.md

QuellCode/CentronERP/Centron.Api.docuFORM/Helper/DocuFormRequestHelper.cs

@@ -0,0 +1,70 @@
+using Centron.Api.docuFORM.Models;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Reflection;
+using System.Text;
+using System.Text.Json.Serialization;
+
+namespace Centron.Api.docuFORM.Helper
+{
+    public static class DocuFormRequestHelper
+    {
+        public static string CreateAuthorizationRequestURI(AuthCodeRequest authCodeRequest, string? baseUriToAdd = null)
+        {
+            var parameters = RequestToParameterString(authCodeRequest);
+            var endPointAndParameters = DocuFormRestApiConstants._endpointAuthCode + "?" + parameters;
+            var baseUri = baseUriToAdd != null
+                ? new Uri(baseUriToAdd)
+                : null;
+
+            return baseUri != null
+                ? new Uri(baseUri, endPointAndParameters).ToString()
+                : endPointAndParameters;
+        }
+
+        public static string RequestToParameterString<T>(T request)
+        {
+            var parameters = RequestToParameters(request);
+            var parameterString = string.Join("&", parameters.Select(f => $"{WebUtility.UrlEncode(f.Key)}={WebUtility.UrlEncode(f.Value)}"));
+
+            return parameterString;
+        }
+
+        public static Dictionary<string, string> RequestToParameters<T>(T request, bool removeParameterWithoutValue = true)
+        {
+            var dict = new Dictionary<string, string>();
+            var props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
+            
+            foreach (var prop in props)
+            {
+                var attr = prop.GetCustomAttribute<JsonPropertyNameAttribute>();
+                var key = attr?.Name ?? prop.Name;
+                var value = prop.GetValue(request)?.ToString();
+
+                if(removeParameterWithoutValue && string.IsNullOrWhiteSpace(value))
+                    continue;
+
+                dict[key] = value ?? string.Empty;
+            }
+
+            return dict;
+        }
+
+        public static string CreateRedirectURI(int? portNumber = null)
+        {
+            var uriBuilder = new UriBuilder(DocuFormRestApiConstants._redirectURI);
+
+            uriBuilder.Port = portNumber.HasValue && portNumber.Value > 0
+                ? portNumber.Value
+                : -1;
+
+            var uri = uriBuilder.ToString();
+
+            while(uri.EndsWith("/"))
+                uri = uri.Substring(0, uri.Length - 1);
+
+            return uri;
+        }
+    }
+}

QuellCode/CentronERP/Centron.Api.docuFORM/Helper/HttpClientExtensions.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http.Headers;
+using System.Text;
+
+namespace Centron.Api.docuFORM.Helper
+{
+    public static class HttpClientExtensions
+    {
+        public static async Task<HttpResponseMessage> SendRequestWithToken(this HttpClient httpClient, HttpRequestMessage httpRequest, string token)
+        {
+            httpRequest.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+            if (httpRequest.Headers.Accept.Count == 0)
+                httpRequest.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
+
+            return await httpClient.SendAsync(httpRequest).ConfigureAwait(false);
+        }
+    }
+}

QuellCode/CentronERP/Centron.Api.docuFORM/Helper/HttpResponseMessageExtensions.cs

@@ -0,0 +1,50 @@
+using Centron.Api.docuFORM.Models.Swagger.Responses;
+using Centron.Interfaces.BL;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Text;
+using System.Text.Json;
+
+namespace Centron.Api.docuFORM.Helper
+{
+    public static class HttpResponseMessageExtensions
+    {
+        public static async Task<string> ReadContentAndThrowIfError(this HttpResponseMessage? response)
+        {
+            if(response == null)
+                throw new HttpRequestException ($"No http response received!");
+
+            var content = await response.Content.ReadAsStringAsync();
+
+            if (!response.IsSuccessStatusCode)
+                throw new HttpRequestException ($"An error occured during the http request: {content}");
+
+            return content;
+        }
+
+        public static async Task<Result<T>> CheckResponseAndDeserializeContent<T>(this HttpResponseMessage? response)
+        {
+            try
+            {
+                if(response == null)
+                    throw new HttpRequestException ($"No http response received!");
+
+                var content = await ReadContentAndThrowIfError(response);
+
+                var options = new JsonSerializerOptions { PropertyNameCaseInsensitive = true };
+
+                var obj = JsonSerializer.Deserialize<T>(content, options);
+
+                if(obj != null)
+                    return Result<T>.AsSuccess(obj);
+
+                return Result<T>.AsError("Unable to deserialize object!");
+            }
+            catch (Exception ex)
+            {
+                return Result<T>.FromException(ex);
+            }
+        }
+    }
+}

QuellCode/CentronERP/Centron.Api.docuFORM/Helper/OAuthHelper.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Centron.Api.docuFORM.Helper
+{
+    public static class OAuthHelper
+    {
+        // Can be used to generate a "state" or the codeVerifier for the "code challenge"
+        public static string GenerateRandomBase64String(int byteLength = 32)
+        {
+            byte[] randomBytes = new byte[byteLength];
+            using (var rng = RandomNumberGenerator.Create())
+            {
+                rng.GetBytes(randomBytes);
+            }
+            
+            // Base64 URL-safe encoding
+            string state = Convert.ToBase64String(randomBytes)
+                .Replace("+", "-")
+                .Replace("/", "_")
+                .Replace("=", "");
+            
+            return state;
+        }
+
+        public static string GenerateCodeChallenge(string codeVerifier)
+        {
+            using (var sha256 = SHA256.Create())
+            {
+                byte[] hash = sha256.ComputeHash(Encoding.ASCII.GetBytes(codeVerifier));
+                string codeChallenge = Convert.ToBase64String(hash)
+                    .Replace("+", "-")
+                    .Replace("/", "_")
+                    .Replace("=", "");
+                return codeChallenge;
+            }
+        }
+    }
+}