Tutorial do Slack: comandos Slash

---

Observação: este conteúdo se aplica apenas às funções do Cloud Run, anteriormente chamadas de Cloud Functions (2ª geração).

Para a versão da 1ª geração deste documento, consulte o Tutorial do Slack (1a geração).

Neste tutorial, você aprenderá a usar o Cloud Run functions para implementar um comando Slash do Slack que pesquisa a API Knowledge Graph do Google.

Objetivos

• Criar um Slash Command no Slack.
• Escrever e implantar um Cloud Run functions HTTP.
• Pesquisar a API Google Knowledge Graph usando o Slash Command.

Custos

Neste documento, você usará os seguintes componentes faturáveis do Google Cloud:

• Cloud Run functions
• Cloud Build
• Artifact Registry
• Cloud Logging

For details, see Cloud Run functions pricing.

Para gerar uma estimativa de custo baseada na projeção de uso deste tutorial, use a calculadora de preços. Novos usuários do Google Cloud podem estar qualificados para uma avaliação gratuita.

Antes de começar

1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

3. Make sure that billing is enabled for your Google Cloud project.

4. Enable the Cloud Functions, Cloud Build, Artifact Registry, and Logging APIs.

   Enable the APIs

5. Install the Google Cloud CLI.

6. To initialize the gcloud CLI, run the following command:

   gcloud init

7. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

8. Make sure that billing is enabled for your Google Cloud project.

9. Enable the Cloud Functions, Cloud Build, Artifact Registry, and Logging APIs.

   Enable the APIs

10. Install the Google Cloud CLI.

11. To initialize the gcloud CLI, run the following command:

    gcloud init

Se a gcloud CLI já estiver instalada, atualize-a executando o seguinte comando:

gcloud components update

12. Prepare seu ambiente de desenvolvimento.

    Node.js

    Acessar o guia de configuração do Node.js

    Python

    Acessar o guia de configuração do Python

    Go

    Acessar o guia de configuração do Go

    Java

    Acessar o guia de configuração do Java

    C#

    Acessar o guia de configuração do .NET

    Ruby

    Acessar o guia de configuração do Ruby

    PHP

    Acessar "Como usar o PHP no Google Cloud"

Como visualizar o fluxo de dados

O fluxo de dados no aplicativo de tutorial do Slack Slash Command envolve vários passos:

1. O usuário executa o Slash Command /kg <search_query> em um canal Slack.
2. O Slack envia o payload do comando ao endpoint do gatilho do Cloud Run functions.
3. O Cloud Run functions envia uma solicitação com a consulta de pesquisa do usuário para a API Knowledge Graph.
4. A API Knowledge Graph responde com todos os resultados encontrados.
5. O Cloud Run function formata a resposta em uma mensagem do Slack.
6. O Cloud Run function envia a mensagem de volta ao Slack.
7. O usuário vê a resposta formatada no canal do Slack.

Isto pode ajudar a visualizar os passos:

Receber credenciais

Para implantar a função, você precisa de uma chave de API fornecida pelo Console do Google Cloud e de uma chave secreta de assinatura do Slack.

Onde encontrar a chave de API do Mapa de informações

Na página Credenciais do Console do Google Cloud, clique no botão Criar credenciais e selecione Chave de API. Lembre-se dessa chave, porque ela será incluída como parte do comando deploy. Essa chave é o que possibilita sua função a acessar a API Knowledge Graph.

Receber a chave secreta de assinatura do Slack

A chave secreta de assinatura do Slack também é necessária para implantar a função. Para receber a chave secreta de assinatura do Slack, crie o app Slack que hospedará o comando Slash do Slack. Esse aplicativo precisa estar associado a uma equipe do Slack em que você tenha permissões para instalar integrações.

1. Acesse a página Seus aplicativos do Slack e clique em Criar novo aplicativo.

2. Selecione Do zero.

3. Forneça um nome para seu app e selecione um espaço de trabalho do Slack em que você tenha permissões para instalar integrações.

4. Clique em Create App.

   O app é criado, e a tela muda para a página Informações básicas.

5. Na página Informações básicas, copie e salve a chave secreta de assinatura do Slack.

6. Salve as alterações.

Em seguida, você precisa receber o código-fonte e implantar a função. Depois de implantar a função, é preciso configurar o app Slack para integrá-la à função implantada, conforme descrito em Como configurar o aplicativo.

Como preparar a função

1. Clone o repositório do app de amostra na máquina local:

   Node.js

   git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git

   Outra alternativa é fazer o download da amostra como um arquivo ZIP e extraí-lo.

   Python

   git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git

   Outra alternativa é fazer o download da amostra como um arquivo ZIP e extraí-lo.

   Go

   git clone https://github.com/GoogleCloudPlatform/golang-samples.git

   Outra alternativa é fazer o download da amostra como um arquivo ZIP e extraí-lo.

   Java

   git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git

   Outra alternativa é fazer o download da amostra como um arquivo ZIP e extraí-lo.

   C#

   git clone https://github.com/GoogleCloudPlatform/dotnet-docs-samples.git

   Outra alternativa é fazer o download da amostra como um arquivo ZIP e extraí-lo.

   Ruby

   git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples.git

   Outra alternativa é fazer o download da amostra como um arquivo ZIP e extraí-lo.

   PHP

   git clone https://github.com/GoogleCloudPlatform/php-docs-samples.git

   Outra alternativa é fazer o download da amostra como um arquivo ZIP e extraí-lo.

2. Mude para o diretório que contém o código de amostra das funções do Cloud Run:

   Node.js

   cd nodejs-docs-samples/functions/slack/

   Python

   cd python-docs-samples/functions/slack/

   Go

   cd golang-samples/functions/functionsv2/slack/

   Java

   cd java-docs-samples/functions/slack/

   C#

   cd dotnet-docs-samples/functions/slack/SlackKnowledgeGraphSearch/

   Ruby

   cd ruby-docs-samples/functions/slack/

   PHP

   cd php-docs-samples/functions/slack_slash_command/

Como implantar a função

Para implantar a função executada quando você (ou o Slack) faz uma solicitação HTTP POST para o endpoint da função, execute o comando a seguir no diretório que contém o código da amostra (ou o arquivo pom.xml para Java):

Substitua YOUR_SLACK_SIGNING_SECRET pelo secret de assinatura fornecido pelo Slack na página Informações básicas da configuração do aplicativo e YOUR_KG_API_KEY pela chave da API Knowledge Graph criada anteriormente.

