Process incoming JSON-RPC requests in Python

This addresses #72 and is targeted for the 5.0 branch. The first two commits are already included in PR #94 . A point for discussion is whether to keep AssertionErrors causing an InvalidParamsResponse. While assertions can be used for argument validation they might also simply check internal server invariants which should cause a generic server error.

When RPC methods raises an exception there is always the same reply returned:

INFO jsonrpcclient.client.response: {"jsonrpc": "2.0", "error": {"code": -32000, "message": "Server error"}, "id": 2}

It would be great if 'message' could contain str(exception) that was thrown by called method.

When raising a jsonrpcserver exception inside a method (such as InvalidParamsError or ApiError), pass debug=True to override the global debug setting and include the data attribute in response.

if some_condition:
    raise InvalidParamsError("Age must be within the range 0-120", debug=True)

Responds with this, regardless of global debug value:

{"jsonrpc": "2.0", "error": {"code": -32602, "message": "Invalid parameters", "data": "Age must be within the range 0-120"}, "id": 1}

Same goes for ApiError.

Hi there's a permission issue with the package published on pypi

/tmp/jsonrpcserver-4.1.0$ find . -type f -exec ls -lha {} \;
-rw-r--r-- 1 pippo pippo 583 Nov 15 00:09 ./README.md
-rw-r--r-- 1 pippo pippo 4.4K Jan  6 02:07 ./CHANGELOG.md
-rw-r--r-- 1 pippo pippo 1.3K Jan  6 02:07 ./setup.py
-rw------- 1 pippo pippo 73 Sep 10 01:56 ./MANIFEST.in
-rw-r--r-- 1 pippo pippo 3.0K Jan  6 00:06 ./jsonrpcserver/methods.py
-rw-r--r-- 1 pippo pippo 151 Jan  6 00:06 ./jsonrpcserver/__init__.py
-rw-r--r-- 1 pippo pippo 3.2K Jan  6 00:06 ./jsonrpcserver/async_dispatcher.py
-rw------- 1 pippo pippo 921 Jan 30  2019 ./jsonrpcserver/server.py
-rw------- 1 pippo pippo 4.1K Apr 13  2019 ./jsonrpcserver/request.py
-rw------- 1 pippo pippo 2.2K Jan 30  2019 ./jsonrpcserver/log.py
-rw-r--r-- 1 pippo pippo 9.2K Jan  6 02:07 ./jsonrpcserver/response.py
-rw------- 1 pippo pippo 1.3K Jan 30  2019 ./jsonrpcserver/request-schema.json
-rw------- 1 pippo pippo 2.1K Jan 30  2019 ./jsonrpcserver/status.py
-rw-r--r-- 1 pippo pippo 891 Jan  6 00:06 ./jsonrpcserver/exceptions.py
-rw-r--r-- 1 pippo pippo 9.9K Jan  6 02:07 ./jsonrpcserver/dispatcher.py
-rw-r--r-- 1 pippo pippo 38 Jan  6 02:19 ./setup.cfg
-rw-r--r-- 1 pippo pippo 1 Jan  6 00:49 ./jsonrpcserver.egg-info/not-zip-safe
-rw------- 1 pippo pippo 14 Jan  6 02:19 ./jsonrpcserver.egg-info/top_level.txt
-rw------- 1 pippo pippo 566 Jan  6 02:19 ./jsonrpcserver.egg-info/SOURCES.txt
-rw------- 1 pippo pippo 127 Jan  6 02:19 ./jsonrpcserver.egg-info/requires.txt
-rw------- 1 pippo pippo 1.3K Jan  6 02:19 ./jsonrpcserver.egg-info/PKG-INFO
-rw------- 1 pippo pippo 1 Jan  6 02:19 ./jsonrpcserver.egg-info/dependency_links.txt
-rw-r--r-- 1 pippo pippo 1.3K Jan  6 02:19 ./PKG-INFO
-rw------- 1 pippo pippo 1.1K Sep 19  2017 ./LICENSE

