| // 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" |
| "net/http" |
| "strings" |
| |
| "github.com/google/safehtml/template" |
| "go.opencensus.io/stats" |
| "go.opencensus.io/stats/view" |
| "go.opencensus.io/tag" |
| "golang.org/x/mod/semver" |
| "golang.org/x/pkgsite/internal" |
| "golang.org/x/pkgsite/internal/middleware" |
| "golang.org/x/pkgsite/internal/stdlib" |
| ) |
| |
| // serveDetails handles requests for package/directory/module details pages. It |
| // expects paths of the form "/<module-path>[@<version>?tab=<tab>]". |
| // stdlib module pages are handled at "/std", and requests to "/mod/std" will |
| // be redirected to that path. |
| func (s *Server) serveDetails(w http.ResponseWriter, r *http.Request, ds internal.DataSource) (err error) { |
| defer middleware.ElapsedStat(r.Context(), "serveDetails")() |
| |
| ctx := r.Context() |
| if r.Method != http.MethodGet && r.Method != http.MethodHead { |
| return &serverError{status: http.StatusMethodNotAllowed} |
| } |
| if r.URL.Path == "/" { |
| s.serveHomepage(ctx, w, r) |
| return nil |
| } |
| if strings.HasSuffix(r.URL.Path, "/") { |
| http.Redirect(w, r, strings.TrimSuffix(r.URL.Path, "/"), http.StatusMovedPermanently) |
| return |
| } |
| |
| // If page statistics are enabled, use the "exp" query param to adjust |
| // the active experiments. |
| if s.serveStats { |
| ctx = setExperimentsFromQueryParam(ctx, r) |
| } |
| |
| urlInfo, err := extractURLPathInfo(r.URL.Path) |
| if err != nil { |
| var epage *errorPage |
| if uerr := new(userError); errors.As(err, &uerr) { |
| epage = &errorPage{MessageData: uerr.userMessage} |
| } |
| return &serverError{ |
| status: http.StatusBadRequest, |
| err: err, |
| epage: epage, |
| } |
| } |
| if !isSupportedVersion(urlInfo.fullPath, urlInfo.requestedVersion) { |
| return invalidVersionError(urlInfo.fullPath, urlInfo.requestedVersion) |
| } |
| if urlPath := stdlibRedirectURL(urlInfo.fullPath); urlPath != "" { |
| http.Redirect(w, r, urlPath, http.StatusMovedPermanently) |
| return |
| } |
| if err := checkExcluded(ctx, ds, urlInfo.fullPath); err != nil { |
| return err |
| } |
| return s.serveUnitPage(ctx, w, r, ds, urlInfo) |
| } |
| |
| func stdlibRedirectURL(fullPath string) string { |
| if !strings.HasPrefix(fullPath, stdlib.GitHubRepo) { |
| return "" |
| } |
| if fullPath == stdlib.GitHubRepo || fullPath == stdlib.GitHubRepo+"/src" { |
| return "/std" |
| } |
| urlPath2 := strings.TrimPrefix(strings.TrimPrefix(fullPath, stdlib.GitHubRepo+"/"), "src/") |
| if fullPath == urlPath2 { |
| return "" |
| } |
| return "/" + urlPath2 |
| } |
| |
| func invalidVersionError(fullPath, requestedVersion string) error { |
| return &serverError{ |
| status: http.StatusBadRequest, |
| epage: &errorPage{ |
| messageTemplate: template.MakeTrustedTemplate(` |
| <h3 class="Error-message">{{.Version}} is not a valid semantic version.</h3> |
| <p class="Error-message"> |
| To search for packages like {{.Path}}, <a href="/search?q={{.Path}}">click here</a>. |
| </p>`), |
| MessageData: struct{ Path, Version string }{fullPath, requestedVersion}, |
| }, |
| } |
| } |
| |
| func datasourceNotSupportedErr() error { |
| return &serverError{ |
| status: http.StatusFailedDependency, |
| epage: &errorPage{ |
| messageTemplate: template.MakeTrustedTemplate( |
| `<h3 class="Error-message">This page is not supported by this datasource.</h3>`), |
| }, |
| } |
| } |
| |
| var ( |
| keyVersionType = tag.MustNewKey("frontend.version_type") |
| versionTypeResults = stats.Int64( |
| "go-discovery/frontend_version_type_count", |
| "The version type of a request to package, module, or directory page.", |
| stats.UnitDimensionless, |
| ) |
| VersionTypeCount = &view.View{ |
| Name: "go-discovery/frontend_version_type/result_count", |
| Measure: versionTypeResults, |
| Aggregation: view.Count(), |
| Description: "version type results, by latest, master, or semver", |
| TagKeys: []tag.Key{keyVersionType}, |
| } |
| ) |
| |
| func recordVersionTypeMetric(ctx context.Context, requestedVersion string) { |
| // Tag versions based on latest, master and semver. |
| v := requestedVersion |
| if semver.IsValid(v) { |
| v = "semver" |
| } |
| stats.RecordWithTags(ctx, []tag.Mutator{ |
| tag.Upsert(keyVersionType, v), |
| }, versionTypeResults.M(1)) |
| } |