# Flask RESTful reqparse

***

**1. Basic Request Parsing:**

```python
from flask_restful import Resource, reqparse

class MyResource(Resource):
    def get(self):
        parser = reqparse.RequestParser()
        parser.add_argument('name', type=str, required=True)
        args = parser.parse_args()
        return {'name': args['name']}
```

**2. Adding Multiple Arguments:**

```python
parser.add_argument('name', type=str, required=True)
parser.add_argument('email', type=str, required=False)
args = parser.parse_args()
```

**3. Setting Default Values:**

```python
parser.add_argument('name', type=str, required=True, default='John Doe')
```

**4. Parsing Files:**

```python
parser.add_argument('file', type=werkzeug.datastructures.FileStorage, location='files')
```

**5. Parsing Nested Objects:**

```python
parser.add_argument('address', type=dict, location='json')  # { 'street': '123 Main St', 'city': 'Anytown' }
```

**6. Parsing Lists:**

```python
parser.add_argument('tags', type=list, location='json')  # ['tag1', 'tag2']
```

**7. Custom Type Conversion:**

```python
def camel_case_to_snake_case(value):
    return value.replace(' ', '_').lower()

parser.add_argument('my_argument', type=camel_case_to_snake_case)
```

**8. Strict Mode:**

```python
parser.add_argument('name', type=str, required=True, help='Name is required')
parser.parse_args(strict=True)  # Will raise an error if extra arguments are present
```

**9. Parsing URL Parameters:**

```python
class MyResource(Resource):
    def get(self, user_id):
        parser = reqparse.RequestParser()
        parser.add_argument('name', type=str, required=True, location='args')
        args = parser.parse_args()
        return {'name': args['name']}
```

**10. Parsing Form Data:**

```python
class MyResource(Resource):
    def post(self):
        parser = reqparse.RequestParser()
        parser.add_argument('name', type=str, required=True, location='form')
        args = parser.parse_args()
        return {'name': args['name']}
```

**11. Parsing Raw Data:**

```python
class MyResource(Resource):
    def post(self):
        parser = reqparse.RequestParser()
        parser.add_argument('data', type=str, location='data')
        args = parser.parse_args()
        return {'data': args['data']}
```

**12. Parsing Headers:**

```python
class MyResource(Resource):
    def get(self):
        parser = reqparse.RequestParser()
        parser.add_argument('Authorization', type=str, location='headers')
        args = parser.parse_args()
        return {'Authorization': args['Authorization']}
```

**13. Parsing Cookies:**

```python
class MyResource(Resource):
    def get(self):
        parser = reqparse.RequestParser()
        parser.add_argument('session', type=str, location='cookies')
        args = parser.parse_args()
        return {'session': args['session']}
```

**14. Specifying Argument Names:**

```python
parser.add_argument('user_name', dest='username', type=str, required=True)
```

**15. Trimming Whitespace:**

```python
parser.add_argument('name', type=str, required=True, trim=True)
```

**16. Suppressing Warnings:**

```python
parser.add_argument('name', type=str, required=True, help='', silent=True)
```

**17. Bundling Arguments:**

```python
class MyResource(Resource):
    def get(self):
        parser = reqparse.RequestParser()
        parser.bundle_args('user_info', ['name', 'email'])
        args = parser.parse_args()
        return {'user_info': args['user_info']}
```

**18. Parsing Binary Data:**

```python
parser.add_argument('file', type=io.BytesIO, location='files')
```

**19. Parsing JSON Data:**

```python
parser.add_argument('data', type=json, location='json')
```

**20. Parsing Data From a File:**

```python
class MyResource(Resource):
    def post(self):
        parser = reqparse.RequestParser()
        parser.add_argument('file', type=werkzeug.datastructures.FileStorage, location='files')
        args = parser.parse_args()
        file_content = args['file'].stream.read()
        return {'file_content': file_content}
```

