[Feature] Add 'OGC API - Features' provider, shortnamed as OAPIF. Onl…

…y non-GUI elements in this commit Funded by Planet
qgis · Oct 25, 2019 · 4a6b49f · 4a6b49f
1 parent 05eee42
commit 4a6b49f
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Showing 16 changed files with 2,257 additions and 1 deletion.
diff --git a/src/providers/wfs/CMakeLists.txt b/src/providers/wfs/CMakeLists.txt
@@ -3,6 +3,7 @@
 # Files
 
 SET(WFS_SRCS
+  ${CMAKE_SOURCE_DIR}/external/nlohmann/json.hpp
   qgswfsprovider.cpp
   qgswfscapabilities.cpp
   qgswfsdataitems.cpp
@@ -19,6 +20,12 @@ SET(WFS_SRCS
   qgsbackgroundcachedshareddata.cpp
   qgscachedirectorymanager.cpp
   qgsbasenetworkrequest.cpp
+  qgsoapiflandingpagerequest.cpp
+  qgsoapifapirequest.cpp
+  qgsoapifcollection.cpp
+  qgsoapifitemsrequest.cpp
+  qgsoapifprovider.cpp
+  qgsoapifutils.cpp
 )
 
 SET (WFS_MOC_HDRS
@@ -35,6 +42,11 @@ SET (WFS_MOC_HDRS
   qgswfsutils.h
   qgsbackgroundcachedfeatureiterator.h
   qgscachedirectorymanager.h
+  qgsoapiflandingpagerequest.h
+  qgsoapifapirequest.h
+  qgsoapifcollection.h
+  qgsoapifitemsrequest.h
+  qgsoapifprovider.h
 )
 
 IF (WITH_GUI)

