How to build a menu feed

In the following tutorial we will demonstrate how to build a feed in JSON using the Google Protocol Buffers (protobuf) definition. We will use the protobuf compiler to generate source code based on the protobuf schema. Building a feed using the generated source code provides an easy interface and prevents feed entities from being created with incorrect field names or field types.

Project setup

• Create a new project directory.
• Copy the contents of food_menu.proto money.proto localized_text.proto from the proto definitions as new files to your project directory root.
• Install the protoc compiler

  In order to generate source code from the .proto files, you will need the protoc compiler. Download the latest pre-built binary from the Protocol Buffers GitHub release page.

  Extract the zip and add the bin path to the PATH environment variable, for example:

  unzip protoc-22.0-linux-x86_64.zip -d /usr/local/protoc
  export PATH="$PATH:/usr/local/protoc/bin"
    

Generate source code

Python

1. Install the Python protobuf library

   pip install protobuf
       

2. Generate client source code.

   Create the proto output directory: generated

   protoc --python_out=./generated food_menu.proto money.proto localized_text.proto
       

   Update the PYTHONPATH environment variable to include the generated path for example:

   export PYTHONPATH="$PYTHONPATH:./generated"
       

   If you are using Bazel, try the py_proto_library rule as an alternative to running protoc.

Usage example

Full example project can be found here.

"""Menu feed example used in

https://developers.google.com/maps-booking/verticals/dining/guides/tutorials/tutorial-menu-feed-protos#python.
"""
import json
from generated import food_menu_pb2
from google.protobuf.json_format import MessageToDict

# create feed
feed = food_menu_pb2.FoodMenuFeed()

# add a menu component to feed data
menuComponent = feed.data.add()
menuComponent.menu.menu_id = 'menu1'
menuComponent.menu.merchant_ids.append('dining-1')
menuDisplayName = menuComponent.menu.display_name.text.add()
menuDisplayName.text = 'Menu'
menuDisplayName.language_code = 'en-us'
menuComponent.menu.language = 'en-us'
menuComponent.menu.last_merchant_update_time.seconds = 1633621547

for i in ['appetizers', 'dinner']:
  menuComponent.menu.menu_section_ids.append(i)

# add a menu section component to feed data
sectionComponent = feed.data.add()
sectionComponent.section.menu_section_id = 'appetizers'
sectionDisplayName = sectionComponent.section.display_name.text.add()
sectionDisplayName.text = 'Lunch Appetizers'
sectionDisplayName.language_code = 'en-us'
sectionComponent.section.menu_item_ids.append('breadsticks-sauce')

# add a menu item component to feed data
itemComponent = feed.data.add()
itemComponent.item.menu_item_id = 'breadsticks-sauce'
itemDisplayName = itemComponent.item.display_name.text.add()
itemDisplayName.text = 'Breadsticks & Sauce'
itemDisplayName.language_code = 'en-us'
itemDescription = itemComponent.item.description.text.add()
itemDescription.text = 'Breakfast basket w/ side of tomato sauce (size 6 or 12)'
itemDescription.language_code = 'en-us'

for i in ['breadstick-sm', 'breadstick-lg']:
  itemComponent.item.menu_item_option_set.menu_item_option_ids.append(i)

for i in [
    'http://www.example.com/photos/breadsticks.jpg',
    'http://www.example.com/photos/sauce.jpg',
]:
  itemImage = itemComponent.item.images.add()
  itemImage.uri = i

# add a menu item option component to feed data
optionComponent = feed.data.add()
optionComponent.option.menu_item_option_id: 'breadstick-sm'
optionComponent.option.value.property_type = (
    food_menu_pb2.MenuItemOptionProperty.PropertyType.SIZE
)
optionTextValue = optionComponent.option.value.text_val.text.add()
optionTextValue.text = 'Small'
optionTextValue.language_code = 'en-us'
optionOffer = optionComponent.option.offer_set.offers.add()
optionOffer.price.currency_code = 'USD'
optionOffer.price.units = 8
optionOffer.price.nanos = 0

feedJSON = json.dumps(MessageToDict(feed, preserving_proto_field_name=True))
print(feedJSON)

    

The code example demonstrates how to create a feed object with one of each of the following entities:

• Menu
• MenuSection
• MenuItem
• MenuItemOption

The example then shows how to serialize the feed to JSON.

