Release 2.0.0: .NET Standard migration and production hardening

.github/workflows/dotnet.yml

@@ -1,5 +1,4 @@
-# This workflow will build a .NET project
-# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-net
+# This workflow will build, test, measure coverage, and pack the library.
 
 name: .NET
 
@@ -22,7 +21,7 @@ jobs:
         dotnet-version: 8.0.x
     - name: Restore dependencies
       run: dotnet restore
-    - name: Build
-      run: dotnet build --no-restore
-    - name: Test
-      run: dotnet test --no-build --verbosity normal
+    - name: Test with coverage
+      run: dotnet test --configuration Release --no-restore --verbosity normal -p:ContinuousIntegrationBuild=true
+    - name: Pack
+      run: dotnet pack StringExtensionLibrary/StringExtensionLibrary.csproj --configuration Release --no-restore --output ./nupkg -p:ContinuousIntegrationBuild=true

.gitignore

@@ -155,3 +155,7 @@ $RECYCLE.BIN/
 # Mac desktop service store files
 .DS_Store
 packages/
+coverage*.xml
+coverage.json
+TestResults/
+nupkg/

CHANGELOG.md

@@ -0,0 +1,18 @@
+# Changelog
+
+## 2.0.0
+
+Breaking changes from the .NET Framework 4.5.1 / Visual Studio 2013 package:
+
+- **Target framework.** The library is now **.NET Standard 2.0** (SDK-style project). It no longer targets .NET Framework 4.5.1 only.
+- **Encrypt / Decrypt.** Windows RSA key-container crypto (`CspParameters` / `RSACryptoServiceProvider`) is replaced with **AES-256-CBC**, **HMAC-SHA256** integrity, and **PBKDF2-HMAC-SHA256** (100,000 iterations) for key derivation. Ciphertext is a hyphen-separated hex payload: salt + IV + ciphertext + tag. Payloads produced by 1.x cannot be decrypted. Wrong passphrase or a tampered payload throws `CryptographicException`.
+- **CreateParameters removed.** The SQL-concatenation helper is gone. Use parameterized queries.
+- **IsValidIPv4.** Uses `IPAddress.TryParse` and requires a canonical dotted-quad (`AddressFamily.InterNetwork`). Scheme-prefixed strings, IPv6, and non-canonical forms such as `127.00.0.1` are rejected.
+- **JsonToObject.** Throws `InvalidOperationException` when JSON deserializes to null instead of returning `default(T)`.
+- **ReplaceLineFeeds.** Removes CR/LF sequences only. It no longer strips `.` characters (the previous regex matched a literal period).
+- **QueryStringToDictionary.** Reads the query after the first `?`, strips a `#` fragment, URL-decodes keys and values (`Uri.UnescapeDataString`; `+` is a space), and last-wins on duplicate keys.
+
+Other notable changes:
+
+- Hash helpers (`CreateHashSha256`, `CreateHashSha512`) and `GetLength` are extension methods (`this`).
+- Several P0 contract fixes: `IsLength` honors the maximum bound; `RemoveSuffix` returns the original string when the suffix is missing; `CountOccurrences` treats the needle as a literal; `Capitalize` / `IsEmailAddress` are null-safe.

CONTRIBUTING.md

@@ -0,0 +1,27 @@
+# Contributing
+
+## Null policy
+
+Keep these contracts consistent when adding methods:
+
+- **Predicates** (`Is*`, `DoesNot*`): accept null and never throw. `IsNull` is true for null; other `Is*` methods return false; `DoesNotStartWith` / `DoesNotEndWith` return true when either side is null.
+- **Ignore-case start/end**: throw `ArgumentNullException` when `val` or the prefix/suffix is null.
+- **Transforms** (`Reverse`, `Left`, `ToBytes`, `SplitTo`, `Replace`, …): throw `ArgumentNullException` (or `ArgumentException` when empty is invalid, e.g. encrypt/hash).
+- **Null-coalescing helpers** (`GetEmptyStringIfNull`, `GetDefaultIfEmpty`, `Truncate`): defined results for null (empty string or the provided default).
+- Use `nameof` in exception arguments. Use invariant culture for case conversion unless the caller passes a culture.
+
+## Tests
+
+Every public method needs a happy path, a null/empty case, and the documented error case. Split tests by concern (`ConversionTests`, `ValidationTests`, `MutationTests`, `JsonAndQueryTests`, `CryptoTests`).
+
+## SQL
+
+Do not add helpers that concatenate untrusted strings into SQL.
+
+## Crypto
+
+`Encrypt` / `Decrypt` use AES-256-CBC with HMAC-SHA256 over the payload and PBKDF2-HMAC-SHA256 (100,000 iterations) for key derivation on all target frameworks. Ciphertext from the old Windows RSA key-container implementation will not decrypt. This is passphrase-based authenticated encryption for application data, not a key-management system.
+
+## Email and IPv4
+
+`IsEmailAddress` is a practical heuristic (plus-tags allowed, input is trimmed). It is not RFC 5322-complete. `IsValidIPv4` requires a canonical dotted-quad.

Directory.Build.props

@@ -0,0 +1,12 @@
+<Project>
+  <PropertyGroup>
+    <LangVersion>latest</LangVersion>
+    <Nullable>enable</Nullable>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <WarningsAsErrors>$(WarningsAsErrors);NU1605</WarningsAsErrors>
+    <AnalysisLevel>latest</AnalysisLevel>
+    <AnalysisMode>Recommended</AnalysisMode>
+    <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+</Project>