class TagServer:
"""
Flask server for tagging images.
Parameters
----------
config_file : str
Path the YAML configuration file.
Methods
-------
start()
Starts the Flask server.
"""
def __init__(self, config_file):
# Set up config and image services
self._config = ConfigReader(config_file)
self._images = Images(self._config)
# Create Flask app and define routes
self._app = Flask(__name__, static_url_path="/static")
self._app.add_url_rule("/", "index", self.show_index)
self._app.add_url_rule("/show_image", "show_image", self.show_image)
self._app.add_url_rule("/image_tags.csv", "download_tags", self.download_tags)
self._app.add_url_rule(
"/store_tags", "store_tags", self.store_tags, methods=["POST"]
)
def start(self):
"""Starts the Flask server with the configured host settings."""
# Get config settings
host = self._config.get("server/host", "127.0.0.1")
port = self._config.get("server/port", "8080")
debug = self._config.get("server/debug mode", False)
host_str = f"http://{host}:{port}/"
# The reloader has not yet run - open the browser
if not os.environ.get("WERKZEUG_RUN_MAIN"):
webbrowser.open_new(host_str)
# Run Flask app
self._app.run(host=host, port=port, debug=debug)
def show_index(self):
"""Routing: Show the main page."""
image_id = request.args.get("image_id")
if not image_id:
untagged = self._images.first_untagged_id()
return redirect(f"/?image_id={untagged}")
else:
content = self._render_image(image_id)
metadata = {
"max_image_width": self._config.get("interface/max_width", 600),
"max_image_height": self._config.get("interface/max_height", 700),
}
return render_template("index.html", content=content, meta=metadata)
def show_image(self):
"""Routing: Sends the image file to the webbrowser."""
image_id = request.args.get("image_id")
image = self._images.get(image_id)
return send_file(image["path"], mimetype="image/jpg")
def store_tags(self):
"""Routing: Stores the (updated) tag data for the image."""
# Get form data
sep = self._config.get("tagging/multi-separator", ", ")
data = {
"id": request.form.get("id"),
"tags": sep.join(request.form.getlist("tags")),
"remark": request.form.get("remark").strip(),
}
self._images.store(data)
next_image = self._images.next_id(data["id"])
target = "/"
if next_image:
target = f"/?image_id={next_image}"
return redirect(location=target)
def download_tags(self):
"""Routing: Download tag information as CSV file."""
tags = self._images.dump_data()
# Use StringIO to capture the to_csv() output
csv_string = io.StringIO()
tags.to_csv(csv_string, index=False)
return Response(csv_string.getvalue(), mimetype="text/csv")
def _render_image(self, image_id):
"""
Renders image template for the provided image ID.
Parameters
----------
image_id : str
MD5 hash for the image to render.
"""
# Load all available tags from cofniguration
shortcuts = self._config.get("tagging/tags")
if not shortcuts:
raise ValueError("Could not read any tags from the configuration file.")
# Load and preprocess the data
data = self._images.get(image_id)
if not data:
raise RuntimeError(f"Cannot render image with ID '{image_id}'.")
if not isinstance(data["remark"], str):
data["remark"] = ""
# Split multiple tags
if isinstance(data["tags"], str):
sep = self._config.get("tagging/multi-separator", ", ")
data["tags"] = data["tags"].split(sep)
else:
data["tags"] = []
# Get next and previous IDs
data["prev_image_id"] = self._images.prev_id(image_id)
data["next_image_id"] = self._images.next_id(image_id)
# Add meta data
data["all_tags"] = list(shortcuts)
data["shortcuts"] = shortcuts
data["tag_question"] = self._config.get("tagging/tag question", "Select tags:")
data["allow_remarks"] = self._config.get("tagging/allow remarks", False)
data["multi_select"] = self._config.get("tagging/multi-select", False)
return render_template("tag_image.html", **data)
