flask restful: passing parameters to GET request

I want to create a resource that supports GET request in following way:

/bar?key1=val1&key2=val2 

I tried this code, but it is not working

app = Flask(__name__) api = Api(app) class BarAPI(Resource): def get(key1, key2): return jsonify(dict(data=[key1, key2])) api.add_resource(BarAPI, '/bar', endpoint='bar') 

Thanks!

3 Answers

Edit: reqparse is no longer the recommended way to do this with flask-restful!, but there is another example using marshmallow below.

The reqparse object is deprecated. See the docs or the second example in this post for alternatives.

Use reqparse. You can see another example in the flask-restful docs.

It performs validation on the parameters and does not require jsonify.

from flask import Flask from flask_restful import Resource, Api, reqparse app = Flask(__name__) api = Api(app) class BarAPI(Resource): def get(self): parser = reqparse.RequestParser() parser.add_argument('key1', type=str) parser.add_argument('key2', type=str) return parser.parse_args() api.add_resource(BarAPI, '/bar', endpoint='bar') if __name__ == '__main__': app.run(debug=True) 

Another way is to use marshmallow.

You can use a Schema class,to validate request.args (for a PUT/POST request you might validate request.form)

from flask import Flask, request, abort from flask_restful import Resource, Api from marshmallow import Schema, fields class BarQuerySchema(Schema): key1 = fields.Str(required=True) key2 = fields.Str(required=True) app = Flask(__name__) api = Api(app) schema = BarQuerySchema() class BarAPI(Resource): def get(self): errors = schema.validate(request.args) if errors: abort(400, str(errors)) return 'ok' api.add_resource(BarAPI, '/bar', endpoint='bar') # omit of you intend to use `flask run` command if __name__ == '__main__': app.run(debug=True) 

This example requires that both parameters be present.

Flask can parse arguments through request

from flask import request 

You can use following lines in the block that requires GET parameters. GET is declared in @app.route() declaration.

args = request.args print (args) # For debugging no1 = args['key1'] no2 = args['key2'] return jsonify(dict(data=[no1, no2])) # or whatever is required 

Since reqparse is deprecated, here is a solution using the WebArgs library:

from flask import Flask from flask_restful import Api, Resource, abort from webargs import fields, validate from webargs.flaskparser import use_kwargs, parser app = Flask(__name__) api = Api(app) class Foo(Resource): args = { 'bar': fields.Str( required=True, validate=validate.OneOf(['baz', 'qux']), ), } @use_kwargs(args) def get(self, bar): return {'bar': bar} api.add_resource(Foo, '/foo', endpoint='foo') # This error handler is necessary for usage with Flask-RESTful. @parser.error_handler def handle_request_parsing_error(err, req, schema, *, error_status_code, error_headers): abort(error_status_code, errors=err.messages) if __name__ == '__main__': app.run(debug=True) 

For more examples, see the Flask-RESTful example in the WebArgs repository.