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Worker

engine

Engine

Source code in src/qgis_server_light/worker/engine.py 
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class Engine:
    def __init__(
        self,
        context: EngineContext,
        svg_paths: Optional[List[str]] = None,
        log_level=logging.WARNING,
    ) -> None:
        self.qgis = Qgis(svg_paths, log_level)
        self.context = context
        self.layer_cache: Dict[Any, Any] = {}

    def __del__(self):
        self.qgis.exitQgis()

    def process(self, job: QslGetMapJob | QslGetFeatureInfoJob) -> JobResult:

        if isinstance(job, QslGetMapJob):
            runner = cast(
                MapRunner,
                RenderRunner(
                    self.qgis,
                    RunnerContext(self.context.base_path),
                    job,
                    layer_cache=self.layer_cache,
                ),
            )
        elif isinstance(job, QslGetFeatureInfoJob):
            runner = cast(
                MapRunner,
                GetFeatureInfoRunner(
                    self.qgis,
                    RunnerContext(self.context.base_path),
                    job,
                    layer_cache=self.layer_cache,
                ),
            )
        elif isinstance(job, QslGetFeatureJob):
            runner = cast(
                MapRunner,
                GetFeatureRunner(
                    self.qgis,
                    RunnerContext(self.context.base_path),
                    job,
                    layer_cache=self.layer_cache,
                ),
            )
        else:
            raise RuntimeError(f"Type {type(job)} not supported")

        return runner.run()

context = context instance-attribute

layer_cache: Dict[Any, Any] = {} instance-attribute

qgis = Qgis(svg_paths, log_level) instance-attribute

__del__()

Source code in src/qgis_server_light/worker/engine.py 
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def __del__(self):
    self.qgis.exitQgis()

__init__(context, svg_paths=None, log_level=logging.WARNING)

Source code in src/qgis_server_light/worker/engine.py 
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def __init__(
    self,
    context: EngineContext,
    svg_paths: Optional[List[str]] = None,
    log_level=logging.WARNING,
) -> None:
    self.qgis = Qgis(svg_paths, log_level)
    self.context = context
    self.layer_cache: Dict[Any, Any] = {}

process(job)

Source code in src/qgis_server_light/worker/engine.py 
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def process(self, job: QslGetMapJob | QslGetFeatureInfoJob) -> JobResult:

    if isinstance(job, QslGetMapJob):
        runner = cast(
            MapRunner,
            RenderRunner(
                self.qgis,
                RunnerContext(self.context.base_path),
                job,
                layer_cache=self.layer_cache,
            ),
        )
    elif isinstance(job, QslGetFeatureInfoJob):
        runner = cast(
            MapRunner,
            GetFeatureInfoRunner(
                self.qgis,
                RunnerContext(self.context.base_path),
                job,
                layer_cache=self.layer_cache,
            ),
        )
    elif isinstance(job, QslGetFeatureJob):
        runner = cast(
            MapRunner,
            GetFeatureRunner(
                self.qgis,
                RunnerContext(self.context.base_path),
                job,
                layer_cache=self.layer_cache,
            ),
        )
    else:
        raise RuntimeError(f"Type {type(job)} not supported")

    return runner.run()

EngineContext dataclass

Source code in src/qgis_server_light/worker/engine.py 
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@dataclass
class EngineContext:
    base_path: Union[str, pathlib.Path]

base_path: Union[str, pathlib.Path] instance-attribute

__init__(base_path)

image_utils

qgis

CredentialsHelper

Bases: QgsCredentials

Source code in src/qgis_server_light/worker/qgis.py 
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class CredentialsHelper(QgsCredentials):
    def __init__(self):
        super().__init__()
        self.setInstance(self)

    def request(self, realm, username, password, message):
        logging.warning(message)
        return True, None, None

    def requestMasterPassword(self, password, stored):
        logging.warning("Master password requested")

__init__()

Source code in src/qgis_server_light/worker/qgis.py 
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def __init__(self):
    super().__init__()
    self.setInstance(self)

request(realm, username, password, message)

Source code in src/qgis_server_light/worker/qgis.py 
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def request(self, realm, username, password, message):
    logging.warning(message)
    return True, None, None

requestMasterPassword(password, stored)

Source code in src/qgis_server_light/worker/qgis.py 
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def requestMasterPassword(self, password, stored):
    logging.warning("Master password requested")

Qgis(svg_paths, log_level)

Source code in src/qgis_server_light/worker/qgis.py 
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def Qgis(svg_paths: Optional[List[str]], log_level):
    # TODO: Is this save for rendering? Currently the image ghcr.io/opengisch/qgis-slim:3.34.8
    #   does not support
    os.environ["QT_QPA_PLATFORM"] = "offscreen"
    qgs = QgsApplication([], False)
    qgs.initQgis()
    if svg_paths:
        _svg_paths = qgs.svgPaths()
        # we do fast set algebra to always have unique list of paths
        # https://docs.python.org/3/library/stdtypes.html#frozenset.union
        qgs.setSvgPaths(list(set(_svg_paths) | set(svg_paths)))
    providers = QgsProviderRegistry.instance().pluginList().split("\n")
    logging.debug(f"Application Path: {qgs.prefixPath()}")
    logging.info(f"QGIS Version {Qgis_.version()}")
    logging.info("Found Providers:")
    for provider in providers:
        logging.info(f" - {provider}")

    if log_level == logging.DEBUG:
        logging.debug("QGIS Debugging enabled")

        def write_log_message(message, tag, level):
            logging.debug(f"{tag}({level}): {message}")

