From d6fe3ab95d434858e0918344450097577afb3027 Mon Sep 17 00:00:00 2001
From: Christian Specht <christi@nspecht.de>
Date: Sun, 5 Apr 2020 22:19:28 +0200
Subject: [PATCH] If passwords contain names of environment variables, replace
 with variable value

(fixes #26)
---
 .../EnvironmentVariableConfigReaderTests.cs   | 46 +++++++++++++++++++
 src/ScmBackup/CompositionRoot/Bootstrapper.cs |  4 +-
 .../EnvironmentVariableConfigReader.cs        | 41 +++++++++++++++++
 3 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 src/ScmBackup.Tests/ConfigTests/EnvironmentVariableConfigReaderTests.cs
 create mode 100644 src/ScmBackup/Configuration/EnvironmentVariableConfigReader.cs

diff --git a/src/ScmBackup.Tests/ConfigTests/EnvironmentVariableConfigReaderTests.cs b/src/ScmBackup.Tests/ConfigTests/EnvironmentVariableConfigReaderTests.cs
new file mode 100644
index 0000000..8703b79
--- /dev/null
+++ b/src/ScmBackup.Tests/ConfigTests/EnvironmentVariableConfigReaderTests.cs
@@ -0,0 +1,46 @@
+using ScmBackup.Configuration;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Xunit;
+
+namespace ScmBackup.Tests.ConfigTests
+{
+    public class EnvironmentVariableConfigReaderTests
+    {
+        private IConfigReader sut;
+        private FakeConfigReader reader;
+
+        public EnvironmentVariableConfigReaderTests()
+        {
+            reader = new FakeConfigReader();
+            reader.SetDefaultFakeConfig();
+            sut = new EnvironmentVariableConfigReader(reader);
+
+            Environment.SetEnvironmentVariable("scmbackup_test", "foo");
+        }
+
+        [Theory]
+        [InlineData("%scmbackup_test%bar", "foobar")]   // part of the password
+        [InlineData("%scmbackup_test%", "foo")]         // whole password
+        public void ReplacesInPassword(string originalPw, string changedPw)
+        {
+            reader.FakeConfig.Sources.First().Password = originalPw;
+
+            var result = sut.ReadConfig();
+
+            Assert.Equal(changedPw, result.Sources.First().Password);
+        }
+
+        [Fact]
+        public void DoesNothingWhenPasswordContainsNoVariable()
+        {
+            reader.FakeConfig.Sources.First().Password = "bar";
+
+            var result = sut.ReadConfig();
+
+            Assert.Equal("bar", result.Sources.First().Password);
+        }
+    }
+}
diff --git a/src/ScmBackup/CompositionRoot/Bootstrapper.cs b/src/ScmBackup/CompositionRoot/Bootstrapper.cs
index d186611..3b2711f 100644
--- a/src/ScmBackup/CompositionRoot/Bootstrapper.cs
+++ b/src/ScmBackup/CompositionRoot/Bootstrapper.cs
@@ -1,4 +1,5 @@
-using ScmBackup.Hosters;
+using ScmBackup.Configuration;
+using ScmBackup.Hosters;
 using ScmBackup.Http;
 using ScmBackup.Loggers;
 using ScmBackup.Scm;
@@ -34,6 +35,7 @@ public static Container BuildContainer()
             container.Register<IConfigBackupMaker, ConfigBackupMaker>();
 
             container.Register<IConfigReader, ConfigReader>(Lifestyle.Singleton);
+            container.RegisterDecorator<IConfigReader, EnvironmentVariableConfigReader>(Lifestyle.Singleton); 
             container.RegisterDecorator<IConfigReader, ValidatingConfigReader>(Lifestyle.Singleton);
 
             container.Register<IHttpRequest, HttpRequest>();
diff --git a/src/ScmBackup/Configuration/EnvironmentVariableConfigReader.cs b/src/ScmBackup/Configuration/EnvironmentVariableConfigReader.cs
new file mode 100644
index 0000000..09d5898
--- /dev/null
+++ b/src/ScmBackup/Configuration/EnvironmentVariableConfigReader.cs
@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ScmBackup.Configuration
+{
+    /// <summary>
+    /// decorator for ConfigReader, replaces %foo% values with the respective environment variables
+    /// </summary>
+    internal class EnvironmentVariableConfigReader : IConfigReader
+    {
+        private readonly IConfigReader configReader;
+        private Config config = null;
+
+        public EnvironmentVariableConfigReader(IConfigReader configReader)
+        {
+            this.configReader = configReader;
+        }
+
+        public Config ReadConfig()
+        {
+            if (this.config != null)
+            {
+                return this.config;
+            }
+
+            var config = this.configReader.ReadConfig();
+            
+            foreach (var source in config.Sources)
+            {
+                if (!string.IsNullOrWhiteSpace(source.Password))
+                {
+                    source.Password = Environment.ExpandEnvironmentVariables(source.Password);    
+                }
+            }
+
+            this.config = config;
+            return config;
+        }
+    }
+}