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config provide some functional configurations for Pait, however, it is only allowed to be initialized once during the entire runtime of the program, and it is recommended to do so after all routes have been added and load_app has been called, as in the following code, config.init_config is called before the run app code block:

from starlette.applications import Starlette
from pait.g import config
from import load_app

# ------
# By `from ... import` import routing module
# ------

app: Starlette = Starlette()
# --------
# app.add_route
# --------
config.init_config(author=("so1n", ))
# --------
# run app
# --------

config.init_config supports the following parameters:

Parameters Description
author Global author of the default route function, if author in @pait is null, the author for the route function is
status Global status of the default route function, if status in @pait is null, the status for the route function is is config.status
json_type_default_value_dict Configure the default value of the json type, which will be useful when auto-generating the response.
python_type_default_value_dict Configure a default value for the python type that will work when auto-generating the response.
json_encoder Pait's Json encoder object
apply_func_list A list of functions that change the attributes of the route function according to certain rules

1.apply func

When using Pait, it may be possible to use different Pait attributes depending on the route function lifecycle. For example, if the status is design, the Mock plugin will be used, and if the status is test, the response check plugin will be used. If you have to change the configuration manually every time, it will be very troublesome, and you can use the apply func function at this time.


This function can be thought of as a routing group, but don't think of it as middleware, as it can't handle routes that aren't decorated by Pait.

Pait provides a series of apply func, each apply func will only handle one kind of Pait attribute, its function protocol is as follows:

from typing import Any, Optional
from pait.model.config import APPLY_FN
from pait.extra.config import MatchRule

def apply_func_demo(
    value: Any, match_rule: Optional["MatchRule"] = None
) -> "APPLY_FN":
It requires 2 parameters, the first parameter is the value to be applied and the second parameter is to match which route functions need to be applied.

The match_rule parameter is an object called MatchRule, which is initialized to accept two parameters, one named key and the other named target. Where key is the Key of the corresponding Pait attribute of the route function, with a default value of all (which means that all route functions match). Target is the value of the attribute to be matched, Key currently supports the following values:

MatchKeyLiteral = Literal[
    "all",              # Match all route functions
    "status",           # The status of the route function will be matched if it corresponds to the value
    "group",            # The group of the route function will be matched to the corresponding value
    "tag",              # The tag of the route function will match the corresponding values
    "method_list",      # The HTTP method of the route function will match the corresponding value
    "path",             # The URL of the route function matches the regular match of the input
They are of three types. The first type is all, such as MatchRule("all") means that all route functions will match. The second type is status, group, tag, method_list, path, such as MatchRule("group", "demo") means that route functions with a group of demo will be matched. The last type starts with !, which means reverse matching, such as MatchRule("!status", "test") means that route functions that match status with a value other than test will be matched.

In addition to this, the matching rules support multi-rule matching for & and | as follows:

from pait.extra.config import MatchRule
from pait.model.status import PaitStatus

# Match the route function whose status is test or dev
MatchRule("status", PaitStatus.test) | MatchRule("status",
# Match the route function whose path is /api/user, method_list is GET, or group is gRPC
MatchRule("path", "/api/user") & (MatchRule("method_list", "GET") | MatchRule("group", "gRPC"))


It is important to note that apply func only appends the value for array-type values, not overrides the value.


When using the Web framework, may use some request parameters through the middleware, these parameters will not be used in the route function. For example, there is a middleware that gets the APP version from the Header, and returns a 404 response for APP versions less than 1, and only allows access if the APP version is greater than 1. In this case, Pait will not be able to get the request values used by the middleware, resulting in the generated OpanAPI data missing these request values. This can be solved by using apply_extra_openapi_model, which is used as follows:

from pydantic import BaseModel
from pait.field import Header
from pait.extra.config import apply_extra_openapi_model
from pait.g import config

class DemoModel(BaseModel):
    """Middleware generally reads the corresponding version value through the header"""
    version_code: int = Header.i(description="Version code")
    version_name: str = Header.i(description="Version name")

# Use the `apply_extra_openapi_model` to apply the current model,
# and use the default value of the MatchRule because the middleware is applied to all route functions.


As with the apply_extra_openapi_model, an exception response may be returned when using a middleware restriction with a version number less than 1. In this case a default response can be added using apply_response_model, used as follows:

from pait.extra.config import apply_response_model
from pait.g import config
from pait.model.response import HtmlResponseModel

class DefaultResponseModel(HtmlResponseModel):
    response_data: str = "<h1> Default Html</h1>"

# Since middleware is applied to all route functions, the matching rules use the default values


Pait is a decorator, so it can only capture the attributes of the route function, like URL, HTTP method parameters need to be added by load_app. However, many web frameworks will automatically supplement the route function with HTTP methods like HEAD, OPTIONS, etc. when registering the route function. This will cause the OpenAPI data of the route function to contain HTTP methods such as HEAD and OPTIONS. In this case, can use apply_block_http_method_set to disable some HTTP methods from being captured by Pait, using the following method:

from pait.extra.config import apply_block_http_method_set
from pait.g import config

config.init_config(apply_func_list=[apply_block_http_method_set({"HEAD", "OPTIONS"})])


Plugins are an important part of Pait, however there are plugins that only work for route functions with certain statuses. It is recommended to use different plugins based on the status of the route function via apply_multi_plugin as follows:

from import MockPlugin
from import CheckJsonRespPlugin
from pait.extra.config import apply_multi_plugin, MatchRule
from pait.g import config
from pait.model.status import PaitStatus

            # In order to be able to reuse the plugin, the lambda writing method is used here,
            # and can also use the create_factory that comes with pait
            # Using the Mock plugin for route functions where status is design
            # Using the CheckJsonPlugin for route functions where status is test
            match_rule=MatchRule(key="status", target=PaitStatus.test)


Most of the time, may use a Token check function for a group of route functions, which is not suitable for middleware, but adding depend one by one to a route function is cumbersome, so can use apply_pre_depend, which is used as follows:

from pait.extra.config import apply_pre_depend, MatchRule
from pait.field import Header
from pait.g import config

def check_token(token: str = Header.i("")) -> bool:
    return bool(token)

        # Match url starting with /api/v1/user
        apply_pre_depend(check_token, match_rule=MatchRule(key="path", target="^/api/v1/user")),
        # Match route functions whose group attribute is user
        apply_pre_depend(check_token, match_rule=MatchRule(key="group", target="user"))