with the old version

:/tmp/jsonrpcserver-4.1.0$ find ../jsonrpcserver-4.0.5/ -type f -exec ls -lha {} \;
-rw-r--r-- 1 pippo pippo 940 Jan 30  2019 ../jsonrpcserver-4.0.5/README.md
-rw-r--r-- 1 pippo pippo 3.5K Sep 10 01:56 ../jsonrpcserver-4.0.5/CHANGELOG.md
-rw-r--r-- 1 pippo pippo 1.1K Sep 10 01:56 ../jsonrpcserver-4.0.5/setup.py
-rw-r--r-- 1 pippo pippo 73 Sep 10 01:56 ../jsonrpcserver-4.0.5/MANIFEST.in
-rw-r--r-- 1 pippo pippo 2.3K Jun 21  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/methods.py
-rw-r--r-- 1 pippo pippo 151 Jan 30  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/__init__.py
-rw-r--r-- 1 pippo pippo 3.2K Apr 13  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/async_dispatcher.py
-rw-r--r-- 1 pippo pippo 921 Jan 30  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/server.py
-rw-r--r-- 1 pippo pippo 4.1K Apr 13  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/request.py
-rw-r--r-- 1 pippo pippo 2.2K Jan 30  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/log.py
-rw-r--r-- 1 pippo pippo 8.9K Jan 30  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/response.py
-rw-r--r-- 1 pippo pippo 1.3K Jan 30  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/request-schema.json
-rw-r--r-- 1 pippo pippo 2.1K Jan 30  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/status.py
-rw-r--r-- 1 pippo pippo 9.5K Jun 22  2019 ../jsonrpcserver-4.0.5/jsonrpcserver/dispatcher.py
-rw-r--r-- 1 pippo pippo 38 Sep 10 01:57 ../jsonrpcserver-4.0.5/setup.cfg
-rw-r--r-- 1 pippo pippo 14 Sep 10 01:57 ../jsonrpcserver-4.0.5/jsonrpcserver.egg-info/top_level.txt
-rw-r--r-- 1 pippo pippo 502 Sep 10 01:57 ../jsonrpcserver-4.0.5/jsonrpcserver.egg-info/SOURCES.txt
-rw-r--r-- 1 pippo pippo 127 Sep 10 01:57 ../jsonrpcserver-4.0.5/jsonrpcserver.egg-info/requires.txt
-rw-r--r-- 1 pippo pippo 1.7K Sep 10 01:57 ../jsonrpcserver-4.0.5/jsonrpcserver.egg-info/PKG-INFO
-rw-r--r-- 1 pippo pippo 1 Sep 10 01:57 ../jsonrpcserver-4.0.5/jsonrpcserver.egg-info/dependency_links.txt
-rw-r--r-- 1 pippo pippo 1.7K Sep 10 01:57 ../jsonrpcserver-4.0.5/PKG-INFO
-rw-r--r-- 1 pippo pippo 1.1K Sep 19  2017 ../jsonrpcserver-4.0.5/LICENSE

This causes import error in particular for

-rw------- 1 pippo pippo 127 Jan  6 02:19 ./jsonrpcserver.egg-info/requires.txt
-rw------- 1 pippo pippo 1.3K Jan  6 02:19 ./jsonrpcserver.egg-info/PKG-INFO

vs

-rw-r--r-- 1 pippo pippo 127 Sep 10 01:57 ../jsonrpcserver-4.0.5/jsonrpcserver.egg-info/requires.txt
-rw-r--r-- 1 pippo pippo 1.7K Sep 10 01:57 ../jsonrpcserver-4.0.5/jsonrpcserver.egg-info/PKG-INFO

can you fix it? thanks Nick

-> chmod 0644

Originally posted by @nicola-lunghi in https://github.com/bcb/jsonrpcserver/issues/106#issuecomment-571632418

I have made a conda-build script which can be used to upload jsonrpcserver to Anaconda Cloud so it can be installed with the Conda package manager.

The script is below. Please let me know if I can assist you in upload the package to the official channel.

conda install -c danieljfarrell_teraview jsonrpcserver

{% set name = "jsonrpcserver"%}
{% set version = "4.0.4" %}

package:
  name: "{{ name|lower }}"
  version: "{{ version }}"

source:
  url: https://github.com/bcb/jsonrpcserver/archive/4.0.4.tar.gz
  sha256: 2ed9c08b6a3ee889fd4e752b84b4335bd1ddbe4e70a5956d4e2cf44d68fe9827

build:
  number: 0
  script: "python -m pip install . --no-deps --ignore-installed -vvv "

requirements:
  host:
    - python
    - apply_defaults<1
    - jsonschema>=2,<4
  run:
    - python
    - apply_defaults
    - jsonschema>=2,<4

about:
  home: https://github.com/bcb/jsonrpcserver
  license: MIT License
  license_family: MIT
  license_file: 
  summary: Process JSON-RPC requests in Python
  doc_url: https://jsonrpcserver.readthedocs.io/
  dev_url: 

extra:
  recipe-maintainers:
    - bcb

I think it is incorrect to specify HTTP error code 4xx on a JSON RPC error, say APIError raised.