        QgsApplication.messageLog().messageReceived.connect(write_log_message)

        qgs.credentialsHelper = CredentialsHelper()

    return qgs

redis

DEFAULT_DATA_ROOT = '/io/data' module-attribute

DEFAULT_SVG_PATH = '/io/svg' module-attribute

RedisEngine

Bases: Engine

Source code in src/qgis_server_light/worker/redis.py 
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class RedisEngine(Engine):
    def __init__(
        self, context: EngineContext, svg_paths: Optional[List] = None
    ) -> None:
        super().__init__(context, svg_paths)
        self.shutdown = False

    def exit_gracefully(self, signum, frame):
        print("Received:", signum)
        self.shutdown = True
        # actually exit the programm (for some reason it is not working with the shutdown switch)
        exit(0)

    def run(self, redis_url):
        signal.signal(signal.SIGINT, self.exit_gracefully)
        signal.signal(signal.SIGTERM, self.exit_gracefully)
        r = redis.Redis.from_url(redis_url)
        p = r.pipeline()
        while True:
            try:
                r.ping()
            except redis.exceptions.ConnectionError:
                logging.warning(
                    f"Could not connect to redis on `{redis_url}`, trying again in 1 second"
                )
                time.sleep(1)
            else:
                break
        logging.info(f"Connection to redis on `{redis_url}`successful.")
        while not self.shutdown:
            retry_count = 0
            try:
                logging.debug(f"Waiting for jobs")
                # this is blocking the loop until a job is found in the redis queue
                _, job_info_json = r.blpop(["jobs"])

                if (
                    f'"type": "{JobRunnerInfoQslGetMapJob.__name__}"'.encode()
                    in job_info_json
                ):
                    job_info = JsonParser().from_bytes(
                        job_info_json, JobRunnerInfoQslGetMapJob
                    )
                elif (
                    f'"type": "{JobRunnerInfoQslGetFeatureInfoJob.__name__}"'.encode()
                    in job_info_json
                ):
                    job_info = JsonParser().from_bytes(
                        job_info_json, JobRunnerInfoQslGetFeatureInfoJob
                    )
                elif (
                    f'"type": "{JobRunnerInfoQslLegendJob.__name__}"'.encode()
                    in job_info_json
                ):
                    job_info = JsonParser().from_bytes(
                        job_info_json, JobRunnerInfoQslLegendJob
                    )
                elif (
                    f'"type": "{JobRunnerInfoQslGetFeatureJob.__name__}"'.encode()
                    in job_info_json
                ):
                    job_info = JsonParser().from_bytes(
                        job_info_json, JobRunnerInfoQslGetFeatureJob
                    )
                else:
                    raise NotImplementedError(
                        f"Type of job not supported by qgis-server-light. {job_info_json}"
                    )
                logging.debug(
                    f"Job info received: id: {job_info.id}, type: {job_info.type}"
                )
            except Exception as e:
                # TODO handle known exceptions like redis.exceptions.ConnectionError separately
                retry_count += 1
                logging.error(e, exc_info=True)
                retry_rate = math.pow(2, retry_count) * 0.01
                logging.warning(f"Retrying in {retry_rate} seconds...")
                time.sleep(retry_rate)
                continue
            key = job_info.id

            p.hset(key, "status", Status.RUNNING.value)
            p.hset(
                key,
                f"timestamp.{Status.RUNNING.value}",
                datetime.datetime.now().isoformat(),
            )
            p.hset(key, "timestamp", datetime.datetime.now().isoformat())
            p.execute()
            try:
                start_time = time.time()
                result = self.process(job_info.job)
                data = pickle.dumps(result)
                p.publish(f"notifications:{key}", data)
                p.hset(key, "content_type", result.content_type)
                p.hset(key, "status", Status.SUCCESS.value)
                duration = time.time() - start_time
                p.hset(key, "duration", str(duration))
                p.hset(
                    key,
                    f"timestamp.{Status.SUCCESS.value}",
                    datetime.datetime.now().isoformat(),
                )
                p.hset(key, "timestamp", datetime.datetime.now().isoformat())
                logging.debug(f"duration of rendering: {duration}")
            except Exception as e:
                p.hset(key, "status", Status.FAILURE.value)
                p.hset(key, "error", f"{e}")
                p.publish(f"notifications:{key}", 0)
                p.hset(
                    key,
                    f"timestamp.{Status.FAILURE.value}",
                    datetime.datetime.now().isoformat(),
                )
                p.hset(key, "timestamp", datetime.datetime.now().isoformat())
                logging.error(e, exc_info=True)
            finally:
                p.execute()

shutdown = False instance-attribute

__init__(context, svg_paths=None)

Source code in src/qgis_server_light/worker/redis.py 
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def __init__(
    self, context: EngineContext, svg_paths: Optional[List] = None
) -> None:
    super().__init__(context, svg_paths)
    self.shutdown = False

exit_gracefully(signum, frame)

