Metadata-Version: 2.1
Name: quick_server
Version: 0.8.4
Summary: QuickServer is a quick to use and easy to set up server implementation.
Author-email: Josua Krause <josua.krause@gmail.com>
License: The MIT License (MIT)
        
        Copyright (c) 2023 Josua Krause
        
        Permission is hereby granted, free of charge, to any person obtaining a copy
        of this software and associated documentation files (the "Software"), to deal
        in the Software without restriction, including without limitation the rights
        to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
        copies of the Software, and to permit persons to whom the Software is
        furnished to do so, subject to the following conditions:
        
        The above copyright notice and this permission notice shall be included in all
        copies or substantial portions of the Software.
        
        THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
        AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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Project-URL: repository, https://github.com/JosuaKrause/quick_server
Keywords: server,REST,file,quick,easy
Classifier: Development Status :: 4 - Beta
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Requires-Python: >=3.10
Description-Content-Type: text/x-rst
License-File: LICENSE

QuickServer
===========

*quick\_server* is a quick to use and easy to set up server
implementation. It has the following goals / features and is primarily
meant to speed up back end implementation / iteration:

-  serve local files as is with basic black- and white-listing
-  provide functionality for dynamic requests
-  provide easy access to worker threads (and caching)
-  provide a basic command interpret loop for server commands

Usage
-----

You can install *quick\_server* with pip:

.. code:: sh

    pip install quick_server

Import it in python via:

.. code:: python

    from quick_server import create_server, msg, setup_restart

Note that python 2 support is discontinued. Use version *0.6.x*:

.. code:: sh

    pip install quick_server<0.7

Note that python 3.9 and lower support is discontinued. Use version *0.7.x*:

.. code:: sh

    pip install quick_server<0.8

Setting up a basic file server
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Following we will set up a basic *quick\_server*. Please refer to the
`inline documentation <https://github.com/JosuaKrause/quick_server/blob/master/quick_server/quick_server.py>`__ of the methods for
full information.

.. code:: python

    setup_restart()  # sets up restart functionality (if not called the `restart` command of the server needs external help to work)
    # should be the first real executed command in the script
    # some services, like heroku, don't play well with this command and it should not be called if in such an environment

    addr = ""  # empty address is equivalent to "localhost"
    port = 8080
    server = create_server((addr, port), parallel=True)  # parallel is recommended unless your code is not thread-safe
    server.bind_path("/", "www")  # binds the "www" directory to the server's root
    server.add_default_white_list()  # adds typical file types to the list of files that will be served; you can use server.add_file_patterns to add more file types
    server.favicon_fallback = "favicon.ico"  # sets the default favicon file to the given file on disk (you'll need a file called "favicon.ico")
    # you can also use server.link_empty_favicon_fallback()

    server.suppress_noise = True  # don't report successful requests (turn off if you want to measure performance)
    server.report_slow_requests = True  # reports requests that take longer than 5s

Starting the actual server:

.. code:: python

    msg(f"{' '.join(sys.argv)}")  # prints how the script was started
    msg(f"starting server at {addr if addr else 'localhost'}:{port}")
    try:
        server.serve_forever()  # starts the server -- only returns when the server stops (e.g., by typing `quit`, `restart`, or `CTRL-C`)
    finally:
        msg("shutting down..")
        msg(f"{' '.join(sys.argv)}")  # print how the script was called before exit -- this way you don't have to scroll up to remember when the server was running for a while
        server.server_close() # make sure to clean up all resources

Adding dynamic requests
~~~~~~~~~~~~~~~~~~~~~~~

Dynamic requests can be set up by annotating a function. The annotation
consists of *return-type* and *http-method*.

A ``POST`` request in ``JSON`` format:

.. code:: python

    from quick_server import QuickServerRequestHandler, ReqArgs

    @server.json_post("/json_request", 0)  # creates a request at http://localhost:8080/json_request -- 0 additional path segments are allowed
    def _json_request(req: QuickServerRequestHandler, args: ReqArgs) -> dict:
        return {
            "post": args["post"],
        }

A ``GET`` request as ``plain text``:

.. code:: python

    @server.text_get("/text_request")  # creates a request at http://localhost:8080/text_request -- additional path segments are allowed
    def _text_request(req: QuickServerRequestHandler, args: ReqArgs) -> str:
        return "plain text"

Other forms of requests are also supported, namely ``DELETE`` and ``PUT``.

``args`` is an object holding all request arguments.
``args["query"]`` contains URL query arguments.
``args["fragment"]`` contains the URL fragment part.
``args["paths"]`` contains the remaining path segments.
``args["post"]`` contains the posted content.
``args["files"]`` contains uploaded files.
``args["meta"]`` starts as empty dict but allows to add additional
info to a request without conflicting with the other fields.

Adding Middleware
~~~~~~~~~~~~~~~~~

Middleware can be added for common operations that apply for many endpoints
such as, e.g., login token verification. The request and argument objects are
passed through the middleware and can be modified by it.

