Merge pull request #51 from Samweli/reworked_pagination

Updates on pagination functionality

src/qgis_stac/api/base.py

@@ -19,6 +19,8 @@
 from .network import ContentFetcherTask
 from ..conf import ConnectionSettings
 
+from ..lib.pystac import ItemCollection
+
 
 class BaseClient(QtCore.QObject):
     """ Base API client, defines main plugin content fetching operations
@@ -37,6 +39,9 @@ class BaseClient(QtCore.QObject):
         list,
         ResourcePagination
     )
+    item_collections_received = QtCore.pyqtSignal(
+        ItemCollection
+    )
     error_received = QtCore.pyqtSignal([str], [str, int, str])
 
     def __init__(
@@ -107,24 +112,6 @@ def get_collections(
 
         QgsApplication.taskManager().addTask(self.content_task)
 
-    def get_pagination(self, item_collection):
-        """ Generates pagination details from the pystac_client item collection
-
-        :param item_collection: Collection of items generator
-        :type item_collection: ItemCollection
-
-        :returns: Pagination instance
-        :rtype: ResourcePagination
-         """
-        pagination = ResourcePagination()
-        for link in item_collection.to_dict()['links']:
-            if link['rel'] == "next":
-                pagination.next_page = link['href']
-            elif link['rel'] == "previous":
-                pagination.previous_page = link['href']
-
-        return pagination
-
     def handle_collections(
             self,
             collections
@@ -137,6 +124,12 @@ def handle_items(
     ):
         raise NotImplementedError
 
+    def handle_item_collections(
+            self,
+            items
+    ):
+        raise NotImplementedError
+
     def handle_error(
             self,
             message: str

src/qgis_stac/api/client.py

@@ -1,4 +1,5 @@
 import datetime
+import typing
 
 from .base import BaseClient
 from .models import (
@@ -10,6 +11,7 @@
 )
 
 from ..utils import log
+from ..lib.pystac import ItemCollection
 
 
 class Client(BaseClient):
@@ -18,7 +20,8 @@ class Client(BaseClient):
         """
     def handle_items(
             self,
-            items_response
+            items_response,
+            pagination
     ):
         """Emits the search results items, so plugin signal observers
         eg. gui can use the data.
@@ -27,9 +30,8 @@ def handle_items(
         :type items_response: List[models.Items]
         """
         items = []
-        pagination = ResourcePagination()
         properties = None
-        for item in items_response.get_items():
+        for item in items_response.items:
             try:
                 item_datetime = datetime.datetime.strptime(
                     item.properties.get("datetime"),
@@ -62,9 +64,25 @@ def handle_items(
 
         self.items_received.emit(items, pagination)
 
+    def handle_item_collections(
+            self,
+            items_response,
+            pagination
+    ):
+        """Emits the search results item collections generator
+
+        :param items_response: Search results items
+        :type items_response: List[models.Items]
+        """
+        self.item_collections_received.emit(
+            items_response.get_item_collections(),
+            pagination
+        )
+
     def handle_collections(
             self,
-            collections_response
+            collections_response,
+            pagination
     ):
         """Emits the search results collections.
 

src/qgis_stac/api/models.py

@@ -23,7 +23,8 @@
 @dataclasses.dataclass
 class ResourcePagination:
     """The plugin resource pagination for the search results"""
-    total_records: int = 0
+    total_items: int = 0
+    total_pages: int = 0
     current_page: int = 1
     page_size: int = 10
     next_page: str = None
@@ -228,7 +229,7 @@ def params(self):
         parameters = {
             "ids": self.ids,
             "collections": self.collections or None,
-            "max_items": self.page_size,
+            "limit": self.page_size,
             "bbox": bbox,
             "datetime": datetime_str,
         }

src/qgis_stac/api/network.py

@@ -38,7 +38,8 @@ class ContentFetcherTask(QgsTask):
 
     response = None
     error = None
-    client: Client = None
+    client = None
+    pagination = None
 
     def __init__(
         self,
@@ -66,9 +67,22 @@ def run(self):
         try:
             if self.resource_type == \
                     ResourceType.FEATURE:
-                self.response = self.client.search(
+                response = self.client.search(
                     **self.search_params.params()
                 )
+                pages = 1
+                items = 0
+                self.pagination = ResourcePagination()
+
+                for i, collection in enumerate(response.get_item_collections()):
+                    pages = pages + i
+                    items += len(collection.items)
+                    if self.search_params.page == (i + 1):
+                        self.response = collection
+
+                self.pagination.total_pages = pages
+                self.pagination.total_items = items
+
             elif self.resource_type == \
                     ResourceType.COLLECTION:
                 self.response = self.client.get_collections()
@@ -89,7 +103,7 @@ def finished(self, result: bool):
         :type result: bool
         """
         if result:
-            self.response_handler(self.response)
+            self.response_handler(self.response, self.pagination)
         else:
             message = f"Problem in fetching content for {self.url!r}," \
                       f"Error {self.error}"

src/qgis_stac/gui/qgis_stac_widget.py

@@ -61,7 +61,13 @@ def __init__(
         self.connections_box.activated.connect(self.update_current_connection)
 