The Python api allows lazy initialization of nested objects by setting the properties.

TypeScript

1. Install the TypeScript protoc plugin.

   npm init
   npm i -D typescript
   npm i ts-proto
         

   Note that ts-proto is not an officially supported Google project.
2. Create the output directory and generate client source code.

   Create the proto output directory: src/generated

   protoc --plugin="./node_modules/.bin/protoc-gen-ts_proto" --ts_proto_opt=useOptionals=all --ts_proto_opt=snakeToCamel=false --ts_proto_opt=onlyTypes=true --ts_proto_out="./src/generated" food_menu.proto money.proto localized_text.proto
         

   If you are using Bazel, try the js_proto_library rule as an alternative to running protoc.

Usage example

Full example project can be found here.

import {FoodMenuFeed, Menu, MenuItem, MenuSection, MenuItemOption, MenuItemOptionProperty_PropertyType} from './generated/food_menu';

const menu: Menu = {
  menu_id: 'menu1',
  merchant_ids: ['dining-1'],
  display_name: {text: [{text: 'Menu', language_code: 'en-us'}]},
  language: 'en-us',
  menu_section_ids: ['appetizers', 'dinner'],
  last_merchant_update_time: new Date()
};

const section: MenuSection = {
  menu_section_id: 'appetizers',
  display_name: {text: [{text: 'Lunch Appetizers', language_code: 'en-us'}]},
  menu_section_ids: ['breadsticks-sauce']
};

const item: MenuItem = {
  menu_item_id: 'breadsticks-sauce',
  display_name: {text: [{text: 'Breadsticks & Sauce', language_code: 'en-us'}]},
  description: {
    text: [{
      text: 'Breakfast basket w/ side of tomato sauce (size 6 or 12)',
      language_code: 'en-us'
    }]
  },
  menu_item_option_set:
      {menu_item_option_ids: ['breadstick-sm', 'breadstick-lg']},
  images: [
    {uri: 'http://www.example.com/photos/breadsticks.jpg'},
    {uri: 'http://www.example.com/photos/sauce.jpg'}
  ]
};

const option: MenuItemOption = {
  menu_item_option_id: 'breadstick-sm',
  value: {
    property_type: MenuItemOptionProperty_PropertyType.SIZE,
    text_val: {
      text: [
        {text: "Small", language_code: "en-us"}
      ]
     }
  },
  offer_set: {
    offers: [{
      price: {
        currency_code: "USD",
        units: 8,
        nanos: 0
      }
    }]
  }
};

const feed: FoodMenuFeed = {
  data: [{menu}, {section}, {item}, {option}]
};

console.log(JSON.stringify(feed));

  

The code example demonstrates how to create a feed object with one of each of the following entities:

• Menu
• MenuSection
• MenuItem
• MenuItemOption

The example then shows how to serialize the feed to JSON.

Java

1. Add the dependencies protobuf-java and protobuf-java-util to your project using either maven or gradle as described here.
2. Generate client source code.

   protoc --java_out=src/main/java food_menu.proto money.proto localized_text.proto
       

   You may use the protobuf-maven-plugin to generate the source code during compile time when using maven.

   If you are using Bazel, try the java_proto_library rule as an alternative to running protoc.