Node.js

gcloud functions deploy nodejs-slack-function \
--gen2 \
--runtime=nodejs20 \
--region=REGION \
--source=. \
--entry-point=kgSearch \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Use a flag --runtime para especificar o ID do ambiente de execução de uma versão do Node.js compatível a fim de executar a função.

Python

gcloud functions deploy python-slack-function \
--gen2 \
--runtime=python312 \
--region=REGION \
--source=. \
--entry-point=kg_search \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Use a flag --runtime para especificar o ID do ambiente de execução de uma versão compatível do Python a fim de executar a função.

Go

gcloud functions deploy go-slack-function \
--gen2 \
--runtime=go121 \
--region=REGION \
--source=. \
--entry-point=KGSearch \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Use a flag --runtime para especificar o ID do ambiente de execução de uma versão do Go compatível a fim de executar a função.

Java

gcloud functions deploy java-slack-function \
--gen2 \
--runtime=java17 \
--region=REGION \
--source=. \
--entry-point=functions.SlackSlashCommand \
--memory=512MB \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Use a flag --runtime para especificar o ID do ambiente de execução de uma versão compatível do Java a fim de executar a função.

C#

gcloud functions deploy csharp-slack-function \
--gen2 \
--runtime=dotnet6 \
--region=REGION \
--source=. \
--entry-point=SlackKnowledgeGraphSearch.Function \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Use a flag --runtime para especificar o ID do ambiente de execução de uma versão do .NET compatível a fim de executar a função.

Ruby

gcloud functions deploy ruby-slack-function \
--gen2 \
--runtime=ruby32 \
--region=REGION \
--source=. \
--entry-point=kg_search \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Use a flag --runtime para especificar o ID do ambiente de execução de uma versão compatível do Ruby a fim de executar a função.

PHP

gcloud functions deploy php-slack-function \
--gen2 \
--runtime=php82 \
--region=REGION \
--source=. \
--entry-point=receiveRequest \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Use a flag --runtime para especificar o ID do ambiente de execução de uma versão do PHP compatível a fim de executar a função.

Observação: para configurar seu aplicativo conforme descrito na seção a seguir, certifique-se de ter implantado sua função com a sinalização --allow-unauthenticated. Como alternativa, é possível usar o Console para conceder o papel de Invocador do Cloud Run functions a allUsers.

Configurar o aplicativo

Depois que a função é implementada, você precisa criar um Slack Slash Command que envia a consulta para a função toda vez que o comando for acionado:

1. Volte para o app Slack criado acima.

2. Selecione o app, acesse Comandos de barra e clique no botão Criar novo comando.

3. Insira /kg como o nome do comando.

4. No campo URL de solicitação, insira o URL da sua função.

   É possível copiar o URL na saída do comando deploy ou acessar a página Visão geral do Cloud Run functions no console do Google Cloud. Clique na função para abra a página Detalhes da função e copie o URL dela.

5. Digite uma breve descrição e clique em Salvar.

6. Vá para Informações básicas.

7. Clique em Instalar no espaço de trabalho e siga as instruções na tela para ativar o aplicativo no seu espaço de trabalho.

   Seu Slack Slash Command ficará on-line em breve.

Como entender o código

Como importar dependências

O aplicativo importa várias dependências para se comunicar com os serviços do Google Cloud Platform:

Node.js

const functions = require('@google-cloud/functions-framework');
const google = require('@googleapis/kgsearch');
const {verifyRequestSignature} = require('@slack/events-api');

// Get a reference to the Knowledge Graph Search component
const kgsearch = google.kgsearch('v1');

Python

import os

from flask import jsonify
import functions_framework
import googleapiclient.discovery
from slack.signature import SignatureVerifier


kgsearch = googleapiclient.discovery.build(
    "kgsearch", "v1", developerKey=os.environ["KG_API_KEY"], cache_discovery=False
)

Go

package slack

import (
	"context"
	"log"
	"os"

	"google.golang.org/api/kgsearch/v1"
	"google.golang.org/api/option"
)

var (
	entitiesService *kgsearch.EntitiesService
	kgKey           string
	slackSecret     string
)

func setup(ctx context.Context) {
	kgKey = os.Getenv("KG_API_KEY")
	slackSecret = os.Getenv("SLACK_SECRET")

	if entitiesService == nil {
		kgService, err := kgsearch.NewService(ctx, option.WithAPIKey(kgKey))
		if err != nil {
			log.Fatalf("kgsearch.NewService: %v", err)
		}
		entitiesService = kgsearch.NewEntitiesService(kgService)
	}
}

Java

private static final Logger logger = Logger.getLogger(SlackSlashCommand.class.getName());
private static final String API_KEY = getenv("KG_API_KEY");
private static final String SLACK_SECRET = getenv("SLACK_SECRET");
private static final Gson gson = new Gson();

private final String apiKey;
private final Kgsearch kgClient;
private final SlackSignature.Verifier verifier;

public SlackSlashCommand() throws IOException, GeneralSecurityException {
  this(new SlackSignature.Verifier(new SlackSignature.Generator(SLACK_SECRET)));
}

SlackSlashCommand(SlackSignature.Verifier verifier) throws IOException, GeneralSecurityException {
  this(verifier, API_KEY);
}

SlackSlashCommand(SlackSignature.Verifier verifier, String apiKey)
    throws IOException, GeneralSecurityException {
  this.verifier = verifier;
  this.apiKey = apiKey;
  this.kgClient = new Kgsearch.Builder(
      GoogleNetHttpTransport.newTrustedTransport(), new GsonFactory(), null).build();
}