In this example https://github.com/bcb/jsonrpcserver/blob/master/examples/flask_server.py we will see status codes in the 400 range for JSON RPC errors even though the transport did not fail in any way.

I think this should be a 200 as the HTTP TRANSPORT did not fail. JSON-RPC 2.0 is designed to be agnostic to the transport protocol so if the transport did its job but the RPC call itself failed, the error should be communicated inside the HTTP payload and in JSON RPC, not relaying on transport error handling mechanisms.

https://www.simple-is-better.org/json-rpc/transport_http.html

Additional motivation:

External authentication handling. I return a 403 if the authentication failed. Anything that is not a 200 is not assumed to be a JSON RPC payload but something deferred outside the concern of the JSON RPC server endpoint. One exception is 202 which could be a reasonable status code for a JSON RPC notify. The dispatch method could flag this as a "notification event" that did not respond with a JSON RPC response.

Over all I think the status_code field should be removed as it mentally connects the two things, http transport and json rpc and that should be avoided.

in this case a JSON-RPC response will never be returned, but in the case of an RPC server task being cancelled while generating an RPC response we can't guarantee the response will be sent anyways

This is a question as much as an issue. I have several jsonrpc methods that require db, redis, and other state/config access that would normally be passed using the the 'app' or 'request' object. What is the best method to access the parent http request and/or web app object from a method?

It seems like its necessary to modify/create/subclass:

• aio.methods
• async_methods.py
• async_dispatcher.dispatch
• AsyncRequest

I will be making these changes for use in our projects (jussi,yo,sbds,hivemind).

I'm thinking that changing the signature of the dispatch method (and all the other methods that lead to the jsonrpc method) to also accept *args, **kwargs is the best, most modular way:

async def handle(aio_http_request):
    statsd = aio_http_request.app.config['statsd_client']
    jsonrpc_request = await aio_http_request.text()
    response = await methods.dispatch(jsonrpc_request, aio_http_request, statsd=statsd)
    return web.json_response(response)

I presume the use case for db/cache/metrics isn't rare, so I thought I would solicit your expertise and opinion about how these changes are implemented, especially if you're interested in adding my changes upstream.

Thanks for you excellent work!

If a handler method returns a value that cannot be JSON-encoded, an internal server error should be generated early, so the client gets an appropriate response and other requests in the same batch still can succeed (fixes #119).

Hi, the errorhandling feature is really useful can you do a small release to include it?

In my code I need to extend the ApiError clas to return some custom application error codes

Thanks Nicola Lunghi

Hi. I was going to use this library in my asynchronous API, but JSON validation is too slow and takes up to a few seconds. It would be great if a faster library was used instead of jsonschema, for example, fastjsonschema.

Currently, the parameters' validation is bound to

    try:
        signature(func).bind(*extract_args(request, context), **extract_kwargs(request))
    except TypeError as exc:
        return Left(InvalidParamsResult(str(exc)))
    return Right(func)

in dispatcher.py

This validation checks if the method's signature is compatible with provided parameters. However, there is no easy way to interfere in this validation, e.g. to provide own error messages, etc.

Would be very nice to have a way to specify some custom parameters' validation callable/class/etc when annotating a method with @method decorator.

Since the server should be stateless and its an request -> reply flow it would be reasonable that the server supported both JSON-RPC 1.0 and 2.0? Just ignore the "jsonrpc": "2.0" and maybe another schema validation (no support for batch, no support for object params). The server would need to track if it was a 1.0 or 2.0 request because the response will depend on that.

https://www.jsonrpc.org/specification_v1

Hello,

I've hit a little issue when using jsonrpcserver with PyInstaller:

FileNotFoundError: [Errno 2] No such file or directory: `path-to\\jsonrpcserver\\request-schema.json'

I've submitted a simple hook for PyInstaller which fixes this but I've hit similar issues with python packaging and non-py files many times in the past and I suggest you consider moving the .json data into a .py file unless there's a good reason not to - it can be a new request_schema.py or any of existing files.

This would prevent similar problems with python packaging in various tools without requiring additional effort.

Either way, thanks for the nice library ♥