**21. Parsing Data From Multiple Sources:**

```python
parser.add_argument('name', type=str, required=True, location=['args', 'json'])
```

**22. Parsing Data From a Custom Location:**

```python
class CustomLocation:
    def __init__(self):
        self.data = None

    def get_data(self):
        if not self.data:
            self.data = {'username': 'example'}
        return self.data

custom_location = CustomLocation()

parser.add_argument('username', type=str, required=True, location=custom_location.get_data)
```

**23. Parsing Data With a Custom Type:**

```python
class MyCustomType:
    def __init__(self, value):
        self.value = value

    @classmethod
    def from_string(cls, value):
        return cls(value)

parser.add_argument('my_custom_type', type=MyCustomType, location='json')
```

**24. Parsing Data With a Predefined List of Values:**

```python
parser.add_argument('status', type=str, required=True, choices=('active', 'inactive'))
```

**25. Parsing Data With Regular Expressions:**

```python
parser.add_argument('phone_number', type=str, required=True, regex=r'\d{3}-\d{3}-\d{4}')
```

**26. Parsing Data With a Default Factory:**

```python
def create_default_user():
    return {
        'name': 'John Doe',
        'email': 'johndoe@example.com'
    }

parser.add_argument('user', type=dict, required=False, default=create_default_user)
```

**27. Parsing Data With a Custom Help Message:**

```python
parser.add_argument('password', type=str, required=True, help='Password is required and must be at least 8 characters long')
```

**28. Parsing Data With a Custom Error Message:**

```python
parser.add_argument('email', type=str, required=True, error='Invalid email address')
```

**29. Parsing Data With a Callback:**

```python
def validate_date(value):
    try:
        datetime.strptime(value, '%Y-%m-%d')
        return value
    except ValueError:
        raise reqparse.ArgumentTypeError('Invalid date format')

parser.add_argument('date', type=validate_date, required=True)
```

**30. Parsing Data With a Namespace:**

```python
ns = reqparse.Namespace('user')
ns.add_argument('name', type=str, required=True)
ns.add_argument('email', type=str, required=False)
parser.add_argument('user', type=ns)
```

**31. Parsing Data With a Required Namespace:**

```python
ns = reqparse.Namespace('user')
ns.add_argument('name', type=str, required=True)
ns.add_argument('email', type=str, required=False)
parser.add_argument('user', type=ns, required=True)
```

**32. Parsing Data With a Custom Namespace Name:**

```python
ns = reqparse.Namespace('user', name='profile')
ns.add_argument('name', type=str, required=True)
ns.add_argument('email', type=str, required=False)
parser.add_argument('user', type=ns)
```

**33. Parsing Data With a Custom Namespace Help Message:**

```python
ns = reqparse.Namespace('user')
ns.add_argument('name', type=str, required=True)
ns.add_argument('email', type=str, required=False)
ns.set_help('User profile information')
parser.add_argument('user', type=ns)
```

**34. Parsing Data With a Custom Namespace Error Message:**

```python
ns = reqparse.Namespace('user')
ns.add_argument('name', type=str, required=True)
ns.add_argument('email', type=str, required=False)
ns.set_error_message('Invalid user profile information')
parser.add_argument('user', type=ns)
```

**35. Parsing Data With a Predefined Namespace:**

```python
ns = reqparse.Namespace()
ns.add_argument('name', type=str, required=True)
ns.add_argument('email', type=str, required=False)
parser.add_argument('user', type=ns, default={'name': 'John Doe', 'email': 'johndoe@example.com'})
```

**36. Parsing Data With Multiple Predefined Namespaces:**

```python
ns1 = reqparse.Namespace('user')
ns1.add_argument('name', type=str, required=True)
ns1.add_argument('email', type=str, required=False)

ns2 = reqparse.Namespace('profile')
ns2.add_argument('avatar', type=str, required=False)
ns2.add_argument('location', type=str, required=False)

parser.add_argument('user', type=ns1)
parser.add_argument('profile', type=ns2)
```