bokeh.application.application#

Provide the Application class.

Application instances are factories for creating new Bokeh Documents.

When a Bokeh server session is initiated, the Bokeh server asks the Application for a new Document to service the session. To do this, the Application first creates a new empty Document, then it passes this new Document to the modify_document method of each of its handlers. When all handlers have updated the Document, it is used to service the user session.

class Application(*handlers: Handler, metadata: Dict[str, Any] | None = None)[source]#

An Application is a factory for Document instances.

Public Data Attributes:

`handlers`	The ordered list of handlers this Application is configured with.
`metadata`	Arbitrary user-supplied metadata to associate with this application.
`safe_to_fork`
`static_path`	Path to any (optional) static resources specified by handlers.

Public Methods:

`__init__`(*handlers[, metadata])	Application factory.
`add`(handler)	Add a handler to the pipeline used to initialize new documents.
`create_document`()	Creates and initializes a document using the Application's handlers.
`initialize_document`(doc)	Fills in a new document using the Application's handlers.
`on_server_loaded`(server_context)	Invoked to execute code when a new session is created.
`on_server_unloaded`(server_context)	Invoked to execute code when the server cleanly exits.
`on_session_created`(session_context)	Invoked to execute code when a new session is created.
`on_session_destroyed`(session_context)	Invoked to execute code when a session is destroyed.
`process_request`(request)	Processes incoming HTTP request returning a dictionary of additional data to add to the session_context.

__init__(*handlers: Handler, metadata: Dict[str, Any] | None = None) → None[source]#

Application factory.

Parameters

handlers (seq[Handler]) – List of handlers to call. The URL is taken from the first one only.

Keyword Arguments

metadata (dict) –

arbitrary user-supplied JSON data to make available with the application.

The server will provide a URL http://applicationurl/metadata which returns a JSON blob of the form:

{
    "data": {
        "hi": "hi",
        "there": "there"
    },
    "url": "/myapp"
}

The user-supplied metadata is returned as-is under the "data" key in the blob.

add(handler: Handler) → None[source]#

Add a handler to the pipeline used to initialize new documents.

Parameters: handler (Handler) – a handler for this Application to use to process Documents

create_document() → Document[source]#: Creates and initializes a document using the Application’s handlers.

initialize_document(doc: Document) → None[source]#: Fills in a new document using the Application’s handlers.

on_server_loaded(server_context: ServerContext) → None[source]#

Invoked to execute code when a new session is created.

This method calls on_server_loaded on each handler, in order, with the server context passed as the only argument.

on_server_unloaded(server_context: ServerContext) → None[source]#

Invoked to execute code when the server cleanly exits. (Before stopping the server’s IOLoop.)

This method calls on_server_unloaded on each handler, in order, with the server context passed as the only argument.

Warning

In practice this code may not run, since servers are often killed by a signal.

async on_session_created(session_context: SessionContext) → None[source]#

Invoked to execute code when a new session is created.

This method calls on_session_created on each handler, in order, with the session context passed as the only argument.

May return a Future which will delay session creation until the Future completes.

async on_session_destroyed(session_context: SessionContext) → None[source]#

Invoked to execute code when a session is destroyed.

This method calls on_session_destroyed on each handler, in order, with the session context passed as the only argument.

Afterwards, session_context.destroyed will be True.

process_request(request: HTTPServerRequest) → Dict[str, Any][source]#

Processes incoming HTTP request returning a dictionary of additional data to add to the session_context.

Parameters: request – HTTP request
Returns: A dictionary of JSON serializable data to be included on the session context.

property handlers: Tuple[Handler, ...]#: The ordered list of handlers this Application is configured with.

property metadata: Dict[str, Any] | None#: Arbitrary user-supplied metadata to associate with this application.

property safe_to_fork: bool#

property static_path: str | None#: Path to any (optional) static resources specified by handlers.

class ServerContext[source]#

A harness for server-specific information and tasks related to collections of Bokeh sessions.

This base class is probably not of interest to general users.

abstract property sessions: List[ServerSession]#

SessionContext instances belonging to this application.

Subclasses must implement this method.

class SessionContext(server_context: ServerContext, session_id: ID)[source]#

A harness for server-specific information and tasks related to Bokeh sessions.

This base class is probably not of interest to general users.

__init__(server_context: ServerContext, session_id: ID) → None[source]#

abstract with_locked_document(func: Callable[[Document], Awaitable[None]]) → Awaitable[None][source]#

Runs a function with the document lock held, passing the document to the function.

Subclasses must implement this method.

Parameters: func (callable) – function that takes a single parameter (the Document) and returns None or a Future
Returns: a Future containing the result of the function

abstract property destroyed: bool#

If True, the session has been discarded and cannot be used.

A new session with the same ID could be created later but this instance will not come back to life.

property id: ID#: The unique ID for the session associated with this context.

property server_context: ServerContext#: The server context for this session context