Add post about jsonpath package and playground

theory · Nov 4, 2024 · 7aa71fa · 7aa71fa
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+---
+title: Introducing RFC 9535 Go JSONPath and Playground
+slug: go-jsonpath-playground
+date: 2024-11-04T18:23:07Z
+lastMod: 2024-11-04T18:23:07Z
+description: |
+  I've made a RFC 9535 JSONPath JSONPath Go package, and compiled it into Wasm to
+  build an in-browser playground for it.
+tags: [Go, JSONPath, Playground, RFC 9535]
+type: post
+---
+
+I've written and release a [RFC 9535 JSONPath][RFC] JSONPath Go package,
+[github.com/theory/jsonpath]. Why? For a personal project, I needed a simpler
+JSONPath engine to complement to the [Go SQL/JSON Path] package, and quickly
+found myself implementing most of the [RFC]. So I decided do the whole thing.
+
+Yes, yet another JSONPath package in Go. I really appreciate the idea of a
+standard --- plus its support for features not included in the [original
+design] from 2007, [such as object slices][slices]! But I could find no
+reference to the RFC on pkg.go.dev. Today [the search] shows one!
+
+Example
+-------
+
+Usage is straightforward; here's a quick example ([Go playground]):
+
+``` go
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/theory/jsonpath"
+)
+
+func main() {
+	// Parse a jsonpath query.
+	p, err := jsonpath.Parse(`$["name", "slogan"]`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Select values from unmarshaled JSON input.
+	json := map[string]any{
+		"name":   "Kamala Harris",
+		"title":  "Vice President of the United States",
+		"home":   "California",
+		"slogan": "We are not going back!",
+	}
+	items := p.Select(json)
+
+	// Show the result.
+	fmt.Printf("%#v\n", items)
+}
+```
+
+And the output:
+
+```go
+[]interface {}{"Kamala Harris", "We are not going back!"}
+```
+
+🛝 Playground
+-------------
+
+No need to write code to try it out, though. I've also written a [playground
+webapp] to encourage experimentation and exploration of the syntax and
+behavior of the package. The implementation follows the precedents set by the
+[Go SQL/JSON Playground] and design of the [Rust JSONPath Playground].
+Moreover, thanks to [TinyGo], the [Wasm] file comes in at a mere 254K!
+
+The webapp loads sample JSON from the [RFC], and randomly rotates through a
+few example JSONPath queries. Fill in your own and tap the "Permalink" button
+to share links. The Playground is a *stateless* JavaScript/Wasm web
+application: data persists only in permalink URLs.[^github]
+
+**🛝 Try this [example Playground permalink][slices] right now!**
+
+Status
+------
+
+The root `jsonpath` package is stable and ready for use. Other packages remain
+in flux, as I refactor and rejigger things in the coming weeks as part of the
+aforementioned personal project. But for actual JSONPath execution and
+querying, it should continue to work as-is for the foreseeable futre.
+
+I hope you find it useful.
+
+  [^github]: And whatever data [GitHub Pages collect] 😔.
+
+  [RFC]: https://www.rfc-editor.org/rfc/rfc9535.html
+    "RFC 9535 JSONPath: Query Expressions for JSON"
+  [github.com/theory/jsonpath]: https://pkg.go.dev/github.com/theory/jsonpath
+  [Go SQL/JSON Path]: {{% ref "/post/postgres/go-sqljson-path" %}}
+    "Introducing Go SQL/JSON Path and Playground"
+  [original design]: https://goessner.net/articles/JsonPath/
+    "Stefan Gössner: JSONPath - XPath for JSON"
+  [slices]: https://theory.github.io/jsonpath/?p=%2524.store.book%255B%253F%2540.author%2520%253D%253D%2520%27Herman%2520Melville%27%255D%255B%27title%27%252C%2520%27author%27%252C%2520%27price%27%255D&j=%257B%250A%2520%2520%2522store%2522%253A%2520%257B%250A%2520%2520%2520%2520%2522book%2522%253A%2520%255B%250A%2520%2520%2520%2520%2520%2520%257B%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522category%2522%253A%2520%2522reference%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522author%2522%253A%2520%2522Nigel%2520Rees%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522title%2522%253A%2520%2522Sayings%2520of%2520the%2520Century%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522price%2522%253A%25208.95%250A%2520%2520%2520%2520%2520%2520%257D%252C%250A%2520%2520%2520%2520%2520%2520%257B%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522category%2522%253A%2520%2522fiction%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522author%2522%253A%2520%2522Evelyn%2520Waugh%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522title%2522%253A%2520%2522Sword%2520of%2520Honour%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522price%2522%253A%252012.99%250A%2520%2520%2520%2520%2520%2520%257D%252C%250A%2520%2520%2520%2520%2520%2520%257B%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522category%2522%253A%2520%2522fiction%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522author%2522%253A%2520%2522Herman%2520Melville%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522title%2522%253A%2520%2522Moby%2520Dick%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522isbn%2522%253A%2520%25220-553-21311-3%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522price%2522%253A%25208.99%250A%2520%2520%2520%2520%2520%2520%257D%252C%250A%2520%2520%2520%2520%2520%2520%257B%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522category%2522%253A%2520%2522fiction%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522author%2522%253A%2520%2522J.%2520R.%2520R.%2520Tolkien%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522title%2522%253A%2520%2522The%2520Lord%2520of%2520the%2520Rings%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522isbn%2522%253A%2520%25220-395-19395-8%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522price%2522%253A%252022.99%250A%2520%2520%2520%2520%2520%2520%257D%250A%2520%2520%2520%2520%255D%252C%250A%2520%2520%2520%2520%2522bicycle%2522%253A%2520%257B%250A%2520%2520%2520%2520%2520%2520%2522color%2522%253A%2520%2522red%2522%252C%250A%2520%2520%2520%2520%2520%2520%2522price%2522%253A%2520399%250A%2520%2520%2520%2520%257D%250A%2520%2520%257D%250A%257D&o=1
+  [the search]: https://pkg.go.dev/search?q=RFC+9535 "pkg.go.dev search: RFC 9535"
+  [Go playground]: https://go.dev/play/p/wmJvZdOl28D
+  [playground webapp]: https://theory.github.io/jsonpath/ "Go JSONPath Playground"
+  [TinyGo]: https://tinygo.org/ "TinyGo - A Go Compiler For Small Places"
+  [Wasm]: https://webassembly.org/ "WebAssembly"
+  [Go SQL/JSON Playground]: https://theory.github.io/sqljson/playground/
+  [Rust JSONPath Playground]: https://serdejsonpath.lives