| // Copyright 2019 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package frontend |
| |
| import ( |
| "context" |
| "errors" |
| "fmt" |
| "html/template" |
| "net/http" |
| "strings" |
| |
| "golang.org/x/discovery/internal" |
| "golang.org/x/discovery/internal/derrors" |
| "golang.org/x/discovery/internal/log" |
| ) |
| |
| // handlePackageDetails handles requests for package details pages. It expects |
| // paths of the form "/<path>[@<version>?tab=<tab>]". |
| func (s *Server) servePackageDetails(w http.ResponseWriter, r *http.Request) error { |
| pkgPath, modulePath, version, err := parseDetailsURLPath(r.URL.Path) |
| if err != nil { |
| return &serverError{ |
| status: http.StatusBadRequest, |
| err: fmt.Errorf("handlePackageDetails: %v", err), |
| } |
| } |
| return s.servePackagePage(w, r, pkgPath, modulePath, version) |
| } |
| |
| // handlePackageDetailsRedirect redirects all redirects to "/pkg" to "/". |
| func (s *Server) handlePackageDetailsRedirect(w http.ResponseWriter, r *http.Request) { |
| urlPath := strings.TrimPrefix(r.URL.Path, "/pkg") |
| http.Redirect(w, r, urlPath, http.StatusMovedPermanently) |
| } |
| |
| // servePackagePage serves details pages for the package with import path |
| // pkgPath, in the module specified by modulePath and version. |
| func (s *Server) servePackagePage(w http.ResponseWriter, r *http.Request, pkgPath, modulePath, version string) error { |
| ctx := r.Context() |
| if err := checkPathAndVersion(ctx, s.ds, pkgPath, version); err != nil { |
| return err |
| } |
| // This function handles top level behavior related to the existence of the |
| // requested pkgPath@version. |
| // 1. If a package exists at this version, serve it. |
| // 2. If there is a directory at this version, serve it. |
| // 3. If there is another version that contains this package path: serve a |
| // 404 and suggest these versions. |
| // 4. Just serve a 404 |
| pkg, err := s.ds.GetPackage(ctx, pkgPath, modulePath, version) |
| if err == nil { |
| return s.servePackagePageWithPackage(ctx, w, r, pkg, version) |
| } |
| if !errors.Is(err, derrors.NotFound) { |
| return err |
| } |
| if version == internal.LatestVersion { |
| // If we've already checked the latest version, then we know that this path |
| // is not a package at any version, so just skip ahead and serve the |
| // directory page. |
| return s.serveDirectoryPage(w, r, pkgPath, modulePath, version) |
| } |
| dir, err := s.ds.GetDirectory(ctx, pkgPath, modulePath, version, internal.AllFields) |
| if err == nil { |
| return s.serveDirectoryPageWithDirectory(ctx, w, r, dir, version) |
| } |
| if !errors.Is(err, derrors.NotFound) { |
| // The only error we expect is NotFound, so serve an 500 here, otherwise |
| // whatever response we resolve below might be inconsistent or misleading. |
| return fmt.Errorf("checking for directory: %v", err) |
| } |
| _, err = s.ds.GetPackage(ctx, pkgPath, modulePath, internal.LatestVersion) |
| if err == nil { |
| return &serverError{ |
| status: http.StatusNotFound, |
| epage: &errorPage{ |
| Message: fmt.Sprintf("Package %s@%s is not available.", pkgPath, displayVersion(version, modulePath)), |
| SecondaryMessage: template.HTML( |
| fmt.Sprintf(`There are other versions of this package that are! To view them, `+ |
| `<a href="/%s?tab=versions">click here</a>.`, |
| pkgPath)), |
| }, |
| } |
| } |
| if !errors.Is(err, derrors.NotFound) { |
| // Unlike the error handling for GetDirectory above, we don't serve an |
| // InternalServerError here. The reasoning for this is that regardless of |
| // the result of GetPackage(..., "latest"), we're going to serve a NotFound |
| // response code. So the semantics of the endpoint are the same whether or |
| // not we get an unexpected error from GetPackage -- we just don't serve a |
| // more informative error response. |
| log.Errorf(ctx, "error checking for latest package: %v", err) |
| return nil |
| } |
| return pathNotFoundError("package") |
| } |
| |
| func (s *Server) servePackagePageWithPackage(ctx context.Context, w http.ResponseWriter, r *http.Request, pkg *internal.VersionedPackage, requestedVersion string) error { |
| |
| pkgHeader, err := createPackage(&pkg.Package, &pkg.ModuleInfo, requestedVersion == internal.LatestVersion) |
| if err != nil { |
| return fmt.Errorf("creating package header for %s@%s: %v", pkg.Path, pkg.Version, err) |
| } |
| |
| tab := r.FormValue("tab") |
| settings, ok := packageTabLookup[tab] |
| if !ok { |
| var tab string |
| if pkg.Package.IsRedistributable { |
| tab = "doc" |
| } else { |
| tab = "overview" |
| } |
| http.Redirect(w, r, fmt.Sprintf(r.URL.Path+"?tab=%s", tab), http.StatusFound) |
| return nil |
| } |
| canShowDetails := pkg.Package.IsRedistributable || settings.AlwaysShowDetails |
| |
| var details interface{} |
| if canShowDetails { |
| var err error |
| details, err = fetchDetailsForPackage(ctx, r, tab, s.ds, pkg) |
| if err != nil { |
| return fmt.Errorf("fetching page for %q: %v", tab, err) |
| } |
| } |
| page := &DetailsPage{ |
| basePage: newBasePage(r, packageHTMLTitle(&pkg.Package)), |
| Title: packageTitle(&pkg.Package), |
| Settings: settings, |
| Header: pkgHeader, |
| BreadcrumbPath: breadcrumbPath(pkgHeader.Path, pkgHeader.Module.ModulePath, |
| pkgHeader.Module.LinkVersion), |
| Details: details, |
| CanShowDetails: canShowDetails, |
| Tabs: packageTabSettings, |
| PageType: "pkg", |
| } |
| s.servePage(ctx, w, settings.TemplateName, page) |
| return nil |
| } |