// Avoid ungraceful deployment failures due to unset environment variables.
// If you get this warning you should redeploy with the variable set.
private static String getenv(String name) {
  String value = System.getenv(name);
  if (value == null) {
    logger.warning("Environment variable " + name + " was not set");
    value = "MISSING";
  }
  return value;
}

C#

using Google.Apis.Kgsearch.v1;
using Google.Apis.Services;
using Google.Cloud.Functions.Hosting;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using System;

// Specify a startup class to use for dependency injection.
// This can also be specified on the function type.
[assembly: FunctionsStartup(typeof(SlackKnowledgeGraphSearch.Startup))]

namespace SlackKnowledgeGraphSearch;

public class Startup : FunctionsStartup
{
    private static readonly TimeSpan SlackTimestampTolerance = TimeSpan.FromMinutes(5);

    public override void ConfigureServices(WebHostBuilderContext context, IServiceCollection services)
    {
        // These can come from an environment variable or a configuration file.
        string kgApiKey = context.Configuration["KG_API_KEY"];
        string slackSigningSecret = context.Configuration["SLACK_SECRET"];

        services.AddSingleton(new KgsearchService(new BaseClientService.Initializer
        {
            ApiKey = kgApiKey
        }));
        services.AddSingleton(new SlackRequestVerifier(slackSigningSecret, SlackTimestampTolerance));
        base.ConfigureServices(context, services);
    }
}

Ruby

require "functions_framework"
require "slack-ruby-client"
require "google/apis/kgsearch_v1"

# This block is executed during cold start, before the function begins
# handling requests. This is the recommended way to create shared resources
# and objects.
FunctionsFramework.on_startup do
  # Create a global handler object, configured with the environment-provided
  # API key and signing secret.
  kg_search = KGSearch.new kg_api_key:     ENV["KG_API_KEY"],
                           signing_secret: ENV["SLACK_SECRET"]
  set_global :kg_search, kg_search
end

# The KGSearch class implements the logic of validating and responding
# to requests. More methods of this class are shown below.
class KGSearch
  def initialize kg_api_key:, signing_secret:
    # Create the global client for the Knowledge Graph Search Service,
    # configuring it with your API key.
    @client = Google::Apis::KgsearchV1::KgsearchService.new
    @client.key = kg_api_key

    # Save signing secret for use by the signature validation method.
    @signing_secret = signing_secret
  end

PHP

use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;
use GuzzleHttp\Psr7\Response;

Como receber o webhook

A função a seguir é executada quando você ou o Slack fazem uma solicitação HTTP POST para o ponto de extremidade da função.

Node.js

/**
 * Receive a Slash Command request from Slack.
 *
 * Trigger this function by creating a Slack slash command with the HTTP Trigger URL.
 * You can find the HTTP URL in the Cloud Console or using `gcloud functions describe`
 *
 * @param {object} req Cloud Function request object.
 * @param {object} req.body The request payload.
 * @param {string} req.rawBody Raw request payload used to validate Slack's message signature.
 * @param {string} req.body.text The user's search query.
 * @param {object} res Cloud Function response object.
 */
functions.http('kgSearch', async (req, res) => {
  try {
    if (req.method !== 'POST') {
      const error = new Error('Only POST requests are accepted');
      error.code = 405;
      throw error;
    }

    if (!req.body.text) {
      const error = new Error('No text found in body.');
      error.code = 400;
      throw error;
    }

    // Verify that this request came from Slack
    verifyWebhook(req);

    // Make the request to the Knowledge Graph Search API
    const response = await makeSearchRequest(req.body.text);

    // Send the formatted message back to Slack
    res.json(response);

    return Promise.resolve();
  } catch (err) {
    console.error(err);
    res.status(err.code || 500).send(err);
    return Promise.reject(err);
  }
});

Python

@functions_framework.http
def kg_search(request):
    if request.method != "POST":
        return "Only POST requests are accepted", 405

    verify_signature(request)
    kg_search_response = make_search_request(request.form["text"])
    return jsonify(kg_search_response)

Go

// Package slack is a Cloud Function which receives a query from
// a Slack command and responds with the KG API result.
package slack

import (
	"context"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	"github.com/GoogleCloudPlatform/functions-framework-go/functions"
)

const (
	version                     = "v0"
	slackRequestTimestampHeader = "X-Slack-Request-Timestamp"
	slackSignatureHeader        = "X-Slack-Signature"
)

type Attachment struct {
	Color     string `json:"color"`
	Title     string `json:"title"`
	TitleLink string `json:"title_link"`
	Text      string `json:"text"`
	ImageURL  string `json:"image_url"`
}

// Message is the a Slack message event.
// see https://api.slack.com/docs/message-formatting
type Message struct {
	ResponseType string       `json:"response_type"`
	Text         string       `json:"text"`
	Attachments  []Attachment `json:"attachments"`
}

func init() {
	functions.HTTP("KGSearch", kgSearch)
	setup(context.Background())
}

// kgSearch uses the Knowledge Graph API to search for a query provided
// by a Slack command.
func kgSearch(w http.ResponseWriter, r *http.Request) {

	bodyBytes, err := io.ReadAll(r.Body)
	if err != nil {
		log.Printf("failed to read body: %v", err)
		http.Error(w, "could not read request body", http.StatusBadRequest)
		return
	}
	if r.Method != "POST" {
		http.Error(w, "Only POST requests are accepted", http.StatusMethodNotAllowed)
		return
	}
	formData, err := url.ParseQuery(string(bodyBytes))
	if err != nil {
		log.Printf("Error: Failed to Parse Form: %v", err)
		http.Error(w, "Couldn't parse form", http.StatusBadRequest)
		return
	}

	result, err := verifyWebHook(r, bodyBytes, slackSecret)
	if err != nil || !result {
		log.Printf("verifyWebhook failed: %v", err)
		http.Error(w, "Failed to verify request signature", http.StatusBadRequest)
		return
	}

	if len(formData.Get("text")) == 0 {
		log.Printf("no search text found: %v", formData)
		http.Error(w, "search text was empty", http.StatusBadRequest)
		return
	}
	kgSearchResponse, err := makeSearchRequest(formData.Get("text"))
	if err != nil {
		log.Printf("makeSearchRequest failed: %v", err)
		http.Error(w, "makeSearchRequest failed", http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	if err = json.NewEncoder(w).Encode(kgSearchResponse); err != nil {
		http.Error(w, fmt.Sprintf("failed to marshal results: %v", err), 500)
		return
	}
}

