How to get scraped items into Pyqt5 widget?

Question

I\'m trying to make a simple GUI for Scrapy crawler, where user can push the Start button to run scraping and see the scraped results in textBrowser (or other qt widget, ple

Answer 1

You can listen to item_scraped event and update the UI with every new Car.

Answer 2

Instead of using subproces.Popen() + QThread you should use QProcess since the task is easier by informing you through signals.

I have created an application that scans all the spiders within a project showing them in a QComboBox where you can select which spider you want to run, then there is a button that allows you to start or stop the application by displaying the log in a QTextBrowser.

Assuming that the scrapy project has the following structure (the project is an example of scrapy, you can find it here):

tutorial
├── scrapy.cfg
└── tutorial
    ├── __init__.py
    ├── items.py
    ├── middlewares.py
    ├── pipelines.py
    ├── settings.py
    └── spiders
        ├── __init__.py
        ├── toscrape-css.py
        └── toscrape-xpath.py

The user has to select the .cfg file, this will show the available spiders, then press the start-stop button as desired.

from functools import partial
from PyQt5 import QtCore, QtGui, QtWidgets

class ScrapyWorker(QtCore.QObject):
    logChanged = QtCore.pyqtSignal(str)
    started = QtCore.pyqtSignal()
    finished = QtCore.pyqtSignal()

    def __init__(self, parent=None):
        super(ScrapyWorker, self).__init__(parent)
        self._process = QtCore.QProcess(self)
        self._process.setProcessChannelMode(QtCore.QProcess.MergedChannels)
        self._process.readyReadStandardOutput.connect(self.on_readyReadStandardOutput)
        self._process.setProgram('scrapy')
        self._process.started.connect(self.started)
        self._process.finished.connect(self.finished)

    def run(self, project, spider):
        self._process.setWorkingDirectory(project)
        self._process.setArguments(['crawl', spider])
        self._process.start()

    @QtCore.pyqtSlot()
    def on_readyReadStandardOutput(self):
        data = self._process.readAllStandardOutput().data().decode()
        self.logChanged.emit(data)

    @QtCore.pyqtSlot()
    def stop(self):
        self._process.kill()

    def spiders(self, project):
        process = QtCore.QProcess()
        process.setProcessChannelMode(QtCore.QProcess.MergedChannels)
        process.setWorkingDirectory(project)
        loop = QtCore.QEventLoop()
        process.finished.connect(loop.quit)
        process.start('scrapy', ['list'])
        loop.exec_()
        return process.readAllStandardOutput().data().decode().split()

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.project_le = QtWidgets.QLineEdit()
        self.project_button = QtWidgets.QPushButton('Select Project')
        self.spider_combobox = QtWidgets.QComboBox()
        self.start_stop_button = QtWidgets.QPushButton("Start", checkable=True)
        self.text_edit = QtWidgets.QTextBrowser()
        central_widget = QtWidgets.QWidget()
        self.setCentralWidget(central_widget)

        lay = QtWidgets.QVBoxLayout(central_widget)
        hlay = QtWidgets.QHBoxLayout()
        hlay.addWidget(self.project_le)
        hlay.addWidget(self.project_button)
        lay.addLayout(hlay)
        hlay2 = QtWidgets.QHBoxLayout()
        hlay2.addWidget(QtWidgets.QLabel("spiders:"))
        hlay2.addWidget(self.spider_combobox, 1)
        lay.addLayout(hlay2)
        lay.addWidget(self.start_stop_button)
        lay.addWidget(self.text_edit)

        self.start_stop_button.setEnabled(False)

        self.scrapy_worker = ScrapyWorker(self)
        self.scrapy_worker.logChanged.connect(self.insert_log)
        self.scrapy_worker.started.connect(self.text_edit.clear)
        self.scrapy_worker.finished.connect(partial(self.start_stop_button.setChecked, False))

        self.start_stop_button.toggled.connect(self.on_checked)
        self.project_button.clicked.connect(self.select_project)
        self.resize(640, 480)

    @QtCore.pyqtSlot(bool)
    def on_checked(self, state):
        if state:
            filename = self.project_le.text()
            finfo = QtCore.QFileInfo(filename)
            directory = finfo.dir().absolutePath()
            self.scrapy_worker.run(directory, self.spider_combobox.currentText())
            self.start_stop_button.setText('Stop')
        else:
            self.start_stop_button.setText('Start')
            self.scrapy_worker.stop()

    @QtCore.pyqtSlot()
    def select_project(self):
        filename, _ = QtWidgets.QFileDialog.getOpenFileName(
            self,
            "Select .cfg file",
            QtCore.QDir.currentPath(),
            "Configure File (*.cfg)"
        )
        if filename:
            self.project_le.setText(filename)
            finfo = QtCore.QFileInfo(filename)
            directory = finfo.dir().absolutePath()
            spiders = self.scrapy_worker.spiders(directory)
            self.spider_combobox.clear()
            self.spider_combobox.addItems(spiders)
            self.start_stop_button.setEnabled(True if spiders else False)

    @QtCore.pyqtSlot(str)
    def insert_log(self, text):
        prev_cursor = self.text_edit.textCursor()
        self.text_edit.moveCursor(QtGui.QTextCursor.End)
        self.text_edit.insertPlainText(text)
        self.text_edit.setTextCursor(prev_cursor)

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    app.setStyle('fusion')
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

Output: