Quickstart¶

Eager to get started? This page gives a good example to use pre-request. It assumes you already have pre-request installed If you do not, head over to the Installation section.

Minimal Example¶

A minimal example looks something like this:

from flask import Flask

from pre_request import pre
from pre_request import Rule

app = Flask(__name__)

req_params = {
   "userId": Rule(type=int, required=True)
}

@app.route("/")
@pre.catch(req_params)
def hello_world(params):
   return str(params)

what happened in this code ?

Use pre-request library to import a global object pre
Define request params rule, userId must be type of int and required
Use @pre.catch(req_params) to filter input value
Use ~flask.g or def hello_world(params) to get formatted input value。

pre singleton¶

pre-request support global singleton object, we can use this object to update runtime params

pre.fuzzy pre-request will fuzzy error message to avoid expose sensitive information
pre.sore_key use another params to store formatted request info
pre.content_type pre-request will response html or json error message, use application/json or text/html
pre.skip_filter pre-request will ignore all of the check filter, but dest is still valid.

Flask Extension¶

pre-request support flask extension configuration to load params.

app = Flask(__name__)

app.config["PRE_FUZZY"] = True
app.config["PRE_STORE_KEY"] = "pp"
app.config["PRE_CONTENT_TYPE"] = "application/json"
app.config["PRE_SKIP_FILTER"] = False

pre.init_app(app=app)

Decorator¶

pre-request use decorator pre.catch to validate request params with special kind of method

@app.route("/get", methods=['get'])
@pre.catch(get=req_params)
def get_handler(params):
    return str(params)

@app.route("/post", methods=['post'])
@pre.catch(post=req_params)
def get_handler(params):
    return str(params)

we can also support validate different rule for different request method.

@app.route("/all", methods=['get', 'post'])
@pre.catch(get=get_field, post=post_field)
def all_handler(params):
    return str(params)

you can validate params for all of the request methods with no key.

@app.route("/all", methods=['get', 'post'])
@pre.catch(rules)
def all_handler(params):
    return str(params)

Use parse¶

We can use function pre.parse instead of decorator @pre.catch(). At this mode, you must catch ParamsValueError by yourself.

args = {
    "params": Rule(email=True)
}

@app.errorhandler(ParamsValueError)
def params_value_error(e):
    return pre.fmt_resp(e)


@app.route("/index")
def example_handler():
    rst = pre.parse(args)
    return str(rst)