cbc6c440e3 doc: add comments and release-notes for JSON-RPC 2.0 (Matthew Zipkin)
e7ee80dcf2 rpc: JSON-RPC 2.0 should not respond to "notifications" (Matthew Zipkin)
bf1a1f1662 rpc: Avoid returning HTTP errors for JSON-RPC 2.0 requests (Matthew Zipkin)
466b90562f rpc: Add "jsonrpc" field and drop null "result"/"error" fields (Matthew Zipkin)
2ca1460ae3 rpc: identify JSON-RPC 2.0 requests (Matthew Zipkin)
a64a2b77e0 rpc: refactor single/batch requests (Matthew Zipkin)
df6e3756d6 rpc: Avoid copies in JSONRPCReplyObj() (Matthew Zipkin)
09416f9ec4 test: cover JSONRPC 2.0 requests, batches, and notifications (Matthew Zipkin)
4202c170da test: refactor interface_rpc.py (Matthew Zipkin)
Pull request description:
Closes https://github.com/bitcoin/bitcoin/issues/2960
Bitcoin Core's JSONRPC server behaves with a special blend of 1.0, 1.1 and 2.0 behaviors. This introduces compliance issues with more strict clients. There are the major misbehaviors that I found:
- returning non-200 HTTP codes for RPC errors like "Method not found" (this is not a server error or an HTTP error)
- returning both `"error"` and `"result"` fields together in a response object.
- different error-handling behavior for single and batched RPC requests (batches contain errors in the response but single requests will actually throw HTTP errors)
https://github.com/bitcoin/bitcoin/pull/15495 added regression tests after a discussion in https://github.com/bitcoin/bitcoin/pull/15381 to kinda lock in our RPC behavior to preserve backwards compatibility.
https://github.com/bitcoin/bitcoin/pull/12435 was an attempt to allow strict 2.0 compliance behind a flag, but was abandoned.
The approach in this PR is not strict and preserves backwards compatibility in a familiar bitcoin-y way: all old behavior is preserved, but new rules are applied to clients that opt in. One of the rules in the [JSON RPC 2.0 spec](https://www.jsonrpc.org/specification#request_object) is that the kv pair `"jsonrpc": "2.0"` must be present in the request. Well, let's just use that to trigger strict 2.0 behavior! When that kv pair is included in a request object, the [response will adhere to strict JSON-RPC 2.0 rules](https://www.jsonrpc.org/specification#response_object), essentially:
- always return HTTP 200 "OK" unless there really is a server error or malformed request
- either return `"error"` OR `"result"` but never both
- same behavior for single and batch requests
If this is merged next steps can be:
- Refactor bitcoin-cli to always use strict 2.0
- Refactor the python test framework to always use strict 2.0 for everything
- Begin deprecation process for 1.0/1.1 behavior (?)
If we can one day remove the old 1.0/1.1 behavior we can clean up the rpc code quite a bit.
ACKs for top commit:
cbergqvist:
re ACK cbc6c440e3
ryanofsky:
Code review ACK cbc6c440e3. Just suggested changes since the last review: changing uncaught exception error code from PARSE_ERROR to MISC_ERROR, renaming a few things, and adding comments.
tdb3:
re ACK for cbc6c440e3
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