feat(geodata): support decoding GeoJSONL input on GeoJSONFeatureClient …

…#217

dart/geodata/CHANGELOG.md

@@ -4,6 +4,9 @@
 
 NOTE: Version 1.1.0 currently under development (1.1.0-dev.0).
 
+🧩 Features:
+* [Support for GeoJSON Text Sequences](https://github.com/navibyte/geospatial/issues/217)
+
 🛠 Maintenance:
 * Adding trailing commas to avoid "Missing a required trailing comma" message.
 

dart/geodata/lib/src/geojson/service/client/geojson_feature_client.dart

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2023 Navibyte (https://navibyte.com). All rights reserved.
+// Copyright (c) 2020-2024 Navibyte (https://navibyte.com). All rights reserved.
 // Use of this source code is governed by a “BSD-3-Clause”-style license that is
 // specified in the LICENSE file.
 //
@@ -19,7 +19,7 @@ import '/src/utils/feature_future_adapter.dart';
 import '/src/utils/feature_http_adapter.dart';
 
 /// A class with static factory methods to create feature sources conforming to
-/// the GeoJSON format.
+/// [GeoJSON] or [GeoJSONL] formats.
 class GeoJSONFeatures {
   /// A client for accessing a `GeoJSON` data resource at [location] via http(s)
   /// conforming to [format].
@@ -38,9 +38,9 @@ class GeoJSONFeatures {
   /// overridden by the feature source implementation).
   ///
   /// When [format] is not given, then [GeoJSON] with default settings is used
-  /// as a default. Note that currently only GeoJSON is supported, but it's
-  /// possible to inject another format implementation (or with custom
-  /// configuration) to the default one.
+  /// as a default. Note that currently only [GeoJSON] and [GeoJSONL] format are
+  /// tested, but it's possible to inject other format implementations too (or
+  /// adapt formats mentioned with a custom configuration).
   ///
   /// Use [crs] to give hints (like axis order, and whether x and y must
   /// be swapped when read in) about coordinate reference system in text input.
@@ -67,9 +67,9 @@ class GeoJSONFeatures {
   /// resource or other sources. Contents must be GeoJSON compliant data.
   ///
   /// When [format] is not given, then [GeoJSON] with default settings is used
-  /// as a default. Note that currently only GeoJSON is supported, but it's
-  /// possible to inject another format implementation (or with custom
-  /// configuration) to the default one.
+  /// as a default. Note that currently only [GeoJSON] and [GeoJSONL] format are
+  /// tested, but it's possible to inject other format implementations too (or
+  /// adapt formats mentioned with a custom configuration).
   ///
   /// Use [crs] to give hints (like axis order, and whether x and y must
   /// be swapped when read in) about coordinate reference system in text input.
@@ -144,18 +144,18 @@ class _GeoJSONFeatureSource implements BasicFeatureSource {
   Future<Paged<FeatureItems>> itemsAllPaged({int? limit}) {
     final src = source;
 
-    // fetch data as JSON Object + parse GeoJSON feature or feature collection
+    // fetch data as text + parse GeoJSON feature collection
     if (src is Uri) {
       // read web resource and convert to entity
-      return adapter!.getEntityFromJsonObject(
+      return adapter!.getEntityFromText(
         src,
-        toEntity: (data, _) => _parseFeatureItems(limit, data, format, crs),
+        toEntity: (text, _) => _parseFeatureItems(limit, text, format, crs),
       );
     } else if (src is Future<String> Function()) {
       // read a future returned by a function
-      return readEntityFromJsonObject(
+      return readEntityFromText(
         src,
-        toEntity: (data) => _parseFeatureItems(limit, data, format, crs),
+        toEntity: (text) => _parseFeatureItems(limit, text, format, crs),
       );
     }
 
@@ -166,14 +166,14 @@ class _GeoJSONFeatureSource implements BasicFeatureSource {
 
 _GeoJSONPagedFeaturesItems _parseFeatureItems(
   int? limit,
-  Map<String, dynamic> data,
+  String text,
   TextReaderFormat<FeatureContent> format,
   CoordRefSys? crs,
 ) {
   // NOTE: get count without actually parsing the whole feature collection
 
   // get the whole collection to get count
-  final collection = FeatureCollection.fromData(data, format: format, crs: crs);
+  final collection = FeatureCollection.parse(text, format: format, crs: crs);
   final count = collection.features.length;
 