         self.search_btn.clicked.connect(
-            self.search_items
+            self.search_items_api
+        )
+        self.next_btn.clicked.connect(
+            self.next_items
+        )
+        self.prev_btn.clicked.connect(
+            self.previous_items
         )
 
         self.fetch_collections_btn.clicked.connect(
@@ -113,6 +119,7 @@ def __init__(
 
         # initialize page
         self.page = 1
+        self.total_pages = 0
 
         self.current_collections = []
         self.get_filters()
@@ -183,7 +190,7 @@ def update_current_connection(self, index: int):
         current_text = self.connections_box.itemText(index)
         if current_text == "":
             return
-        current_connection = settings_manager.\
+        current_connection = settings_manager. \
             find_connection_by_name(current_text)
         settings_manager.set_current_connection(current_connection.id)
         if current_connection:
@@ -208,18 +215,31 @@ def update_connections_box(self):
             )
             current_connection = settings_manager.get_current_connection()
             if current_connection is not None:
-                current_index = self.connections_box.\
+                current_index = self.connections_box. \
                     findText(current_connection.name)
                 self.connections_box.setCurrentIndex(current_index)
             else:
                 self.connections_box.setCurrentIndex(0)
 
+    def search_items_api(self):
+        self.current_progress_message = tr(
+            f"Searching items ..."
+        )
+        self.page = 1
+        self.search_items()
+
     def previous_items(self):
         self.page -= 1
+        self.current_progress_message = tr(
+            f"Retrieving data"
+        )
         self.search_items()
 
     def next_items(self):
         self.page += 1
+        self.current_progress_message = tr(
+            f"Retrieving data"
+        )
         self.search_items()
 
     def search_items(self):
@@ -229,8 +249,6 @@ def search_items(self):
         search operation.
         """
         self.search_type = ResourceType.FEATURE
-        self.current_progress_message = tr("Searching for items...")
-
         start_dte = self.start_dte.dateTime() \
             if not self.start_dte.dateTime().isNull() else None
         end_dte = self.end_dte.dateTime() \
@@ -243,6 +261,7 @@ def search_items(self):
             ItemSearch(
                 collections=collections,
                 page_size=page_size,
+                page=self.page,
                 start_datetime=start_dte,
                 end_datetime=end_dte,
                 spatial_extent=spatial_extent,
@@ -312,6 +331,8 @@ def update_search_inputs(self, enabled):
         self.extent_box.setEnabled(enabled)
         self.metadata_group.setEnabled(enabled)
         self.search_btn.setEnabled(enabled)
+        self.next_btn.setEnabled(self.page < self.total_pages)
+        self.prev_btn.setEnabled(self.page > 1)
 
     def prepare_message_bar(self):
         """ Initializes the widget message bar settings"""
@@ -343,7 +364,7 @@ def prepare_extent_box(self):
         self.extent_box.setOutputExtentFromCurrent()
         self.extent_box.setMapCanvas(map_canvas)
 
-    def display_results(self, results):
+    def display_results(self, results, pagination):
         """ Shows the found results into their respective view. Emits
         the search end signal after completing loading up the results
         into the view.
@@ -361,9 +382,19 @@ def display_results(self, results):
             self.save_filters()
 
         elif self.search_type == ResourceType.FEATURE:
-            self.result_items_la.setText(
-                tr("Found {} STAC item(s)").format(len(results))
-            )
+            if pagination.total_items != 0:
+                self.result_items_la.setText(
+                    tr(
+                        "Page {} out {} pages, "
+                        "total {} STAC item(s) found.").format(
+                        self.page,
+                        pagination.total_pages,
+                        pagination.total_items
+                    )
+                )
+            self.total_pages = pagination.total_pages
+            self.next_btn.setEnabled(self.page < pagination.total_pages)
+            self.prev_btn.setEnabled(self.page > 1)
 
             items_model = ItemsModel(items=results)
             self.items_proxy_model.setSourceModel(items_model)

src/qgis_stac/ui/qgis_stac_widget.ui

@@ -604,9 +604,9 @@
           </spacer>
          </item>
          <item>
-          <widget class="QPushButton" name="previous_btn">
+          <widget class="QPushButton" name="prev_btn">
            <property name="enabled">
-            <bool>false</bool>
+            <bool>true</bool>
            </property>
            <property name="sizePolicy">
             <sizepolicy hsizetype="Minimum" vsizetype="Maximum">
@@ -615,7 +615,7 @@
             </sizepolicy>
            </property>
            <property name="toolTip">
-            <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;Go to previous page&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
+            <string>Go back to previous page</string>
            </property>
            <property name="text">
             <string>Previous</string>
@@ -625,7 +625,7 @@
          <item>
           <widget class="QPushButton" name="next_btn">
            <property name="enabled">
-            <bool>false</bool>
+            <bool>true</bool>
            </property>
            <property name="sizePolicy">
             <sizepolicy hsizetype="Minimum" vsizetype="Maximum">
@@ -634,7 +634,7 @@
             </sizepolicy>
            </property>
            <property name="toolTip">
-            <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;Go to next page&lt;/p&gt;&lt;p&gt;&lt;br/&gt;&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
+            <string>Go to next page</string>
            </property>
            <property name="text">
             <string>Next</string>