Java

/**
 * Receive a Slash Command request from Slack.
 *
 * @param request Cloud Function request object.
 * @param response Cloud Function response object.
 * @throws IOException if Knowledge Graph request fails
 */
@Override
public void service(HttpRequest request, HttpResponse response) throws IOException {

  // Validate request
  if (!"POST".equals(request.getMethod())) {
    response.setStatusCode(HttpURLConnection.HTTP_BAD_METHOD);
    return;
  }

  // reader can only be read once per request, so we preserve its contents
  String bodyString = request.getReader().lines().collect(Collectors.joining());

  // Slack sends requests as URL-encoded strings
  //   Java 11 doesn't have a standard library
  //   function for this, so do it manually
  Map<String, String> body = new HashMap<>();
  for (String keyValuePair : bodyString.split("&")) {
    String[] keyAndValue = keyValuePair.split("=");
    if (keyAndValue.length == 2) {
      String key = keyAndValue[0];
      String value = keyAndValue[1];

      body.put(key, value);
    }
  }

  if (body == null || !body.containsKey("text")) {
    response.setStatusCode(HttpURLConnection.HTTP_BAD_REQUEST);
    return;
  }

  if (!isValidSlackWebhook(request, bodyString)) {
    response.setStatusCode(HttpURLConnection.HTTP_UNAUTHORIZED);
    return;
  }

  String query = body.get("text");

  // Call knowledge graph API
  JsonObject kgResponse = searchKnowledgeGraph(query);

  // Format response to Slack
  // See https://api.slack.com/docs/message-formatting
  BufferedWriter writer = response.getWriter();

  writer.write(formatSlackMessage(kgResponse, query));

  response.setContentType("application/json");
}

C#

private readonly ILogger _logger;
private readonly KgsearchService _kgService;
private readonly SlackRequestVerifier _verifier;

public Function(ILogger<Function> logger, KgsearchService kgService, SlackRequestVerifier verifier) =>
    (_logger, _kgService, _verifier) = (logger, kgService, verifier);

public async Task HandleAsync(HttpContext context)
{
    var request = context.Request;
    var response = context.Response;
    var cancellationToken = context.RequestAborted;

    // Validate request
    if (request.Method != "POST")
    {
        _logger.LogWarning("Unexpected request method '{method}'", request.Method);
        response.StatusCode = (int) HttpStatusCode.MethodNotAllowed;
        return;
    }

    if (!request.HasFormContentType)
    {
        _logger.LogWarning("Unexpected content type '{contentType}'", request.ContentType);
        response.StatusCode = (int) HttpStatusCode.BadRequest;
        return;
    }

    // We need to read the request body twice: once to validate the signature,
    // and once to read the form content. We copy it into a memory stream,
    // so that we can rewind it after reading.
    var bodyCopy = new MemoryStream();
    await request.Body.CopyToAsync(bodyCopy, cancellationToken);
    request.Body = bodyCopy;
    bodyCopy.Position = 0;

    if (!_verifier.VerifyRequest(request, bodyCopy.ToArray()))
    {
        _logger.LogWarning("Slack request verification failed");
        response.StatusCode = (int) HttpStatusCode.Unauthorized;
        return;
    }

    var form = await request.ReadFormAsync();
    if (!form.TryGetValue("text", out var query))
    {
        _logger.LogWarning("Slack request form did not contain a text element");
        response.StatusCode = (int) HttpStatusCode.BadRequest;
        return;
    }

    var kgResponse = await SearchKnowledgeGraphAsync(query, cancellationToken);
    string formattedResponse = FormatSlackMessage(kgResponse, query);
    response.ContentType = "application/json";
    await response.WriteAsync(formattedResponse);
}

Ruby

# Handler for the function endpoint.
FunctionsFramework.http "kg_search" do |request|
  # Return early if the request is not a POST.
  unless request.post?
    return [405, {}, ["Only POST requests are accepted."]]
  end

  # Access the global Knowledge Graph Search client
  kg_search = global :kg_search

  # Verify the request signature and return early if it failed.
  unless kg_search.signature_valid? request
    return [401, {}, ["Signature validation failed."]]
  end

  # Query the Knowledge Graph and format a Slack message with the response.
  # This method returns a nested hash, which the Functions Framework will
  # convert to JSON automatically.
  kg_search.make_search_request request.params["text"]
end

PHP

/**
 * Receive a Slash Command request from Slack.
 */
function receiveRequest(ServerRequestInterface $request): ResponseInterface
{
    // Validate request
    if ($request->getMethod() !== 'POST') {
        // [] = empty headers
        return new Response(405);
    }

    // Parse incoming URL-encoded requests from Slack
    // (Slack requests use the "application/x-www-form-urlencoded" format)
    $bodyStr = $request->getBody();
    parse_str($bodyStr, $bodyParams);

    if (!isset($bodyParams['text'])) {
        // [] = empty headers
        return new Response(400);
    }

    if (!isValidSlackWebhook($request, $bodyStr)) {
        // [] = empty headers
        return new Response(403);
    }

    $query = $bodyParams['text'];

    // Call knowledge graph API
    $kgResponse = searchKnowledgeGraph($query);

    // Format response to Slack
    // See https://api.slack.com/docs/message-formatting
    $formatted_message = formatSlackMessage($kgResponse, $query);

    return new Response(
        200,
        ['Content-Type' => 'application/json'],
        $formatted_message
    );
}

