From 9e05e1dcaa8204cc05314f48798f674e4415f660 Mon Sep 17 00:00:00 2001
From: Pascal Verdage <pascal.verdage@sgcib.com>
Date: Mon, 16 Oct 2023 11:21:55 +0200
Subject: [PATCH] Check property name variations

Apply relaxed binding as spring boot implementations
---
 .../springdotenv/DotenvPropertyLoader.java    |  4 ++
 .../springdotenv/DotenvPropertySource.java    | 60 ++++++++++++++++++-
 .../DotenvPropertySourceTest.java             | 15 +++++
 3 files changed, 77 insertions(+), 2 deletions(-)

diff --git a/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertyLoader.java b/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertyLoader.java
index 43b6c55..dd26326 100644
--- a/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertyLoader.java
+++ b/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertyLoader.java
@@ -32,4 +32,8 @@ public DotenvPropertyLoader(DotenvConfig dotenvConfig) {
   public Object getValue(String key) {
     return dotenv.get(key);
   }
+
+  boolean containsProperty(String key) {
+    return getValue(key) != null;
+  }
 }
diff --git a/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertySource.java b/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertySource.java
index 8a45009..cb982df 100644
--- a/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertySource.java
+++ b/library/src/main/java/me/paulschwarz/springdotenv/DotenvPropertySource.java
@@ -48,6 +48,14 @@ public DotenvPropertySource(DotenvConfig dotenvConfig) {
 
   /**
    * Return the value associated with the given name, or {@code null} if not found.
+   * Handles Spring Boot relaxed binding by allowing multiple naming conventions
+   * for the property name (omitting the preifx):
+   * <ul>
+   *   <li>requested name</li>
+   *   <li>requested name replacing dots, dashes or both by underscores</li>
+   *   <li>requested name in uppercase</li>
+   *   <li>requested name in uppercase replacing dots, dashes or both by underscores</li>
+   * </ul>
    *
    * @param name the property to find
    * @see PropertyResolver#getRequiredProperty(String)
@@ -58,15 +66,63 @@ public Object getProperty(String name) {
       return null;
     }
 
-    Object value = getSource().getValue(name.substring(prefix.length()));
+    String noPrefix = name.substring(prefix.length());
 
-    if (Objects.nonNull(value)) {
+    String actualName = resolvePropertyName(noPrefix);
+    if (log.isTraceEnabled() && !name.equals(actualName)) {
+      logger.trace(LogMessage.format("PropertySource \"%s\" does not contain " +
+          "property \"%s\", but found equivalent \"%s\"", getName(), name, actualName));
+    }
+    Object value = getSource().getValue(actualName);
+
+    if (Objects.nonNull(value) && log.isTraceEnabled()) {
       log.trace(LogMessage.format("Got env property for \"%s\"", name));
     }
 
     return value;
   }
 
+  protected final String resolvePropertyName(String name) {
+    Objects.requireNonNull(name, "Property name must not be null");
+    String resolvedName = checkPropertySymbolVariants(name);
+    if (resolvedName != null) {
+      return resolvedName;
+    }
+    String uppercaseName = name.toUpperCase();
+    if (!name.equals(uppercaseName)) {
+      resolvedName = checkPropertySymbolVariants(uppercaseName);
+      if (resolvedName != null) {
+        return resolvedName;
+      }
+    }
+    return name;
+  }
+
+  @Nullable
+  private String checkPropertySymbolVariants(String name) {
+    // Check name as-is
+    if (this.getSource().containsProperty(name)) {
+      return name;
+    }
+    // Check name with just dots replaced
+    String noDotName = name.replace('.', '_');
+    if (!name.equals(noDotName) && this.source.containsProperty(noDotName)) {
+      return noDotName;
+    }
+    // Check name with just hyphens replaced
+    String noHyphenName = name.replace('-', '_');
+    if (!name.equals(noHyphenName) && this.source.containsProperty(noHyphenName)) {
+      return noHyphenName;
+    }
+    // Check name with dots and hyphens replaced
+    String noDotNoHyphenName = noDotName.replace('-', '_');
+    if (!noDotName.equals(noDotNoHyphenName) && this.source.containsProperty(noDotNoHyphenName)) {
+      return noDotNoHyphenName;
+    }
+    // Give up
+    return null;
+  }
+
   public static void addToEnvironment(ConfigurableEnvironment environment) {
     DotenvConfig dotenvConfig = new DotenvConfig(DotenvConfigProperties.loadProperties());
     DotenvPropertySource dotenvPropertySource = new DotenvPropertySource(dotenvConfig);
diff --git a/library/src/test/java/me/paulschwarz/springdotenv/DotenvPropertySourceTest.java b/library/src/test/java/me/paulschwarz/springdotenv/DotenvPropertySourceTest.java
index 7dd2b62..c7509c4 100644
--- a/library/src/test/java/me/paulschwarz/springdotenv/DotenvPropertySourceTest.java
+++ b/library/src/test/java/me/paulschwarz/springdotenv/DotenvPropertySourceTest.java
@@ -40,4 +40,19 @@ void valueFromEnvironment() {
   void valueFromEnvironmentOverride() {
     assertThat(source.getProperty("EXAMPLE_MESSAGE_3")).isEqualTo("Message 3 from system environment");
   }
+
+  @Test
+  void valueFromEnvironmentAsLowerCaseWithDots() {
+    assertThat(source.getProperty("example.message.2")).isEqualTo("Message 2 from system environment");
+  }
+
+  @Test
+  void valueFromEnvironmentAsLowerCaseWithDashes() {
+    assertThat(source.getProperty("example-message-2")).isEqualTo("Message 2 from system environment");
+  }
+
+  @Test
+  void valueFromEnvironmentAsLowerCaseWithDotsAndDashes() {
+    assertThat(source.getProperty("example.message-2")).isEqualTo("Message 2 from system environment");
+  }
 }