Move wm_flow off of views and onto Sky

sky/tools/skygo/sky_server.go

 // Copyright (c) 2014 The Chromium 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 main
 
 import (
     "flag"
+    "fmt"
     "io/ioutil"
     "net/http"
+    "os"
     "path"
+    "path/filepath"
     "strings"
 )
 
 type skyHandlerRoot struct {
     root string
 }
 
 func skyHandler(root string) http.Handler {
     return &skyHandlerRoot{root}
 }
 
 func (handler *skyHandlerRoot) ServeHTTP(w http.ResponseWriter, r *http.Request) {
     path := path.Join(handler.root, r.URL.Path)
     if strings.HasSuffix(path, ".sky") {
         w.Header().Set("Content-Type", "text/sky")
     }
     http.ServeFile(w, r, path)
 }
 
+func usage() {
+    fmt.Fprintf(os.Stderr, "Usage: sky_server [flags] MOJO_SRC_ROOT PORT\n\n")
+    fmt.Fprintf(os.Stderr, "launches a basic http server with mappings into the\n")
+    fmt.Fprintf(os.Stderr, "mojo repository for framework/service paths.\n")
+    fmt.Fprintf(os.Stderr, "[flags] MUST be before arguments, because go:flag.\n\n")
+    flag.PrintDefaults()
+    os.Exit(2)
+}
+
+func addMapping(from_path string, to_path string) {
+    // Print to stderr to it's more obvious what this binary does.
+    fmt.Fprintf(os.Stderr, "  %s -> %s\n", from_path, to_path)
+    http.Handle(from_path, http.StripPrefix(from_path, skyHandler(to_path)))
+}
+
 func main() {
     var configuration = flag.String("t", "Release", "The target configuration (i.e. Release or Debug)")
+
     flag.Parse()
+    flag.Usage = usage
+    // The built-in go:flag is awful.  It only allows short-name arguments
+    // and they *must* be before any unnamed arguments.  There are better ones:
+    // https://godoc.org/github.com/jessevdk/go-flags
+    // but for now we're using raw-go.
+    if flag.NArg() != 2 {
+        usage()
+    }
 
-    args := flag.Args()
-    root := args[0]
-    port := args[1]
+    root, _ := filepath.Abs(flag.Arg(0))
+    port := flag.Arg(1)
 
     genRoot := path.Join(root, "out", *configuration, "gen")
 
+    fmt.Fprintf(os.Stderr, "Mappings for localhost:%s:\n", port)
+
+    fmt.Fprintf(os.Stderr, "  / -> %s\n", root)
     http.Handle("/", skyHandler(root))
+
+    fmt.Fprintf(os.Stderr, "  /echo_post -> custom echo handler\n")
     http.HandleFunc("/echo_post", func(w http.ResponseWriter, r *http.Request) {
         defer r.Body.Close()
         body, _ := ioutil.ReadAll(r.Body)
         w.Write(body)
     })
-    http.Handle("/mojo/public/", http.StripPrefix("/mojo/public/", skyHandler(path.Join(genRoot, "mojo", "public"))))
-    http.Handle("/mojo/services/", http.StripPrefix("/mojo/services/", skyHandler(path.Join(genRoot, "mojo", "services"))))
-    http.Handle("/sky/services/", http.StripPrefix("/sky/services/", skyHandler(path.Join(genRoot, "sky", "services"))))
+
+    addMapping("/gen/", genRoot)
+
+    // FIXME: Unclear if these are correct now that we have /gen.
+    // /gen is more explicit, but also is less like how a 3rd party might
+    // deploy a sky app.
+    addMapping("/mojo/public/", path.Join(genRoot, "mojo", "public"))
+    addMapping("/mojo/services/", path.Join(genRoot, "mojo", "services"))
+    addMapping("/sky/services/", path.Join(genRoot, "sky", "services"))
 
     http.ListenAndServe(":" + port, nil)
 }