golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e: html.TextNode

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify golang.org/x/net/html.TextNode in pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e
Demonstrate these symbols/APIs:
  - golang.org/x/net/html.TextNode

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:694fc0e09e5f4fc3a60094fb8b2b8ee7cd2d26c57a94387123207f4f86d33edd","contract":["html.TextNode is a NodeType constant","NewTextNode creates a Node with Type equal to html.TextNode and matching Data","IsTextNode correctly identifies nodes with Type html.TextNode","ExtractText collects Data from all html.TextNode instances in parsed HTML","html.Render properly escapes special characters in html.TextNode"],"goal":"verify golang.org/x/net/html.TextNode in pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e"],"schemaVersion":1,"symbols":["golang.org/x/net/html.TextNode"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e","symbols":["golang.org/x/net/html.TextNode"],"verifierAdapter":"golang@1"}

module sample

go 1.21

require golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e

golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e h1:3G+cUijn7XD+S4eJFddp53Pv7+slrESplyjG25HgL+k=
golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/net/html.TextNode in pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20200324143707-d3edc9973b7e"
  ],
  "symbols": [
    "golang.org/x/net/html.TextNode"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

	"golang.org/x/net/html"
	"sample"
)

func main() {
	// Assertion 1: html.TextNode is a NodeType constant
	var nodeType html.NodeType = html.TextNode
	if nodeType != html.TextNode {
		fmt.Fprintf(os.Stderr, "type mismatch for html.TextNode\n")
		os.Exit(1)
	}

	if html.TextNode == html.ElementNode || html.TextNode == html.CommentNode {
		fmt.Fprintf(os.Stderr, "html.TextNode must be distinct from other NodeType constants\n")
		os.Exit(1)
	}

	// Assertion 2: NewTextNode creates a Node with Type equal to html.TextNode and matching Data
	rawText := "Hello, World!"
	node := sample.NewTextNode(rawText)
	if node == nil {
		fmt.Fprintf(os.Stderr, "expected non-nil node from NewTextNode\n")
		os.Exit(1)
	}
	if node.Type != html.TextNode {
		fmt.Fprintf(os.Stderr, "expected node.Type to be html.TextNode, got %v\n", node.Type)
		os.Exit(1)
	}
	if node.Data != rawText {
		fmt.Fprintf(os.Stderr, "expected node.Data to be %q, got %q\n", rawText, node.Data)
		os.Exit(1)
	}

	// Assertion 3: IsTextNode correctly identifies nodes with Type html.TextNode
	if !sample.IsTextNode(node) {
		fmt.Fprintf(os.Stderr, "expected IsTextNode to return true for TextNode\n")
		os.Exit(1)
	}
	elemNode := &html.Node{Type: html.ElementNode, Data: "div"}
	if sample.IsTextNode(elemNode) {
		fmt.Fprintf(os.Stderr, "expected IsTextNode to return false for ElementNode\n")
		os.Exit(1)
	}
	if sample.IsTextNode(nil) {
		fmt.Fprintf(os.Stderr, "expected IsTextNode to return false for nil node\n")
		os.Exit(1)
	}

	// Assertion 4: ExtractText collects Data from all html.TextNode instances in parsed HTML
	htmlDoc := "<div class=\"container\"><p>Hello <span>World</span>!</p><p>Second line</p></div>"
	doc, err := html.Parse(strings.NewReader(htmlDoc))
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to parse HTML: %v\n", err)
		os.Exit(1)
	}
	extracted := sample.ExtractText(doc)
	expectedText := "Hello World!Second line"
	if extracted != expectedText {
		fmt.Fprintf(os.Stderr, "expected extracted text %q, got %q\n", expectedText, extracted)
		os.Exit(1)
	}

	// Assertion 5: html.Render properly escapes special characters in html.TextNode
	specialNode := sample.NewTextNode("<script>alert('xss')</script> & more")
	rendered, err := sample.RenderNode(specialNode)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to render text node: %v\n", err)
		os.Exit(1)
	}
	expectedRendered := "&lt;script&gt;alert(&#39;xss&#39;)&lt;/script&gt; &amp; more"
	if rendered != expectedRendered {
		fmt.Fprintf(os.Stderr, "expected rendered string %q, got %q\n", expectedRendered, rendered)
		os.Exit(1)
	}

	fmt.Println("All html.TextNode contract assertions passed.")
}

package sample

import (
	"bytes"
	"strings"

	"golang.org/x/net/html"
)

// NewTextNode creates a new html.Node with Type set to html.TextNode.
func NewTextNode(data string) *html.Node {
	return &html.Node{
		Type: html.TextNode,
		Data: data,
	}
}

// IsTextNode reports whether the given node is a TextNode.
func IsTextNode(n *html.Node) bool {
	if n == nil {
		return false
	}
	return n.Type == html.TextNode
}

// ExtractText traverses the node tree rooted at n and extracts text from all TextNodes.
func ExtractText(n *html.Node) string {
	if n == nil {
		return ""
	}
	var sb strings.Builder
	var traverse func(*html.Node)
	traverse = func(curr *html.Node) {
		if curr.Type == html.TextNode {
			sb.WriteString(curr.Data)
		}
		for c := curr.FirstChild; c != nil; c = c.NextSibling {
			traverse(c)
		}
	}
	traverse(n)
	return sb.String()
}

// RenderNode renders an html.Node tree to an HTML string.
func RenderNode(n *html.Node) (string, error) {
	var buf bytes.Buffer
	if err := html.Render(&buf, n); err != nil {
		return "", err
	}
	return buf.String(), nil
}