Skip to content

K
k3s
Commit 49b8c975 authored by Tim St. Clair's avatar Tim St. Clair
Browse files
Options

Update the URL-rewriting logic to make minimal modifications.

The new approach avoids building a complete parse tree, instead using the lower level token stream. Doing so removes the need for creating "missing" HTML elements, reducing the collateral changes to the rewritten HTML. Resolves: #9766
parent 1b5292fa
Show whitespace changes
Inline Side-by-side
Showing with 71 additions and 78 deletions
pkg/util/proxy/transport.go
View file @ 49b8c975
......@@ -29,39 +29,40 @@ import (
"github.com/golang/glog"
"golang.org/x/net/html"
"golang.org/x/net/html/atom"
"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
)
// tagsToAttrs states which attributes of which tags require URL substitution.
// atomsToAttrs states which attributes of which tags require URL substitution.
// Sources: http://www.w3.org/TR/REC-html40/index/attributes.html
// http://www.w3.org/html/wg/drafts/html/master/index.html#attributes-1
var tagsToAttrs = map[string]util.StringSet{
"a": util.NewStringSet("href"),
"applet": util.NewStringSet("codebase"),
"area": util.NewStringSet("href"),
"audio": util.NewStringSet("src"),
"base": util.NewStringSet("href"),
"blockquote": util.NewStringSet("cite"),
"body": util.NewStringSet("background"),
"button": util.NewStringSet("formaction"),
"command": util.NewStringSet("icon"),
"del": util.NewStringSet("cite"),
"embed": util.NewStringSet("src"),
"form": util.NewStringSet("action"),
"frame": util.NewStringSet("longdesc", "src"),
"head": util.NewStringSet("profile"),
"html": util.NewStringSet("manifest"),
"iframe": util.NewStringSet("longdesc", "src"),
"img": util.NewStringSet("longdesc", "src", "usemap"),
"input": util.NewStringSet("src", "usemap", "formaction"),
"ins": util.NewStringSet("cite"),
"link": util.NewStringSet("href"),
"object": util.NewStringSet("classid", "codebase", "data", "usemap"),
"q": util.NewStringSet("cite"),
"script": util.NewStringSet("src"),
"source": util.NewStringSet("src"),
"video": util.NewStringSet("poster", "src"),
var atomsToAttrs = map[atom.Atom]util.StringSet{
atom.A: util.NewStringSet("href"),
atom.Applet: util.NewStringSet("codebase"),
atom.Area: util.NewStringSet("href"),
atom.Audio: util.NewStringSet("src"),
atom.Base: util.NewStringSet("href"),
atom.Blockquote: util.NewStringSet("cite"),
atom.Body: util.NewStringSet("background"),
atom.Button: util.NewStringSet("formaction"),
atom.Command: util.NewStringSet("icon"),
atom.Del: util.NewStringSet("cite"),
atom.Embed: util.NewStringSet("src"),
atom.Form: util.NewStringSet("action"),
atom.Frame: util.NewStringSet("longdesc", "src"),
atom.Head: util.NewStringSet("profile"),
atom.Html: util.NewStringSet("manifest"),
atom.Iframe: util.NewStringSet("longdesc", "src"),
atom.Img: util.NewStringSet("longdesc", "src", "usemap"),
atom.Input: util.NewStringSet("src", "usemap", "formaction"),
atom.Ins: util.NewStringSet("cite"),
atom.Link: util.NewStringSet("href"),
atom.Object: util.NewStringSet("classid", "codebase", "data", "usemap"),
atom.Q: util.NewStringSet("cite"),
atom.Script: util.NewStringSet("src"),
atom.Source: util.NewStringSet("src"),
atom.Video: util.NewStringSet("poster", "src"),
// TODO: css URLs hidden in style elements.
}
......@@ -108,7 +109,7 @@ func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
return resp, nil
}
return t.fixLinks(req, resp)
return t.rewriteResponse(req, resp)
}
// rewriteURL rewrites a single URL to go through the proxy, if the URL refers
......@@ -139,36 +140,42 @@ func (t *Transport) rewriteURL(targetURL string, sourceURL *url.URL) string {
return url.String()
}
// updateURLs checks and updates any of n's attributes that are listed in tagsToAttrs.
// Any URLs found are, if they share the source host, updated with the necessary changes
// to make a visit to that URL also go through the proxy.
// sourceURL is the URL of the page which we're currently on.
func (t *Transport) updateURLs(n *html.Node, sourceURL *url.URL) {
if n.Type != html.ElementNode {
return
// rewriteHTML scans the HTML for tags with url-valued attributes, and updates
// those values with the urlRewriter function. The updated HTML is output to the
// writer.