   // analyze if only a first set or all items should be returned
@@ -187,7 +187,7 @@ _GeoJSONPagedFeaturesItems _parseFeatureItems(
   }
 
   // return as paged collection (paging through already fetched data)
-  return _GeoJSONPagedFeaturesItems.parse(format, crs, data, count, range);
+  return _GeoJSONPagedFeaturesItems.parse(format, crs, text, count, range);
 }
 
 class _GeoJSONPagedFeaturesItems with Paged<FeatureItems> {
@@ -196,20 +196,20 @@ class _GeoJSONPagedFeaturesItems with Paged<FeatureItems> {
     this.crs,
     this.features,
     this.count, [
-    this.data,
+    this.text,
     this.nextRange,
   ]);
 
   factory _GeoJSONPagedFeaturesItems.parse(
     TextReaderFormat<FeatureContent> format,
     CoordRefSys? crs,
-    Map<String, dynamic> data,
+    String text,
     int count,
     _Range? range,
   ) {
     // parse feature items for the range and
-    final collection = FeatureCollection.fromData(
-      data,
+    final collection = FeatureCollection.parse(
+      text,
       format: format,
       crs: crs,
       options: range != null
@@ -234,7 +234,7 @@ class _GeoJSONPagedFeaturesItems with Paged<FeatureItems> {
 
     // return a paged result either with ref to next range or without
     return nextRange != null
-        ? _GeoJSONPagedFeaturesItems(format, crs, items, count, data, nextRange)
+        ? _GeoJSONPagedFeaturesItems(format, crs, items, count, text, nextRange)
         : _GeoJSONPagedFeaturesItems(format, crs, items, count);
   }
 
@@ -244,24 +244,24 @@ class _GeoJSONPagedFeaturesItems with Paged<FeatureItems> {
   final FeatureItems features;
   final int count;
 
-  final Map<String, dynamic>? data;
+  final String? text;
   final _Range? nextRange;
 
   @override
   FeatureItems get current => features;
 
   @override
-  bool get hasNext => !(nextRange == null || data == null);
+  bool get hasNext => !(nextRange == null || text == null);
 
   @override
   Future<Paged<FeatureItems>?> next() async {
-    if (nextRange == null || data == null) {
+    if (nextRange == null || text == null) {
       return null;
     }
     return _GeoJSONPagedFeaturesItems.parse(
       format,
       crs,
-      data!,
+      text!,
       count,
       nextRange,
     );

dart/geodata/lib/src/ogcapi_features/service/client/ogc_feature_client.dart

@@ -1,9 +1,11 @@
-// Copyright (c) 2020-2023 Navibyte (https://navibyte.com). All rights reserved.
+// Copyright (c) 2020-2024 Navibyte (https://navibyte.com). All rights reserved.
 // Use of this source code is governed by a “BSD-3-Clause”-style license that is
 // specified in the LICENSE file.
 //
 // Docs: https://github.com/navibyte/geospatial
 
+import 'dart:convert';
+
 import 'package:geobase/common.dart';
 import 'package:geobase/coordinates.dart';
 import 'package:geobase/meta.dart';
@@ -157,9 +159,11 @@ class _OGCFeatureClientHttp extends OGCClientHttp implements OGCFeatureService {
       _cachedConformance.getAsync(() {
         // fetch data as JSON Object, and parse conformance classes
         final url = resolveSubResource(endpoint, 'conformance');
-        return adapter.getEntityFromJson(
+        return adapter.getEntityFromText(
           url,
-          toEntity: (data, _) {
+          toEntity: (text, _) {
+            final data = json.decode(text);
+
             if (data is Map<String, dynamic>) {
               // standard: root has JSON Object with "conformsTo" containing
               // conformance classes

dart/geodata/lib/src/utils/feature_future_adapter.dart

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2023 Navibyte (https://navibyte.com). All rights reserved.
+// Copyright (c) 2020-2024 Navibyte (https://navibyte.com). All rights reserved.
 // Use of this source code is governed by a “BSD-3-Clause”-style license that is
 // specified in the LICENSE file.
 //
@@ -14,14 +14,14 @@ import '/src/core/features/feature_failure.dart';
 /// Maps a JSON Object read from [source] to an entity using [toEntity].
 ///
 /// The source function returns a future that fetches data from a file, a web
-/// resource or other sources. Contents must be GeoJSON compliant data.
+/// resource or other sources. Content must be GeoJSON compliant data.
 @internal
 Future<T> readEntityFromJsonObject<T>(
   Future<String> Function() source, {
   required T Function(Map<String, dynamic> data) toEntity,
 }) async {
   try {
-    // read contents as text
+    // read content as text
     final text = await source();
 
