Added basic functionality to make the module executable

docxtpl/__main__.py

@@ -0,0 +1,116 @@
+from .template import DocxTemplate,TemplateError
+import argparse, json
+from pathlib import Path
+from argparse import ArgumentError
+
+
+def make_arg_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(
+        usage='docxtpl template_path json_path output_filename',
+        description='Make docx file from existing template docx and json data.',
+        add_help=True)
+    parser.add_argument('Template',
+                        metavar='template_path',
+                        type=str,
+                        help='The path to the template docx file.')
+    parser.add_argument('Json',
+                        metavar='json_path',
+                        type=str,
+                        help='The path to the json file with the data.')
+    parser.add_argument('Output',
+                        metavar='output_filename',
+                        type=str,
+                        help='The filename to save the generated docx.')
+    return parser
+
+
+def get_args(parser: argparse.ArgumentParser) -> dict:
+    try:
+        parsed_args = vars(parser.parse_args())
+        return parsed_args
+    # There is a bug that prevents argparser from catching ArgumentError
+    # manually. For more info: https://bugs.python.org/issue41255
+    # I know bare exceptions are wrong, could not find another way to catch
+    # wrong arguments.
+    except:
+        raise RuntimeError(f'Correct usage is:\n{parser.usage}')
+
+
+def is_argument_valid(arg_name: str, arg_value: str) -> bool:
+    if arg_name == 'Template':
+        return Path(arg_value).is_file() and arg_value.endswith('.docx')
+    elif arg_name == 'Json':
+        return Path(arg_value).is_file() and arg_value.endswith('.json')
+    elif arg_name == 'Output':
+        return arg_value.endswith('.docx') and check_exists_ask_overwrite(
+            arg_value)
+
+
+def check_exists_ask_overwrite(arg_value) -> bool:
+    if Path(arg_value).exists():
+        try:
+            if input(f'File {arg_value} already exists, would you like to overwrite the existing file? (y/n)').lower() == 'y':
+                return True
+            else:
+                raise FileExistsError
+        except FileExistsError as e:
+            raise RuntimeError(f'File {arg_value} already exists, please choose a different name.') from e
+    else:
+        return True
+
+
+def validate_all_args(parsed_args) -> None:
+    try:
+        for arg_name, arg_value in parsed_args.items():
+            if not is_argument_valid(arg_name, arg_value):
+                raise AttributeError
+    except ArgumentError as e:
+        raise RuntimeError(
+            f'The specified {arg_name} "{arg_value}" is not valid.')
+
+
+def get_json_data(json_path: Path) -> dict:
+    with open(json_path) as file:
+        try:
+            json_data = json.load(file)
+            return json_data
+        except json.JSONDecodeError as e:
+            print(
+                f'There was an error on line {e.lineno}, column {e.colno} while trying to parse file {json_path}')
+            raise RuntimeError('Failed to get json data.')
+
+
+def make_docxtemplate(template_path: Path) -> DocxTemplate:
+    try:
+        return DocxTemplate(template_path)
+    except TemplateError as e:
+        raise RuntimeError('Could not create docx template.') from e
+
+
+def save_file(doc: DocxTemplate, output_path: Path) -> None:
+    try:
+        doc.save(output_path)
+        print(f'Document successfully generated and saved at {output_path}')
+    except PermissionError as e:
+        print(f'{e.strerror}. Could not save file {e.filename}.')
+        raise RuntimeError('Failed to save file.') from e
+
+
+def main() -> None:
+    parser = make_arg_parser()
+    try:
+        parsed_args = get_args(parser)
+        validate_all_args(parsed_args)
+        json_data = get_json_data(Path(parsed_args['Json']).resolve())
+        doc = make_docxtemplate(Path(parsed_args['Template']).resolve())
+        doc.render(json_data)
+        save_file(doc, Path(parsed_args['Output']).resolve())
+    except RuntimeError as e:
+        print(e)
+        return
+    finally:
+        print('Exiting program!')
+
+
+if __name__ == '__main__':
+    main()