Slack Tutorial - Slash Commands

View on GitHub

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/src/main/java/functions/SlackSlashCommand.java

View on GitHub

import os

from flask import jsonify
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

View on GitHub


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

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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

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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

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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

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

Receiving the webhook

The following function is executed when you (or Slack) make an HTTP POST request to the function's endpoint:

Node.js

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/**
 * Receive a Slash Command request from Slack.
 *
 * Trigger this function by creating a Slack slash command with this URL:
 * https://[YOUR_REGION]-[YOUR_PROJECT_ID].cloudfunctions.net/kgSearch
 *
 * @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.
 */
exports.kgSearch = async (req, res) => {
  try {
    if (req.method !== 'POST') {
      const error = new Error('Only POST requests are accepted');
      error.code = 405;
      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/src/main/java/functions/SlackSlashCommand.java

View on GitHub

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

View on GitHub


// 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

View on GitHub Feedback

/**
 * 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

View on GitHub Feedback

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

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# 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

View on GitHub Feedback

/**
 * 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
    );
}

The following function authenticates the incoming request by verifying the X-Slack-Signature header provided by Slack:

Node.js

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/**
 * 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/src/main/java/functions/SlackSlashCommand.java

View on GitHub

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

View on GitHub


// 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

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/**
 * 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

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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

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# 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

View on GitHub Feedback

/**
 * 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;
}

Querying the Knowledge Graph API

The following function sends a request with the user's search query to the Knowledge Graph API:

Node.js

View on GitHub Feedback

/**
 * 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/src/main/java/functions/SlackSlashCommand.java

View on GitHub

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

View on GitHub

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

View on GitHub Feedback

/**
 * 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

View on GitHub Feedback

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

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# 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

View on GitHub Feedback

/**
 * 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;
}

Formatting the Slack message

Finally, the following function formats the Knowledge Graph result into a richly formatted Slack message that will be displayed to the user:

Node.js

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/**
 * 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/src/main/java/functions/SlackSlashCommand.java

View on GitHub

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

View on GitHub


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

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/**
 * 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

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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

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# 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