Added: Process variables recursively in Thymeleaf

CHANGELOG.md

@@ -170,3 +170,4 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Enable minus in variables of email context
 - Last document variables in email context
 - Support for Thymeleaf standard processor by converting hyphenated variables to camel case
+- Process variables recursively in Thymeleaf

src/main/java/de/samply/email/thymeleaf/EmailContextProcessor.java

@@ -8,6 +8,8 @@
 import org.thymeleaf.templatemode.TemplateMode;
 
 import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public class EmailContextProcessor extends AbstractElementTagProcessor {
 
@@ -50,9 +52,80 @@ protected void doProcess(ITemplateContext context, IProcessableElementTag tag, I
                     ? defaultValue
                     : "";
 
+            // Replace ${XXX} variables with their values from the context
+            finalValue = resolveVariables(finalValue, context);
+
             // Replace the tag with the final value
             structureHandler.replaceWith(finalValue, false);
+
         }
     }
 
+    // TODO: Ideally, we should let Thymeleaf continue processing the replaced content
+    // so that all applicable processors (e.g., variable resolution, additional dialects)
+    // are automatically applied.
+    // Currently, setting `processable` to true in `structureHandler.replaceWith`
+    // only triggers the `StandardInliningTextProcessor`, which simply writes the content
+    // to the output without further processing.
+
+    /**
+     * Resolves ${XXX} variables in the input string using the Thymeleaf context.
+     *
+     * @param content The content with placeholders.
+     * @param context The Thymeleaf context.
+     * @return The content with variables replaced by their resolved values.
+     */
+    /*
+    private String resolveVariables(String content, ITemplateContext context) {
+        // Regular expression to find ${XXX} placeholders
+        Pattern pattern = Pattern.compile("\\$\\{([^}]+)}");
+        Matcher matcher = pattern.matcher(content);
+
+        StringBuffer resolvedContent = new StringBuffer();
+
+        while (matcher.find()) {
+            String variableName = matcher.group(1); // Extract variable name inside ${}
+            Object variableValue = context.getVariable(variableName); // Resolve variable
+            String replacement = (variableValue != null) ? variableValue.toString() : ""; // Use empty string if not found
+            matcher.appendReplacement(resolvedContent, Matcher.quoteReplacement(replacement));
+        }
+        matcher.appendTail(resolvedContent);
+
+        return resolvedContent.toString();
+    }
+
+     */
+    private String resolveVariables(String content, ITemplateContext context) {
+        // Combined regular expression to match both ${variable} and <key /> patterns
+        Pattern combinedPattern = Pattern.compile(
+                "(\\$\\{([^}]+)})|(<\\s*([a-zA-Z0-9_-]+)\\s*/>)"
+        );
+        Matcher combinedMatcher = combinedPattern.matcher(content);
+
+        StringBuffer resolvedContent = new StringBuffer();
+
+        // Process the combined matches
+        while (combinedMatcher.find()) {
+            if (combinedMatcher.group(1) != null) {
+                // Match found for ${variable}
+                String variableName = combinedMatcher.group(2); // Extract variable name inside ${}
+                Object variableValue = context.getVariable(variableName); // Resolve variable
+                String replacement = (variableValue != null) ? variableValue.toString() : ""; // Use empty string if not found
+                combinedMatcher.appendReplacement(resolvedContent, Matcher.quoteReplacement(replacement));
+            } else if (combinedMatcher.group(3) != null) {
+                // Match found for <key />
+                String tagName = combinedMatcher.group(4); // Extract the tag name
+                Object tagValue = context.getVariable(tagName); // Resolve the value from context
+                String replacement = (tagValue != null) ? tagValue.toString() : ""; // Use empty string if not found
+                combinedMatcher.appendReplacement(resolvedContent, Matcher.quoteReplacement(replacement));
+            }
+        }
+
+        // Append any remaining content after the last match
+        combinedMatcher.appendTail(resolvedContent);
+
+        return resolvedContent.toString();
+    }
+
+
 }