p1: /v2/scrape, /v1/fetch, auth, CLI, contract tests

Single Fetcher.Fetch on the Guard that holds DenyPrefixes. skipTlsVerification
is ignored. No 502. keys add writes the secret only to --out. Release binary
has no -test-allow-prefix.

vendor/github.com/JohannesKaufmann/dom/dom_representation.go

@@ -0,0 +1,64 @@
+package dom
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+func writePipeChar(buf *bytes.Buffer, index int) {
+	if index == 0 {
+		return
+	}
+	buf.WriteString(strings.Repeat("│ ", index-1))
+	buf.WriteString("├─")
+}
+func writeNode(buf *bytes.Buffer, node *html.Node) {
+	name := NodeName(node)
+	buf.WriteString(name)
+
+	if len(node.Attr) != 0 {
+		buf.WriteString(" (")
+	}
+	for i, attr := range node.Attr {
+		buf.WriteString(fmt.Sprintf("%s=%q", attr.Key, attr.Val))
+
+		if i < len(node.Attr)-1 {
+			buf.WriteString(" ")
+		}
+	}
+	if len(node.Attr) != 0 {
+		buf.WriteString(")")
+	}
+
+	if name == "#text" {
+		buf.WriteString(fmt.Sprintf(" %q", node.Data))
+	}
+
+}
+
+// RenderRepresentation is useful for debugging.
+// It renders out the *structure* of the dom.
+func RenderRepresentation(startNode *html.Node) string {
+	var buf bytes.Buffer
+	var finder func(*html.Node, int)
+	finder = func(node *html.Node, index int) {
+		writePipeChar(&buf, index)
+		writeNode(&buf, node)
+		buf.WriteRune('\n')
+
+		for child := node.FirstChild; child != nil; child = child.NextSibling {
+			finder(child, index+1)
+		}
+	}
+
+	if startNode.Parent == nil {
+		finder(startNode, 0)
+	} else {
+		finder(startNode, 1)
+	}
+
+	return strings.TrimSpace(buf.String())
+}