cmd/xurls: retry with GET if HEAD results in a 405

When using `xurls -fix` in another project, HEAD on https://pkgs.alpinelinux.org/packages?name=shfmt resulted in a 405 "Method Not Allowed", but GET still succeeds.
mvdan · Nov 22, 2022 · e87b85f · e87b85f
1 parent f6175bc
commit e87b85f
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Showing 3 changed files with 57 additions and 35 deletions.
diff --git a/cmd/xurls/main.go b/cmd/xurls/main.go
@@ -127,7 +127,9 @@ func scanPath(re *regexp.Regexp, path string) error {
 							return nil
 						},
 					}
-					req, err := http.NewRequest(http.MethodHead, fixed, nil)
+					method := http.MethodHead
+				retry:
+					req, err := http.NewRequest(method, fixed, nil)
 					if err != nil {
 						r.appendBroken(match, err.Error())
 						continue
@@ -139,6 +141,11 @@ func scanPath(re *regexp.Regexp, path string) error {
 						continue
 					}
 					if code := resp.StatusCode; code >= 400 {
+						if code == http.StatusMethodNotAllowed {
+							method = http.MethodGet
+							resp.Body.Close()
+							goto retry
+						}
 						r.appendBroken(match, fmt.Sprintf("%d %s", code, http.StatusText(code)))
 					}
 					resp.Body.Close()

diff --git a/cmd/xurls/main_test.go b/cmd/xurls/main_test.go
@@ -29,54 +29,65 @@ func TestScript(t *testing.T) {
 		RequireExplicitExec: true,
 		Setup: func(env *testscript.Env) error {
 			mux := http.NewServeMux()
-			handle := func(pattern string, handler func(http.ResponseWriter, *http.Request)) {
+			handle := func(method, pattern string, handler func(http.ResponseWriter, *http.Request)) {
 				mux.HandleFunc(pattern, func(w http.ResponseWriter, r *http.Request) {
-					if r.Method != http.MethodHead {
-						t.Errorf("expected all requests to be %q, got %q", http.MethodHead, r.Method)
+					if r.Method != method {
+						t.Errorf("expected all requests to be %q, got %q", method, r.Method)
 					}
 					handler(w, r)
 				})
 			}
-			handle("/plain", func(w http.ResponseWriter, r *http.Request) {
-				fmt.Fprintf(w, "plaintext")
+			handle("HEAD", "/plain-head", func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(200)
 			})
-			handle("/redir-1", func(w http.ResponseWriter, r *http.Request) {
-				http.Redirect(w, r, "/plain", http.StatusMovedPermanently)
+			handle("HEAD", "/redir-1", func(w http.ResponseWriter, r *http.Request) {
+				http.Redirect(w, r, "/plain-head", http.StatusMovedPermanently)
 			})
-			handle("/redir-2", func(w http.ResponseWriter, r *http.Request) {
+			handle("HEAD", "/redir-2", func(w http.ResponseWriter, r *http.Request) {
 				http.Redirect(w, r, "/redir-1", http.StatusMovedPermanently)
 			})
 
-			handle("/redir-longer", func(w http.ResponseWriter, r *http.Request) {
+			handle("HEAD", "/redir-longer", func(w http.ResponseWriter, r *http.Request) {
 				http.Redirect(w, r, "/redir-longtarget", http.StatusMovedPermanently)
 			})
-			handle("/redir-longtarget", func(w http.ResponseWriter, r *http.Request) {
-				fmt.Fprintf(w, "long target")
+			handle("HEAD", "/redir-longtarget", func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(200)
 			})
-			handle("/redir-fragment", func(w http.ResponseWriter, r *http.Request) {
-				http.Redirect(w, r, "/plain#bar", http.StatusMovedPermanently)
+			handle("HEAD", "/redir-fragment", func(w http.ResponseWriter, r *http.Request) {
+				http.Redirect(w, r, "/plain-head#bar", http.StatusMovedPermanently)
 			})
 
-			handle("/redir-301", func(w http.ResponseWriter, r *http.Request) {
-				http.Redirect(w, r, "/plain", 301)
+			handle("HEAD", "/redir-301", func(w http.ResponseWriter, r *http.Request) {
+				http.Redirect(w, r, "/plain-head", 301)
 			})
-			handle("/redir-302", func(w http.ResponseWriter, r *http.Request) {
-				http.Redirect(w, r, "/plain", 302)
+			handle("HEAD", "/redir-302", func(w http.ResponseWriter, r *http.Request) {
+				http.Redirect(w, r, "/plain-head", 302)
 			})
-			handle("/redir-307", func(w http.ResponseWriter, r *http.Request) {
-				http.Redirect(w, r, "/plain", 307)
+			handle("HEAD", "/redir-307", func(w http.ResponseWriter, r *http.Request) {
+				http.Redirect(w, r, "/plain-head", 307)
 			})
-			handle("/redir-308", func(w http.ResponseWriter, r *http.Request) {
-				http.Redirect(w, r, "/plain", 308)
+			handle("HEAD", "/redir-308", func(w http.ResponseWriter, r *http.Request) {
+				http.Redirect(w, r, "/plain-head", 308)
 			})
 
-			handle("/404", func(w http.ResponseWriter, r *http.Request) {
+			handle("HEAD", "/404", func(w http.ResponseWriter, r *http.Request) {
 				http.Error(w, "", 404)
 			})
-			handle("/500", func(w http.ResponseWriter, r *http.Request) {
+			handle("HEAD", "/500", func(w http.ResponseWriter, r *http.Request) {
 				http.Error(w, "", 500)
 			})
 
+			handle("GET", "/plain-get", func(w http.ResponseWriter, r *http.Request) {
+				fmt.Fprintf(w, "plaintext")
+			})
+			mux.HandleFunc("/get-only", func(w http.ResponseWriter, r *http.Request) {
+				if r.Method == "GET" {
+					http.Redirect(w, r, "/plain-get", 301)
+				} else {
+					http.Error(w, "", 405)
+				}
+			})
+
 			ln, err := net.Listen("tcp", ":0")
 			if err != nil {
 				return err

diff --git a/cmd/xurls/testdata/script/fix.txtar b/cmd/xurls/testdata/script/fix.txtar
@@ -34,9 +34,9 @@ stderr -count=1 'totallydoesnotexist.localhost/ - Head .* dial tcp'
 cmp broken broken.golden
 
 -- nothing --
-No redirect: ${SERVER}/plain
+No redirect: ${SERVER}/plain-head
 -- redirects --
-No redirect: ${SERVER}/plain
+No redirect: ${SERVER}/plain-head
 One redirect: ${SERVER}/redir-1
 Two redirects: ${SERVER}/redir-2
 Redirect inherits fragment: ${SERVER}/redir-1#foo
@@ -53,31 +53,35 @@ Permanent redirect codes:
 Temporary redirect codes:
 * ${SERVER}/redir-302
 * ${SERVER}/redir-307
+
+Only GET allowed, HEAD fails: ${SERVER}/get-only
 -- redirects.golden --
-No redirect: ${SERVER}/plain
-One redirect: ${SERVER}/plain
-Two redirects: ${SERVER}/plain
-Redirect inherits fragment: ${SERVER}/plain#foo
-Redirect replaces fragment: ${SERVER}/plain#bar
+No redirect: ${SERVER}/plain-head
+One redirect: ${SERVER}/plain-head
+Two redirects: ${SERVER}/plain-head
+Redirect inherits fragment: ${SERVER}/plain-head#foo
+Redirect replaces fragment: ${SERVER}/plain-head#bar
 
-Three links in one line: ${SERVER}/plain + ${SERVER}/plain + ${SERVER}/plain
+Three links in one line: ${SERVER}/plain-head + ${SERVER}/plain-head + ${SERVER}/plain-head
 
 Redirect to a longer path ${SERVER}/redir-longtarget with trailing text
 
 Permanent redirect codes:
-* ${SERVER}/plain
-* ${SERVER}/plain
+* ${SERVER}/plain-head
+* ${SERVER}/plain-head
 
 Temporary redirect codes:
 * ${SERVER}/redir-302
 * ${SERVER}/redir-307
+
+Only GET allowed, HEAD fails: ${SERVER}/plain-get
 -- broken --
 One redirect: ${SERVER}/redir-1
 404 errors: ${SERVER}/404 ${SERVER}/404
 500 errors: ${SERVER}/500 ${SERVER}/500
 Dial error: http://totallydoesnotexist.localhost/
 -- broken.golden --
-One redirect: ${SERVER}/plain
+One redirect: ${SERVER}/plain-head
 404 errors: ${SERVER}/404 ${SERVER}/404
 500 errors: ${SERVER}/500 ${SERVER}/500
 Dial error: http://totallydoesnotexist.localhost/