Pageable/start from 1

data-runtime/src/main/java/io/micronaut/data/runtime/config/DataConfiguration.java

@@ -36,13 +36,15 @@ public class DataConfiguration implements DataSettings {
     public static class PageableConfiguration {
         public static final int    DEFAULT_MAX_PAGE_SIZE = 100;
         public static final boolean DEFAULT_SORT_IGNORE_CASE = false;
+        public static final boolean DEFAULT_START_FROM_PAGE_ONE = false;
         public static final String DEFAULT_SORT_PARAMETER = "sort";
         public static final String DEFAULT_SIZE_PARAMETER = "size";
         public static final String DEFAULT_PAGE_PARAMETER = "page";
         public static final String PREFIX = "pageable";
         private int maxPageSize = DEFAULT_MAX_PAGE_SIZE;
         private Integer defaultPageSize = null; // When is not specified the maxPageSize should be used
         private boolean sortIgnoreCase = DEFAULT_SORT_IGNORE_CASE;
+        private boolean startFromPageOne = DEFAULT_START_FROM_PAGE_ONE;
         private String sortParameterName = DEFAULT_SORT_PARAMETER;
         private String sizeParameterName = DEFAULT_SIZE_PARAMETER;
         private String pageParameterName = DEFAULT_PAGE_PARAMETER;
@@ -78,6 +80,23 @@ public void setSortDelimiter(String sortDelimiter) {
             }
         }
 
+        /**
+         * @return Whether the first page parameter starts at one
+         */
+        public boolean isStartFromPageOne() {
+            return startFromPageOne;
+        }
+
+        /**
+         * This parameter is used to shift the provided page number back one when this is true.
+         * So when the page parameter is entered as one, the first page (0) is provided.
+         *
+         * @param startFromPageOne Whether the first page is 1
+         */
+        public void setStartFromPageOne(boolean startFromPageOne) {
+            this.startFromPageOne = startFromPageOne;
+        }
+
         /**
          * @return The maximum page size when binding {@link io.micronaut.data.model.Pageable} objects.
          */
@@ -95,7 +114,7 @@ public void setMaxPageSize(int maxPageSize) {
 
         /**
          * @return the page size to use when binding {@link io.micronaut.data.model.Pageable}
-         * objects and no size parameter is used. By default is set to the same vale as {@link #maxPageSize}
+         * objects and no size parameter is used. By default is set to the same value as {@link #maxPageSize}
          */
         public int getDefaultPageSize() {
             return defaultPageSize == null ? maxPageSize : defaultPageSize;

data-runtime/src/main/java/io/micronaut/data/runtime/http/PageableRequestArgumentBinder.java

@@ -26,6 +26,7 @@
 import io.micronaut.http.bind.binders.RequestArgumentBinder;
 import io.micronaut.http.bind.binders.TypedRequestArgumentBinder;
 
+import io.micronaut.http.exceptions.HttpStatusException;
 import jakarta.inject.Singleton;
 import java.util.List;
 import java.util.Locale;
@@ -96,6 +97,13 @@ public BindingResult<Pageable> bind(ArgumentConversionContext<Pageable> context,
             sort = Sort.of(orders);
         }
 
+        if (configuration.isStartFromPageOne()) {
+            if (page < 1) {
+                throw new IllegalArgumentException(String.format("%s parameter starts at 1", configuration.getPageParameterName()));
+            }
+            page--;
+        }
+
         if (size < 1) {
             if (page == 0 && configuredMaxSize < 1 && sort == null) {
                 pageable = Pageable.UNPAGED;

data-runtime/src/test/groovy/io/micronaut/data/runtime/http/PageableConfigSpec.groovy

@@ -28,7 +28,8 @@ class PageableConfigSpec extends Specification {
                 'micronaut.data.pageable.default-page-size': 10,
                 'micronaut.data.pageable.sort-parameter-name': 's',
                 'micronaut.data.pageable.page-parameter-name': 'index',
-                'micronaut.data.pageable.size-parameter-name': 'max'
+                'micronaut.data.pageable.size-parameter-name': 'max',
+                'micronaut.data.pageable.start-from-page-one': true
         )
         DataConfiguration.PageableConfiguration configuration = context.getBean(DataConfiguration.PageableConfiguration)
 
@@ -38,6 +39,7 @@ class PageableConfigSpec extends Specification {
         configuration.sortParameterName == 's'
         configuration.pageParameterName == 'index'
         configuration.sizeParameterName == 'max'
+        configuration.startFromPageOne
 
         cleanup:
         context.close()

data-runtime/src/test/groovy/io/micronaut/data/runtime/http/PageableRequestArgumentBinderSpec.groovy

@@ -72,10 +72,10 @@ class PageableRequestArgumentBinderSpec extends Specification {
     void 'test bind size #size and page #page with custom configuration'() {
         given:
         def configuration = new DataConfiguration.PageableConfiguration()
-        configuration.defaultPageSize=40
-        configuration.maxPageSize=200
-        configuration.sizeParameterName="perPage"
-        configuration.pageParameterName="myPage"
+        configuration.defaultPageSize = 40
+        configuration.maxPageSize = 200
+        configuration.sizeParameterName = "perPage"
+        configuration.pageParameterName = "myPage"
         PageableRequestArgumentBinder binder = new PageableRequestArgumentBinder(configuration)
         def get = HttpRequest.GET('/')
         get.parameters.add("perPage", size)
@@ -94,4 +94,38 @@ class PageableRequestArgumentBinderSpec extends Specification {
         "-1"   | "0"  | 40       | 0   // negative    => uses default != max
         "junk" | "0"  | 40       | 0   // can't be parsed
     }
+
+    @Unroll
+    void 'test page #page is or is not shifted with custom configuration for startFromPageOne #startFromPageOne'() {
+        given:
+        def configuration = new DataConfiguration.PageableConfiguration()
+        configuration.startFromPageOne = startFromPageOne
+        PageableRequestArgumentBinder binder = new PageableRequestArgumentBinder(configuration)
+        def get = HttpRequest.GET('/')
+        get.parameters.add("page", page)
+        Pageable p = binder.bind(ConversionContext.of(Pageable), get).get()
+
+        expect:
+        p.number == pageNumber
+
+        where:
+        page | pageNumber | startFromPageOne
+        "1"  | 0          | true  // first page is shifted to 0
+        "5"  | 4          | true  // fifth page is shifted to 4
+    }
+
+    void 'test IllegalArgumentException is thrown when startFromPageOne is true and page provided is 0'() {
+        given:
+        def configuration = new DataConfiguration.PageableConfiguration()
+        configuration.startFromPageOne = true
+        PageableRequestArgumentBinder binder = new PageableRequestArgumentBinder(configuration)
+        def get = HttpRequest.GET('/')
+        get.parameters.add("page", "0")
+
+        when:
+        binder.bind(ConversionContext.of(Pageable), get).get()
+
+        then:
+        thrown(IllegalArgumentException)
+    }
 }

data-spring/src/main/java/io/micronaut/data/spring/runtime/http/SpringPageableRequestArgumentBinder.java

@@ -100,6 +100,13 @@ public BindingResult<Pageable> bind(ArgumentConversionContext<Pageable> context,
             sort = Sort.unsorted();
         }
 
+        if (configuration.isStartFromPageOne()) {
+            if (page < 1) {
+                throw new IllegalArgumentException(String.format("%s parameter starts at 1", configuration.getPageParameterName()));
+            }
+            page--;
+        }
+
         if (size < 1) {
             if (page == 0 && configuredMaxSize < 1 && sort.isUnsorted()) {
                 pageable = Pageable.unpaged();