Added Chapter 8 code

Author: alandmoore

Chapter08/ABQ_Data_Entry/.gitignore

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+*.pyc
+__pycache__/

Chapter08/ABQ_Data_Entry/README.rst

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+============================
+ ABQ Data Entry Application
+============================
+
+Description
+===========
+
+This program provides a data entry form for ABQ Agrilabs laboratory data.
+
+Features
+--------
+
+  * Provides a validated entry form to ensure correct data
+  * Stores data to ABQ-format CSV files
+  * Auto-fills form fields whenever possible
+
+Authors
+=======
+
+Alan D Moore, 2021
+
+Requirements
+============
+
+  * Python 3.7 or higher
+  * Tkinter
+
+Usage
+=====
+
+To start the application, run::
+
+  python3 ABQ_Data_Entry/abq_data_entry.py
+
+
+General Notes
+=============
+
+The CSV file will be saved to your current directory in the format
+``abq_data_record_CURRENTDATE.csv``, where CURRENTDATE is today's date in ISO format.
+
+This program only appends to the CSV file.  You should have a spreadsheet program
+installed in case you need to edit or check the file.

Chapter08/ABQ_Data_Entry/abq_data_entry.py

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+from abq_data_entry.application import Application
+
+app = Application()
+app.mainloop()

Chapter08/ABQ_Data_Entry/abq_data_entry/__init__.py

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+"""The application/controller class for ABQ Data Entry"""
+
+import tkinter as tk
+from tkinter import ttk
+from tkinter import messagebox
+from tkinter import filedialog
+
+from . import views as v
+from . import models as m
+from .mainmenu import MainMenu
+
+class Application(tk.Tk):
+  """Application root window"""
+
+
+  def __init__(self, *args, **kwargs):
+    super().__init__(*args, **kwargs)
+
+    # Hide window while GUI is built
+    self.withdraw()
+
+    # Authenticate
+    if not self._show_login():
+      self.destroy()
+      return
+
+    # show the window
+    self.deiconify()
+
+   # Create model
+    self.model = m.CSVModel()
+
+    # Load settings
+    # self.settings = {
+    #   'autofill date': tk.BooleanVar(),
+    #   'autofill sheet data': tk.BoleanVar()
+    # }
+    self.settings_model = m.SettingsModel()
+    self._load_settings()
+
+    # Begin building GUI
+    self.title("ABQ Data Entry Application")
+    self.columnconfigure(0, weight=1)
+
+    # Create the menu
+    menu = MainMenu(self, self.settings)
+    self.config(menu=menu)
+    event_callbacks = {
+      '<<FileSelect>>': self._on_file_select,
+      '<<FileQuit>>': lambda _: self.quit(),
+      # new for ch8
+      '<<ShowRecordlist>>': self._show_recordlist,
+      '<<NewRecord>>': self._new_record,
+
+    }
+    for sequence, callback in event_callbacks.items():
+      self.bind(sequence, callback)
+    ttk.Label(
+      self,
+      text="ABQ Data Entry Application",
+      font=("TkDefaultFont", 16)
+    ).grid(row=0)
+
+    # The notebook
+    self.notebook = ttk.Notebook(self)
+    self.notebook.enable_traversal()
+    self.notebook.grid(row=1, padx=10, sticky='NSEW')
+
+    # The data record form
+    self.recordform = v.DataRecordForm(self, self.model, self.settings)
+    self.recordform.bind('<<SaveRecord>>', self._on_save)
+    self.notebook.add(self.recordform, text='Entry Form')
+
+
+    # The data record list
+    # new for ch8
+    self.recordlist = v.RecordList(self)
+    self.notebook.insert(0, self.recordlist, text='Records')
+    self._populate_recordlist()
+    self.recordlist.bind('<<OpenRecord>>', self._open_record)
+
+
+    self._show_recordlist()
+
+    # status bar
+    self.status = tk.StringVar()
+    self.statusbar = ttk.Label(self, textvariable=self.status)
+    self.statusbar.grid(sticky=(tk.W + tk.E), row=3, padx=10)
+
+
+    self.records_saved = 0
+
+
+  def _on_save(self, *_):
+    """Handles file-save requests"""
+
+    # Check for errors first
+
+    errors = self.recordform.get_errors()
+    if errors:
+      self.status.set(
+        "Cannot save, error in fields: {}"
+        .format(', '.join(errors.keys()))
+      )
+      message = "Cannot save record"
+      detail = "The following fields have errors: \n  * {}".format(
+        '\n  * '.join(errors.keys())
+      )
+      messagebox.showerror(
+        title='Error',
+        message=message,
+        detail=detail
+      )
+      return False
+
+    data = self.recordform.get()
+    rownum = self.recordform.current_record
+    self.model.save_record(data, rownum)
+    self.records_saved += 1
+    self.status.set(
+      "{} records saved this session".format(self.records_saved)
+    )
+    self.recordform.reset()
+    self._populate_recordlist()
+
+  def _on_file_select(self, *_):
+    """Handle the file->select action"""
+
+    filename = filedialog.asksaveasfilename(
+      title='Select the target file for saving records',
+      defaultextension='.csv',
+      filetypes=[('CSV', '*.csv *.CSV')]
+    )
+    if filename:
+      self.model = m.CSVModel(filename=filename)
+      self._populate_recordlist()
+
+  @staticmethod
+  def _simple_login(username, password):
+    """A basic authentication backend with a hardcoded user and password"""
+    return username == 'abq' and password == 'Flowers'
+
+  def _show_login(self):
+    """Show login dialog and attempt to login"""
+    error = ''
+    title = "Login to ABQ Data Entry"
+    while True:
+      login = v.LoginDialog(self, title, error)
+      if not login.result:  # User canceled
+        return False
+      username, password = login.result
+      if self._simple_login(username, password):
+        return True
+      error = 'Login Failed' # loop and redisplay
+
+  def _load_settings(self):
+    """Load settings into our self.settings dict."""
+
+    vartypes = {
+      'bool': tk.BooleanVar,
+      'str': tk.StringVar,
+      'int': tk.IntVar,
+      'float': tk.DoubleVar
+    }
+
+    # create our dict of settings variables from the model's settings.
+    self.settings = dict()
+    for key, data in self.settings_model.fields.items():
+      vartype = vartypes.get(data['type'], tk.StringVar)
+      self.settings[key] = vartype(value=data['value'])
+
+    # put a trace on the variables so they get stored when changed.
+    for var in self.settings.values():
+      var.trace_add('write', self._save_settings)
+
+  def _save_settings(self, *_):
+    """Save the current settings to a preferences file"""
+
+    for key, variable in self.settings.items():
+      self.settings_model.set(key, variable.get())
+    self.settings_model.save()
+
+  # new for ch8
+  def _show_recordlist(self, *_):
+    """Show the recordform"""
+    self.notebook.select(self.recordlist)
+
+  def _populate_recordlist(self):
+    try:
+      rows = self.model.get_all_records()
+    except Exception as e:
+      messagebox.showerror(
+        title='Error',
+        message='Problem reading file',
+        detail=str(e)
+      )
+    else:
+      self.recordlist.populate(rows)
+
+  def _new_record(self, *_):
+    """Open the record form with a blank record"""
+    self.recordform.load_record(None, None)
+    self.notebook.select(self.recordform)
+
+
+  def _open_record(self, *_):
+    """Open the Record selected recordlist id in the recordform"""
+    rowkey = self.recordlist.selected_id
+    try:
+      record = self.model.get_record(rowkey)
+    except Exception as e:
+      messagebox.showerror(
+        title='Error', message='Problem reading file', detail=str(e)
+      )
+      return
+    self.recordform.load_record(rowkey, record)
+    self.notebook.select(self.recordform)