A função a seguir autentica a solicitação recebida verificando o cabeçalho X-Slack-Signature fornecido pelo Slack:

Node.js

/**
 * Verify that the webhook request came from Slack.
 *
 * @param {object} req Cloud Function request object.
 * @param {string} req.headers Headers Slack SDK uses to authenticate request.
 * @param {string} req.rawBody Raw body of webhook request to check signature against.
 */
const verifyWebhook = req => {
  const signature = {
    signingSecret: process.env.SLACK_SECRET,
    requestSignature: req.headers['x-slack-signature'],
    requestTimestamp: req.headers['x-slack-request-timestamp'],
    body: req.rawBody,
  };

  // This method throws an exception if an incoming request is invalid.
  verifyRequestSignature(signature);
};

Python

def verify_signature(request):
    request.get_data()  # Decodes received requests into request.data

    verifier = SignatureVerifier(os.environ["SLACK_SECRET"])

    if not verifier.is_valid_request(request.data, request.headers):
        raise ValueError("Invalid request/credentials.")

Go

// verifyWebHook verifies the request signature.
// See https://api.slack.com/docs/verifying-requests-from-slack.
func verifyWebHook(r *http.Request, body []byte, slackSigningSecret string) (bool, error) {
	timeStamp := r.Header.Get(slackRequestTimestampHeader)
	slackSignature := r.Header.Get(slackSignatureHeader)

	t, err := strconv.ParseInt(timeStamp, 10, 64)
	if err != nil {
		return false, fmt.Errorf("strconv.ParseInt(%s): %w", timeStamp, err)
	}

	if ageOk, age := checkTimestamp(t); !ageOk {
		return false, fmt.Errorf("checkTimestamp(%v): %v %v", t, ageOk, age)
	}

	if timeStamp == "" || slackSignature == "" {
		return false, fmt.Errorf("timeStamp and/or signature headers were blank")
	}

	baseString := fmt.Sprintf("%s:%s:%s", version, timeStamp, body)

	signature := getSignature([]byte(baseString), []byte(slackSigningSecret))

	trimmed := strings.TrimPrefix(slackSignature, fmt.Sprintf("%s=", version))
	signatureInHeader, err := hex.DecodeString(trimmed)

	if err != nil {
		return false, fmt.Errorf("hex.DecodeString(%v): %w", trimmed, err)
	}

	return hmac.Equal(signature, signatureInHeader), nil
}

func getSignature(base []byte, secret []byte) []byte {
	h := hmac.New(sha256.New, secret)
	h.Write(base)

	return h.Sum(nil)
}

// checkTimestamp allows requests time stamped less than 5 minutes ago.
func checkTimestamp(timeStamp int64) (bool, time.Duration) {
	t := time.Since(time.Unix(timeStamp, 0))

	return t.Minutes() <= 5, t
}

Java

/**
 * Verify that the webhook request came from Slack.
 *
 * @param request Cloud Function request object in {@link HttpRequest} format.
 * @param requestBody Raw body of webhook request to check signature against.
 * @return true if the provided request came from Slack, false otherwise
 */
boolean isValidSlackWebhook(HttpRequest request, String requestBody) {
  // Check for headers
  Optional<String> maybeTimestamp = request.getFirstHeader("X-Slack-Request-Timestamp");
  Optional<String> maybeSignature = request.getFirstHeader("X-Slack-Signature");
  if (!maybeTimestamp.isPresent() || !maybeSignature.isPresent()) {
    return false;
  }

  Long nowInMs = ZonedDateTime.now().toInstant().toEpochMilli();

  return verifier.isValid(maybeTimestamp.get(), requestBody, maybeSignature.get(), nowInMs);
}

C#

using Microsoft.AspNetCore.Http;
using System;
using System.Security.Cryptography;
using System.Text;

namespace SlackKnowledgeGraphSearch;

public class SlackRequestVerifier
{
    private const string Version = "v0";
    private const string SignaturePrefix = Version + "=";
    private static readonly byte[] VersionBytes = Encoding.UTF8.GetBytes(Version);
    private static readonly byte[] ColonBytes = Encoding.UTF8.GetBytes(":");

    private readonly byte[] _signingKeyBytes;
    private readonly TimeSpan _timestampTolerance;

    public SlackRequestVerifier(string signingKey, TimeSpan timestampTolerance) =>
        (_signingKeyBytes, _timestampTolerance) =
        (Encoding.UTF8.GetBytes(signingKey), timestampTolerance);

    /// <summary>
    /// Verifies a request signature with the given content, which would
    /// normally have been read from the request beforehand.
    /// </summary>
    public bool VerifyRequest(HttpRequest request, byte[] content)
    {
        if (!request.Headers.TryGetValue("X-Slack-Request-Timestamp", out var timestampHeader) ||
            !request.Headers.TryGetValue("X-Slack-Signature", out var signatureHeader))
        {
            return false;
        }

        // Validate that the request isn't too old.
        if (!int.TryParse(timestampHeader, out var unixSeconds))
        {
            return false;
        }
        var timestamp = DateTimeOffset.FromUnixTimeSeconds(unixSeconds);
        if (timestamp + _timestampTolerance < DateTimeOffset.UtcNow)
        {
            return false;
        }

        // Hash the version:timestamp:content
        using var hmac = new HMACSHA256(_signingKeyBytes);
        AddToHash(VersionBytes);
        AddToHash(ColonBytes);
        AddToHash(Encoding.UTF8.GetBytes(timestampHeader));
        AddToHash(ColonBytes);
        byte[] hash = hmac.ComputeHash(content);
        void AddToHash(byte[] bytes) => hmac.TransformBlock(bytes, 0, bytes.Length, null, 0);

        // Compare the resulting signature with the signature in the request.
        return CreateSignature(hash) == (string) signatureHeader;
    }

    private const string Hex = "0123456789abcdef";
    private static string CreateSignature(byte[] hash)
    {
        var builder = new StringBuilder(SignaturePrefix, SignaturePrefix.Length + hash.Length * 2);
        foreach (var b in hash)
        {
            builder.Append(Hex[b >> 4]);
            builder.Append(Hex[b & 0xf]);
        }
        return builder.ToString();
    }
}