Usage example

Full example project can be found here.

package com.example;

import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.Timestamp;
import com.google.type.Money;
import com.google.protobuf.util.JsonFormat;
import com.google.type.LocalizedText;
import food.menu.v1.FoodMenu.FoodMenuFeed;
import food.menu.v1.FoodMenu.Menu;
import food.menu.v1.FoodMenu.MenuComponent;
import food.menu.v1.FoodMenu.MenuItem;
import food.menu.v1.FoodMenu.MenuSection;
import food.menu.v1.FoodMenu.TextField;
import food.menu.v1.FoodMenu.MenuItemOption;
import food.menu.v1.FoodMenu.MenuItemOptionProperty;
import food.menu.v1.FoodMenu.OfferSet;
import food.menu.v1.FoodMenu.Offer;

/**
 * Menu feed example used in
 *
 * <p>https://developers.google.com/maps-booking/verticals/dining/guides/tutorials/tutorial-menu-feed-protos#java.
 */
public class Feed {

  public static void main(String[] args) throws InvalidProtocolBufferException {
    Feed feed = new Feed();
    feed.createMenuFeed();
  }

  public void createMenuFeed() throws InvalidProtocolBufferException {

    Menu.Builder menu =
        Menu.newBuilder()
            .setMenuId("menu1")
            .addMerchantIds("dining-1")
            .setDisplayName(
                TextField.newBuilder()
                    .addText(LocalizedText.newBuilder().setText("Menu").setLanguageCode("en-us")))
            .setLanguage("en-us")
            .setLastMerchantUpdateTime(Timestamp.newBuilder().setSeconds(1633621547));

    MenuSection.Builder section =
        MenuSection.newBuilder()
            .setMenuSectionId("appetizers")
            .setDisplayName(
                TextField.newBuilder()
                    .addText(
                        LocalizedText.newBuilder()
                            .setText("Lunch Appetizers")
                            .setLanguageCode("en-us")))
            .addMenuItemIds("breadsticks-sauce");

    MenuItem.Builder item =
        MenuItem.newBuilder()
            .setMenuItemId("breadsticks-sauce")
            .setDisplayName(
                TextField.newBuilder()
                    .addText(
                        LocalizedText.newBuilder()
                            .setText("Breadsticks & Sauce")
                            .setLanguageCode("en-us")))
            .setDescription(
                TextField.newBuilder()
                    .addText(
                        LocalizedText.newBuilder()
                            .setText("Breadsticks & Sauce")
                            .setLanguageCode("en-us")));

    MenuItemOption.Builder option =
        MenuItemOption.newBuilder()
          .setMenuItemOptionId("breadstick-sm")
          .setValue(
              MenuItemOptionProperty.newBuilder()
                .setPropertyType(MenuItemOptionProperty.PropertyType.SIZE)
                .setTextVal(TextField.newBuilder()
                    .addText(
                        LocalizedText.newBuilder()
                            .setText("Small")
                            .setLanguageCode("en-us"))))
          .setOfferSet(
              OfferSet.newBuilder()
                .addOffers(
                    Offer.newBuilder()
                      .setPrice(
                          Money.newBuilder()
                            .setCurrencyCode("USD")
                            .setUnits(8)
                            .setNanos(0))));

    FoodMenuFeed.Builder foodMenuFeed =
        FoodMenuFeed.newBuilder()
            .addData(MenuComponent.newBuilder().setMenu(menu))
            .addData(MenuComponent.newBuilder().setSection(section))
            .addData(MenuComponent.newBuilder().setItem(item))
            .addData(MenuComponent.newBuilder().setOption(option));

    String feedJSON =
        JsonFormat.printer()
            .omittingInsignificantWhitespace()
            .preservingProtoFieldNames()
            .print(foodMenuFeed);

    System.out.println(feedJSON);
  }
}

    

The code example demonstrates how to create a feed object with one of each of the following entities:

• Menu
• MenuSection
• MenuItem
• MenuItemOption

The example then shows how to serialize the feed to JSON.

Go

1. Install the protoc plugin for go

   go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
       

   Update the PATH environment variable to include the protoc-gen-go plugin, for example:

   export PATH="$PATH:$(go env GOPATH)/bin"
       

2. Initialize app and generate client source code.

   go mod init feed/app
   mkdir generated
   protoc --go_out=./generated/ food_menu.proto money.proto localized_text.proto
       

   If you are using Bazel, try the go_proto_library rule as an alternative to running protoc.

Usage example

Full example project can be found here.

