Tutorial su Slack - Comandi con barra

Questo tutorial illustra l'utilizzo di Cloud Functions per implementare un comando Slash Slash che cerca nell'API Google Knowledge Graph.

Obiettivi

  • Crea un comando Slash in Slack.
  • Scrivi e sottoponi a deployment una funzione Cloud HTTP.
  • Cerca nell'API Google Knowledge Graph utilizzando il comando Slash.

Costi

Questo tutorial utilizza i seguenti componenti fatturabili di Google Cloud:

  • Cloud Functions

Per generare una stima dei costi in base all'utilizzo previsto, utilizza il Calcolatore prezzi. I nuovi utenti di Google Cloud possono beneficiare di una prova gratuita.

Prima di iniziare

  1. Accedi al tuo account Google Cloud. Se non conosci Google Cloud, crea un account per valutare le prestazioni dei nostri prodotti in scenari reali. I nuovi clienti ricevono anche 300 $di crediti gratuiti per l'esecuzione, il test e il deployment dei carichi di lavoro.

  2. Nella pagina del selettore dei progetti in Google Cloud Console, seleziona o crea un progetto Google Cloud.

    Vai al selettore progetti

  3. Assicurati che la fatturazione sia attivata per il tuo progetto Cloud. Scopri come verificare se la fatturazione è abilitata su un progetto.

  4. Abilita le API Cloud Functions, Cloud Build, and Google Knowledge Graph Search.

    Abilita le API

  5. Installa e inizializza l'interfaccia a riga di comando di Google Cloud.

  6. Nella pagina del selettore dei progetti in Google Cloud Console, seleziona o crea un progetto Google Cloud.

    Vai al selettore progetti

  7. Assicurati che la fatturazione sia attivata per il tuo progetto Cloud. Scopri come verificare se la fatturazione è abilitata su un progetto.

  8. Abilita le API Cloud Functions, Cloud Build, and Google Knowledge Graph Search.

    Abilita le API

  9. Installa e inizializza l'interfaccia a riga di comando di Google Cloud.

    10. Se hai già installato l'interfaccia a riga di comando gcloud, aggiornala eseguendo il comando seguente:

    gcloud components update
  10. Prepara l'ambiente di sviluppo.

Visualizzare il flusso dei dati

Il flusso di dati nell'applicazione tutorial Slash Command richiede diversi passaggi:

  1. L'utente esegue il comando Slash /kg <search_query> in un canale Slack.
  2. Slack invia il payload del comando all'endpoint di attivazione della funzione Cloud Functions.
  3. La funzione Cloud Functions invia una richiesta con la query di ricerca dell'utente all'API Knowledge Graph.
  4. L'API Knowledge Graph risponde con qualsiasi risultato corrispondente.
  5. La funzione Cloud Functions formatta la risposta in un messaggio Slack.
  6. La funzione Cloud restituisce il messaggio a Slack.
  7. L'utente visualizza la risposta formattata nel canale Slack.

Potrebbe essere utile visualizzare i passaggi:

Creazione della chiave API Knowledge Graph

Nella pagina Credenziali di Google Cloud Console, fai clic sul pulsante Crea credenziali e seleziona Chiave API. Ricorda questa chiave, poiché la utilizzerai per accedere all'API Knowledge Graph nella sezione successiva.

Preparazione della funzione in corso...

  1. Clona il repository delle app di esempio sul tuo computer locale:

    Node.js 

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

    In alternativa, puoi scaricare l'esempio come file ZIP ed estrarlo.

    Python 

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

    In alternativa, puoi scaricare l'esempio come file ZIP ed estrarlo.

    Go 

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

    In alternativa, puoi scaricare l'esempio come file ZIP ed estrarlo.

    Java 

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

    In alternativa, puoi scaricare l'esempio come file ZIP ed estrarlo.

    C# 

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

    In alternativa, puoi scaricare l'esempio come file ZIP ed estrarlo.

    Ruby 

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

    In alternativa, puoi scaricare l'esempio come file ZIP ed estrarlo.

    PHP 

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

    In alternativa, puoi scaricare l'esempio come file ZIP ed estrarlo.

