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:
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/.
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.
FAQs
QuickServer is a quick to use and easy to set up server implementation.
We found that quick-server demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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