godoc: add GoogleCN property to pages

Use that property to determine whether to show share functionality
or link to sites that are blocked in mainland China.

This change requires https://go-review.googlesource.com/c/52872

Change-Id: I47327f9dbd2624206564fa99eb1cc6a10b4f46db
Reviewed-on: https://go-review.googlesource.com/52873
Reviewed-by: Chris Broadfoot <cbro@golang.org>

godoc/README.md

@@ -10,7 +10,7 @@ binary. It can be tedious to recompile assets every time, but you can pass a
 flag to load CSS/JS/templates from disk every time a page loads:
 
 ```
-godoc --templates=$GOPATH/src/golang.org/x/tools/godoc/static --http=:6060
+godoc -templates=$GOPATH/src/golang.org/x/tools/godoc/static -http=:6060
 ```
 
 ## Recompiling static assets

godoc/godoc.go

@@ -423,7 +423,7 @@ func sanitizeFunc(src string) string {
 type PageInfo struct {
 	Dirname  string // directory containing the package
 	Err      error  // error or nil
-	Share   bool   // show share button on examples
+	GoogleCN bool   // page is being served from golang.google.cn
 
 	Mode PageInfoMode // display metadata from query string
 
@@ -683,8 +683,8 @@ func (p *Presentation) example_htmlFunc(info *PageInfo, funcName string) string
 
 		err := p.ExampleHTML.Execute(&buf, struct {
 			Name, Doc, Code, Play, Output string
-			Share                         bool
+			GoogleCN                      bool
-		}{eg.Name, eg.Doc, code, play, out, info.Share})
+		}{eg.Name, eg.Doc, code, play, out, info.GoogleCN})
 		if err != nil {
 			log.Print(err)
 		}

godoc/page.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 )
 
 // Page describes the contents of the top-level godoc webpage.
@@ -19,7 +20,7 @@ type Page struct {
 	SrcPath  string
 	Query    string
 	Body     []byte
-	Share    bool
+	GoogleCN bool // page is being served from golang.google.cn
 
 	// filled in by servePage
 	SearchBox  bool
@@ -51,19 +52,25 @@ func (p *Presentation) ServeError(w http.ResponseWriter, r *http.Request, relpat
 		Title:    "File " + relpath,
 		Subtitle: relpath,
 		Body:     applyTemplate(p.ErrorHTML, "errorHTML", err),
-		Share:    allowShare(r),
+		GoogleCN: googleCN(r),
 	})
 }
 
-var onAppengine = false // overriden in appengine.go when on app engine
+var onAppengine = false // overridden in appengine.go when on app engine
 
-func allowShare(r *http.Request) bool {
+func googleCN(r *http.Request) bool {
+	if r.FormValue("googlecn") != "" {
+		return true
+	}
 	if !onAppengine {
+		return false
+	}
+	if strings.HasSuffix(r.Host, ".cn") {
 		return true
 	}
 	switch r.Header.Get("X-AppEngine-Country") {
 	case "", "ZZ", "CN":
-		return false
-	}
 		return true
 	}
+	return false
+}

godoc/proxy/proxy.go

@@ -19,6 +19,7 @@ import (
 	"net/http"
 	"net/http/httputil"
 	"net/url"
+	"strings"
 	"time"
 
 	"golang.org/x/net/context"
@@ -147,8 +148,8 @@ func cacheKey(body string) string {
 }
 
 func share(w http.ResponseWriter, r *http.Request) {
-	if !allowShare(r) {
+	if googleCN(r) {
-		http.Error(w, "Forbidden", http.StatusForbidden)
+		http.Error(w, http.StatusText(http.StatusForbidden), http.StatusForbidden)
 		return
 	}
 	target, _ := url.Parse(playgroundURL)
@@ -157,13 +158,19 @@ func share(w http.ResponseWriter, r *http.Request) {
 	p.ServeHTTP(w, r)
 }
 
-func allowShare(r *http.Request) bool {
+func googleCN(r *http.Request) bool {
+	if r.FormValue("googlecn") != "" {
+		return true
+	}
 	if appengine.IsDevAppServer() {
+		return false
+	}
+	if strings.HasSuffix(r.Host, ".cn") {
 		return true
 	}
 	switch r.Header.Get("X-AppEngine-Country") {
 	case "", "ZZ", "CN":
-		return false
-	}
 		return true
 	}
+	return false
+}

godoc/search.go

@@ -126,7 +126,7 @@ func (p *Presentation) HandleSearch(w http.ResponseWriter, r *http.Request) {
 		Tabtitle: query,
 		Query:    query,
 		Body:     body.Bytes(),
-		Share:    allowShare(r),
+		GoogleCN: googleCN(r),
 	})
 }
 

godoc/server.go

@@ -312,13 +312,13 @@ func (h *handlerServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		info.TypeInfoIndex[ti.Name] = i
 	}
 
-	info.Share = allowShare(r)
+	info.GoogleCN = googleCN(r)
 	h.p.ServePage(w, Page{
 		Title:    title,
 		Tabtitle: tabtitle,
 		Subtitle: subtitle,
 		Body:     applyTemplate(h.p.PackageHTML, "packageHTML", info),
-		Share:    info.Share,
+		GoogleCN: info.GoogleCN,
 	})
 }
 
@@ -583,7 +583,7 @@ func (p *Presentation) serveTextFile(w http.ResponseWriter, r *http.Request, abs
 		SrcPath:  relpath,
 		Tabtitle: relpath,
 		Body:     buf.Bytes(),
-		Share:    allowShare(r),
+		GoogleCN: googleCN(r),
 	})
 }
 
@@ -654,7 +654,7 @@ func (p *Presentation) serveDirectory(w http.ResponseWriter, r *http.Request, ab
 		SrcPath:  relpath,
 		Tabtitle: relpath,
 		Body:     applyTemplate(p.DirlistHTML, "dirlistHTML", list),
-		Share:    allowShare(r),
+		GoogleCN: googleCN(r),
 	})
 }
 
@@ -683,7 +683,7 @@ func (p *Presentation) ServeHTMLDoc(w http.ResponseWriter, r *http.Request, absp
 	page := Page{
 		Title:    meta.Title,
 		Subtitle: meta.Subtitle,
-		Share:    allowShare(r),
+		GoogleCN: googleCN(r),
 	}
 
 	// evaluate as template if indicated

godoc/static/example.html

@@ -13,7 +13,7 @@
 				<div class="buttons">
 					<a class="run" title="Run this code [shift-enter]">Run</a>
 					<a class="fmt" title="Format this code">Format</a>
-					{{if $.Share}}
+					{{if not $.GoogleCN}}
 					<a class="share" title="Share this code">Share</a>
 					{{end}}
 				</div>

godoc/static/godoc.html

@@ -55,7 +55,7 @@ func main() {
 	<div class="buttons">
 		<a class="run" title="Run this code [shift-enter]">Run</a>
 		<a class="fmt" title="Format this code">Format</a>
-		{{if $.Share}}
+		{{if not $.GoogleCN}}
 		<a class="share" title="Share this code">Share</a>
 		{{end}}
 	</div>