README.md

@@ -0,0 +1,16 @@
+# Testing
+
+With the go-get command
+
+```sh
+$ go get -v -u jbowen.dev/cereal
+get "jbowen.dev/cereal": found meta tag get.metaImport{Prefix:"jbowen.dev/cereal", VCS:"git", RepoRoot:"https://github.com/jamesbo13/cereal"} at //jbowen.dev/cereal?go-get=1
+jbowen.dev/cereal (download)
+```
+
+With the httpie command
+
+```sh
+$ http --body "https://gopkg.in/yaml.v3?go-get=1"
+...
+```

app.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+type Application struct {
+	Config *Config
+	Mux    *http.ServeMux
+	Log    *LogFile
+}
+
+func (app *Application) routes() {
+	m := http.NewServeMux()
+
+	m.HandleFunc("/healthcheck", healthcheck)
+	m.HandleFunc("/reloadRules", reloadRules(app.Config))
+	m.HandleFunc("/", serveLogger(app.Log)(serveRules(app.Config)))
+
+	app.Mux = m
+}
+
+func (app *Application) Setup(port string) *http.Server {
+	app.routes()
+	return &http.Server{
+		Addr:    fmt.Sprintf(":%s", port),
+		Handler: app.Mux,
+	}
+}

conf.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+)
+
+type Config struct {
+	MappingFilePath string
+	MappingRules    ImportRulesMappings
+}
+
+type ImportRulesMappings struct {
+	Mappings []struct {
+		Protocol  string `json:"protocol"`
+		VanityUrl string `json:"vanity_url"`
+		RealUrl   string `json:"real_url"`
+	} `json:"mappings"`
+}
+
+type ImportRuleStruct struct {
+	VanityUrl string
+	Proto     string
+	RepoUrl   string
+}
+
+// isFile - check if fp is a valid file
+func isFile(fp string) bool {
+	info, err := os.Stat(fp)
+	if os.IsNotExist(err) || !info.Mode().IsRegular() {
+		return false
+	}
+	return true
+}
+
+// load mapping file
+func (c *Config) LoadMappingFile(fp string) error {
+	var mapping ImportRulesMappings
+	mappingFilePath := fp
+	if len(c.MappingFilePath) == 0 {
+		ok := isFile(mappingFilePath)
+		if !ok {
+			return fmt.Errorf("%s is not found", mappingFilePath)
+		}
+	}
+	mappingFile, err := os.Open(mappingFilePath)
+	if err != nil {
+		return err
+	}
+	defer mappingFile.Close()
+
+	err = json.NewDecoder(mappingFile).Decode(&mapping)
+	if err != nil {
+		return err
+	}
+	c.MappingRules = mapping
+	if len(c.MappingFilePath) == 0 {
+		c.MappingFilePath = mappingFilePath
+	}
+	return nil
+}

embed.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"embed"
+	"html/template"
+)
+
+// go:embed templates/*
+var tmpls embed.FS
+
+func GetServeHtml() *template.Template {
+	data, _ := tmpls.ReadFile("success.html")
+	return template.Must(template.New("main").Parse(string(data)))
+}
+
+func GetDefaultHtml() []byte {
+	data, _ := tmpls.ReadFile("default.html")
+	return data
+}

handlers.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"bytes"
+	"net/http"
+	"strings"
+)
+
+func healthcheck(w http.ResponseWriter, r *http.Request) {
+	w.Write([]byte("ok"))
+}
+
+func reloadRules(c *Config) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		err := c.LoadMappingFile("")
+		if err != nil {
+			errorLog.Printf("Cannot reload rules: %+v", err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		w.Write([]byte("ok"))
+	}
+}
+
+func serveRules(c *Config) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusInternalServerError)
+			return
+		}
+
+		// if go-get param is absent, return nothing
+		if r.FormValue("go-get") != "1" {
+			w.Write(GetDefaultHtml())
+			return
+		}
+
+		nameOfPkg := r.Host + r.URL.Path
+
+		var vanityUrl, proto, repoUrl string
+		for _, rule := range c.MappingRules.Mappings {
+			if strings.HasPrefix(strings.ToLower(nameOfPkg), strings.ToLower(rule.VanityUrl+"/")) {
+				repo := strings.Replace(strings.ToLower(nameOfPkg), strings.ToLower(rule.VanityUrl), "", -1)
+				repo = strings.Split(repo, "/")[1]
+
+				vanityUrl = rule.VanityUrl + "/" + repo
+				repoUrl = rule.RealUrl + "/" + repo
+				proto = rule.Protocol
+
+				break
+			}
+		}
+
+		d := ImportRuleStruct{
+			VanityUrl: vanityUrl,
+			Proto:     proto,
+			RepoUrl:   repoUrl,
+		}
+		tmpl := GetServeHtml()
+
+		var buf bytes.Buffer
+		err := tmpl.Execute(&buf, &d)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		w.Header().Set("Cache-Control", "public, max-age=500")
+		w.Write(buf.Bytes())
+	}
+}

