github.com/decred/dcrd/rpc/jsonrpc/types/v2 (go): Package types implements concrete types for marshalling to and from the dcrd JSON-RPC commands, return values, and notifications.  When communicating via the JSON-RPC protocol, all requests and responses must be marshalled to and from the wire in the appropriate format.  This package provides data structures and primitives that are registered with dcrjson to ease this process.  An overview specific to this package is provided here, however it is also instructive to read the documentation for the dcrjson package (https://pkg.go.dev/github.com/decred/dcrd/dcrjson/v3).  The types in this package map to the required parts of the protocol as discussed in the dcrjson documentation  To simplify the marshalling of the requests and responses, the dcrjson.MarshalCmd and dcrjson.MarshalResponse functions may be used.  They return the raw bytes ready to be sent across the wire.  Unmarshalling a received Request object is a two step process:  This approach is used since it provides the caller with access to the additional fields in the request that are not part of the command such as the ID.  Unmarshalling a received Response object is also a two step process:  As above, this approach is used since it provides the caller with access to the fields in the response such as the ID and Error.  This package provides two approaches for creating a new command.  This first, and preferred, method is to use one of the New<Foo>Cmd functions.  This allows static compile-time checking to help ensure the parameters stay in sync with the struct definitions.  The second approach is the dcrjson.NewCmd function which takes a method (command) name and variable arguments.  Since this package registers all of its types with dcrjson, the function will recognize them and includes full checking to ensure the parameters are accurate according to provided method, however these checks are, obviously, run-time which means any mistakes won't be found until the code is actually executed.  However, it is quite useful for user-supplied commands that are intentionally dynamic.  To facilitate providing consistent help to users of the RPC server, the dcrjson package exposes the GenerateHelp and function which uses reflection on commands and notifications registered by this package, as well as the provided expected result types, to generate the final help text.  In addition, the dcrjson.MethodUsageText function may be used to generate consistent one-line usage for registered commands and notifications using reflection.
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