Use en locale for uppercase/lowercase (fixes #156)

acme4j-client/src/main/java/org/shredzone/acme4j/Status.java

@@ -14,6 +14,7 @@
 package org.shredzone.acme4j;
 
 import java.util.Arrays;
+import java.util.Locale;
 
 /**
  * An enumeration of status codes of challenges and authorizations.
@@ -84,7 +85,7 @@ public enum Status {
      *         no match
      */
     public static Status parse(String str) {
-        var check = str.toUpperCase();
+        var check = str.toUpperCase(Locale.ENGLISH);
         return Arrays.stream(values())
                 .filter(s -> s.name().equals(check))
                 .findFirst()

acme4j-client/src/main/java/org/shredzone/acme4j/toolbox/AcmeUtils.java

@@ -183,7 +183,7 @@ public final class AcmeUtils {
      */
     public static String toAce(String domain) {
         Objects.requireNonNull(domain, "domain");
-        return IDN.toASCII(domain.trim()).toLowerCase();
+        return IDN.toASCII(domain.trim()).toLowerCase(Locale.ENGLISH);
     }
 
     /**
@@ -307,7 +307,7 @@ public final class AcmeUtils {
                 if (charset != null && !"utf-8".equalsIgnoreCase(charset)) {
                     throw new AcmeProtocolException("Unsupported charset " + charset);
                 }
-                return m.group(1).trim().toLowerCase();
+                return m.group(1).trim().toLowerCase(Locale.ENGLISH);
             }
         }
         return null;

acme4j-client/src/test/java/org/shredzone/acme4j/StatusTest.java

@@ -15,6 +15,8 @@ package org.shredzone.acme4j;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import java.util.Locale;
+
 import org.junit.jupiter.api.Test;
 
 /**
@@ -27,8 +29,11 @@ public class StatusTest {
      */
     @Test
     public void testParse() {
+        // Would break toUpperCase() if English locale is not set, see #156.
+        Locale.setDefault(new Locale("tr"));
+
         for (var s : Status.values()) {
-            var parsed = Status.parse(s.name().toLowerCase());
+            var parsed = Status.parse(s.name().toLowerCase(Locale.ENGLISH));
             assertThat(parsed).isEqualTo(s);
         }
 

acme4j-smime/src/main/java/org/shredzone/acme4j/smime/wrapper/SignedMail.java

@@ -18,6 +18,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.List;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.Set;
 import java.util.TreeSet;
@@ -74,7 +75,7 @@ public class SignedMail implements Mail {
         while (en.hasMoreElements()) {
             var h = en.nextElement();
             var name = h.getName();
-            if (IGNORE_HEADERS.contains(name.toUpperCase())) {
+            if (IGNORE_HEADERS.contains(name.toUpperCase(Locale.ENGLISH))) {
                 continue;
             }
 
@@ -95,7 +96,7 @@ public class SignedMail implements Mail {
         while (en.hasMoreElements()) {
             var h = en.nextElement();
             var name = h.getName();
-            if (IGNORE_HEADERS.contains(name.toUpperCase())) {
+            if (IGNORE_HEADERS.contains(name.toUpperCase(Locale.ENGLISH))) {
                 continue;
             }
 
@@ -122,7 +123,7 @@ public class SignedMail implements Mail {
         while (en.hasMoreElements()) {
             var h = en.nextElement();
             var name = h.getName();
-            if (IGNORE_HEADERS.contains(name.toUpperCase())) {
+            if (IGNORE_HEADERS.contains(name.toUpperCase(Locale.ENGLISH))) {
                 continue;
             }
 
@@ -252,7 +253,7 @@ public class SignedMail implements Mail {
                 .filter(mh -> "AUTO-SUBMITTED".equalsIgnoreCase(mh.name))
                 .map(mh -> mh.value)
                 .map(String::trim)
-                .map(String::toLowerCase)
+                .map(mh -> mh.toLowerCase(Locale.ENGLISH))
                 .anyMatch(h -> h.equals("auto-generated") || h.startsWith("auto-generated;"));
     }
 
@@ -266,7 +267,7 @@ public class SignedMail implements Mail {
         headers.stream()
                 .filter(mh -> mh.trusted)
                 .map(mh -> mh.name)
-                .map(String::toUpperCase)
+                .map(mh -> mh.toUpperCase(Locale.ENGLISH))
                 .forEach(missing::remove);
         return missing;
     }

acme4j-smime/src/main/java/org/shredzone/acme4j/smime/wrapper/SimpleMail.java

@@ -19,6 +19,7 @@ import static java.util.stream.Collectors.toUnmodifiableList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Locale;
 import java.util.Optional;
 
 import jakarta.mail.Message;
@@ -136,7 +137,7 @@ public class SimpleMail implements Mail {
             }
             return Arrays.stream(autoSubmitted)
                     .map(String::trim)
-                    .map(String::toLowerCase)
+                    .map(as -> as.toLowerCase(Locale.ENGLISH))
                     .anyMatch(h -> h.equals("auto-generated") || h.startsWith("auto-generated;"));
         } catch (MessagingException ex) {
             throw new AcmeInvalidMessageException("Could not read '" + HEADER_AUTO_SUBMITTED + "' header", ex);