Source code in src/qgis_server_light/worker/redis.py 
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def exit_gracefully(self, signum, frame):
    print("Received:", signum)
    self.shutdown = True
    # actually exit the programm (for some reason it is not working with the shutdown switch)
    exit(0)

run(redis_url)

Source code in src/qgis_server_light/worker/redis.py 
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def run(self, redis_url):
    signal.signal(signal.SIGINT, self.exit_gracefully)
    signal.signal(signal.SIGTERM, self.exit_gracefully)
    r = redis.Redis.from_url(redis_url)
    p = r.pipeline()
    while True:
        try:
            r.ping()
        except redis.exceptions.ConnectionError:
            logging.warning(
                f"Could not connect to redis on `{redis_url}`, trying again in 1 second"
            )
            time.sleep(1)
        else:
            break
    logging.info(f"Connection to redis on `{redis_url}`successful.")
    while not self.shutdown:
        retry_count = 0
        try:
            logging.debug(f"Waiting for jobs")
            # this is blocking the loop until a job is found in the redis queue
            _, job_info_json = r.blpop(["jobs"])

            if (
                f'"type": "{JobRunnerInfoQslGetMapJob.__name__}"'.encode()
                in job_info_json
            ):
                job_info = JsonParser().from_bytes(
                    job_info_json, JobRunnerInfoQslGetMapJob
                )
            elif (
                f'"type": "{JobRunnerInfoQslGetFeatureInfoJob.__name__}"'.encode()
                in job_info_json
            ):
                job_info = JsonParser().from_bytes(
                    job_info_json, JobRunnerInfoQslGetFeatureInfoJob
                )
            elif (
                f'"type": "{JobRunnerInfoQslLegendJob.__name__}"'.encode()
                in job_info_json
            ):
                job_info = JsonParser().from_bytes(
                    job_info_json, JobRunnerInfoQslLegendJob
                )
            elif (
                f'"type": "{JobRunnerInfoQslGetFeatureJob.__name__}"'.encode()
                in job_info_json
            ):
                job_info = JsonParser().from_bytes(
                    job_info_json, JobRunnerInfoQslGetFeatureJob
                )
            else:
                raise NotImplementedError(
                    f"Type of job not supported by qgis-server-light. {job_info_json}"
                )
            logging.debug(
                f"Job info received: id: {job_info.id}, type: {job_info.type}"
            )
        except Exception as e:
            # TODO handle known exceptions like redis.exceptions.ConnectionError separately
            retry_count += 1
            logging.error(e, exc_info=True)
            retry_rate = math.pow(2, retry_count) * 0.01
            logging.warning(f"Retrying in {retry_rate} seconds...")
            time.sleep(retry_rate)
            continue
        key = job_info.id

        p.hset(key, "status", Status.RUNNING.value)
        p.hset(
            key,
            f"timestamp.{Status.RUNNING.value}",
            datetime.datetime.now().isoformat(),
        )
        p.hset(key, "timestamp", datetime.datetime.now().isoformat())
        p.execute()
        try:
            start_time = time.time()
            result = self.process(job_info.job)
            data = pickle.dumps(result)
            p.publish(f"notifications:{key}", data)
            p.hset(key, "content_type", result.content_type)
            p.hset(key, "status", Status.SUCCESS.value)
            duration = time.time() - start_time
            p.hset(key, "duration", str(duration))
            p.hset(
                key,
                f"timestamp.{Status.SUCCESS.value}",
                datetime.datetime.now().isoformat(),
            )
            p.hset(key, "timestamp", datetime.datetime.now().isoformat())
            logging.debug(f"duration of rendering: {duration}")
        except Exception as e:
            p.hset(key, "status", Status.FAILURE.value)
            p.hset(key, "error", f"{e}")
            p.publish(f"notifications:{key}", 0)
            p.hset(
                key,
                f"timestamp.{Status.FAILURE.value}",
                datetime.datetime.now().isoformat(),
            )
            p.hset(key, "timestamp", datetime.datetime.now().isoformat())
            logging.error(e, exc_info=True)
        finally:
            p.execute()

main()

Source code in src/qgis_server_light/worker/redis.py 
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def main() -> None:
    parser = argparse.ArgumentParser()

    parser.add_argument("--redis-url", type=str, help="redis url")

    parser.add_argument(
        "--log-level",
        type=str,
        help="log level (debug, info, warning or error)",
        default="info",
    )

    parser.add_argument(
        "--data-root",
        type=str,
        help=f"Absolute path to the data dir. Defaults to {DEFAULT_DATA_ROOT}",
        default=DEFAULT_DATA_ROOT,
    )

    parser.add_argument(
        "--svg-path",
        type=str,
        help=f"Absolute path to additional svg files. Multiple paths can be separated by `:`. Defaults to {DEFAULT_SVG_PATH}",
        default=DEFAULT_SVG_PATH,
    )

    args = parser.parse_args()

    logging.basicConfig(
        level=args.log_level.upper(), format="%(asctime)s [%(levelname)s] %(message)s"
    )

    log = logging.getLogger(__name__)
    log.info(json.dumps(dict(os.environ), indent=2))