.. code:: python

    from quick_server import PreventDefaultResponse, Response, ReqNext

    def check_login(req: QuickServerRequestHandler, args: ReqArgs, okay: ReqNext) -> ReqNext | dict:
        if is_valid(args["post"].get("token")):
            args["meta"]["username"] = ...  # we can manipulate the args object
            return okay  # proceed with the next middleware / main request
        # Response allows to return non-default status codes.
        # It can be used in normal request functions as well.
        return Response("Authentication Required", 401)
        # Alternatively we could just return a normal response with details here
        return {
            "success": False,
            "msg": ...,
        }
        # If a non-control flow response is needed the PreventDefaultResponse
        # exception allows to return non-default status codes from anywhere.
        # This also works in normal request functions as well.
        raise PreventDefaultResponse(401, "Authentication Required")

    @server.json_post("/user_details")
    @server.middleware(check_login)
    def _user_details(req: QuickServerRequestHandler, args: ReqArgs) -> dict:
        return {
            "success": True,
            "username": args["meta"]["username"],
        }

Worker threads and caching
~~~~~~~~~~~~~~~~~~~~~~~~~~

Worker threads are long running server side computations.
The client can start a request, gets an immediate response,
and will check periodically if the computation has finished.
From the client's perspective it looks like a normal request.

Worker threads require support from the client side.

First, provide the necessary JavaScript file via

.. code:: python

    server.link_worker_js("/js/worker.js")

(use ``server.link_legacy_worker_js("/js/worker.js")`` if you are *not* using a transpiler)

and load it on the client side:

.. code:: html

    <script src="js/worker.js" charset="utf-8"></script>

A worker request can be set up on the server side with

.. code:: python

    from quick_server import WorkerArgs

    @server.json_worker("/json_worker")
    def _json_worker(post: WorkerArgs) -> dict:
        # post contains all post arguments
        # ...
        # long, slow computation
        return myresult  # myresult must be JSON convertible

and accessed from the client. An instance of the ``Worker`` class is
needed:

.. code:: javascript

    var work = new quick_server.Worker();
    work.status((req) => {
      ...
      // req contains the number of currently active requests (-1 indicates an error state)
      // it can be used to tell the user that something is happening
    });

Accessing the worker:

.. code:: javascript

    // the first argument identifies worker jobs
    // jobs with the same name get replaced when a new one has been started
    // the second argument is the URL
    work.post('worker_name', 'json_worker', {
      ... // this object will appear as args on the server side
    }, (data) => {
      ...
      // data is the result of the worker function of the server side
      // this function is only called if the request was successful
    });

A worker can be cancelled using its name:

.. code:: javascript

    work.cancel('worker_name');

Note that all running workers are cancelled when the page is unloaded.

Workers can automatically cache the server response using
`quick\_cache <https://pypi.python.org/pypi/quick-cache>`__. The
server needs to be set up for this:

.. code:: python

    cache = QuickCache(base_file, quota=500, ram_quota=100, warnings=msg)
    server.cache = cache

Then caching can be used for workers:

.. code:: python

    @server.json_worker("/json_worker", cache_id=lambda args: {
            ...  # uniquely identify the task from its arguments (must be JSON convertible)
        })
    def _json_worker(post: WorkerArgs) -> dict:
        # ...
        # long, slow computation
        return myresult  # myresult must be JSON convertible

Note that caching can also be used for other types of requests.

Using workers with babel or react
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you're using *babel* (e.g., with *react*) you can also
mirror the file into your source folder:

.. code:: python

    server.mirror_worker_js("src/worker.js")

and then import it:

.. code:: javascript

    import './worker.js';

    const WORKER = new window.quick_server.Worker();
    export function registerStatus(cb) {
      WORKER.status(cb);
    }

    export function fetchWorker(ref, url, post, cb) {
      WORKER.post(ref, url, post, cb);
    }

    export function cancelWorker(ref) {
      WORKER.cancel(ref);
    }

Note that for a build you need to actually copy
``worker.js`` into you source folder since the build
system gets confused with filesystem links.
To use *quick\_server* with a build bind the build folder:

.. code:: python

    server.bind_path("/", "build/")

During development it is recommended to forward
requests from the *react* server to *quick\_server*.
For this add the following line to your ``package.json``:

.. code:: javascript

    "proxy": "http://localhost:8080"

where the proxy field redirects to the *quick\_server*.

Tokens
~~~~~~

