Remove Template Expression naming restrictions (OpenFeign#1139)

kdavisk6 · web-flow · commit 033de93ccac0 · 2019-12-27T09:47:03.000-05:00
Fixes OpenFeign#1036 Relaxed the regular expression used to determine if an expression is valid to support additional expression variable names. We will no longer restrict what an expression name can be.
diff --git a/core/src/main/java/feign/template/Expressions.java b/core/src/main/java/feign/template/Expressions.java
@@ -38,7 +38,8 @@ public final class Expressions {
      *
      * see https://tools.ietf.org/html/rfc6570#section-2.3 for more information.
      */
-    expressions.put(Pattern.compile("(\\w[-\\w.\\[\\]]*[ ]*)(:(.+))?"),
+
+    expressions.put(Pattern.compile("^([+#./;?&]?)(.*)$"),
         SimpleExpression.class);
   }
 
@@ -70,10 +71,18 @@ public static Expression create(final String value, final FragmentType type) {
     Matcher matcher = expressionPattern.matcher(expression);
     if (matcher.matches()) {
       /* we have a valid variable expression, extract the name from the first group */
-      variableName = matcher.group(1).trim();
-      if (matcher.group(2) != null && matcher.group(3) != null) {
-        /* this variable contains an optional pattern */
-        variablePattern = matcher.group(3);
+      variableName = matcher.group(2).trim();
+      if (variableName.contains(":")) {
+        /* split on the colon */
+        String[] parts = variableName.split(":");
+        variableName = parts[0];
+        variablePattern = parts[1];
+      }
+
+      /* look for nested expressions */
+      if (variableName.contains("{")) {
+        /* nested, literal */
+        return null;
       }
     }
 
diff --git a/core/src/test/java/feign/template/QueryTemplateTest.java b/core/src/test/java/feign/template/QueryTemplateTest.java
@@ -176,4 +176,15 @@ public void expandCollectionValueWithBrackets() {
     /* brackets will be pct-encoded */
     assertThat(expanded).isEqualToIgnoringCase("collection%5B%5D=1,2");
   }
+
+  @Test
+  public void expandCollectionValueWithDollar() {
+    QueryTemplate template =
+        QueryTemplate.create("$collection", Collections.singletonList("{$collection}"),
+            Util.UTF_8, CollectionFormat.CSV);
+    String expanded = template.expand(Collections.singletonMap("$collection",
+        Arrays.asList("1", "2")));
+    /* brackets will be pct-encoded */
+    assertThat(expanded).isEqualToIgnoringCase("$collection=1,2");
+  }
 }