    if not args.redis_url:
        raise AssertionError(
            "no redis host specified: start qgis-server-light with '--redis-url <QSL_REDIS_URL>'"
        )

    svg_paths = args.svg_path.split(":")
    engine = RedisEngine(EngineContext(args.data_root), svg_paths)
    engine.run(
        args.redis_url,
    )

runner

GetFeatureInfoRunner

Bases: MapRunner

Source code in src/qgis_server_light/worker/runner.py 
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class GetFeatureInfoRunner(MapRunner):
    def __init__(
        self,
        qgis: QgsApplication,
        context: RunnerContext,
        job: QslGetFeatureInfoJob,
        layer_cache: Optional[Dict] = None,
    ) -> None:
        super().__init__(qgis, context, job, layer_cache)

    def _clean_attribute(self, attribute, idx, layer):
        if attribute == NULL:
            return None
        setup = layer.editorWidgetSetup(idx)
        fieldFormatter = QgsApplication.fieldFormatterRegistry().fieldFormatter(
            setup.type()
        )
        return fieldFormatter.representValue(
            layer, idx, setup.config(), None, attribute
        )

    def _clean_attributes(self, attributes, layer):
        return [
            self._clean_attribute(attr, idx, layer)
            for idx, attr in enumerate(attributes)
        ]

    def run(self):
        layer_registry = self.context.theme.config.get("layers")
        for dataset in self.job.query_layers:
            self._init_layers(layer_registry, dataset)
        map_settings = self._get_map_settings(self.map_layers)
        # Estimate queryable bbox (2mm)
        map_to_pixel = map_settings.mapToPixel()
        map_point = map_to_pixel.toMapCoordinates(self.job.x, self.job.y)
        # Create identifiable bbox in map coordinates, ±2mm
        tolerance = 0.002 * 39.37 * map_settings.outputDpi()
        tl = QgsPointXY(map_point.x() - tolerance, map_point.y() - tolerance)
        br = QgsPointXY(map_point.x() + tolerance, map_point.y() + tolerance)
        rect = QgsRectangle(tl, br)
        render_context = QgsRenderContext.fromMapSettings(map_settings)

        features = list()
        for layer in self.map_layers:
            renderer = layer.renderer().clone() if layer.renderer() else None
            if renderer:
                renderer.startRender(render_context, layer.fields())

            if layer.type() == QgsMapLayerType.VectorLayer:
                layer_rect = map_settings.mapToLayerCoordinates(layer, rect)
                request = (
                    QgsFeatureRequest()
                    .setFilterRect(layer_rect)
                    .setFlags(QgsFeatureRequest.ExactIntersect)
                )
                for feature in layer.getFeatures(request):
                    if renderer.willRenderFeature(feature, render_context):
                        properties = OrderedDict(
                            zip(
                                feature.fields().names(),
                                self._clean_attributes(feature.attributes(), layer),
                            )
                        )
                        features.append({"type": "Feature", "properties": properties})
            else:
                raise RuntimeError(
                    f"Layer type `{layer.type().name}` of layer `{layer.shortName()}` not supported by GetFeatureInfo"
                )
            if renderer:
                renderer.stopRender(render_context)

        featurecollection = {"features": features, "type": "FeatureCollection"}
        return JobResult(
            data=json.dumps(featurecollection).encode("utf-8"),
            content_type="application/json",
        )

__init__(qgis, context, job, layer_cache=None)

Source code in src/qgis_server_light/worker/runner.py 
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def __init__(
    self,
    qgis: QgsApplication,
    context: RunnerContext,
    job: QslGetFeatureInfoJob,
    layer_cache: Optional[Dict] = None,
) -> None:
    super().__init__(qgis, context, job, layer_cache)

run()

Source code in src/qgis_server_light/worker/runner.py 
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def run(self):
    layer_registry = self.context.theme.config.get("layers")
    for dataset in self.job.query_layers:
        self._init_layers(layer_registry, dataset)
    map_settings = self._get_map_settings(self.map_layers)
    # Estimate queryable bbox (2mm)
    map_to_pixel = map_settings.mapToPixel()
    map_point = map_to_pixel.toMapCoordinates(self.job.x, self.job.y)
    # Create identifiable bbox in map coordinates, ±2mm
    tolerance = 0.002 * 39.37 * map_settings.outputDpi()
    tl = QgsPointXY(map_point.x() - tolerance, map_point.y() - tolerance)
    br = QgsPointXY(map_point.x() + tolerance, map_point.y() + tolerance)
    rect = QgsRectangle(tl, br)
    render_context = QgsRenderContext.fromMapSettings(map_settings)

    features = list()
    for layer in self.map_layers:
        renderer = layer.renderer().clone() if layer.renderer() else None
        if renderer:
            renderer.startRender(render_context, layer.fields())

        if layer.type() == QgsMapLayerType.VectorLayer:
            layer_rect = map_settings.mapToLayerCoordinates(layer, rect)
            request = (
                QgsFeatureRequest()
                .setFilterRect(layer_rect)
                .setFlags(QgsFeatureRequest.ExactIntersect)
            )
            for feature in layer.getFeatures(request):
                if renderer.willRenderFeature(feature, render_context):
                    properties = OrderedDict(
                        zip(
                            feature.fields().names(),
                            self._clean_attributes(feature.attributes(), layer),
                        )
                    )
                    features.append({"type": "Feature", "properties": properties})
        else:
            raise RuntimeError(
                f"Layer type `{layer.type().name}` of layer `{layer.shortName()}` not supported by GetFeatureInfo"
            )
        if renderer:
            renderer.stopRender(render_context)

    featurecollection = {"features": features, "type": "FeatureCollection"}
    return JobResult(
        data=json.dumps(featurecollection).encode("utf-8"),
        content_type="application/json",
    )