logger.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+)
+
+// some headers not worth logging
+var (
+	hdrsToNotLog = []string{
+		"Accept-Language",
+		"Cache-Control",
+		"Cf-Ray",
+		"CF-Visitor",
+		"CF-Connecting-IP",
+		"Cdn-Loop",
+		"Cookie",
+		"Connection",
+		"Dnt",
+		"If-Modified-Since",
+		"Sec-Fetch-Dest",
+		"Sec-Ch-Ua-Mobile",
+		// "Sec-Ch-Ua",
+		"Sec-Ch-Ua-Platform",
+		"Sec-Fetch-Site",
+		"Sec-Fetch-Mode",
+		"Sec-Fetch-User",
+		"Upgrade-Insecure-Requests",
+		"X-Request-Start",
+		"X-Forwarded-For",
+		"X-Forwarded-Proto",
+		"X-Forwarded-Host",
+	}
+	hdrsToNotLogMap map[string]bool
+)
+
+type LogFile struct {
+	handle *os.File
+	logger *log.Logger
+	path   string
+}
+
+type LogFileRec struct {
+	Method string `json:"method"`
+	IpAddr string `json:"ipAddr"`
+	Url    string `json:"url"`
+}
+
+func newFileLogger(path string) (*LogFile, error) {
+	f, err := os.OpenFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666)
+	if err != nil {
+		return nil, err
+	}
+	return &LogFile{
+		handle: f,
+		logger: log.New(f, "", 0),
+		path:   path,
+	}, nil
+}
+
+func (f *LogFile) Close() error {
+	if f == nil {
+		return nil
+	}
+	err := f.handle.Close()
+	f.handle = nil
+	return err
+}
+
+func extractFirstFragment(header *http.Header, headerName string) string {
+	s := header.Get(headerName)
+	if len(strings.TrimSpace(s)) == 0 {
+		return s
+	}
+	fragments := strings.Split(s, ",")
+	return strings.TrimSpace(fragments[0])
+}
+
+// Get Ip Address of the client
+func extractIpAddress(r *http.Request) string {
+	var ipAddr string
+	if r == nil {
+		return ""
+	}
+	possibleIpHeaders := []string{"CF-Connecting-IP", "X-Real-Ip", "X-Forwarded-For"}
+	for _, header := range possibleIpHeaders {
+		ipAddr = extractFirstFragment(&r.Header, header)
+		if len(strings.TrimSpace(ipAddr)) != 0 {
+			return ipAddr
+		}
+	}
+	// pull ip from Request.RemoteAddr
+	if len(strings.TrimSpace(r.RemoteAddr)) != 0 {
+		index := strings.LastIndex(r.RemoteAddr, ";")
+		if index == -1 {
+			return r.RemoteAddr
+		}
+		ipAddr = r.RemoteAddr[:index]
+	}
+	return ipAddr
+}
+
+func canSkipExtraHeaders(r *http.Request) bool {
+	ref := r.Header.Get("Referer")
+	if len(strings.TrimSpace(ref)) == 0 {
+		return false
+	}
+	return strings.Contains(ref, r.Host)
+}
+
+func shouldLogHeader(s string) bool {
+	if hdrsToNotLogMap == nil {
+		hdrsToNotLogMap = map[string]bool{}
+		for _, h := range hdrsToNotLog {
+			h = strings.ToLower(h)
+			hdrsToNotLogMap[h] = true
+		}
+	}
+	s = strings.ToLower(s)
+	return !hdrsToNotLogMap[s]
+}
+
+func (f *LogFile) WriteLog(r *http.Request) error {
+	if f == nil {
+		return nil
+	}
+	var rec = make(map[string]string)
+	rec["method"] = r.Method
+	rec["requestUri"] = r.RequestURI
+	rec["Host"] = r.Host
+	rec["ipAddr"] = extractIpAddress(r)
+	if !canSkipExtraHeaders(r) {
+		for key, val := range r.Header {
+			if shouldLogHeader(key) && len(val) > 0 {
+				rec[key] = val[0]
+			}
+		}
+	}
+	b, err := json.Marshal(rec)
+	if err != nil {
+		return err
+	}
+	f.logger.Println(string(b))
+	return nil
+}

main.go

@@ -1,5 +1,115 @@
 package main
 
-func main() {
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+)
 