Ruby

# slack-ruby-client expects a Rails-style request object with a "headers"
# method, but the Functions Framework provides only a Rack request.
# To avoid bringing in Rails as a dependency, we'll create a simple class
# that implements the "headers" method and delegates everything else back to
# the Rack request object.
require "delegate"
class RequestWithHeaders < SimpleDelegator
  def headers
    env.each_with_object({}) do |(key, val), result|
      if /^HTTP_(\w+)$/ =~ key
        header = Regexp.last_match(1).split("_").map(&:capitalize).join("-")
        result[header] = val
      end
    end
  end
end

# This is a method of the KGSearch class.
# It determines whether the given request's signature is valid.
def signature_valid? request
  # Wrap the request with our class that provides the "headers" method.
  request = RequestWithHeaders.new request

  # Validate the request signature.
  slack_request = Slack::Events::Request.new request,
                                             signing_secret: @signing_secret
  slack_request.valid?
end

PHP

/**
 * Verify that the webhook request came from Slack.
 */
function isValidSlackWebhook(ServerRequestInterface $request): bool
{
    $SLACK_SECRET = getenv('SLACK_SECRET');

    // Check for headers
    $timestamp = $request->getHeaderLine('X-Slack-Request-Timestamp');
    $signature = $request->getHeaderLine('X-Slack-Signature');
    if (!$timestamp || !$signature) {
        return false;
    }

    // Compute signature
    $plaintext = sprintf('v0:%s:%s', $timestamp, $request->getBody());
    $hash = sprintf('v0=%s', hash_hmac('sha256', $plaintext, $SLACK_SECRET));

    return $hash === $signature;
}

Como consultar a API Knowledge Graph

A função a seguir envia uma solicitação com a consulta de pesquisa do usuário para a API Knowledge Graph:

Node.js

/**
 * Send the user's search query to the Knowledge Graph API.
 *
 * @param {string} query The user's search query.
 */
const makeSearchRequest = query => {
  return new Promise((resolve, reject) => {
    kgsearch.entities.search(
      {
        auth: process.env.KG_API_KEY,
        query: query,
        limit: 1,
      },
      (err, response) => {
        console.log(err);
        if (err) {
          reject(err);
          return;
        }

        // Return a formatted message
        resolve(formatSlackMessage(query, response));
      }
    );
  });
};

Python

def make_search_request(query):
    req = kgsearch.entities().search(query=query, limit=1)
    res = req.execute()
    return format_slack_message(query, res)

Go

func makeSearchRequest(query string) (*Message, error) {
	res, err := entitiesService.Search().Query(query).Limit(1).Do()
	if err != nil {
		return nil, err
	}
	return formatSlackMessage(query, res)
}

Java

/**
 * Send the user's search query to the Knowledge Graph API.
 *
 * @param query The user's search query.
 * @return The Knowledge graph API results as a {@link JsonObject}.
 * @throws IOException if Knowledge Graph request fails
 */
JsonObject searchKnowledgeGraph(String query) throws IOException {
  Kgsearch.Entities.Search kgRequest = kgClient.entities().search();
  kgRequest.setQuery(query);
  kgRequest.setKey(apiKey);

  return gson.fromJson(kgRequest.execute().toString(), JsonObject.class);
}

C#

private async Task<SearchResponse> SearchKnowledgeGraphAsync(string query, CancellationToken cancellationToken)
{
    _logger.LogInformation("Performing Knowledge Graph search for '{query}'", query);
    var request = _kgService.Entities.Search();
    request.Limit = 1;
    request.Query = query;
    return await request.ExecuteAsync(cancellationToken);
}

Ruby

# This is a method of the KGSearch class.
# It makes an API call to the Knowledge Graph Search Service, and formats
# a Slack message as a nested Hash object.
def make_search_request query
  response = @client.search_entities query: query, limit: 1
  format_slack_message query, response
end

PHP

/**
 * Send the user's search query to the Knowledge Graph API.
 */
function searchKnowledgeGraph(string $query): Google_Service_Kgsearch_SearchResponse
{
    $API_KEY = getenv('KG_API_KEY');

    $apiClient = new Google\Client();
    $apiClient->setDeveloperKey($API_KEY);

    $service = new Google_Service_Kgsearch($apiClient);

    $params = ['query' => $query];

    $kgResults = $service->entities->search($params);

    return $kgResults;
}

Como formatar a mensagem do Slack

Por fim, a seguinte função exibe para o usuário o resultado do Knowledge Graph em uma mensagem do Slack ricamente formatada:

Node.js

/**
 * Format the Knowledge Graph API response into a richly formatted Slack message.
 *
 * @param {string} query The user's search query.
 * @param {object} response The response from the Knowledge Graph API.
 * @returns {object} The formatted message.
 */
const formatSlackMessage = (query, response) => {
  let entity;

  // Extract the first entity from the result list, if any
  if (
    response &&
    response.data &&
    response.data.itemListElement &&
    response.data.itemListElement.length > 0
  ) {
    entity = response.data.itemListElement[0].result;
  }

  // Prepare a rich Slack message
  // See https://api.slack.com/docs/message-formatting
  const slackMessage = {
    response_type: 'in_channel',
    text: `Query: ${query}`,
    attachments: [],
  };

  if (entity) {
    const attachment = {
      color: '#3367d6',
    };
    if (entity.name) {
      attachment.title = entity.name;
      if (entity.description) {
        attachment.title = `${attachment.title}: ${entity.description}`;
      }
    }
    if (entity.detailedDescription) {
      if (entity.detailedDescription.url) {
        attachment.title_link = entity.detailedDescription.url;
      }
      if (entity.detailedDescription.articleBody) {
        attachment.text = entity.detailedDescription.articleBody;
      }
    }
    if (entity.image && entity.image.contentUrl) {
      attachment.image_url = entity.image.contentUrl;
    }
    slackMessage.attachments.push(attachment);
  } else {
    slackMessage.attachments.push({
      text: 'No results match your query...',
    });
  }

  return slackMessage;
};