  2. Passa alla directory che contiene il codice campione di Cloud Functions:

    Node.js 

    cd nodejs-docs-samples/functions/slack/

    Python 

    cd python-docs-samples/functions/slack/

    Go 

    cd golang-samples/functions/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/

Deployment della funzione in corso...

Per il deployment della funzione che viene eseguita quando (o Slack) esegui una richiesta HTTP POST all'endpoint della funzione, esegui il comando seguente nella directory contenente il codice campione (o il file pom.xml per Java):

Sostituisci YOUR_SLACK_SIGNING_SECRET con il secret di firma fornito da Slack nella pagina Informazioni di base della configurazione dell'app e YOUR_KG_API_KEY con la chiave API Knowledge Graph da te creata in precedenza.

Node.js 

gcloud functions deploy kgSearch \
--runtime nodejs16 \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated
Per specificare la versione di Node.js preferita, puoi utilizzare i seguenti valori per il flag --runtime:
  • nodejs16 (consigliato)
  • nodejs14
  • nodejs12
  • nodejs10

Python 

gcloud functions deploy kg_search \
--runtime python39 \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated
Puoi utilizzare i seguenti valori per il flag --runtime per specificare la tua versione di Python preferita:
  • python310 (anteprima)
  • python39 (consigliato)
  • python38
  • python37

Go 

gcloud functions deploy KGSearch \
--runtime go116 \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated
Puoi utilizzare i seguenti valori per il flag --runtime per specificare la tua versione Go preferita:
  • go116 (consigliato)
  • go113
  • go111

Java 

gcloud functions deploy java-slack-function \
--entry-point functions.SlackSlashCommand \
--runtime java11 \
--memory 512MB \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated
Puoi utilizzare i seguenti valori per il flag --runtime per specificare la tua versione di Java preferita:
  • java17 (anteprima)
  • java11 (consigliato)

C# 

gcloud functions deploy csharp-slack-function \
--entry-point SlackKnowledgeGraphSearch.Function \
--runtime dotnet3 \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated

Ruby 

gcloud functions deploy kg_search --runtime ruby30 \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated
Per specificare la versione di Ruby preferita, puoi utilizzare i seguenti valori per il flag --runtime:
  • ruby30 (consigliato)
  • ruby27
  • ruby26

PHP 

gcloud functions deploy searchKnowledgeGraph --runtime php74 \
--trigger-http \
--set-env-vars "SLACK_SECRET=YOUR_SLACK_SIGNING_SECRET,KG_API_KEY=YOUR_KG_API_KEY" \
--allow-unauthenticated
Puoi utilizzare i seguenti valori per il flag --runtime per specificare la tua versione PHP preferita:
  • php81 (anteprima)
  • php74 (consigliato)

Configurazione dell'applicazione

Dopo aver eseguito il deployment della funzione, devi creare un comando Slash Slash che invii la query alla Funzione Cloud ogni volta che viene attivato il comando:

  1. Crea un'app Slack per ospitare il tuo comando Slash. Associalo a un team Slack in cui hai le autorizzazioni per installare le integrazioni.

  2. Vai a Comandi slash e fai clic sul pulsante Crea nuovo comando.

  3. Inserisci /kg come nome del comando.

  4. Inserisci l'URL per il comando:

    Node.js 

    https://YOUR_REGION-YOUR_PROJECT_ID.cloudfunctions.net/kgSearch

    Python 

    https://YOUR_REGION-YOUR_PROJECT_ID.cloudfunctions.net/kg_search

    Go 

    https://YOUR_REGION-YOUR_PROJECT_ID.cloudfunctions.net/KGSearch

    Java 

    https://YOUR_REGION-YOUR_PROJECT_ID.cloudfunctions.net/java-slack-function

    C# 

    https://YOUR_REGION-YOUR_PROJECT_ID.cloudfunctions.net/csharp-slack-function

    Ruby 

    https://YOUR_REGION-YOUR_PROJECT_ID.cloudfunctions.net/kg_search

    PHP 

    https://YOUR_REGION-YOUR_PROJECT_ID.cloudfunctions.net/searchKnowledgeGraph

    dove YOUR_REGION è l'area geografica in cui viene eseguito il deployment della funzione Cloud e YOUR_PROJECT_ID è l'ID progetto Cloud.

    Entrambi i valori sono visibili nel terminale al termine del deployment della funzione.

