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.go

@@ -0,0 +1,88 @@
+// dom makes it easier to interact with the html document.
+//
+// Node = return all the nodes
+// Element = return all the nodes that are of type Element. This e.g. excludes #text nodes.
+package dom
+
+import "golang.org/x/net/html"
+
+// AllNodes recursively gets all the nodes in the tree.
+func AllNodes(startNode *html.Node) (allNodes []*html.Node) {
+	var finder func(*html.Node)
+	finder = func(node *html.Node) {
+		allNodes = append(allNodes, node)
+
+		for child := node.FirstChild; child != nil; child = child.NextSibling {
+			finder(child)
+		}
+	}
+
+	finder(startNode)
+
+	return allNodes
+}
+
+// - - - - - - - - - - - - - - - //
+
+func AllChildNodes(node *html.Node) (children []*html.Node) {
+	for child := node.FirstChild; child != nil; child = child.NextSibling {
+		children = append(children, child)
+	}
+	return children
+}
+
+// AllChildElements is similar to AllChildNodes but only returns
+// nodes of type `ElementNode`.
+func AllChildElements(node *html.Node) (children []*html.Node) {
+	for child := node.FirstChild; child != nil; child = child.NextSibling {
+		if child.Type == html.ElementNode {
+			children = append(children, child)
+		}
+	}
+	return children
+}
+
+// - - - - - - - - - - - - - - - //
+
+func FirstChildNode(node *html.Node) *html.Node {
+	return node.FirstChild
+}
+func FirstChildElement(node *html.Node) *html.Node {
+	for child := node.FirstChild; child != nil; child = child.NextSibling {
+		if child.Type == html.ElementNode {
+			return child
+		}
+	}
+	return nil
+}
+
+// - - - - - - - - - - - - - - - //
+
+func PrevSiblingNode(node *html.Node) *html.Node {
+	return node.PrevSibling
+}
+func PrevSiblingElement(node *html.Node) *html.Node {
+	for sibling := node.PrevSibling; sibling != nil; sibling = sibling.PrevSibling {
+		if sibling.Type == html.ElementNode {
+			return sibling
+		}
+	}
+	return nil
+}
+
+// - - - - - - - - - - - - - - - //
+
+func NextSiblingNode(node *html.Node) *html.Node {
+	return node.NextSibling
+}
+
+// NextSiblingElement returns the element immediately following the passed-in node or nil.
+// In contrast to `node.NextSibling` this only returns the next `ElementNode`.
+func NextSiblingElement(node *html.Node) *html.Node {
+	for sibling := node.NextSibling; sibling != nil; sibling = sibling.NextSibling {
+		if sibling.Type == html.ElementNode {
+			return sibling
+		}
+	}
+	return nil
+}