Chapter08/ABQ_Data_Entry/abq_data_entry/application.py

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+"""Global constants and classes needed by other modules in ABQ Data Entry"""
+from enum import Enum, auto
+
+class FieldTypes(Enum):
+  string = auto()
+  string_list = auto()
+  short_string_list = auto()
+  iso_date_string = auto()
+  long_string = auto()
+  decimal = auto()
+  integer = auto()
+  boolean = auto()

Chapter08/ABQ_Data_Entry/abq_data_entry/constants.py

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+"""The Main Menu class for ABQ Data Entry"""
+
+import tkinter as tk
+from tkinter import messagebox
+
+class MainMenu(tk.Menu):
+  """The Application's main menu"""
+
+  def _event(self, sequence):
+    """Return a callback function that generates the sequence"""
+    def callback(*_):
+      root = self.master.winfo_toplevel()
+      root.event_generate(sequence)
+
+    return callback
+
+  def __init__(self, parent, settings, **kwargs):
+    """Constructor for MainMenu
+
+    arguments:
+      parent - The parent widget
+      settings - a dict containing Tkinter variables
+    """
+    super().__init__(parent, **kwargs)
+    self.settings = settings
+
+    # The help menu
+    help_menu = tk.Menu(self, tearoff=False)
+    help_menu.add_command(label='About…', command=self.show_about)
+
+    # The file menu
+    file_menu = tk.Menu(self, tearoff=False)
+    file_menu.add_command(
+      label="Select file…",
+      command=self._event('<<FileSelect>>')
+    )
+
+    file_menu.add_separator()
+    file_menu.add_command(
+      label="Quit",
+      command=self._event('<<FileQuit>>')
+    )
+
+    # The options menu
+    options_menu = tk.Menu(self, tearoff=False)
+    options_menu.add_checkbutton(
+      label='Autofill Date',
+      variable=self.settings['autofill date']
+    )
+    options_menu.add_checkbutton(
+      label='Autofill Sheet data',
+      variable=self.settings['autofill sheet data']
+    )
+
+    # switch from recordlist to recordform
+    go_menu = tk.Menu(self, tearoff=False)
+    go_menu.add_command(
+      label="Record List",
+      command=self._event('<<ShowRecordlist>>')
+    )
+    go_menu.add_command(
+      label="New Record",
+      command=self._event('<<NewRecord>>')
+    )
+
+    # add the menus in order to the main menu
+    self.add_cascade(label='File', menu=file_menu)
+    self.add_cascade(label='Go', menu=go_menu)
+    self.add_cascade(label='Options', menu=options_menu)
+    self.add_cascade(label='Help', menu=help_menu)
+
+
+  def show_about(self):
+    """Show the about dialog"""
+
+    about_message = 'ABQ Data Entry'
+    about_detail = (
+      'by Alan D Moore\n'
+      'For assistance please contact the author.'
+    )
+
+    messagebox.showinfo(title='About', message=about_message, detail=about_detail)