GetFeatureRunner

Bases: MapRunner

Source code in src/qgis_server_light/worker/runner.py 
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class GetFeatureRunner(MapRunner):
    def __init__(
        self,
        qgis: QgsApplication,
        context: RunnerContext,
        job: QslGetFeatureJob,
        layer_cache: Optional[Dict] = None,
    ) -> None:
        super().__init__(qgis, context, job, layer_cache)

    def _clean_attribute(self, attribute_value: Any, idx: int, layer: QgsVectorLayer):
        if attribute_value == NULL:
            return None
        return attribute_value

    def _clean_attributes(self, attributes, layer):
        return [
            self._clean_attribute(attr, idx, layer)
            for idx, attr in enumerate(attributes)
        ]

    def _load_style(
        self, requested_style_name: str, qgs_layer: QgsMapLayer, dataset: DataSet
    ):
        logging.info(f" ✓ Omit style loading on WFS layer operation.")

    def run(self):
        query_collection = QueryCollection()
        numbers_matched = 0
        for query in self.job.queries:
            # we need to reset this because we want always only the layers related to the current query
            self.map_layers = []
            wfs_filter_definition = query.filter
            for dataset in query.datasets:
                self._init_layers(dataset)

            for layer in self.map_layers:
                feature_collection = FeatureCollection(layer.name())
                query_collection.feature_collections.append(feature_collection)
                if isinstance(layer, QgsVectorLayer):
                    if wfs_filter_definition:
                        # TODO: This is potentially bad: We always get all features from datasource. However, QGIS
                        #   does not seem to support sliding window feature filter out of the box...
                        logging.info(" Layer is filtered by:")
                        logging.info(f" {wfs_filter_definition}")
                        filter_doc = QDomDocument()
                        filter_doc.setContent(wfs_filter_definition)
                        # This is not correct in the WFS 2.0 way. We apply a filter to a layer. But WFS 2.0
                        # allows filters on multiple layers.
                        expression = QgsOgcUtils.expressionFromOgcFilter(
                            filter_doc.documentElement(),
                            QgsOgcUtils.FilterVersion.FILTER_FES_2_0,
                        )
                        logging.info(
                            f" This was transformed to the QGIS expression (valid: {expression.isValid()})"
                        )
                        logging.info(f" '{expression.dump()}'")
                        feature_request = QgsFeatureRequest(expression)
                    else:
                        feature_request = QgsFeatureRequest()
                    layer_features = list(layer.getFeatures(feature_request))
                    numbers_matched += len(layer_features)
                    logging.info(f" Found {len(layer_features)} features")
                    if self.job.count:
                        layer_features = layer_features[
                            self.job.start_index : self.job.start_index + self.job.count
                        ]
                    for layer_feature in layer_features:
                        property_list = zip(
                            layer_feature.fields().names(),
                            self._clean_attributes(layer_feature.attributes(), layer),
                        )
                        feature = Feature(
                            geometry=Attribute(
                                name="geometry",
                                value=bytearray(layer_feature.geometry().asWkb()),
                            )
                        )
                        feature_collection.features.append(feature)
                        for name, value in property_list:
                            feature.attributes.append(Attribute(name=name, value=value))
                else:
                    raise RuntimeError(
                        f"Layer type `{layer.type().name}` of layer `{layer.shortName()}` not supported by GetFeatureInfo"
                    )
        if numbers_matched > 0:
            query_collection.numbers_matched = numbers_matched
        data = JsonSerializer().render(query_collection).encode()
        return JobResult(
            data=data,
            content_type="application/qgis-server-light.interface.qgis.QueryCollection",
        )

__init__(qgis, context, job, layer_cache=None)

Source code in src/qgis_server_light/worker/runner.py 
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def __init__(
    self,
    qgis: QgsApplication,
    context: RunnerContext,
    job: QslGetFeatureJob,
    layer_cache: Optional[Dict] = None,
) -> None:
    super().__init__(qgis, context, job, layer_cache)

run()

