Module urest.api.base
Implements the 'Abstract' Base Class for all the nouns used by the
RESTServer
class in defining resources.
Note
MicroPython does not implement the
abc
module which provides
language-level support for abstract base classes. Therefore the
RESTServer
class checks the ancestors of the class
passed as a resource for the API to ensure they derive from APIBase
.
Any class which does not have APIBase
as an ancestor will
therefore not work as a valid resource.
This also means that APIBase
is not a pure virtual ABC, and
so implements a minimum set of methods which hold and manipulate resource state.
However all methods such as APIBase.get_state()
and
APIBase.set_state()
are expected to be overridden in working
implementations.
Licence
This module, and all included code, is made available under the terms of the MIT Licence
Copyright (c) 2022-2023 David Love
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Expand source code
"""
Implements the 'Abstract' Base Class for all the nouns used by the
`urest.http.server.RESTServer` class in defining resources.
.. Note::
MicroPython does not implement the
[`abc` module](https://docs.python.org/3.10/library/abc.html) which provides
language-level support for abstract base classes. Therefore the
`urest.http.server.RESTServer` class checks the ancestors of the class
passed as a resource for the API to ensure they derive from `urest.api.base.APIBase`.
Any class which _does not_ have `urest.api.base.APIBase` as an ancestor will
therefore **not** work as a valid resource.
This also means that `urest.api.base.APIBase` is not a pure virtual ABC, and
so implements a minimum set of methods which hold and manipulate resource state.
However all methods such as `urest.api.base.APIBase.get_state` and
`urest.api.base.APIBase.set_state` are expected to be overridden in working
implementations.
Licence
-------
This module, and all included code, is made available under the terms of the MIT
Licence
> Copyright (c) 2022-2023 David Love
> Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
> The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""
class APIBase:
##
## Constructor
##
def __init__(self):
"""The Abstract Base Class for the nouns, used in the response from the server.
This base class defines the minimum interface used in marshalling requests from
the clients by the `urest.http.server.RESTServer` class. The API defined by the
server consists of 'nouns' representing the resources defined by the sub-classes
of this base class, and the methods which act upon those resources (which map to
the 'verbs' of the HTTP requests made to the `urest.http.server.RESTServer` class.
Where data is returned to the client by the, e.g by the `get_state` method, JSON
will ultimately be used as the encoding format. Sub-classes do not need to
implement the saving of the object state to the client: however to assist they
should be aware of the type of the each `value` returned as part of a `key/value`
pair in the `Dictionary`.
When returning data to the client, the `value` of each entry in the `Dictionary`
will attempt to be inferred using the normal Python type library. If the type can be
identified, then an appropriate JSON type will be used: otherwise the `value` of that
`Dictionary` entry will be returned as a string.
.. Warning:: Data will be returned to the client 'as is'
No further checking on the validity (or otherwise) of the content of
the `Dictionary` will be undertaken past this point. Anything that appear to be in
a valid `Dictionary` will be returned to the client. It is the module consumers
responsibility to ensure the returned data follows the form expected by those clients.
"""
self._state_attributes = []
""" Holds the current state and attributes of the resource """
##
## State Manipulation Methods
##
def get_state(self) -> dict:
"""Returns the state of the resource.
Return the state of the resource, as defined by the sub-classes. By default
this method will return the contents of the private `state_attributes` `Dictionary`
to the client; assuming that `Dictionary` has been appropriately completed
in the processing of the resource.
Returns
-------
Dictionary
A mapping of (key, value) pairs which defines the resource state to return to the
client.
"""
return self._state_attributes
def set_state(self, state_attributes: dict):
"""Sets the full state of the resource.
The exact mechanism for updating the internal state of the resource represented
by sub-classes is implementation defined. By default this method expects the
_full_ state to be represented by the `state_attributes` parameters; and by
default the new state will be exactly as stated by the `Dictionary` passed in
through `state_attributes`.
Parameters
----------
state_attributes: Dictionary
A list of (key, value) pairs representing the _full_ state of the
resource. No merging of state is undertaken, or attempted.
"""
if state_attributes is not None and isinstance(state_attributes, dict):
self._state_attributes = state_attributes
else:
self._state_attributes = []
def update_state(self, state_attributes: dict):
"""Updates the state of the resource, using the 'key/value' pairs of the
`Dictionary` in `state_attributes`.
The exact mechanism for updating the internal state of the resource represented
by sub-classes is implementation defined. By default this expects to update
only part of the state through the use of the partial state defined in
`state_attributes`. This defines a `Dictionary` of (key, value) pairs which
can be interpreted by sub-classes to update the true internal state as needed.
