A RegEx based router
rerouter routes string commands to annotated functions.
How to define the 'grammar':
"Grammar" is the pattern that tells rerouter which handler a string command should be routed to.
For example, github slack client supports slash commands like:
subscribe user/repo +label:"teams/designers" +label:"urgent"
subscribe user/repo commits:myBranch author:"hotfix"
close [issue link]
open [pull request link]Suppose we want to build a router that routes various command to different handlers, we can do:
router = RegExRouter()
@router.route("subscribe <user_repo> [<option(+label|commits|author)>:<value>]+")
def handle_subscribe(rns, *args, **kwargs):
"""Handle commands like:
subscribe user/repo +label:"teams/designers" +label:"urgent"
subscribe user/repo commits:myBranch author:"hotfix"
"""
pass
@router.route("(close|open) [link:<link_url>]+")
def handle_open_close(rns, *args, **kwargs):
"""Handle commands like:
close [issue link]
open [pull request link]
"""
passMore examples:
@router.route("settings (set|get|delete) project:<jira_project>")
def f_settings(rns, *args, **kwargs):
"""Matches:
settings set project:TEST-PROJ
settings get project:TEST-PROJ
settings delete project:TEST-PROJ
"""
pass
@router.routex(
("(subscribe)", ""),
("(?P<feature>reviews|pushes|checks)", ""),
(
"(?P<filter_name>[+-]path|[+-]fork|[+-]branch|[+-]reviewer):(?P<filter_value>[^:]+)", # noqa
"+",
),
)
def f_subscribe(rns):
"""Matches:
subscribe reviews +path:foo/bar/* -fork:main/release +path:infra/tools/*
subscribe pushes path:foo/bar/* fork:main/release path:infra/tools/*
"""
pass
@router.route("a+ b")
@router.route("a* c* b")
def f_abc(rns, *args, **kwargs):
"""Matches:
aa
ab
aab
aaab
acb
aacb
cb
ccb
"""
passHow to start routing:
This is done by calling the RegExRouter::route_to method, example:
router = RegExRouter()
@router.route("hello <user>")
def handle_subscribe(rns, *args, **kwargs):
return rns.named("user")
res = router.route_to("hello world") # res == 'world'Behind the scene, rerouter translates the routing syntax into a list of regex patterns, aka:
| grammar: | (close|open) [link:<link_url>]+ |
| re patterns: | 1. (close|open); 2. (link):(^(?P<{link_url}>[^:]+)$)
|
In the callback function, the rns is a RegExRouteMatch object which has the following properties:
-
conclusion: bool: whether the grammar match the command. (for annotation use cases, this is always true) -
matches: a list of RegEx match objects, for example, command:close https://example.comwill be routed tohandle_open_close(...)and thematcheswill be- <re.Match object, match='close'>
- <re.Match object, match='http://example.com''>
-
grammar: the grammar which the command matches, in our example, its value is(close|open) [link:<link_url>]+