/*
Menu feed example used in
https://developers.google.com/maps-booking/verticals/dining/guides/tutorials/tutorial-menu-feed-protos#go.
*
*/
package main

import (
	pb "feed/app/generated/food/menu/v1/proto"
	"fmt"

	localized_text "google.golang.org/genproto/googleapis/type/localized_text"
	money "google.golang.org/genproto/googleapis/type/money"
	"google.golang.org/protobuf/encoding/protojson"
	timestamppb "google.golang.org/protobuf/types/known/timestamppb"
)

func main() {

	//create a menu component
	menu := &pb.Menu{
		MenuId:      "menu1",
		MerchantIds: []string{"dining-1"},
		DisplayName: &pb.TextField{
			Text: []*localized_text.LocalizedText{{
				Text:         "Menu",
				LanguageCode: "en-us",
			}},
		},
		Language: "en-us",
		LastMerchantUpdateTime: &timestamppb.Timestamp{
			Seconds: 1633621547,
		},
	}

	//create a menu section component
	section := &pb.MenuSection{
		MenuSectionId: "appetizers",
		DisplayName: &pb.TextField{
			Text: []*localized_text.LocalizedText{{
				Text:         "Lunch Appetizers",
				LanguageCode: "en-us",
			}},
		},
		MenuItemIds: []string{"breadsticks-sauce"},
	}

	//create a menu item component
	item := &pb.MenuItem{
		MenuItemId: "breadsticks-sauce",
		DisplayName: &pb.TextField{
			Text: []*localized_text.LocalizedText{{
				Text:         "Breadsticks & Sauce",
				LanguageCode: "en-us",
			}},
		},
		Description: &pb.TextField{
			Text: []*localized_text.LocalizedText{{
				Text:         "Breakfast basket w/ side of tomato sauce (size 6 or 12)",
				LanguageCode: "en-us",
			}},
		},
		Pricing: &pb.MenuItem_MenuItemOptionSet_{
			MenuItemOptionSet: &pb.MenuItem_MenuItemOptionSet{
				MenuItemOptionIds: []string{"breadstick-sm", "breadstick-lg"},
			},
		},
	}
	imageUris := []string{
		"http://www.example.com/photos/breadsticks.jpg",
		"http://www.example.com/photos/sauce.jpg",
	}
	for _, uri := range imageUris {
		image := &pb.Image{
			Uri: uri,
		}
		item.Images = append(item.Images, image)
	}

	//create a menu item option
	option := &pb.MenuItemOption{
		MenuItemOptionId: "breadstick-sm",
		Value: &pb.MenuItemOptionProperty{
			PropertyType: pb.MenuItemOptionProperty_SIZE,
			Value: &pb.MenuItemOptionProperty_TextVal{
				TextVal: &pb.TextField{
					Text: []*localized_text.LocalizedText{{
						Text:         "Small",
						LanguageCode: "en-us",
					}},
				},
			},
		},
		OfferSet: &pb.OfferSet{
			Offers: []*pb.Offer{{
				Price: &money.Money{
					CurrencyCode: "USD",
					Units:        8,
					Nanos:        0,
				},
			}},
		},
	}

	//create feed
	feed := &pb.FoodMenuFeed{
		Data: []*pb.MenuComponent{{
			Type: &pb.MenuComponent_Menu{
				Menu: menu,
			},
		},
			{
				Type: &pb.MenuComponent_Section{
					Section: section,
				},
			},
			{
				Type: &pb.MenuComponent_Item{
					Item: item,
				},
			},
			{
				Type: &pb.MenuComponent_Option{
					Option: option,
				},
			}},
	}

	marshalOptions := protojson.MarshalOptions{
		UseProtoNames: true,
	}
	jsonBytes, _ := marshalOptions.Marshal(feed)
	fmt.Printf("message = %s", string(jsonBytes))
}


    

The code example demonstrates how to create a feed object with one of each of the following entities:

• Menu
• MenuSection
• MenuItem
• MenuItemOption

The example then shows how to serialize the feed to JSON.