gopkg/main.go
2014-03-31 14:49:30 -03:00

313 lines
7.7 KiB
Go

package main
import (
"errors"
"flag"
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
"regexp"
"strconv"
"strings"
"text/template"
)
var httpFlag = flag.String("http", ":8080", "Serve HTTP at given address")
var httpsFlag = flag.String("https", "", "Serve HTTPS at given address")
var certFlag = flag.String("cert", "", "Use the provided TLS certificate")
var keyFlag = flag.String("key", "", "Use the provided TLS key")
func main() {
if err := run(); err != nil {
fmt.Fprintf(os.Stderr, "error: %v\n", err)
os.Exit(1)
}
}
func run() error {
flag.Parse()
if len(flag.Args()) > 0 {
return fmt.Errorf("too many arguments: %s", flag.Args()[0])
}
http.HandleFunc("/", handler)
if *httpFlag == "" && *httpsFlag == "" {
return fmt.Errorf("must provide -http and/or -https")
}
if (*httpsFlag != "" || *certFlag != "" || *keyFlag != "") && (*httpsFlag == "" || *certFlag == "" || *keyFlag == "") {
return fmt.Errorf("-https -cert and -key must be used together")
}
ch := make(chan error, 2)
if *httpFlag != "" {
go func() {
ch <- http.ListenAndServe(*httpFlag, nil)
}()
}
if *httpsFlag != "" {
go func() {
ch <- http.ListenAndServeTLS(*httpsFlag, *certFlag, *keyFlag, nil)
}()
}
return <-ch
}
var tmpl = template.Must(template.New("").Parse(`
<html>
<head>
<meta name="go-import" content="{{.PkgRoot}} git {{.GitRoot}}">
</head>
<body>
<script>
window.location = "http://godoc.org/{{.PkgPath}}" + window.location.hash;
</script>
</body>
</html>
`))
type Repo struct {
GitRoot string
HubRoot string
PkgRoot string
PkgPath string
Version Version
}
var patternOld = regexp.MustCompile(`^/([a-z0-9][-a-z0-9]+/)?((?:v0|v[1-9][0-9]*)(?:\.0|\.[1-9][0-9]*){0,2})/([a-zA-Z][-a-zA-Z0-9]*)(?:\.git)?((?:/[a-zA-Z][-a-zA-Z0-9]*)*)$`)
var patternNew = regexp.MustCompile(`^/([a-z0-9][-a-z0-9]+/)?([a-zA-Z][-a-zA-Z0-9]*)\.((?:v0|v[1-9][0-9]*)(?:\.0|\.[1-9][0-9]*){0,2})(?:\.git)?((?:/[a-zA-Z][-a-zA-Z0-9]*)*)$`)
func handler(resp http.ResponseWriter, req *http.Request) {
if req.URL.Path == "/health-check" {
resp.Write([]byte("ok"))
return
}
log.Printf("%s requested %s", req.RemoteAddr, req.URL)
if req.URL.Path == "/" {
resp.Header().Set("Location", "http://labix.org/gopkg.in")
resp.WriteHeader(http.StatusTemporaryRedirect)
return
}
m := patternNew.FindStringSubmatch(req.URL.Path)
compat := false
if m == nil {
m = patternOld.FindStringSubmatch(req.URL.Path)
if m == nil {
sendNotFound(resp, "Unsupported URL pattern; see the documentation at gopkg.in for details.")
return
}
m[2], m[3] = m[3], m[2]
compat = true
}
if strings.Contains(m[3], ".") {
sendNotFound(resp, "Import paths take the major version only (.%s instead of .%s); see docs at gopkg.in for the reasoning.",
m[3][:strings.Index(m[3], ".")], m[3])
return
}
var repo *Repo
if m[1] == "" {
repo = &Repo{
GitRoot: "https://github.com/go-" + m[2] + "/" + m[2],
PkgRoot: "gopkg.in/" + m[2] + "." + m[3],
PkgPath: "gopkg.in/" + m[2] + "." + m[3] + m[4],
}
if compat {
repo.PkgRoot = "gopkg.in/" + m[3] + "/" + m[2]
repo.PkgPath = "gopkg.in/" + m[3] + "/" + m[2] + m[4]
}
} else {
repo = &Repo{
GitRoot: "https://github.com/" + m[1] + m[2],
PkgRoot: "gopkg.in/" + m[1] + m[2] + "." + m[3],
PkgPath: "gopkg.in/" + m[1] + m[2] + "." + m[3] + m[4],
}
if compat {
repo.PkgRoot = "gopkg.in/" + m[1] + m[3] + "/" + m[2]
repo.PkgPath = "gopkg.in/" + m[1] + m[3] + "/" + m[2] + m[4]
}
}
var ok bool
repo.Version, ok = parseVersion(m[3])
if !ok {
sendNotFound(resp, "Version %q improperly considered invalid; please warn the service maintainers.", m[3])
}
repo.HubRoot = repo.GitRoot
// Run this concurrently to avoid waiting later.