func rewriteHTML(reader io.Reader, writer io.Writer, urlRewriter func(string) string) error {
// Note: This assumes the content is UTF-8.
tokenizer := html.NewTokenizer(reader)
var err error
for err == nil {
tokenType := tokenizer.Next()
switch tokenType {
case html.ErrorToken:
err = tokenizer.Err()
case html.StartTagToken, html.SelfClosingTagToken:
token := tokenizer.Token()
if urlAttrs, ok := atomsToAttrs[token.DataAtom]; ok {
for i, attr := range token.Attr {
if urlAttrs.Has(attr.Key) {
token.Attr[i].Val = urlRewriter(attr.Val)
}
attrs, ok := tagsToAttrs[n.Data]
if !ok {
return
}
for i, attr := range n.Attr {
if !attrs.Has(attr.Key) {
continue
}
n.Attr[i].Val = t.rewriteURL(attr.Val, sourceURL)
_, err = writer.Write([]byte(token.String()))
default:
_, err = writer.Write(tokenizer.Raw())
}
}
// scan recursively calls f for every n and every subnode of n.
func (t *Transport) scan(n *html.Node, f func(*html.Node)) {
f(n)
for c := n.FirstChild; c != nil; c = c.NextSibling {
t.scan(c, f)
}
if err != io.EOF {
return err
}
return nil
}
// fixLinks modifies links in an HTML file such that they will be redirected through the proxy if needed.
func (t *Transport) fixLinks(req *http.Request, resp *http.Response) (*http.Response, error) {
// rewriteResponse modifies an HTML response by updating absolute links refering
// to the original host to instead refer to the proxy transport.
func (t *Transport) rewriteResponse(req *http.Request, resp *http.Response) (*http.Response, error) {
origBody := resp.Body
defer origBody.Close()
......@@ -195,17 +202,15 @@ func (t *Transport) fixLinks(req *http.Request, resp *http.Response) (*http.Resp
return resp, nil
}
doc, err := html.Parse(reader)
urlRewriter := func(targetUrl string) string {
return t.rewriteURL(targetUrl, req.URL)
}
err := rewriteHTML(reader, writer, urlRewriter)
if err != nil {
glog.Errorf("Parse failed: %v", err)
glog.Errorf("Failed to rewrite URLs: %v", err)
return resp, err
}
t.scan(doc, func(n *html.Node) { t.updateURLs(n, req.URL) })
if err := html.Render(writer, doc); err != nil {
glog.Errorf("Failed to render: %v", err)
}
resp.Body = ioutil.NopCloser(newContent)
// Update header node with new content-length
// TODO: Remove any hash/signature headers here?
......
pkg/util/proxy/transport_test.go
View file @ 49b8c975
......@@ -17,7 +17,6 @@ limitations under the License.
package proxy
import (
"bytes"
"fmt"
"io/ioutil"
"net/http"
......@@ -25,8 +24,6 @@ import (
"net/url"
"strings"
"testing"
"golang.org/x/net/html"
)
func parseURLOrDie(inURL string) *url.URL {
......@@ -37,19 +34,6 @@ func parseURLOrDie(inURL string) *url.URL {
return parsed
}
// fmtHTML parses and re-emits 'in', effectively canonicalizing it.
func fmtHTML(in string) string {
doc, err := html.Parse(strings.NewReader(in))
if err != nil {
panic(err)
}
out := &bytes.Buffer{}
if err := html.Render(out, doc); err != nil {
panic(err)
}
return string(out.Bytes())
}
func TestProxyTransport(t *testing.T) {
testTransport := &Transport{
Scheme: "http",
......@@ -81,6 +65,14 @@ func TestProxyTransport(t *testing.T) {
contentType: "text/html",
forwardedURI: "/proxy/minion/minion1:10250/logs/log.log",
},
"full document": {
input: `<html><header></header><body><pre><a href="kubelet.log">kubelet.log</a><a href="/google.log">google.log</a></pre></body></html>`,
sourceURL: "http://myminion.com/logs/log.log",
transport: testTransport,
output: `<html><header></header><body><pre><a href="kubelet.log">kubelet.log</a><a href="http://foo.com/proxy/minion/minion1:10250/google.log">google.log</a></pre></body></html>`,
contentType: "text/html",
forwardedURI: "/proxy/minion/minion1:10250/logs/log.log",
},
"trailing slash": {
input: `<pre><a href="kubelet.log">kubelet.log</a><a href="/google.log/">google.log</a></pre>`,
sourceURL: "http://myminion.com/logs/log.log",
......@@ -161,10 +153,6 @@ func TestProxyTransport(t *testing.T) {
}
testItem := func(name string, item *Item) {
// Canonicalize the html so we can diff.
item.input = fmtHTML(item.input)
item.output = fmtHTML(item.output)
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Check request headers.
if got, want := r.Header.Get("X-Forwarded-Uri"), item.forwardedURI; got != want {
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment