feat: Form body field coercion against ObjectSchema property types

Author: thced

src/main/java/com/retailsvc/http/internal/FormUrlEncodedParser.java

@@ -1,5 +1,7 @@
 package com.retailsvc.http.internal;
 
+import com.retailsvc.http.spec.schema.ArraySchema;
+import com.retailsvc.http.spec.schema.ObjectSchema;
 import com.retailsvc.http.spec.schema.Schema;
 import java.net.URLDecoder;
 import java.nio.charset.Charset;
@@ -54,12 +56,33 @@ private static void addEntry(Map<String, Object> out, String key, String value)
     out.put(key, list);
   }
 
-  /**
-   * Returns the parsed map after coercing field values against the given body schema. Coercion is
-   * added in a subsequent task; for now this delegates to {@link #parse}.
-   */
+  /** Returns the parsed map after coercing field values against the given body schema. */
   public Map<String, Object> parseAndCoerce(byte[] body, String contentTypeHeader, Schema schema) {
-    return parse(body, contentTypeHeader);
+    Map<String, Object> parsed = parse(body, contentTypeHeader);
+    if (!(schema instanceof ObjectSchema obj)) {
+      return parsed;
+    }
+    Map<String, Schema> properties = obj.properties();
+    for (Map.Entry<String, Object> e : parsed.entrySet()) {
+      Schema propSchema = properties.get(e.getKey());
+      if (propSchema == null) {
+        continue;
+      }
+      String pointer = "/" + e.getKey();
+      Object value = e.getValue();
+      if (propSchema instanceof ArraySchema arr && value instanceof List<?> list) {
+        List<Object> coerced = new ArrayList<>(list.size());
+        for (int i = 0; i < list.size(); i++) {
+          coerced.add(ValueCoercion.coerce((String) list.get(i), arr.items(), pointer + "/" + i));
+        }
+        e.setValue(coerced);
+      } else if (propSchema instanceof ArraySchema arr && value instanceof String s) {
+        e.setValue(List.of(ValueCoercion.coerce(s, arr.items(), pointer + "/0")));
+      } else if (value instanceof String s) {
+        e.setValue(ValueCoercion.coerce(s, propSchema, pointer));
+      }
+    }
+    return parsed;
   }
 
   private static Charset resolveCharset(String header) {

src/test/java/com/retailsvc/http/internal/FormUrlEncodedParserTest.java

@@ -2,9 +2,16 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+import com.retailsvc.http.spec.schema.ArraySchema;
+import com.retailsvc.http.spec.schema.IntegerSchema;
+import com.retailsvc.http.spec.schema.ObjectSchema;
+import com.retailsvc.http.spec.schema.Schema;
+import com.retailsvc.http.spec.schema.StringSchema;
+import com.retailsvc.http.spec.schema.TypeName;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import org.junit.jupiter.api.Test;
 
 class FormUrlEncodedParserTest {
@@ -70,4 +77,78 @@ void charsetFromHeader() {
     assertThat(parser.parse(iso, "application/x-www-form-urlencoded; charset=iso-8859-1"))
         .containsExactly(Map.entry("x", "räka"));
   }
+
+  @Test
+  void coercesIntegerProperty() {
+    IntegerSchema intSchema = anIntegerSchema();
+    ObjectSchema bodySchema = anObjectSchema(Map.of("age", intSchema));
+
+    Map<String, Object> out =
+        parser.parseAndCoerce("age=30".getBytes(StandardCharsets.UTF_8), null, bodySchema);
+
+    assertThat(out).containsExactly(Map.entry("age", 30L));
+  }
+
+  @Test
+  void coercesArrayOfIntegersProperty() {
+    IntegerSchema intItems = anIntegerSchema();
+    ArraySchema arrSchema = anArraySchemaOf(intItems);
+    ObjectSchema bodySchema = anObjectSchema(Map.of("ids", arrSchema));
+
+    Map<String, Object> out =
+        parser.parseAndCoerce("ids=1&ids=2".getBytes(StandardCharsets.UTF_8), null, bodySchema);
+
+    assertThat(out).containsExactly(Map.entry("ids", List.of(1L, 2L)));
+  }
+
+  @Test
+  void coercionFailureThrowsValidationExceptionAtPropertyPointer() {
+    IntegerSchema intSchema = anIntegerSchema();
+    ObjectSchema bodySchema = anObjectSchema(Map.of("age", intSchema));
+
+    org.assertj.core.api.Assertions.assertThatThrownBy(
+            () ->
+                parser.parseAndCoerce("age=abc".getBytes(StandardCharsets.UTF_8), null, bodySchema))
+        .isInstanceOf(com.retailsvc.http.ValidationException.class)
+        .extracting("error.pointer", "error.keyword")
+        .containsExactly("/age", "type");
+  }
+
+  @Test
+  void unknownPropertyPassesThroughUnchanged() {
+    ObjectSchema bodySchema = anObjectSchema(Map.of());
+
+    Map<String, Object> out =
+        parser.parseAndCoerce("anything=v".getBytes(StandardCharsets.UTF_8), null, bodySchema);
+
+    assertThat(out).containsExactly(Map.entry("anything", "v"));
+  }
+
+  @Test
+  void nonObjectSchemaReturnsRawMap() {
+    StringSchema strSchema = aStringSchema();
+
+    Map<String, Object> out =
+        parser.parseAndCoerce("a=1".getBytes(StandardCharsets.UTF_8), null, strSchema);
+
+    assertThat(out).containsExactly(Map.entry("a", "1"));
+  }
+
+  private static IntegerSchema anIntegerSchema() {
+    return new IntegerSchema(
+        Set.of(TypeName.INTEGER), null, null, null, null, null, null, Map.of());
+  }
+
+  private static StringSchema aStringSchema() {
+    return new StringSchema(Set.of(TypeName.STRING), null, null, null, null, null, Map.of());
+  }
+
+  private static ArraySchema anArraySchemaOf(Schema items) {
+    return new ArraySchema(Set.of(TypeName.ARRAY), items, null, null, false, Map.of());
+  }
+
+  private static ObjectSchema anObjectSchema(Map<String, Schema> properties) {
+    return new ObjectSchema(
+        Set.of(TypeName.OBJECT), properties, List.of(), null, null, null, Map.of());
+  }
 }