nameVersioned := nameHasVersion(repo)
refs, err := hackedRefs(repo)
switch err {
case nil:
repo.GitRoot = "https://" + repo.PkgRoot
case ErrNoRepo:
if <-nameVersioned {
v := repo.Version.String()
repo.GitRoot += "-" + v
repo.HubRoot += "-" + v
break
}
sendNotFound(resp, "GitHub repository not found at %s", repo.HubRoot)
return
case ErrNoVersion:
v := repo.Version.String()
if repo.Version.Minor == -1 {
sendNotFound(resp, `GitHub repository at %s has no branch or tag "%s", "%s.N" or "%s.N.M"`, repo.HubRoot, v, v, v)
} else if repo.Version.Patch == -1 {
sendNotFound(resp, `GitHub repository at %s has no branch or tag "%s" or "%s.N"`, repo.HubRoot, v, v)
} else {
sendNotFound(resp, `GitHub repository at %s has no branch or tag "%s"`, repo.HubRoot, v)
}
return
default:
resp.WriteHeader(http.StatusBadGateway)
resp.Write([]byte(fmt.Sprintf("Cannot obtain refs from GitHub: %v", err)))
return
}
if m[4] == "/git-upload-pack" {
resp.Header().Set("Location", repo.HubRoot+"/git-upload-pack")
resp.WriteHeader(http.StatusMovedPermanently)
return
}
if m[4] == "/info/refs" {
resp.Header().Set("Content-Type", "application/x-git-upload-pack-advertisement")
resp.Write(refs)
return
}
resp.Header().Set("Content-Type", "text/html")
tmpl.Execute(resp, repo)
}
func sendNotFound(resp http.ResponseWriter, msg string, args ...interface{}) {
if len(args) > 0 {
msg = fmt.Sprintf(msg, args...)
}
resp.WriteHeader(http.StatusNotFound)
resp.Write([]byte(msg))
}
// TODO Timeouts for these http interactions. Use the new support coming in 1.3.
const refsSuffix = ".git/info/refs?service=git-upload-pack"
// Obsolete. Drop this.
func nameHasVersion(repo *Repo) chan bool {
ch := make(chan bool, 1)
go func() {
resp, err := http.Head(repo.HubRoot + "-" + repo.Version.String() + refsSuffix)
if err != nil {
ch <- false
}
if resp.Body != nil {
resp.Body.Close()
}
ch <- resp.StatusCode == 200
}()
return ch
}
var ErrNoRepo = errors.New("repository not found in github")
var ErrNoVersion = errors.New("version reference not found in github")
func hackedRefs(repo *Repo) (data []byte, err error) {
resp, err := http.Get(repo.HubRoot + refsSuffix)
if err != nil {
return nil, fmt.Errorf("cannot talk to GitHub: %v", err)
}
switch resp.StatusCode {
case 200:
defer resp.Body.Close()
case 401, 404:
return nil, ErrNoRepo
default:
return nil, fmt.Errorf("error from GitHub: %v", resp.Status)
}
data, err = ioutil.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("error reading from GitHub: %v", err)
}
var mrefi, mrefj int
var vrefi, vrefj int
var vrefv = InvalidVersion
var unversioned = true
sdata := string(data)
for i, j := 0, 0; i < len(data); i = j {
size, err := strconv.ParseInt(sdata[i:i+4], 16, 32)
if err != nil {
return nil, fmt.Errorf("cannot parse refs line size: %s", string(data[i:i+4]))
}
if size == 0 {
size = 4
}
j = i + int(size)
if j > len(sdata) {
return nil, fmt.Errorf("incomplete refs data received from GitHub")
}
if sdata[0] == '#' {
continue
}
hashi := i + 4
hashj := strings.IndexByte(sdata[hashi:j], ' ')
if hashj < 0 || hashj != 40 {
continue
}
hashj += hashi
namei := hashj + 1
namej := strings.IndexAny(sdata[namei:j], "\n\x00")
if namej < 0 {
namej = j
} else {
namej += namei
}
name := sdata[namei:namej]
if name == "refs/heads/master" {
mrefi = hashi
mrefj = hashj
}
if strings.HasPrefix(name, "refs/heads/v") || strings.HasPrefix(name, "refs/tags/v") {
v, ok := parseVersion(name[strings.IndexByte(name, 'v'):])
if ok && repo.Version.Contains(v) && (!vrefv.IsValid() || vrefv.Less(v)) {
vrefv = v
vrefi = hashi
vrefj = hashj
}
if ok {
unversioned = false
}
}
}
// If there were absolutely no versions, and v0 was requested, accept the master as-is.
if unversioned && repo.Version == (Version{0, -1, -1}) {
return data, nil
}
if mrefi == 0 || vrefi == 0 {
return nil, ErrNoVersion
}
copy(data[mrefi:mrefj], data[vrefi:vrefj])
return data, nil
}