github/kubernetes
1
0
Fork 0
mirror of https://github.com/k3s-io/kubernetes.git synced 2025-07-31 07:20:13 +00:00
Code Issues Projects Releases Wiki Activity

Rewrite proxy code for clarity and correctness.

Browse Source
This commit is contained in:
Daniel Smith 2014-09-03 17:14:22 -07:00
parent e2b645ec15
commit 6554ee96f7
1 changed files with 84 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

135
pkg/apiserver/proxy.go
View File

@ -27,12 +27,47 @@ import (
"strings"
"github.com/GoogleCloudPlatform/kubernetes/pkg/httplog"
"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
"code.google.com/p/go.net/html"
"code.google.com/p/go.net/html/atom"
"github.com/golang/glog"
)
// tagsToAttrs 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"),
// TODO: css URLs hidden in style elements.
}
// ProxyHandler provides a http.Handler which will proxy traffic to locations
// specified by items implementing Redirector.
type ProxyHandler struct {
prefix string
storage map[string]RESTStorage
@ -105,10 +140,7 @@ func (t *proxyTransport) RoundTrip(req *http.Request) (*http.Response, error) {
resp, err := http.DefaultTransport.RoundTrip(req)
if err != nil {
message := err.Error() + "\n" + req.URL.String()
if strings.Contains(err.Error(), "connection refused") {
message = fmt.Sprintf("Failed to connect to %s (%s)", req.URL.Host, err)
}
message := fmt.Sprintf("Error: '%s'\nTrying to reach: '%v'", err.Error(), req.URL.String())
resp = &http.Response{
StatusCode: http.StatusServiceUnavailable,
Body: ioutil.NopCloser(strings.NewReader(message)),
@ -118,64 +150,65 @@ func (t *proxyTransport) RoundTrip(req *http.Request) (*http.Response, error) {
if resp.Header.Get("Content-Type") != "text/html" {
// Do nothing, simply pass through
return resp, err
return resp, nil
}
resp, err = t.fixLinks(req, resp)
return resp, err
return t.fixLinks(req, resp)
}
// updateURLs checks and updates any of n's attributes that are listed in tagsToAttrs.
// Any URLs found are, if they're relative, 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; it's required to make
// relative links work.
func (t *proxyTransport) updateURLs(n *html.Node, sourceURL *url.URL) {
if n.Type != html.ElementNode {
return
}
attrs, ok := tagsToAttrs[n.Data]
if !ok {
return
}
for i, attr := range n.Attr {
if !attrs.Has(attr.Key) {
continue
}
url, err := url.Parse(attr.Val)
if err != nil {
continue
}
// Is this URL relative?
if url.Host == "" || url.Host == sourceURL.Host {
url.Scheme = t.proxyScheme
url.Host = t.proxyHost
url.Path = path.Join(t.proxyPathPrepend, path.Dir(sourceURL.Path), url.Path, "/")
n.Attr[i].Val = url.String()
}
}
}
// scan recursively calls f for every n and every subnode of n.
func (t *proxyTransport) scan(n *html.Node, f func(*html.Node)) {
f(n)
for c := n.FirstChild; c != nil; c = c.NextSibling {
t.scan(c, f)
}
}
// fixLinks modifies links in an HTML file such that they will be redirected through the proxy if needed.
func (t *proxyTransport) fixLinks(req *http.Request, resp *http.Response) (*http.Response, error) {
body, err := ioutil.ReadAll(resp.Body)
resp.Body.Close()
if err != nil {
// copying the response body did not work
return nil, err
}
defer resp.Body.Close()
bodyNode := &html.Node{
Type: html.ElementNode,
Data: "body",
DataAtom: atom.Body,
}
nodes, err := html.ParseFragment(bytes.NewBuffer(body), bodyNode)
doc, err := html.Parse(resp.Body)
if err != nil {
glog.Errorf("Failed to found <body> node: %v", err)
glog.Errorf("Parse failed: %v", err)
return resp, err
}
// Define the method to traverse the doc tree and update href node to
// point to correct minion
var updateHRef func(*html.Node)
updateHRef = func(n *html.Node) {
if n.Type == html.ElementNode && n.Data == "a" {
for i, attr := range n.Attr {
if attr.Key == "href" {
url, err := url.Parse(attr.Val)
if err != nil {
continue
}
url.Scheme = t.proxyScheme
url.Host = t.proxyHost
url.Path = path.Join(t.proxyPathPrepend, path.Dir(req.URL.Path), url.Path, "/")
n.Attr[i].Val = url.String()
break
}
}
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
updateHRef(c)
}
}
newContent := &bytes.Buffer{}
for _, n := range nodes {
updateHRef(n)
err = html.Render(newContent, n)
if err != nil {
glog.Errorf("Failed to render: %v", err)
}
t.scan(doc, func(n *html.Node) { t.updateURLs(n, req.URL) })
if err := html.Render(newContent, doc); err != nil {
glog.Errorf("Failed to render: %v", err)
}
resp.Body = ioutil.NopCloser(newContent)