Parameters
----------
state_attributes: Dictionary
A list of (key, value) pairs representing the _partial_ state of the
resource. The exact mechanism for merging this partial state if left
to the implementation of the sub-classes.
"""
if state_attributes is not None and isinstance(state_attributes, dict):
for key in state_attributes:
try:
self._state_attributes[key] = state_attributes[key]
except KeyError:
self._state_attributes[key] = None
else:
self._state_attributes = []
def delete_state(self):
"""Removes the internal state of the resource, essentially 'resetting' or
re-initialising the object.
The exact mechanism for returning the state to the defaults are left to
the implementation. However it is expected that once this call completes
the internal state will be _identical_ to that of the default constructor.
"""
self._state_attributes = []
Classes
class APIBase
-
The Abstract Base Class for the nouns, used in the response from the server.
This base class defines the minimum interface used in marshalling requests from the clients by the
RESTServer
class. The API defined by the server consists of 'nouns' representing the resources defined by the sub-classes of this base class, and the methods which act upon those resources (which map to the 'verbs' of the HTTP requests made to theRESTServer
class.Where data is returned to the client by the, e.g by the
get_state
method, JSON will ultimately be used as the encoding format. Sub-classes do not need to implement the saving of the object state to the client: however to assist they should be aware of the type of the eachvalue
returned as part of akey/value
pair in theDictionary
.When returning data to the client, the
value
of each entry in theDictionary
will attempt to be inferred using the normal Python type library. If the type can be identified, then an appropriate JSON type will be used: otherwise thevalue
of thatDictionary
entry will be returned as a string.Warning: Data will be returned to the client 'as is'
No further checking on the validity (or otherwise) of the content of the
Dictionary
will be undertaken past this point. Anything that appear to be in a validDictionary
will be returned to the client. It is the module consumers responsibility to ensure the returned data follows the form expected by those clients.Expand source code
class APIBase: ## ## Constructor ## def __init__(self): """The Abstract Base Class for the nouns, used in the response from the server. This base class defines the minimum interface used in marshalling requests from the clients by the `urest.http.server.RESTServer` class. The API defined by the server consists of 'nouns' representing the resources defined by the sub-classes of this base class, and the methods which act upon those resources (which map to the 'verbs' of the HTTP requests made to the `urest.http.server.RESTServer` class. Where data is returned to the client by the, e.g by the `get_state` method, JSON will ultimately be used as the encoding format. Sub-classes do not need to implement the saving of the object state to the client: however to assist they should be aware of the type of the each `value` returned as part of a `key/value` pair in the `Dictionary`. When returning data to the client, the `value` of each entry in the `Dictionary` will attempt to be inferred using the normal Python type library. If the type can be identified, then an appropriate JSON type will be used: otherwise the `value` of that `Dictionary` entry will be returned as a string. .. Warning:: Data will be returned to the client 'as is' No further checking on the validity (or otherwise) of the content of the `Dictionary` will be undertaken past this point. Anything that appear to be in a valid `Dictionary` will be returned to the client. It is the module consumers responsibility to ensure the returned data follows the form expected by those clients. """ self._state_attributes = [] """ Holds the current state and attributes of the resource """ ## ## State Manipulation Methods ## def get_state(self) -> dict: """Returns the state of the resource. Return the state of the resource, as defined by the sub-classes. By default this method will return the contents of the private `state_attributes` `Dictionary` to the client; assuming that `Dictionary` has been appropriately completed in the processing of the resource. Returns ------- Dictionary A mapping of (key, value) pairs which defines the resource state to return to the client. """ return self._state_attributes def set_state(self, state_attributes: dict): """Sets the full state of the resource. The exact mechanism for updating the internal state of the resource represented by sub-classes is implementation defined. By default this method expects the _full_ state to be represented by the `state_attributes` parameters; and by default the new state will be exactly as stated by the `Dictionary` passed in through `state_attributes`. Parameters ---------- state_attributes: Dictionary A list of (key, value) pairs representing the _full_ state of the resource. No merging of state is undertaken, or attempted. """ if state_attributes is not None and isinstance(state_attributes, dict): self._state_attributes = state_attributes else: self._state_attributes = [] def update_state(self, state_attributes: dict): """Updates the state of the resource, using the 'key/value' pairs of the `Dictionary` in `state_attributes`. The exact mechanism for updating the internal state of the resource represented by sub-classes is implementation defined. By default this expects to update only part of the state through the use of the partial state defined in `state_attributes`. This defines a `Dictionary` of (key, value) pairs which can be interpreted by sub-classes to update the true internal state as needed. Parameters ---------- state_attributes: Dictionary A list of (key, value) pairs representing the _partial_ state of the resource. The exact mechanism for merging this partial state if left to the implementation of the sub-classes. """ if state_attributes is not None and isinstance(state_attributes, dict): for key in state_attributes: try: self._state_attributes[key] = state_attributes[key] except KeyError: self._state_attributes[key] = None else: self._state_attributes = [] def delete_state(self): """Removes the internal state of the resource, essentially 'resetting' or re-initialising the object. The exact mechanism for returning the state to the defaults are left to the implementation. However it is expected that once this call completes the internal state will be _identical_ to that of the default constructor. """ self._state_attributes = []
Subclasses
Methods
def delete_state(self)
-
Removes the internal state of the resource, essentially 'resetting' or re-initialising the object.
The exact mechanism for returning the state to the defaults are left to the implementation. However it is expected that once this call completes the internal state will be identical to that of the default constructor.
Expand source code
def delete_state(self): """Removes the internal state of the resource, essentially 'resetting' or re-initialising the object. The exact mechanism for returning the state to the defaults are left to the implementation. However it is expected that once this call completes the internal state will be _identical_ to that of the default constructor. """ self._state_attributes = []
def get_state(self) ‑> dict
-
Returns the state of the resource.
Return the state of the resource, as defined by the sub-classes. By default this method will return the contents of the private
state_attributes
Dictionary
to the client; assuming thatDictionary
has been appropriately completed in the processing of the resource.Returns
Dictionary
A mapping of (key, value) pairs which defines the resource state to return to the client.
Expand source code
def get_state(self) -> dict: """Returns the state of the resource. Return the state of the resource, as defined by the sub-classes. By default this method will return the contents of the private `state_attributes` `Dictionary` to the client; assuming that `Dictionary` has been appropriately completed in the processing of the resource. Returns ------- Dictionary A mapping of (key, value) pairs which defines the resource state to return to the client. """ return self._state_attributes
def set_state(self, state_attributes: dict)
-
Sets the full state of the resource.
The exact mechanism for updating the internal state of the resource represented by sub-classes is implementation defined. By default this method expects the full state to be represented by the
state_attributes
parameters; and by default the new state will be exactly as stated by theDictionary
passed in throughstate_attributes
.Parameters
state_attributes
:Dictionary
- A list of (key, value) pairs representing the full state of the resource. No merging of state is undertaken, or attempted.
Expand source code
def set_state(self, state_attributes: dict): """Sets the full state of the resource. The exact mechanism for updating the internal state of the resource represented by sub-classes is implementation defined. By default this method expects the _full_ state to be represented by the `state_attributes` parameters; and by default the new state will be exactly as stated by the `Dictionary` passed in through `state_attributes`. Parameters ---------- state_attributes: Dictionary A list of (key, value) pairs representing the _full_ state of the resource. No merging of state is undertaken, or attempted. """ if state_attributes is not None and isinstance(state_attributes, dict): self._state_attributes = state_attributes else: self._state_attributes = []
def update_state(self, state_attributes: dict)
-
Updates the state of the resource, using the 'key/value' pairs of the
Dictionary
instate_attributes
.The exact mechanism for updating the internal state of the resource represented by sub-classes is implementation defined. By default this expects to update only part of the state through the use of the partial state defined in
state_attributes
. This defines aDictionary
of (key, value) pairs which can be interpreted by sub-classes to update the true internal state as needed.Parameters
state_attributes
:Dictionary
- A list of (key, value) pairs representing the partial state of the resource. The exact mechanism for merging this partial state if left to the implementation of the sub-classes.
Expand source code
def update_state(self, state_attributes: dict): """Updates the state of the resource, using the 'key/value' pairs of the `Dictionary` in `state_attributes`. The exact mechanism for updating the internal state of the resource represented by sub-classes is implementation defined. By default this expects to update only part of the state through the use of the partial state defined in `state_attributes`. This defines a `Dictionary` of (key, value) pairs which can be interpreted by sub-classes to update the true internal state as needed. Parameters ---------- state_attributes: Dictionary A list of (key, value) pairs representing the _partial_ state of the resource. The exact mechanism for merging this partial state if left to the implementation of the sub-classes. """ if state_attributes is not None and isinstance(state_attributes, dict): for key in state_attributes: try: self._state_attributes[key] = state_attributes[key] except KeyError: self._state_attributes[key] = None else: self._state_attributes = []