Mercurial > gemma
view pkg/controllers/proxy.go @ 1234:1a5564655f2a
refac: Sidebar reorganized
In order to make context switches between administrative tasks
which are map related and those which are system related, we now have
a category "administration" and "systemadministration".
The Riverbedmorphology does nothing than display the map, so it is
renamed to that (map). In case the context of "systemadministration"
is chosen, the "map" brings you just back to the map.
author | Thomas Junk <thomas.junk@intevation.de> |
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date | Tue, 20 Nov 2018 09:54:53 +0100 |
parents | 71ba4a66ec95 |
children | 813342f2e927 |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2018 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> package controllers import ( "compress/flate" "compress/gzip" "crypto/hmac" "crypto/sha256" "encoding/base64" "encoding/xml" "io" "io/ioutil" "log" "net/http" "net/url" "regexp" "strings" "time" "github.com/gorilla/mux" "golang.org/x/net/html/charset" "gemma.intevation.de/gemma/pkg/config" "gemma.intevation.de/gemma/pkg/middleware" ) // proxyBlackList is a set of URLs that should not be rewritten by the proxy. var proxyBlackList = map[string]struct{}{ "http://www.w3.org/2001/XMLSchema-instance": struct{}{}, "http://www.w3.org/1999/xlink": struct{}{}, "http://www.w3.org/2001/XMLSchema": struct{}{}, "http://www.w3.org/XML/1998/namespace": struct{}{}, "http://www.opengis.net/wfs/2.0": struct{}{}, "http://www.opengis.net/ows/1.1": struct{}{}, "http://www.opengis.net/gml/3.2": struct{}{}, "http://www.opengis.net/fes/2.0": struct{}{}, "http://schemas.opengis.net/gml": struct{}{}, "http://www.opengis.net/wfs": struct{}{}, } func proxyDirector(lookup func(string) (string, bool)) func(*http.Request) { return func(req *http.Request) { //log.Printf("proxyDirector: %s\n", req.RequestURI) abort := func(format string, args ...interface{}) { log.Printf(format, args...) panic(http.ErrAbortHandler) } vars := mux.Vars(req) var s string if entry, found := vars["entry"]; found { if s, found = lookup(entry); !found { log.Printf("warn: cannot find eintry '%s'\n", entry) panic(middleware.ErrNotFound) } } else { expectedMAC, err := base64.URLEncoding.DecodeString(vars["hash"]) if err != nil { abort("Cannot base64 decode hash: %v\n", err) } url, err := base64.URLEncoding.DecodeString(vars["url"]) if err != nil { abort("Cannot base64 decode url: %v\n", err) } mac := hmac.New(sha256.New, config.ProxyKey()) mac.Write(url) messageMAC := mac.Sum(nil) s = string(url) if !hmac.Equal(messageMAC, expectedMAC) { abort("HMAC of URL %s failed.\n", s) } } nURL := s + "?" + req.URL.RawQuery //log.Printf("%v\n", nURL) u, err := url.Parse(nURL) if err != nil { abort("Invalid url: %v\n", err) } req.URL = u req.Host = u.Host //req.Header.Del("If-None-Match") //log.Printf("headers: %v\n", req.Header) } } type nopCloser struct { io.Writer } func (nopCloser) Close() error { return nil } func encoding(h http.Header) ( func(io.Reader) (io.ReadCloser, error), func(io.Writer) (io.WriteCloser, error), ) { switch enc := h.Get("Content-Encoding"); { case strings.Contains(enc, "gzip"): log.Println("gzip compression") return func(r io.Reader) (io.ReadCloser, error) { return gzip.NewReader(r) }, func(w io.Writer) (io.WriteCloser, error) { return gzip.NewWriter(w), nil } case strings.Contains(enc, "deflate"): log.Println("Deflate compression") return func(r io.Reader) (io.ReadCloser, error) { return flate.NewReader(r), nil }, func(w io.Writer) (io.WriteCloser, error) { return flate.NewWriter(w, flate.DefaultCompression) } default: log.Println("No content compression") return func(r io.Reader) (io.ReadCloser, error) { if r2, ok := r.(io.ReadCloser); ok { return r2, nil } return ioutil.NopCloser(r), nil }, func(w io.Writer) (io.WriteCloser, error) { if w2, ok := w.