Python

def format_slack_message(query, response):
    entity = None
    if (
        response
        and response.get("itemListElement") is not None
        and len(response["itemListElement"]) > 0
    ):
        entity = response["itemListElement"][0]["result"]

    message = {
        "response_type": "in_channel",
        "text": f"Query: {query}",
        "attachments": [],
    }

    attachment = {}
    if entity:
        name = entity.get("name", "")
        description = entity.get("description", "")
        detailed_desc = entity.get("detailedDescription", {})
        url = detailed_desc.get("url")
        article = detailed_desc.get("articleBody")
        image_url = entity.get("image", {}).get("contentUrl")

        attachment["color"] = "#3367d6"
        if name and description:
            attachment["title"] = "{}: {}".format(entity["name"], entity["description"])
        elif name:
            attachment["title"] = name
        if url:
            attachment["title_link"] = url
        if article:
            attachment["text"] = article
        if image_url:
            attachment["image_url"] = image_url
    else:
        attachment["text"] = "No results match your query."
    message["attachments"].append(attachment)

    return message

Go

package slack

import (
	"encoding/json"
	"fmt"

	"google.golang.org/api/kgsearch/v1"
)

type ItemList struct {
	Items []ItemListElement `json:"itemListElement"`
}
type ItemListElement struct {
	Result EntitySearchResult `json:"result"`
}
type EntitySearchResult struct {
	Name         string       `json:"name"`
	Description  string       `json:"description"`
	DetailedDesc DetailedDesc `json:"detailedDescription"`
	URL          string       `json:"url"`
	Image        Image
}
type DetailedDesc struct {
	ArticleBody string
	URL         string
}
type Image struct {
	ContentURL string
}

func formatSlackMessage(query string, response *kgsearch.SearchResponse) (*Message, error) {
	if response == nil {
		return nil, fmt.Errorf("empty response")
	}

	if response.ItemListElement == nil || len(response.ItemListElement) == 0 {
		message := &Message{
			ResponseType: "in_channel",
			Text:         fmt.Sprintf("Query: %s", query),
			Attachments: []Attachment{
				{
					Color: "#d6334b",
					Text:  "No results match your query.",
				},
			},
		}
		return message, nil
	}

	// The KnowledgeGraph API returns an empty interface. To make this more
	// useful, we convert it back to json, and unmarshal into specific types.
	jsonstring, err := response.MarshalJSON()
	if err != nil {
		return nil, err
	}
	r := &ItemList{}
	if err := json.Unmarshal(jsonstring, r); err != nil {
		return nil, fmt.Errorf("failed to unmarshal json: %w", err)
	}
	result := r.Items[0].Result

	attach := Attachment{Color: "#3367d6"}
	attach.Title = result.Name
	attach.TitleLink = result.DetailedDesc.URL
	attach.Text = result.DetailedDesc.ArticleBody
	attach.ImageURL = result.Image.ContentURL

	message := &Message{
		ResponseType: "in_channel",
		Text:         fmt.Sprintf("Query: %s", query),
		Attachments:  []Attachment{attach},
	}
	return message, nil
}

Java

/**
 * Helper method to copy properties between {@link JsonObject}s
 */
void addPropertyIfPresent(
    JsonObject target, String targetName, JsonObject source, String sourceName) {
  if (source.has(sourceName)) {
    target.addProperty(targetName, source.get(sourceName).getAsString());
  }
}

/**
 * Format the Knowledge Graph API response into a richly formatted Slack message.
 *
 * @param kgResponse The response from the Knowledge Graph API as a {@link JsonObject}.
 * @param query The user's search query.
 * @return The formatted Slack message as a JSON string.
 */
String formatSlackMessage(JsonObject kgResponse, String query) {
  JsonObject attachmentJson = new JsonObject();

  JsonObject responseJson = new JsonObject();
  responseJson.addProperty("response_type", "in_channel");
  responseJson.addProperty("text", String.format("Query: %s", query));

  JsonArray entityList = kgResponse.getAsJsonArray("itemListElement");

  // Extract the first entity from the result list, if any
  if (entityList.size() == 0) {
    attachmentJson.addProperty("text", "No results match your query...");
    responseJson.add("attachments", attachmentJson);

    return gson.toJson(responseJson);
  }

  JsonObject entity = entityList.get(0).getAsJsonObject().getAsJsonObject("result");

  // Construct Knowledge Graph response attachment
  String title = entity.get("name").getAsString();
  if (entity.has("description")) {
    title = String.format("%s: %s", title, entity.get("description").getAsString());
  }
  attachmentJson.addProperty("title", title);

  if (entity.has("detailedDescription")) {
    JsonObject detailedDescJson = entity.getAsJsonObject("detailedDescription");
    addPropertyIfPresent(attachmentJson, "title_link", detailedDescJson, "url");
    addPropertyIfPresent(attachmentJson, "text", detailedDescJson, "articleBody");
  }

  if (entity.has("image")) {
    JsonObject imageJson = entity.getAsJsonObject("image");
    addPropertyIfPresent(attachmentJson, "image_url", imageJson, "contentUrl");
  }