diff --git a/src/providers/wfs/qgsoapifapirequest.cpp b/src/providers/wfs/qgsoapifapirequest.cpp
@@ -0,0 +1,132 @@
+/***************************************************************************
+    qgsoapifapirequest.cpp
+    ---------------------
+    begin                : October 2019
+    copyright            : (C) 2019 by Even Rouault
+    email                : even.rouault at spatialys.com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include <nlohmann/json.hpp>
+using namespace nlohmann;
+
+#include "qgslogger.h"
+#include "qgsoapifapirequest.h"
+
+#include <QTextCodec>
+
+QgsOapifApiRequest::QgsOapifApiRequest( const QgsDataSourceUri &baseUri, const QString &url ):
+  QgsBaseNetworkRequest( QgsAuthorizationSettings( baseUri.username(), baseUri.password(), baseUri.authConfigId() ), tr( "OAPIF" ) ),
+  mUrl( url )
+{
+  // Using Qt::DirectConnection since the download might be running on a different thread.
+  // In this case, the request was sent from the main thread and is executed with the main
+  // thread being blocked in future.waitForFinished() so we can run code on this object which
+  // lives in the main thread without risking havoc.
+  connect( this, &QgsBaseNetworkRequest::downloadFinished, this, &QgsOapifApiRequest::processReply, Qt::DirectConnection );
+}
+
+bool QgsOapifApiRequest::request( bool synchronous, bool forceRefresh )
+{
+  if ( !sendGET( QUrl( mUrl ), QStringLiteral( "application/vnd.oai.openapi+json;version=3.0, application/openapi+json;version=3.0, application/json" ), synchronous, forceRefresh ) )
+  {
+    emit gotResponse();
+    return false;
+  }
+  return true;
+}
+
+QString QgsOapifApiRequest::errorMessageWithReason( const QString &reason )
+{
+  return tr( "Download of API page failed: %1" ).arg( reason );
+}
+
+void QgsOapifApiRequest::processReply()
+{
+  if ( mErrorCode != QgsBaseNetworkRequest::NoError )
+  {
+    emit gotResponse();
+    return;
+  }
+  const QByteArray &buffer = mResponse;
+  if ( buffer.isEmpty() )
+  {
+    mErrorMessage = tr( "empty response" );
+    mErrorCode = QgsBaseNetworkRequest::ServerExceptionError;
+    emit gotResponse();
+    return;
+  }
+
+  QgsDebugMsgLevel( QStringLiteral( "parsing API response: " ) + buffer, 4 );
+
+  QTextCodec::ConverterState state;
+  QTextCodec *codec = QTextCodec::codecForName( "UTF-8" );
+  Q_ASSERT( codec );
+
+  const QString utf8Text = codec->toUnicode( buffer.constData(), buffer.size(), &state );
+  if ( state.invalidChars != 0 )
+  {
+    mErrorCode = QgsBaseNetworkRequest::ApplicationLevelError;
+    mAppLevelError = ApplicationLevelError::JsonError;
+    mErrorMessage = errorMessageWithReason( tr( "Invalid UTF-8 content" ) );
+    emit gotResponse();
+    return;
+  }
+
+  try
+  {
+    const json j = json::parse( utf8Text.toStdString() );
+    if ( j.is_object() && j.contains( "components" ) )
+    {
+      const auto components = j["components"];
+      if ( components.is_object() && components.contains( "parameters" ) )
+      {
+        const auto parameters = components["parameters"];
+        if ( parameters.is_object() && parameters.contains( "limit" ) )
+        {
+          const auto limit = parameters["limit"];
+          if ( limit.is_object() && limit.contains( "schema" ) )
+          {
+            const auto schema = limit["schema"];
+            if ( schema.is_object() )
+            {
+              if ( schema.contains( "maximum" ) )
+              {
+                const auto maximum = schema["maximum"];
+                if ( maximum.is_number_integer() )
+                {
+                  mMaxLimit = maximum.get<int>();
+                }
+              }
+
+              if ( schema.contains( "default" ) )
+              {
+                const auto defaultL = schema["default"];
+                if ( defaultL.is_number_integer() )
+                {
+                  mDefaultLimit = defaultL.get<int>();
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  catch ( const json::parse_error &ex )
+  {
+    mErrorCode = QgsBaseNetworkRequest::ApplicationLevelError;
+    mAppLevelError = ApplicationLevelError::JsonError;
+    mErrorMessage = errorMessageWithReason( tr( "Cannot decode JSon document: %1" ).arg( QString::fromStdString( ex.what() ) ) );
+    emit gotResponse();
+    return;
+  }
+
+  emit gotResponse();
+}
diff --git a/src/providers/wfs/qgsoapifapirequest.h b/src/providers/wfs/qgsoapifapirequest.h
@@ -0,0 +1,72 @@
+/***************************************************************************
+    qgsoapifapirequest.h
+    ---------------------
+    begin                : October 2019
+    copyright            : (C) 2019 by Even Rouault
+    email                : even.rouault at spatialys.com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSOAPIFAPIREQUEST_H
+#define QGSOAPIFAPIREQUEST_H
+
+#include <QObject>
+
+#include "qgsdatasourceuri.h"
+#include "qgsbasenetworkrequest.h"
+
+//! Manages the /api request
+class QgsOapifApiRequest : public QgsBaseNetworkRequest
+{
+    Q_OBJECT
+  public:
+    explicit QgsOapifApiRequest( const QgsDataSourceUri &baseUri, const QString &url );
+
+    //! Issue the request
+    bool request( bool synchronous, bool forceRefresh );
+
+    //! Application level error
+    enum class ApplicationLevelError
+    {
+      NoError,
+      JsonError,
+      IncompleteInformation
+    };
+
+    //! Returns application level error
+    ApplicationLevelError applicationLevelError() const { return mAppLevelError; }
+
+    //! Return the maximum number of features that can be requested at once (-1 if unknown)
+    int maxLimit() const { return mMaxLimit; }
+
+    //! Return the default number of features that are requested at once (-1 if unknown)
+    int defaultLimit() const { return mDefaultLimit; }
+
+  signals:
+    //! emitted when the capabilities have been fully parsed, or an error occurred */
+    void gotResponse();
+
+  private slots:
+    void processReply();
+
+  protected:
+    QString errorMessageWithReason( const QString &reason ) override;
+
+  private:
+    QString mUrl;
+
+    int mMaxLimit = -1;
+
+    int mDefaultLimit = -1;
+
+    ApplicationLevelError mAppLevelError = ApplicationLevelError::NoError;
+
+};
+
+#endif // QGSOAPIFAPIREQUEST_H