(io.WriteCloser); ok { return w2, nil } return nopCloser{w}, nil } } } func proxyModifyResponse(suffix string) func(*http.Response) error { return func(resp *http.Response) error { if !isXML(resp.Header) { return nil } pr, pw := io.Pipe() var ( r io.ReadCloser w io.WriteCloser err error ) reader, writer := encoding(resp.Header) if r, err = reader(resp.Body); err != nil { return err } if w, err = writer(pw); err != nil { return err } go func(force io.ReadCloser) { start := time.Now() defer func() { //r.Close() w.Close() pw.Close() force.Close() log.Printf("rewrite took %s\n", time.Since(start)) }() if err := rewrite(suffix, w, r); err != nil { log.Printf("rewrite failed: %v\n", err) return } log.Println("rewrite successful") }(resp.Body) resp.Body = pr return nil } } var xmlContentTypes = []string{ "application/xml", "text/xml", "application/gml+xml", "application/vnd.ogc.wms_xml", } func isXML(h http.Header) bool { for _, t := range h["Content-Type"] { t = strings.ToLower(t) for _, ct := range xmlContentTypes { if strings.Contains(t, ct) { return true } } } return false } var replaceRe = regexp.MustCompile(`\b(https?://[^\s\?'"]*)`) func replace(suffix, s string) string { proxyKey := config.ProxyKey() proxyPrefix := config.ProxyPrefix() + suffix return replaceRe.ReplaceAllStringFunc(s, func(s string) string { if _, found := proxyBlackList[s]; found { return s } mac := hmac.New(sha256.New, proxyKey) b := []byte(s) mac.Write(b) expectedMAC := mac.Sum(nil) hash := base64.URLEncoding.EncodeToString(expectedMAC) enc := base64.URLEncoding.EncodeToString(b) return proxyPrefix + hash + "/" + enc }) } func rewrite(suffix string, w io.Writer, r io.Reader) error { decoder := xml.NewDecoder(r) decoder.CharsetReader = charset.NewReaderLabel encoder := xml.NewEncoder(w) var n nsdef tokens: for { tok, err := decoder.Token() switch { case tok == nil && err == io.EOF: break tokens case err != nil: return err } switch t := tok.(type) { case xml.StartElement: t = t.Copy() isDef := n.isDef(t.Name.Space) n = n.push() for i := range t.Attr { t.Attr[i].Value = replace(suffix, t.Attr[i].Value) n.checkDef(&t.Attr[i]) } for i := range t.Attr { n.adjust(&t.Attr[i]) } switch { case isDef: t.Name.Space = "" default: if s := n.lookup(t.Name.Space); s != "" { t.Name.Space = "" t.Name.Local = s + ":" + t.Name.Local } } tok = t case xml.CharData: tok = xml.CharData(replace(suffix, string(t))) case xml.Directive: tok = xml.Directive(replace(suffix, string(t))) case xml.EndElement: s := n.lookup(t.Name.Space) n = n.pop() if n.isDef(t.Name.Space) { t.Name.Space = "" } else if s != "" { t.Name.Space = "" t.Name.Local = s + ":" + t.Name.Local } tok = t } if err := encoder.EncodeToken(tok); err != nil { return err } } return encoder.Flush() } type nsframe struct { def string ns map[string]string } type nsdef []nsframe func (n nsdef) setDef(def string) { if l := len(n); l > 0 { n[l-1].def = def } } func (n nsdef) isDef(s string) bool { for i := len(n) - 1; i >= 0; i-- { if x := n[i].def; x != "" { return s == x } } return false } func (n nsdef) define(ns, s string) { if l := len(n); l > 0 { n[l-1].ns[ns] = s } } func (n nsdef) lookup(ns string) string { for i := len(n) - 1; i >= 0; i-- { if s := n[i].ns[ns]; s != "" { return s } } return "" } func (n nsdef) checkDef(at *xml.Attr) { if at.Name.Space == "" && at.Name.Local == "xmlns" { n.setDef(at.Value) } } func (n nsdef) adjust(at *xml.Attr) { switch { case at.Name.Space == "xmlns": n.define(at.Value, at.Name.Local) at.Name.Local = "xmlns:" + at.Name.Local at.Name.Space = "" case at.Name.Space != "": if n.isDef(at.Name.Space) { at.Name.Space = "" } else if s := n.lookup(at.Name.Space); s != "" { at.Name.Local = s + ":" + at.Name.Local at.Name.Space = "" } } } func (n nsdef) push() nsdef { return append(n, nsframe{ns: make(map[string]string)}) } func (n nsdef) pop() nsdef { if l := len(n); l > 0 { n[l-1] = nsframe{} n = n[:l-1] } return n }