+var errorLog *log.Logger = log.New(os.Stderr, "", log.LstdFlags)
+
+const (
+	DEFAULT_RULES_FILE string = "/var/lib/gocustomurls/rules.json"
+	DEFAULT_LOG_FILE   string = "/var/log/gocustomurls/app.log"
+)
+
+// flagsSet returns a set of all the flags what were actually set on the
+// command line.
+func flagsSet(flags *flag.FlagSet) map[string]bool {
+	s := make(map[string]bool)
+	flags.Visit(func(f *flag.Flag) {
+		s[f.Name] = true
+	})
+	return s
+}
+
+func main() {
+	programName := os.Args[0]
+	// errorLog = log.New(os.Stderr, "", log.LstdFlags)
+
+	flags := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+	flags.Usage = func() {
+		out := flags.Output()
+		fmt.Fprintf(out, "Usage: %v [flags]\n\n", programName)
+		fmt.Fprint(out, "  This utility serves vanity urls for the go get/install command.\n")
+		fmt.Fprint(out, "  By default, the server listens on localhost:7070.\n")
+		flags.PrintDefaults()
+	}
+
+	portFlag := flags.String("port", "7070", "port to listen to")
+	rulesFileFlag := flags.String("config", DEFAULT_RULES_FILE, "contains go-import mapping")
+	logFileFlag := flags.String("logfile", DEFAULT_LOG_FILE, "default log file")
+	flags.Parse(os.Args[1:])
+
+	if len(flags.Args()) > 1 {
+		errorLog.Println("Error: too many command-line arguments")
+		flags.Usage()
+		os.Exit(1)
+	}
+
+	allSetFlags := flagsSet(flags)
+
+	var port string
+	if allSetFlags["port"] {
+		port = *portFlag
+	}
+
+	var rulesFile string
+	if allSetFlags["config"] {
+		rulesFile = *rulesFileFlag
+	}
+
+	var logFile string
+	if allSetFlags["logFile"] {
+		logFile = *logFileFlag
+	}
+
+	// load rules mapping
+	c := &Config{}
+	err := c.LoadMappingFile(rulesFile)
+	if err != nil {
+		errorLog.Println(err)
+		os.Exit(1)
+	}
+	l, err := newFileLogger(logFile)
+	if err != nil {
+		errorLog.Println(err)
+		os.Exit(1)
+	}
+
+	app := &Application{
+		Config: c,
+		Log:    l,
+	}
+	srv := app.Setup(port)
+
+	// For graceful shutdowns
+	go func() {
+		err := srv.ListenAndServe()
+		if !errors.Is(err, http.ErrServerClosed) {
+			errorLog.Printf("HTTP Server error: %+v\n", err)
+			os.Exit(1)
+		}
+		app.Log.logger.Println("Stopped serving new connections.")
+	}()
+
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+	<-sigChan
+
+	shutdownCtx, shutdownRelease := context.WithTimeout(context.Background(), 10*time.Second)
+	defer shutdownRelease()
+
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		errorLog.Printf("HTTP shutdown error: %+v\n", err)
+		os.Exit(1)
+	}
+	app.Log.logger.Println("Graceful shutdown complete.")
 }

middleware.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"net/http"
+)
+
+// serveLogger is a logging middleware for serving. It generates logs for
+// requests sent to the server.
+func serveLogger(l *LogFile) func(http.HandlerFunc) http.HandlerFunc {
+	return func(next http.HandlerFunc) http.HandlerFunc {
+		return func(w http.ResponseWriter, r *http.Request) {
+			l.WriteLog(r)
+			next(w, r)
+		}
+	}
+}
+
+// func serveLogger(logger *LogFile, next http.Handler) http.Handler {
+// 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+// 		logger.WriteLog(r)
+// 		next.ServeHTTP(w, r)
+// 	})
+// }

templates/default.html

@@ -0,0 +1,6 @@
+<html>
+    <head></head>
+    <body>
+        <h5>Nothing here. Move along.</h5>
+    </body>
+</html>

templates/success.html

@@ -0,0 +1,7 @@
+<html>
+    <head>
+        <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
+        <meta name="go-import" content="{{.VanityUrl}} {{.Proto}} {{.RepoUrl}}">
+        <meta name="go-source" content="{{.VanityUrl}} {{.RepoUrl}} {{.RepoUrl}}/tree/main{/dir} {{.RepoUrl}}/blob/main{/dir}/{file}#L{line}">                   
+    </head>
+</html>