  5. Fai clic su Salva.

  6. Vai a Informazioni di base.

  7. Fai clic su Installa l'app nell'area di lavoro e segui le istruzioni sullo schermo per abilitare l'applicazione per l'area di lavoro.

    Il comando Slash Slash dovrebbe essere disponibile online a breve.

Nozioni di base sul codice

Importazione delle dipendenze

L'applicazione deve importare diverse dipendenze per comunicare con i servizi di Google Cloud Platform:

Node.js

Functions/slack/index.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

Functions/slack/main.py 
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

Functions/slack/setup.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

Functions/slack/src/main/java/functions/SlackSlashCommand.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 JacksonFactory(), 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#

Functions/slack/SlackKnowledgeGraphSearch/Startup.cs 
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

Functions/slack/app.rb 
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

Functions/slack_slash_command/index.php 
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;
use GuzzleHttp\Psr7\Response;

Ricezione del webhook

La funzione seguente viene eseguita quando (o Slack) effettui una richiesta HTTP POST all'endpoint della funzione:

Node.js

Functions/slack/index.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/slack/main.py 
@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

Functions/slack/search.go 

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

import (
	"bytes"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"strconv"
	"strings"
	"time"
)

type oldTimeStampError struct {
	s string
}

func (e *oldTimeStampError) Error() string {
	return e.s
}

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"`
}

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

	bodyBytes, err := ioutil.ReadAll(r.Body)
	if err != nil {
		log.Fatalf("Couldn't read request body: %v", err)
	}
	r.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))

	if r.Method != "POST" {
		http.Error(w, "Only POST requests are accepted", 405)
	}
	if err := r.ParseForm(); err != nil {
		http.Error(w, "Couldn't parse form", 400)
		log.Fatalf("ParseForm: %v", err)
	}

	// Reset r.Body as ParseForm depletes it by reading the io.ReadCloser.
	r.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))
	result, err := verifyWebHook(r, slackSecret)
	if err != nil {
		log.Fatalf("verifyWebhook: %v", err)
	}
	if !result {
		log.Fatalf("signatures did not match.")
	}

	if len(r.Form["text"]) == 0 {
		log.Fatalf("empty text in form")
	}
	kgSearchResponse, err := makeSearchRequest(r.Form["text"][0])
	if err != nil {
		log.Fatalf("makeSearchRequest: %v", err)
	}
	w.Header().Set("Content-Type", "application/json")
	if err = json.NewEncoder(w).Encode(kgSearchResponse); err != nil {
		log.Fatalf("json.Marshal: %v", err)
	}
}

Java

Functions/slack/src/main/java/functions/SlackSlashCommand.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#

Functions/slack/SlackKnowledgeGraphSearch/Function.cs 
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;

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

Ruby

Functions/slack/app.rb 
# 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

Functions/slack_slash_command/index.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
    );
}

La seguente funzione autentica la richiesta in entrata verificando l'intestazione X-Slack-Signature fornita da Slack:

Node.js

Functions/slack/index.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

Functions/slack/main.py 
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

Functions/slack/search.go 

// verifyWebHook verifies the request signature.
// See https://api.slack.com/docs/verifying-requests-from-slack.
func verifyWebHook(r *http.Request, 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): %v", timeStamp, err)
	}

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

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

	body, err := ioutil.ReadAll(r.Body)
	if err != nil {
		return false, fmt.Errorf("ioutil.ReadAll(%v): %v", r.Body, err)
	}

	// Reset the body so other calls won't fail.
	r.Body = ioutil.NopCloser(bytes.NewBuffer(body))

	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): %v", 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)
}

// Arbitrarily trusting 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

Functions/slack/src/main/java/functions/SlackSlashCommand.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#

Functions/slack/SlackKnowledgeGraphSearch/SlackRequestVerifier.cs 
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

Functions/slack/app.rb 
# 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

Functions/slack_slash_command/index.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;
}

Query sull'API Knowledge Graph

La seguente funzione invia una richiesta con la query di ricerca dell'utente all'API Knowledge Graph:

Node.js

Functions/slack/index.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

Functions/slack/main.py 
def make_search_request(query):
    req = kgsearch.entities().search(query=query, limit=1)
    res = req.execute()
    return format_slack_message(query, res)

