(serve): Migrate code and setup the Serve method

gomods.go

@@ -1,13 +1,21 @@
 package gomods
 
 import (
+	"encoding/json"
+	"fmt"
+	"io"
 	"net/http"
 	"os"
 	"regexp"
+	"strings"
 
 	"github.com/gomods/athens/pkg/download"
+	"github.com/gomods/athens/pkg/download/addons"
 	"github.com/gomods/athens/pkg/module"
+	"github.com/gomods/athens/pkg/paths"
+	"github.com/gomods/athens/pkg/stash"
 	"github.com/gomods/athens/pkg/storage"
+	"github.com/gomods/athens/pkg/storage/fs"
 	"github.com/spf13/afero"
 )
 
@@ -26,3 +34,167 @@ type ModuleHandler interface {
 var gomodsRegex = regexp.MustCompile("(list|info|mod|zip)")
 var modVersionRegex = regexp.MustCompile("(.*)\\.(info|mod|zip)")
 var DefaultGoBinaryPath = os.Getenv("GOROOT") + "/bin/go"
+
+func (conf *Config) Serve(w http.ResponseWriter, r *http.Request) error {
+	m := Module{}
+	if err := m.ParseImportPath(r.URL.Path); err != nil {
+		return fmt.Errorf("module url is empty")
+	}
+
+	dp, err := m.fetch(r, *conf)
+	if err != nil {
+		return err
+	}
+
+	switch m.FileExt {
+	case "list":
+		list, err := dp.List(r.Context(), m.Name)
+		if err != nil {
+			return err
+		}
+		_, err = w.Write([]byte(strings.Join(list, "\n")))
+		if err != nil {
+			return err
+		}
+		return nil
+	case "info":
+		info, err := dp.Info(r.Context(), m.Name, m.Version)
+		if err != nil {
+			return err
+		}
+		_, err = w.Write(info)
+		if err != nil {
+			return err
+		}
+		return nil
+	case "mod":
+		mod, err := dp.GoMod(r.Context(), m.Name, m.Version)
+		if err != nil {
+			return err
+		}
+		_, err = w.Write(mod)
+		if err != nil {
+			return err
+		}
+		return nil
+	case "zip":
+		zip, err := dp.Zip(r.Context(), m.Name, m.Version)
+		if err != nil {
+			return err
+		}
+		defer zip.Close()
+		w.Write([]byte{})
+		_, err = io.Copy(w, zip)
+		if err != nil {
+			return err
+		}
+		return nil
+	case "latest":
+		info, err := dp.Latest(r.Context(), m.Name)
+		if err != nil {
+			return err
+		}
+		json, err := json.Marshal(info)
+		if err != nil {
+			return err
+		}
+		_, err = w.Write(json)
+		if err != nil {
+			return err
+		}
+		return nil
+	default:
+		return fmt.Errorf("the requested file's extension is not supported")
+	}
+}
+
+func (m Module) fetch(r *http.Request, c Config) (download.Protocol, error) {
+	fetcher, err := module.NewGoGetFetcher(c.GoBinary, c.Fs)
+	if err != nil {
+		return nil, err
+	}
+	s, err := m.storage(c)
+	if err != nil {
+		return nil, err
+	}
+	dp := m.dp(fetcher, s, c)
+	return dp, nil
+}
+
+func (m Module) storage(c Config) (storage.Backend, error) {
+	switch c.Cache.Type {
+	case "local":
+		// Check if cache storage path exists, if not create it
+		if _, err := os.Stat(c.Cache.Path); os.IsNotExist(err) {
+			if err = os.MkdirAll(c.Cache.Path, os.ModePerm); err != nil {
+				return nil, fmt.Errorf("couldn't create the cache storage directory on %s: %s", c.Cache.Path, err.Error())
+			}
+		}
+		s, err := fs.NewStorage(c.Cache.Path, afero.NewOsFs())
+		if err != nil {
+			return nil, fmt.Errorf("could not create new storage from os fs (%s)", err)
+		}
+		return s, nil
+	case "tmp":
+		s, err := fs.NewStorage(c.Cache.Path, afero.NewOsFs())
+		if err != nil {
+			return nil, fmt.Errorf("could not create new storage from os fs (%s)", err)
+		}
+		return s, nil
+	}
+	return nil, fmt.Errorf("Invalid storage config for gomods")
+}
+
+func (m Module) dp(fetcher module.Fetcher, s storage.Backend, c Config) download.Protocol {
+	lister := download.NewVCSLister(c.GoBinary, c.Fs)
+	st := stash.New(fetcher, s, stash.WithPool(c.Workers), stash.WithSingleflight)
+	dpOpts := &download.Opts{
+		Storage: s,
+		Stasher: st,
+		Lister:  lister,
+	}
+	dp := download.New(dpOpts, addons.WithPool(c.Workers))
+	return dp
+}
+
+// ParseImportPath parses the request path and exports the
+// module's import path, module's version and file extension
+func (m *Module) ParseImportPath(path string) error {
+	if strings.Contains(path, "@latest") {
+		pathLatest := strings.Split(path, "/@")
+		m.Name, m.Version, m.FileExt = pathLatest[0][1:], "", pathLatest[1]
+		if err := m.DecodeImportPath(); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	// First item in array is modules import path and the secondd item is version+extension
+	pathSlice := strings.Split(path, "/@v/")
+	if pathSlice[1] == "list" {
+		m.Name, m.Version, m.FileExt = pathSlice[0][1:], "", "list"
+		if err := m.DecodeImportPath(); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	versionExt := modVersionRegex.FindAllStringSubmatch(pathSlice[1], -1)[0]
+	m.Name, m.Version, m.FileExt = pathSlice[0][1:], versionExt[1], versionExt[2]
+	if err := m.DecodeImportPath(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// DecodeImportPath decodes the module's import path. For more information check
+// https://github.com/golang/go/blob/master/src/cmd/go/internal/module/module.go#L375-L433
+func (m *Module) DecodeImportPath() error {
+	decoded, err := paths.DecodePath(m.Name)
+	if err != nil {
+		return err
+	}
+	m.Name = decoded
+	return nil
+}

setup.go

@@ -1,7 +1,6 @@
 package gomods
 
 import (
-	"fmt"
 	"net/http"
 
 	"github.com/caddyserver/caddy"
@@ -64,8 +63,7 @@ type Gomods struct {
 }
 
 func (rd Gomods) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
-	// rd.Config.Serve(w, r)
-	if err := fmt.Errorf(""); err != nil {
+	if err := rd.Config.Serve(w, r); err != nil {
 		if err.Error() == "option disabled" {
 			return rd.Next.ServeHTTP(w, r)
 		}