Source code in src/qgis_server_light/worker/runner.py 
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def run(self):
    query_collection = QueryCollection()
    numbers_matched = 0
    for query in self.job.queries:
        # we need to reset this because we want always only the layers related to the current query
        self.map_layers = []
        wfs_filter_definition = query.filter
        for dataset in query.datasets:
            self._init_layers(dataset)

        for layer in self.map_layers:
            feature_collection = FeatureCollection(layer.name())
            query_collection.feature_collections.append(feature_collection)
            if isinstance(layer, QgsVectorLayer):
                if wfs_filter_definition:
                    # TODO: This is potentially bad: We always get all features from datasource. However, QGIS
                    #   does not seem to support sliding window feature filter out of the box...
                    logging.info(" Layer is filtered by:")
                    logging.info(f" {wfs_filter_definition}")
                    filter_doc = QDomDocument()
                    filter_doc.setContent(wfs_filter_definition)
                    # This is not correct in the WFS 2.0 way. We apply a filter to a layer. But WFS 2.0
                    # allows filters on multiple layers.
                    expression = QgsOgcUtils.expressionFromOgcFilter(
                        filter_doc.documentElement(),
                        QgsOgcUtils.FilterVersion.FILTER_FES_2_0,
                    )
                    logging.info(
                        f" This was transformed to the QGIS expression (valid: {expression.isValid()})"
                    )
                    logging.info(f" '{expression.dump()}'")
                    feature_request = QgsFeatureRequest(expression)
                else:
                    feature_request = QgsFeatureRequest()
                layer_features = list(layer.getFeatures(feature_request))
                numbers_matched += len(layer_features)
                logging.info(f" Found {len(layer_features)} features")
                if self.job.count:
                    layer_features = layer_features[
                        self.job.start_index : self.job.start_index + self.job.count
                    ]
                for layer_feature in layer_features:
                    property_list = zip(
                        layer_feature.fields().names(),
                        self._clean_attributes(layer_feature.attributes(), layer),
                    )
                    feature = Feature(
                        geometry=Attribute(
                            name="geometry",
                            value=bytearray(layer_feature.geometry().asWkb()),
                        )
                    )
                    feature_collection.features.append(feature)
                    for name, value in property_list:
                        feature.attributes.append(Attribute(name=name, value=value))
            else:
                raise RuntimeError(
                    f"Layer type `{layer.type().name}` of layer `{layer.shortName()}` not supported by GetFeatureInfo"
                )
    if numbers_matched > 0:
        query_collection.numbers_matched = numbers_matched
    data = JsonSerializer().render(query_collection).encode()
    return JobResult(
        data=data,
        content_type="application/qgis-server-light.interface.qgis.QueryCollection",
    )

GetLegendRunner

Bases: MapRunner

Source code in src/qgis_server_light/worker/runner.py 
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class GetLegendRunner(MapRunner):
    def __init__(self, qgis, context: RunnerContext, job: QslLegendJob) -> None:
        super().__init__(qgis, context, job)
        self.job = job

    def run(self):
        # TODO Implement ....
        raise NotImplementedError()

job = job instance-attribute

__init__(qgis, context, job)

Source code in src/qgis_server_light/worker/runner.py 
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def __init__(self, qgis, context: RunnerContext, job: QslLegendJob) -> None:
    super().__init__(qgis, context, job)
    self.job = job

run()

Source code in src/qgis_server_light/worker/runner.py 
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def run(self):
    # TODO Implement ....
    raise NotImplementedError()

MapRunner

Base class for any runner that interacts with a map. Not runnable by itself.

Source code in src/qgis_server_light/worker/runner.py 
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class MapRunner:
    """Base class for any runner that interacts with a map.
    Not runnable by itself.
    """

    map_layers: List[QgsMapLayer]

    def __init__(
        self,
        qgis: QgsApplication,
        context: RunnerContext,
        job: QslGetMapJob | QslGetFeatureInfoJob | QslLegendJob | QslGetFeatureJob,
        layer_cache: Optional[Dict] = None,
    ) -> None:
        self.qgis = qgis
        self.context = context
        self.job = job
        self.map_layers = list()
        self.layer_cache = layer_cache

    def _get_map_settings(self, layers: List[QgsMapLayer]) -> QgsMapSettings:
        """Produces a QgsMapSettings object from a set of layers"""
        expression_context_scope = QgsExpressionContextScope()
        expression_context_scope.setVariable("map_id", str(uuid.uuid4()))
        expression_context = QgsExpressionContext()
        expression_context.appendScope(expression_context_scope)
        settings = QgsMapSettings()
        settings.setExpressionContext(expression_context)

        def preprocessor(path):
            print(path)
            return path

        settings.pathResolver().setPathPreprocessor(preprocessor)
        settings.setOutputSize(
            QSize(
                int(self.job.service_params.WIDTH), int(self.job.service_params.HEIGHT)
            )
        )
        if self.job.service_params.dpi:
            settings.setOutputDpi(self.job.service_params.dpi)
        minx, miny, maxx, maxy = self.job.service_params.bbox
        bbox = QgsRectangle(float(minx), float(miny), float(maxx), float(maxy))
        settings.setExtent(bbox)
        settings.setExtentBuffer(self.job.extent_buffer)
        settings.setLayers(layers)
        settings.setBackgroundColor(QColor(Qt.transparent))
        crs = self.job.service_params.CRS
        destinationCrs = QgsCoordinateReferenceSystem.fromOgcWmsCrs(crs)
        settings.setDestinationCrs(destinationCrs)
        return settings

    def _load_style(
        self, requested_style_name: str, qgs_layer: QgsMapLayer, dataset: DataSet
    ):
        logging.info(f"Preparing layer Style: {requested_style_name}")
        style_doc = QDomDocument()
        style_doc.setContent(
            zlib.decompress(
                urlsafe_b64decode(
                    dataset.get_style_by_name(requested_style_name).definition
                )
            )
        )
        style_loaded = qgs_layer.importNamedStyle(style_doc)
        qgs_layer.styleManager().setCurrentStyle(requested_style_name)
        logging.info(f" ✓ Style loaded: {style_loaded}")