  JsonArray attachmentList = new JsonArray();
  attachmentList.add(attachmentJson);

  responseJson.add("attachments", attachmentList);

  return gson.toJson(responseJson);
}

C#

private string FormatSlackMessage(SearchResponse kgResponse, string query)
{
    JObject attachment = new JObject();
    JObject response = new JObject();

    response["response_type"] = "in_channel";
    response["text"] = $"Query: {query}";

    var element = kgResponse.ItemListElement?.FirstOrDefault() as JObject;
    if (element is object && element.TryGetValue("result", out var entityToken) &&
        entityToken is JObject entity)
    {
        string title = (string) entity["name"];
        if (entity.TryGetValue("description", out var description))
        {
            title = $"{title}: {description}";
        }
        attachment["title"] = title;
        if (entity.TryGetValue("detailedDescription", out var detailedDescriptionToken) &&
            detailedDescriptionToken is JObject detailedDescription)
        {
            AddPropertyIfPresent(detailedDescription, "url", "title_link");
            AddPropertyIfPresent(detailedDescription, "articleBody", "text");
        }
        if (entity.TryGetValue("image", out var imageToken) &&
            imageToken is JObject image)
        {
            AddPropertyIfPresent(image, "contentUrl", "image_url");
        }
    }
    else
    {
        attachment["text"] = "No results match your query...";
    }
    response["attachments"] = new JArray { attachment };
    return response.ToString();

    void AddPropertyIfPresent(JObject parent, string sourceProperty, string targetProperty)
    {
        if (parent.TryGetValue(sourceProperty, out var propertyValue))
        {
            attachment[targetProperty] = propertyValue;
        }
    }
}

Ruby

# This is a method of the KGSearch class.
# It takes a raw SearchResponse from the Knowledge Graph Search Service,
# and formats a Slack message.
def format_slack_message query, response
  result = response.item_list_element&.first&.fetch "result", nil
  attachment =
    if result
      name = result.fetch "name", nil
      description = result.fetch "description", nil
      details = result.fetch "detailedDescription", {}
      { "title"      => name && description ? "#{name}: #{description}" : name,
        "title_link" => details.fetch("url", nil),
        "text"       => details.fetch("articleBody", nil),
        "image_url"  => result.fetch("image", nil)&.fetch("contentUrl", nil) }
    else
      { "text" => "No results match your query." }
    end
  { "response_type" => "in_channel",
    "text"          => "Query: #{query}",
    "attachments"   => [attachment.compact] }
end

PHP

/**
 * Format the Knowledge Graph API response into a richly formatted Slack message.
 */
function formatSlackMessage(Google_Service_Kgsearch_SearchResponse $kgResponse, string $query): string
{
    $responseJson = [
        'response_type' => 'in_channel',
        'text' => 'Query: ' . $query
    ];

    $entityList = $kgResponse['itemListElement'];

    // Extract the first entity from the result list, if any
    if (empty($entityList)) {
        $attachmentJson = ['text' => 'No results match your query...'];
        $responseJson['attachments'] = $attachmentJson;

        return json_encode($responseJson);
    }

    $entity = $entityList[0]['result'];

    // Construct Knowledge Graph response attachment
    $title = $entity['name'];
    if (isset($entity['description'])) {
        $title = $title . ' ' . $entity['description'];
    }
    $attachmentJson = ['title' => $title];

    if (isset($entity['detailedDescription'])) {
        $detailedDescJson = $entity['detailedDescription'];
        $attachmentJson = array_merge([
            'title_link' => $detailedDescJson[ 'url'],
            'text' => $detailedDescJson['articleBody'],
        ], $attachmentJson);
    }

    if (isset($entity['image'])) {
        $imageJson = $entity['image'];
        $attachmentJson['image_url'] = $imageJson['contentUrl'];
    }

    $responseJson['attachments'] = array($attachmentJson);

    return json_encode($responseJson);
}

Tempos limite da API Slack

A API do Slack espera que sua função responda dentro de 3 segundos após receber uma solicitação de webhook.

Os comandos deste tutorial, no geral, levam menos de 3 segundos para responder. Para comando de execução mais longa, recomendamos configurar uma função para pedidos push (incluindo seu response_url) para um tópico do Pub/Sub que atua como uma fila de tarefas.

Em seguida, crie uma segunda função acionada por Pub/Sub que processa essas tarefas e envia os resultados de volta para o response_url do Slack.

Como usar o comando Slash

1. Quando a implantação da função for concluída, digite este comando no canal do Slack:

   /kg giraffe

   Você verá a entrada do Mapa de informações de "giraffe".

2. Verifique os registros para ver a saída da execução da função:

   gcloud functions logs read --limit 100

Limpar

Para evitar cobranças na sua conta do Google Cloud pelos recursos usados no tutorial, exclua o projeto que os contém ou mantenha o projeto e exclua os recursos individuais.

Excluir o projeto

O jeito mais fácil de evitar cobranças é excluindo o projeto que você criou para o tutorial.

Para excluir o projeto:

Cuidado: excluir um projeto tem os seguintes efeitos:

• Tudo no projeto é excluído. Se você tiver usado um projeto existente para as tarefas neste documento, a exclusão dele incluirá a exclusão de quaisquer outros trabalhos feitos no projeto.
• Os IDs do projeto personalizados são perdidos. Ao criar o projeto, você pode ter criado um código do projeto personalizado para ser usado no futuro. Para preservar os URLs que usam o ID do projeto, como um URL appspot.com, exclua recursos específicos do projeto, em vez de excluir o projeto inteiro.

Se você planeja passar por várias arquiteturas, tutoriais ou guias de início rápido, a reutilização de projetos pode evitar que você exceda os limites da cota do projeto.

1. In the Google Cloud console, go to the Manage resources page.

   Go to Manage resources

2. In the project list, select the project that you want to delete, and then click Delete.
3. In the dialog, type the project ID, and then click Shut down to delete the project.

Como excluir a função

Para excluir a função do Cloud Run criada neste tutorial, execute o seguinte comando:

Node.js

gcloud functions delete nodejs-slack-function --gen2 --region REGION 

Python

gcloud functions delete python-slack-function --gen2 --region REGION 

Go

gcloud functions delete go-slack-function --gen2 --region REGION 

Java

gcloud functions delete java-slack-function --gen2 --region REGION 

C#

gcloud functions delete csharp-slack-function --gen2 --region REGION 

Ruby

gcloud functions delete ruby-slack-function --gen2 --region REGION 

PHP

gcloud functions delete php-slack-function --gen2 --region REGION 

Também é possível excluir funções do Cloud Run pelo Console do Google Cloud.