Tokens are means to store client information on the server.
For that the server must send the token-id to the client:

.. code:: python

    server.create_token()  # creates a new token -- send this to the client

The server can now access (read / write) data associated with this token:

.. code:: python

    @server.json_post("/json_request", 0)
    def _json_request(req: QuickServerRequestHandler, args: ReqArgs) -> ...:
        # assuming the token-id was sent via post
        # expire can be the expiration time in seconds of a token,
        # None for no expiration, or be omitted for the default expiration (1h)
        with server.get_token_obj(args["post"]["token"], expire=None) as obj:
            ...  # do stuff with obj

CORS and proxying
~~~~~~~~~~~~~~~~~

CORS can be activated with:

.. code:: python

    server.cross_origin = True

and requests can be redirected via proxy (if you want to avoid CORS):

.. code:: python

    server.bind_proxy("/foo/", "http://localhost:12345")

redirects every request that begins with ``/foo/`` and
has not been handled by *quick\_server* to ``http://localhost:12345``.

Custom server commands
~~~~~~~~~~~~~~~~~~~~~~

By default *quick\_server* provides the commands ``help`` (list of
available commands), ``restart`` (restart the server), and ``quit``
(terminates the server). You can add own commands via

.. code:: python

    @server.cmd()
    def name(args: list[str]) -> None:  # creates the command name
        if not args:
            msg("hello")
        else:
            msg(f"hi {' '.join(args)}")  # words typed after name are printed here

A common command to add when having caching functionality (e.g.,
provided by
`quick\_cache <https://pypi.python.org/pypi/quick-cache>`__) is to
clear caches. This show-cases also auto-complete functionality:

.. code:: python

    def complete_cache_clear(args: list[str], text: str) -> list[str]:  # args contains already completed arguments; text the currently started one
        if args:  # we only allow up to one argument
            return []
        return [ section for section in cache.list_sections() if section.startswith(text) ]  # cache is the quick_cache object

    @server.cmd(complete=complete_cache_clear)
    def cache_clear(args: list[str]) -> None:
        if len(args) > 1: # we only allow up to one argument
          msg(f"too many extra arguments! expected one got {' '.join(args)}")
          return
        msg(f"clear {'' if args else 'all '}cache{' ' if args else 's'}{args[0] if args else ''}")
        cache.clean_cache(args[0] if args else None)

Server without command loop
~~~~~~~~~~~~~~~~~~~~~~~~~~~

The easiest way to start the server without a command loop (e.g., when
started as service) is to stop the loop with an EOF by calling the
script like this:

.. code:: sh

    cat /dev/null | python yourscript.py

or use the ``no_command_loop`` flag and run the script normally:

.. code:: python

    server.no_command_loop = True

HTTPS
~~~~~

You can wrap the server socket to support HTTPS:

.. code:: python

    import ssl

    addr = ""  # empty address is equivalent to "localhost"
    port = 443  # the HTTPS default port 443 might require root privileges
    server = create_server((addr, port), parallel=True)
    server.socket = ssl.wrap_socket(server.socket, certfile="path/to/localhost.pem", server_side=True)

    # setup your server

    try:
        server.serve_forever()
    finally:
        server.server_close()

More examples
~~~~~~~~~~~~~

`example.py <https://github.com/JosuaKrause/quick_server/blob/master/example/example.py>`__ and
`example2.py <https://github.com/JosuaKrause/quick_server/blob/master/example/example2.py>`__ also contain minimal example
servers. You can run them with ``./example.py`` and ``./example2.py``
respectively from the examples directory. Then you can browse to
http://localhost:8000/example/.

Contributing
------------

Pull requests are highly appreciated :) Also, feel free to open
`issues <https://github.com/JosuaKrause/quick_server/issues>`__ for any
questions or bugs you may encounter.
