connect.py

from qgis.PyQt.QtCore import QThread, pyqtSignal
import tempfile
import os
from owslib.wps import WebProcessingService


class ResponseOutput:
    def __init__(self, filepath, mimetype):
        self.filepath = filepath
        self.mimetype = mimetype


class Response():
    status = 200
    data = ""
    output = {}


# TODO create superclass for these classes
class GetProcesses(QThread):
    statusChanged = pyqtSignal(object)
    url = None
    timeout = 5

    def setUrl(self, url):
        self.url = url

    def setTimeout(self, timeout):
        self.timeout = timeout

    def run(self):
        responseToReturn = Response()
        try:
            wps = WebProcessingService(self.url)
            wps.getcapabilities()
            responseToReturn.status = 200
            responseToReturn.data = wps.processes
        except Exception as e:
            responseToReturn.data = {"message": str(e)}
            responseToReturn.status = 500
        self.statusChanged.emit(responseToReturn)


class GetProcess(QThread):
    statusChanged = pyqtSignal(object)
    url = None
    timeout = 5
    identifier = ''

    def setUrl(self, url):
        self.url = url

    def setTimeout(self, timeout):
        self.timeout = timeout

    def setIdentifier(self, identifier):
        self.identifier = identifier

    def run(self):
        responseToReturn = Response()
        if self.identifier != "":
            try:
                wps = WebProcessingService(self.url)
                process = wps.describeprocess(self.identifier)
                responseToReturn.status = 200
                responseToReturn.data = process
            except Exception as e:
                responseToReturn.status = 500
        else:
            responseToReturn.status = 500
        self.statusChanged.emit(responseToReturn)


class ExecuteProcess(QThread):
    statusChanged = pyqtSignal(object)
    url = None
    timeout = 60
    identifier = ''
    inputs = []

    def setUrl(self, url):
        self.url = url

    def setTimeout(self, timeout):
        self.timeout = timeout

    def setIdentifier(self, identifier):
        self.identifier = identifier

    def setInputs(self, inputs):
        self.inputs = inputs

    def getFilePath(self, mimeType):
        temp_name = next(tempfile._get_candidate_names())
        defult_tmp_dir = tempfile._get_default_tempdir()
        suffix = 'zip'
        if mimeType == 'application/csv':
            suffix = 'csv'
        elif mimeType == 'image/tiff; subtype=geotiff':
            suffix = 'tif'
        elif mimeType == 'application/json':
            suffix = 'json'
        return os.path.join(defult_tmp_dir, temp_name + "." + suffix)

    def run(self):
        """
        * Call the `Execute` request on WPS service with all intpus
        * Wait for result
        * After executed, download all outputs and show the progress
        * Handle Execeptions
        """
        responseToReturn = Response()
        if self.identifier != "" and len(self.inputs) > 0:
            try:
                wps = WebProcessingService(self.url)
                execution = wps.execute(
                        self.identifier, self.inputs, output=[]
                )
                self.monitorExecution(execution)
                if len(execution.errors) > 0:
                    raise Exception(execution.errors[0].text)
                for output in execution.processOutputs:
                    filePath = self.getFilePath(output.mimeType)
                    responseToReturn.output[output.identifier] = \
                        ResponseOutput(filePath, output.mimeType)
                    data_output = execution.getOutput(
                            filePath, output.identifier
                    )
                    self.__downloadData(output, data_output)
                responseToReturn.status = 200
            except Exception as e:
                responseToReturn.status = 500
                responseToReturn.data = str(e)
        else:
            responseToReturn.status = 500
        self.statusChanged.emit(responseToReturn)

    def __downloadData(self, output, data_output=None):
        """
        Read download progress from the execution.getOutput method. Result is
        number from 0 to 1 - so basically % of downloaded file

        Show progress in status message
        """
        if data_output is not None:
            for i in data_output:
                responseToReturn = Response()
                responseToReturn.status = 201
                responseToReturn.data = {
                    "message": "Downloading ouput {}".format(
                        output.identifier
                    ),
                    "status":  "Download",
                    "percent": int(i*100)
                }
                self.statusChanged.emit(responseToReturn)

    def monitorExecution(
            self, execution, sleepSecs=3, download=False, filepath=None):
        '''
        Custom implementation of monitorExecution from owslib/owslib/wps.py
        '''
        responseToReturn = Response()
        while execution.isComplete() is False:
            execution.checkStatus(sleepSecs=sleepSecs)

            responseToReturn.status = 201
            responseToReturn.data = {
                "status": execution.status,
                "message": execution.statusMessage,
                "percent": execution.percentCompleted
            }

            self.statusChanged.emit(responseToReturn)