     // decode JSON and expect a JSON Object as `Map<String, dynamic>`
@@ -36,3 +36,26 @@ Future<T> readEntityFromJsonObject<T>(
     throw ServiceException(FeatureFailure.clientError, cause: e, trace: st);
   }
 }
+
+/// Maps text data read from [source] to an entity using [toEntity].
+///
+/// The source function returns a future that fetches data from a file, a web
+/// resource or other sources. Content must be GeoJSON compliant data.
+@internal
+Future<T> readEntityFromText<T>(
+  Future<String> Function() source, {
+  required T Function(String text) toEntity,
+}) async {
+  try {
+    // read content as text
+    final text = await source();
+
+    // map text to an entity
+    return toEntity(text);
+  } on ServiceException<FeatureFailure> {
+    rethrow;
+  } catch (e, st) {
+    // other exceptions (including errors)
+    throw ServiceException(FeatureFailure.clientError, cause: e, trace: st);
+  }
+}

dart/geodata/lib/src/utils/feature_http_adapter.dart

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2023 Navibyte (https://navibyte.com). All rights reserved.
+// Copyright (c) 2020-2024 Navibyte (https://navibyte.com). All rights reserved.
 // Use of this source code is governed by a “BSD-3-Clause”-style license that is
 // specified in the LICENSE file.
 //
@@ -54,21 +54,23 @@ class FeatureHttpAdapter {
     Map<String, String>? headers = _acceptJSON,
     List<String>? expect = _expectJSON,
   }) =>
-      getEntityFromJson(
+      getEntityFromText(
         url,
-        toEntity: (data, responseHeaders) =>
-            toEntity(data as Map<String, dynamic>, responseHeaders),
+        toEntity: (text, responseHeaders) {
+          final data = json.decode(text);
+          return toEntity(data as Map<String, dynamic>, responseHeaders);
+        },
         headers: headers,
         expect: expect,
       );
 
   /// Makes `GET` request to [url] with optional [headers].
   ///
-  /// Returns an entity mapped from JSON element using [toEntity].
-  Future<T> getEntityFromJson<T>(
+  /// Returns an entity mapped from body text using [toEntity].
+  Future<T> getEntityFromText<T>(
     Uri url, {
     required T Function(
-      dynamic data,
+      String text,
       Map<String, String> responseHeaders,
     ) toEntity,
     Map<String, String>? headers = _acceptJSON,
@@ -101,11 +103,8 @@ class FeatureHttpAdapter {
             }
           }
 
-          // decode JSON
-          final data = json.decode(response.body);
-
-          // map JSON data to an entity
-          return toEntity(data, response.headers);
+          // map response body text to an entity
+          return toEntity(response.body, response.headers);
         case 302:
           throw const ServiceException(FeatureFailure.found);
         case 303:

dart/geodata/test/data/london.geojson

@@ -0,0 +1,29 @@
+{
+    "type": "FeatureCollection",
+    "features": [
+      {
+        "type": "Feature",
+        "id": "ROG",
+        "geometry": {
+          "type": "Point",
+          "coordinates": [-0.0014, 51.4778, 45.0]  
+        },
+        "properties": {
+          "title": "Royal Observatory",
+          "place": "Greenwich"
+        }
+      }, 
+      {
+        "type": "Feature",
+        "id": "TB",
+        "geometry": {
+          "type": "Point",
+          "coordinates": [-0.075406, 51.5055]  
+        },
+        "properties": {
+          "title": "Tower Bridge",
+          "built": 1886
+        }
+      } 
+    ]
+  }

dart/geodata/test/data/london.geojsonl

@@ -0,0 +1,2 @@
+{"type":"Feature","id":"ROG","geometry":{"type":"Point","coordinates":[-0.0014,51.4778,45]},"properties":{"title":"Royal Observatory","place":"Greenwich"}}
+{"type":"Feature","id":"TB","geometry":{"type":"Point","coordinates":[-0.075406,51.5055]},"properties":{"title":"Tower Bridge","built":1886}}