haraldrudell / parsify

Declarative Extensible JSON parsing in Golang by Harald Rudell

parsify

Declarative Extensible JSON parsing by Harald Rudell

© 2018-present Harald Rudell [e-mail] (http://www.haraldrudell.com)

Benefits

• JSON field verification and value extraction declarative
• In the declaration it is easy to see what values are relevant
• Extensible parsing functions, provided to parsify.New
  see parsifiers.go for examples

Adding to a Project

• Install to your local Go on the commad-line:
  go get -u github.com/haraldrudell/parsify
• Import in a .go file:
  import (… "github.com/haraldrudell/parsify"…
• Use in that same .go file:
  parsify.New(…)

Example Usage

• First pass checks that the JSON-RPC version is correct and that the response id matches the request id. Then returns the result object value
• Second pass extracts data from the result value: TimeStamp and BlockNumber both numeric strings (hexadecimal)
• A reader parses JSON as a stream

	steps := New("Verify JSON-RPC response", []Step{
		{"VerifyStringProperty", "jsonrpc", aJSONRpcVersion, nil},
		{"VerifyNumberProperty", "id", float64(rqID), nil},
		{"EnterKey", "result", nil, nil},
	}, nil, nil)
	data, e := steps.ParsifyReader(strings.NewReader(string(jsonString)))
	if e != nil {
		panic(e)
	}

	type Block struct {
		TimeStamp   uint64
		BlockNumber uint64
	}
	block := Block{}
	ps := &Steps{
		"Parsing result",
		data,
		[]Step{
			{"StoreNumber", "timestamp", nil, &block.TimeStamp},
			{"StoreNumber", "number", nil, &block.BlockNumber},
		},
		0,
		nil,
	}

The JSON input:

{
	"jsonrpc":"2.0",
	"id":0,
	"result": {
		"timestamp":"0x5bf1ec6e",
		"number":"0x66b15f"
	}
}

© 2018-present Harald Rudell [e-mail] (http://www.haraldrudell.com)