Go

Functions/slack/search.go 
func makeSearchRequest(query string) (*Message, error) {
	res, err := entitiesService.Search().Query(query).Limit(1).Do()
	if err != nil {
		return nil, fmt.Errorf("Do: %v", err)
	}
	return formatSlackMessage(query, res)
}

Java

Functions/slack/src/main/java/functions/SlackSlashCommand.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#

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

Ruby

Functions/slack/app.rb 
# 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

Functions/slack_slash_command/index.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;
}

Formattazione del messaggio Slack

Infine, la seguente funzione formatta il risultato del Knowledge Graph in un messaggio Slack rich formattato che verrà mostrato all'utente:

Node.js

Functions/slack/index.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

Functions/slack/main.py 
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': 'Query: {}'.format(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

Functions/slack/format.go 

package slack

import (
	"fmt"

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

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
	}

	entity, ok := response.ItemListElement[0].(map[string]interface{})
	if !ok {
		return nil, fmt.Errorf("could not parse response entity")
	}
	result, ok := entity["result"].(map[string]interface{})
	if !ok {
		return nil, fmt.Errorf("error formatting response result")
	}

	attach := attachment{Color: "#3367d6"}
	if name, ok := result["name"].(string); ok {
		if description, ok := result["description"].(string); ok {
			attach.Title = fmt.Sprintf("%s: %s", name, description)
		} else {
			attach.Title = name
		}
	}
	if detailedDesc, ok := result["detailedDescription"].(map[string]interface{}); ok {
		if url, ok := detailedDesc["url"].(string); ok {
			attach.TitleLink = url
		}
		if article, ok := detailedDesc["articleBody"].(string); ok {
			attach.Text = article
		}
	}
	if image, ok := result["image"].(map[string]interface{}); ok {
		if imageURL, ok := image["contentUrl"].(string); ok {
			attach.ImageURL = imageURL
		}
	}

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

Java

Functions/slack/src/main/java/functions/SlackSlashCommand.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#

Functions/slack/SlackKnowledgeGraphSearch/Function.cs 
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

Functions/slack/app.rb 
# 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

Functions/slack_slash_command/index.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);
}

Timeout API Slack

L'API Slack prevede che la tua funzione risponda entro 3 secondi dalla ricezione di una richiesta webhook.

Generalmente i comandi di questo tutorial richiedono meno di tre secondi per rispondere. Per i comandi a lunga esecuzione, ti consigliamo di configurare una funzione per le richieste di push (incluse le response_url) a un argomento Pub/Sub che funga da coda di attività.

Quindi, puoi creare una seconda funzione attivata da Pub/Sub che elabora tali attività e invia i risultati allo response_urldi Slack.

Utilizzo del comando Slash

  1. Digita il comando nel tuo canale Slack:

    /kg giraffe

  2. Controlla i log per assicurarti che le esecuzioni siano state completate:

    gcloud functions logs read --limit 100

esegui la pulizia

Per evitare che al tuo Account Google Cloud vengano addebitati costi relativi alle risorse utilizzate in questo tutorial, elimina il progetto che contiene le risorse oppure mantieni il progetto ed elimina le singole risorse.

Elimina il progetto

Il modo più semplice per eliminare la fatturazione è eliminare il progetto che hai creato per il tutorial.

Per eliminare il progetto:

  1. In Cloud Console, vai alla pagina Gestisci risorse.

    Vai a Gestisci risorse

  2. Nell'elenco dei progetti, seleziona il progetto da eliminare, quindi fai clic su Elimina.
  3. Nella finestra di dialogo, digita l'ID del progetto e fai clic su Chiudi per eliminare il progetto.

Eliminazione della funzione Cloud Functions

Per eliminare la funzione Cloud Functions di cui hai eseguito il deployment in questo tutorial, esegui questo comando:

Node.js 

gcloud functions delete kgSearch

Python 

gcloud functions delete kg_search

Go 

gcloud functions delete KGSearch

Java 

gcloud functions delete java-slack-function

C# 

gcloud functions delete csharp-slack-function

Ruby 

gcloud functions delete kg_search

PHP 

gcloud functions delete searchKnowledgeGraph

Puoi anche eliminare Cloud Functions da Google Cloud Console.