A client/server helper wrapper for endpoints in Go.

go/src/infra/gae/libs/ephelper/ephelper.go

+// Copyright 2015 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 ephelper
+
+import (
+        "errors"
+        "fmt"
+
+        "github.com/GoogleCloudPlatform/go-endpoints/endpoints"
+)
+
+const errPrefix = "endpoints.Register: "
+
+var (
+        // ErrServerNil is returned if you pass a nil server to Register. Don't do
+        // that.
+        ErrServerNil = errors.New(errPrefix + "server is nil")
+
+        // ErrServiceNil is returned if you pass a nil service to Register. Don't do
+        // that.
+        ErrServiceNil = errors.New(errPrefix + "service is nil")
+)
+
+// MethodInfoMap is the common registry for an endpoints service. It's
+// used by infra/libs/endpoints_client to populate its API.
+type MethodInfoMap map[string]*endpoints.MethodInfo
+
+// Register adds an endpoints.RegisterService-compatible service object using
+// the MethodInfoMap to look up the MethodInfo objects by methodName. It is
+// intended to be called at init()-time of an app or client which relies on
+// these endpoints.
+//
+// service should be an instance of your service type (as if you were passing
+// it to "go-endpoints/endpoints".RegisterService).
+func Register(server *endpoints.Server, service interface{}, si *endpoints.ServiceInfo, mi MethodInfoMap) error {
+        if server == nil {
+                return ErrServerNil
+        }
+        if service == nil {
+                return ErrServiceNil
+        }
+        if si == nil {
+                si = &endpoints.ServiceInfo{Default: true}
+        }
+
+        api, err := server.RegisterService(service, si.Name, si.Version,
+                si.Description, si.Default)
+        if err != nil {
+                return err
+        }
+
+        for methodName, info := range mi {
+                method := api.MethodByName(methodName)
+                if method == nil {
+                        return fmt.Errorf(
+                                errPrefix+"no method %q (did you forget to export it?)", methodName)
+                }
+                curInfo := method.Info()
+                // These three are set automatically based on reflection, so only override
+                // them if the info object contains something new.
+                if info.Name == "" {
+                        info.Name = curInfo.Name
+                }
+                if info.Path == "" {
+                        info.Path = curInfo.Path
+                }
+                if info.HTTPMethod == "" {
+                        info.HTTPMethod = curInfo.HTTPMethod
+                }
+                *curInfo = *info
+                mi[methodName] = curInfo // So that we can observe the merged result
+        }
+
+        return nil
+}