asset_viewer.py

import sys
import os as os
from PySide2 import QtCore, QtGui, QtWidgets
import json
import shutil
from datetime import datetime

class AssetViewer(QtWidgets.QWidget):
    '''
    Small editor that loads metadata information from json file, parses them and fills form.
    Shows preview of an image that holds that metadata.
    Stores updated metadata in .json file
    '''
    IMAGE_WIDTH = 400
    IMAGE_HEIGHT = IMAGE_WIDTH / 1.77778

    ASSET_DIR_PATH = "{}/{}".format(os.getcwd(), 'assets')
    JSON_FILE_NAME = 'assets.json'

    def __init__(self):
        super(AssetViewer, self).__init__(parent=None)

        self.setWindowTitle("AssetViewer")
        self.setMinimumSize(400, 300)

        self.create_widgets()
        self.create_layout()
        self.create_connections()

        self.load_assets_from_json()

        self.refresh_asset_details()

    def create_widgets(self):
        self.asset_list_lbl = QtWidgets.QLabel("Asset Code:")
        self.asset_list_cmb  = QtWidgets.QComboBox()

        self.image_preview_lbl = QtWidgets.QLabel()
        self.image_preview_lbl.setFixedHeight(self.IMAGE_WIDTH)
        self.image_preview_lbl.setFixedHeight(self.IMAGE_HEIGHT)

        self.name_le = QtWidgets.QLineEdit()
        self.description_ple = QtWidgets.QPlainTextEdit()
        self.creator_le = QtWidgets.QLineEdit()
        self.creator_le.setReadOnly(True)
        self.created_le = QtWidgets.QLineEdit()
        self.created_le.setReadOnly(True)
        self.modified_le = QtWidgets.QLineEdit()
        self.modified_le.setReadOnly(True)

        self.save_btn = QtWidgets.QPushButton("Save")
        self.cancel_btn = QtWidgets.QPushButton("Cancel")

    def create_layout(self):
        asset_list_layout = QtWidgets.QHBoxLayout()
        asset_list_layout.addStretch()
        asset_list_layout.addWidget(self.asset_list_lbl)
        asset_list_layout.addWidget(self.asset_list_cmb)

        asset_description_layout = QtWidgets.QFormLayout()
        asset_description_layout.addRow("Name", self.name_le)
        asset_description_layout.addRow("Description", self.description_ple)
        asset_description_layout.addRow("Creator", self.creator_le)
        asset_description_layout.addRow("Created", self.created_le)
        asset_description_layout.addRow("Modified", self.modified_le)

        button_layout = QtWidgets.QHBoxLayout()
        button_layout.addStretch()
        button_layout.addWidget(self.save_btn)
        button_layout.addWidget(self.cancel_btn)

        main_layout = QtWidgets.QVBoxLayout(self)
        main_layout.setContentsMargins(3,3,3,3)
        main_layout.addLayout(asset_list_layout)
        main_layout.addWidget(self.image_preview_lbl)
        main_layout.addLayout(asset_description_layout)
        main_layout.addLayout(button_layout)

    def create_connections(self):
        self.asset_list_cmb.currentIndexChanged.connect(self.refresh_asset_details)

        self.save_btn.clicked.connect(self.save_assets_to_json)

    def refresh_asset_details(self):
        """ Updates asset information
            Sets image preview
        """
        asset_details = self.content[self.asset_list_cmb.currentText()]
        self.load_image_preview(asset_details["image_path"])

        self.name_le.setText(asset_details["name"])
        self.description_ple.setPlainText(asset_details["description"])
        self.creator_le.setText(asset_details["creator"])
        self.created_le.setText(asset_details["created"])
        self.modified_le.setText(asset_details["modified"])

    def load_assets_from_json(self):
        """ Parse json file to produce codes in asset_list_cmb """
        url = "{}/{}".format(self.ASSET_DIR_PATH, self.JSON_FILE_NAME)

        with open(url, 'r') as asset_file:
            self.content = json.load(asset_file)

            for asset in self.content.keys():
                self.asset_list_cmb.addItem(asset)

    def load_image_preview(self, file_name):
        """ loads PixMap of file_name to QLabel """
        img_url = "{}/{}".format(self.ASSET_DIR_PATH, file_name)
        file_info = QtCore.QFileInfo(img_url)
        if file_info:
            image = QtGui.QImage(img_url)
            image.scaled(self.image_preview_lbl.width(), self.image_preview_lbl.height(), QtCore.Qt.KeepAspectRatio,
                         QtCore.Qt.SmoothTransformation)

            pixmap = QtGui.QPixmap(image)
        else:
            pixmap = QtGui.QPixmap(self.preview_image_label.size())
            pixmap.fill(QtCore.Qt.transparent)

        self.image_preview_lbl.setPixmap(pixmap)

    def save_assets_to_json(self):
        """
            Stores updated value from form to json file
            Called via "Save" button
        """
        asset_code = self.asset_list_cmb.currentText()
        self.content[asset_code]["name"] = self.name_le.text()
        self.content[asset_code]["description"] = self.description_ple.toPlainText()
        self.content[asset_code]["creator"] = self.creator_le.text()
        self.content[asset_code]["created"] = self.created_le.text()
        self.content[asset_code]["modified"] = datetime.now().strftime("%Y/%m/%d, %H:%M:%S")

        url = "{}/{}".format(self.ASSET_DIR_PATH, self.JSON_FILE_NAME)
        shutil.copyfile(url, url+'.tmp')
        try:
            with open(url, 'w') as asset_file:
                json.dump(self.content, asset_file)
        except:
            shutil.copyfile(url + '.tmp', url)
        finally:
            os.remove(url + '.tmp')

if __name__ == "__main__":
    app = QtWidgets.QApplication()

    window = AssetViewer()
    window.show()

    app.exec_()