    def _init_layers(self, dataset: Vector | Raster | Custom):
        """Initializes the map_layers list with all the specified layer_names, looking up style and other
        information in layer_registry
        Returns:
            None
        Parameters:
            layer_name: the layer or group to initialize. In case of a group, will recursively follow.
        """

        if isinstance(dataset, Vector):
            qgs_layer = self._prepare_vector_layer(dataset)
        elif isinstance(dataset, Raster):
            qgs_layer = self._prepare_raster_layer(dataset)
        elif isinstance(dataset, Custom):
            qgs_layer = self._prepare_custom_layer(dataset)
        else:
            raise KeyError(f"Type not implemented: {dataset}")
        # applying the style to the layer
        self._load_style(dataset.style_name, qgs_layer, dataset)
        self.map_layers.append(qgs_layer)

    def _prepare_vector_layer(self, dataset: Vector) -> QgsVectorLayer:
        """Initializes a vector layer"""
        if dataset.source.ogr is not None:
            if dataset.source.ogr.remote:
                layer_source_path = dataset.path
            else:
                layer_source_path = os.path.join(self.context.base_path, dataset.path)
        elif (dataset.source.postgres or dataset.source.wfs) is not None:
            layer_source_path = dataset.path
        else:
            raise KeyError(f"Driver not implemented: {dataset.driver}")

        cache_name = (
            f"{dataset.name}.{dataset.style_name}.{dataset.filter}.{dataset.path}"
        )
        if self.layer_cache is not None and cache_name in self.layer_cache:
            logging.debug(
                f"Using cached layer {dataset.name} (identifier: {cache_name}"
            )
            qgs_layer = self.layer_cache[cache_name]
        else:
            logging.debug(f"Load layer {layer_source_path}")
            options = QgsVectorLayer.LayerOptions(
                loadDefaultStyle=False, readExtentFromXml=False
            )
            options.skipCrValidation = True
            options.forceReadOnly = True
            qgs_layer = QgsVectorLayer(
                layer_source_path, dataset.name, dataset.driver, options
            )
            if dataset.filter:
                if isinstance(dataset.filter, OgcFilter110):
                    # TODO: This is potentially bad: We always get all features from datasource. However, QGIS
                    #   does not seem to support sliding window feature filter out of the box...
                    logging.info(" Layer is filtered by:")
                    logging.info(dataset.filter.definition)
                    filter_doc = QDomDocument()
                    filter_doc.setContent(dataset.filter.definition)
                    filter_expression = QgsOgcUtils.expressionFromOgcFilter(
                        filter_doc.documentElement(),
                        QgsOgcUtils.FilterVersion.FILTER_OGC_1_1,
                        qgs_layer,
                    )
                    existingExpression = qgs_layer.subsetString()
                    if existingExpression:
                        # Combining with AND the originally defined expression always takes precedence
                        expression = f"({existingExpression}) AND ({filter_expression.expression()})"
                    else:
                        expression = filter_expression.expression()
                    qgs_layer.setSubsetString(expression)

            if not qgs_layer.isValid():
                raise RuntimeError(
                    f"Layer {dataset.name} is not valid.\n    Path: {layer_source_path}"
                )
            else:
                logging.info(f" ✓ Layer: {dataset.name}")
                if self.layer_cache is not None:
                    self.layer_cache[cache_name] = qgs_layer
        return qgs_layer

    def _prepare_custom_layer(self, dataset: Custom) -> QgsVectorTileLayer:
        """Initializes a raster layer"""
        if dataset.source.vector_tile is not None:
            if dataset.source.vector_tile.remote:
                layer_source_path = dataset.path
                logging.debug(f"Loading layer source: {layer_source_path}")
            else:
                raise NotImplementedError(
                    "Currently only remote VectorTiles are supported"
                )
        else:
            raise KeyError(f"Driver not implemented: {dataset.driver}")
        # TODO: make sure cached layers reload the style if changed
        if self.layer_cache is not None and dataset.name in self.layer_cache:
            logging.debug(f"Using cached layer {dataset.name}")
            qgs_layer = self.layer_cache[dataset.name]
        else:
            qgs_layer = QgsVectorTileLayer(layer_source_path, dataset.name)
            if not qgs_layer.isValid():
                raise RuntimeError(f"Layer {dataset.name} is not valid")
            else:
                logging.info(f" ✓ Layer: {dataset.name}")
                if self.layer_cache is not None:
                    self.layer_cache[dataset.name] = qgs_layer
        return qgs_layer

    def _prepare_raster_layer(self, dataset: Raster) -> QgsRasterLayer:
        """Initializes a raster layer"""
        if dataset.source.gdal is not None:
            if dataset.source.gdal.remote:
                layer_source_path = dataset.path
            else:
                layer_source_path = os.path.join(self.context.base_path, dataset.path)
        elif dataset.source.wms is not None:
            layer_source_path = dataset.path
        elif dataset.source.wmts is not None:
            layer_source_path = dataset.path
        else:
            logging.error(f"Not able to handle datasource {dataset.source}")
            raise KeyError(f"Driver not implemented: {dataset.driver}")
        logging.debug(f"Loading layer source: {layer_source_path}")
        # TODO: make sure cached layers reload the style if changed
        if self.layer_cache is not None and dataset.name in self.layer_cache:
            logging.debug(f"Using cached layer {dataset.name}")
            qgs_layer = self.layer_cache[dataset.name]
        else:
            qgs_layer = QgsRasterLayer(layer_source_path, dataset.name, dataset.driver)
            if not qgs_layer.isValid():
                raise RuntimeError(f"Layer {dataset.name} is not valid")
            else:
                logging.info(f" ✓ Layer: {dataset.name}")
                if self.layer_cache is not None:
                    self.layer_cache[dataset.name] = qgs_layer
        return qgs_layer

    def run(self):
        # This is an abstract base class which is not runnable itself
        raise NotImplementedError()

context = context instance-attribute

job = job instance-attribute

layer_cache = layer_cache instance-attribute

map_layers: List[QgsMapLayer] = list() instance-attribute

qgis = qgis instance-attribute

__init__(qgis, context, job, layer_cache=None)

Source code in src/qgis_server_light/worker/runner.py 
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def __init__(
    self,
    qgis: QgsApplication,
    context: RunnerContext,
    job: QslGetMapJob | QslGetFeatureInfoJob | QslLegendJob | QslGetFeatureJob,
    layer_cache: Optional[Dict] = None,
) -> None:
    self.qgis = qgis
    self.context = context
    self.job = job
    self.map_layers = list()
    self.layer_cache = layer_cache

run()

Source code in src/qgis_server_light/worker/runner.py 
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def run(self):
    # This is an abstract base class which is not runnable itself
    raise NotImplementedError()

RenderRunner

Bases: MapRunner

Responsible for rendering a QslRenderJob to an image.

Source code in src/qgis_server_light/worker/runner.py 
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class RenderRunner(MapRunner):
    """Responsible for rendering a QslRenderJob to an image."""

    def __init__(
        self,
        qgis: QgsApplication,
        context: RunnerContext,
        job: QslGetMapJob,
        layer_cache: Optional[Dict] = None,
    ) -> None:
        super().__init__(qgis, context, job, layer_cache)

    def run(self):
        """Run this runner.
        Returns:
            A JobResult with the content_type and image_data (bytes) of the rendered image.
        """
        feature_filter = QgsFeatureFilter()
        for index, layer_name in enumerate(self.job.service_params.layers):
            self._init_layers(self.job.get_dataset_by_name(layer_name))
        map_settings = self._get_map_settings(self.map_layers)
        filter_providers = QgsFeatureFilterProviderGroup()
        filter_providers.addProvider(feature_filter)
        renderer = QgsMapRendererParallelJob(map_settings)
        renderer.setFeatureFilterProvider(filter_providers)
        event_loop = QEventLoop(self.qgis)
        renderer.finished.connect(event_loop.quit)
        renderer.start()
        event_loop.exec_()
        img = renderer.renderedImage()
        img.setDotsPerMeterX(int(map_settings.outputDpi() * 39.37))
        img.setDotsPerMeterY(int(map_settings.outputDpi() * 39.37))
        image_data, content_type = _encode_image(img, self.job.service_params.FORMAT)
        return JobResult(content_type, image_data)

__init__(qgis, context, job, layer_cache=None)

Source code in src/qgis_server_light/worker/runner.py 
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def __init__(
    self,
    qgis: QgsApplication,
    context: RunnerContext,
    job: QslGetMapJob,
    layer_cache: Optional[Dict] = None,
) -> None:
    super().__init__(qgis, context, job, layer_cache)

run()

Run this runner. Returns: A JobResult with the content_type and image_data (bytes) of the rendered image.

Source code in src/qgis_server_light/worker/runner.py 
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def run(self):
    """Run this runner.
    Returns:
        A JobResult with the content_type and image_data (bytes) of the rendered image.
    """
    feature_filter = QgsFeatureFilter()
    for index, layer_name in enumerate(self.job.service_params.layers):
        self._init_layers(self.job.get_dataset_by_name(layer_name))
    map_settings = self._get_map_settings(self.map_layers)
    filter_providers = QgsFeatureFilterProviderGroup()
    filter_providers.addProvider(feature_filter)
    renderer = QgsMapRendererParallelJob(map_settings)
    renderer.setFeatureFilterProvider(filter_providers)
    event_loop = QEventLoop(self.qgis)
    renderer.finished.connect(event_loop.quit)
    renderer.start()
    event_loop.exec_()
    img = renderer.renderedImage()
    img.setDotsPerMeterX(int(map_settings.outputDpi() * 39.37))
    img.setDotsPerMeterY(int(map_settings.outputDpi() * 39.37))
    image_data, content_type = _encode_image(img, self.job.service_params.FORMAT)
    return JobResult(content_type, image_data)

RunnerContext dataclass

Source code in src/qgis_server_light/worker/runner.py 
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@dataclass
class RunnerContext:
    base_path: str | Path

base_path: str | Path instance-attribute

__init__(base_path)