Allow posting content to Facebook Pages (#353) (#354)

bees/bees.go

@@ -264,6 +264,19 @@ func (bee *Bee) SetOptions(options BeeOptions) {
 	bee.config.Options = options
 }
 
+// SetOption sets one option for a bee.
+func (bee *Bee) SetOption(name string, value string) bool {
+	for i := 0 ; i < len(bee.config.Options); i++ {
+		if bee.config.Options[i].Name == name {
+			bee.config.Options[i].Value = value
+
+			return true
+		}
+	}
+
+	return false
+}
+
 // SetSigChan sets the signaling channel for a bee.
 func (bee *Bee) SetSigChan(c chan bool) {
 	bee.SigChan = c

bees/facebookbee/facebookbee.go

@@ -22,9 +22,16 @@
 package facebookbee
 
 import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"jaytaylor.com/html2text"
+	"net/http"
 	"net/url"
 	"path"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/huandu/facebook"
@@ -39,9 +46,11 @@ import (
 type FacebookBee struct {
 	bees.Bee
 
-	clientID     string
-	clientSecret string
-	accessToken  string
+	clientID        string
+	clientSecret    string
+	accessToken     string
+	pageID          string
+	pageAccessToken string
 
 	session *facebook.Session
 
@@ -50,6 +59,12 @@ type FacebookBee struct {
 
 // Run executes the Bee's event loop.
 func (mod *FacebookBee) Run(eventChan chan bees.Event) {
+	err := mod.handlePermanentPageToken()
+
+	if err != nil {
+		mod.LogErrorf("Error while handling permanent page token: %v", err)
+	}
+
 	mod.evchan = eventChan
 
 	since := strconv.FormatInt(time.Now().UTC().Unix(), 10)
@@ -71,30 +86,206 @@ func (mod *FacebookBee) Run(eventChan chan bees.Event) {
 	}
 }
 
+func (mod *FacebookBee) handlePermanentPageToken() error {
+	if mod.pageAccessToken != "" {
+		return nil
+	}
+
+	mod.Logf("Attempting to fetch long lived user access token")
+
+	longToken, err := mod.fetchLongLivedUserAccessToken()
+
+	if longToken == "" || err != nil {
+		return fmt.Errorf("no long lived user access token: %w", err)
+	}
+
+	// mod.Logf("Long lived user access token: \"%s\"", longToken)
+	accountID, err := mod.fetchAccountID(longToken)
+
+	if accountID == "" || err != nil {
+		return fmt.Errorf("no account id: %w", err)
+	}
+
+	pageToken, err := mod.fetchPermanentPageAccessToken(accountID, longToken)
+
+	if pageToken == "" || err != nil {
+		return fmt.Errorf("no permanent page token: %w", err)
+	}
+
+	mod.Logf("Permanent pageToken: \"%s\"", pageToken)
+
+	setRes := mod.SetOption("page_access_token", pageToken)
+
+	if !setRes {
+		return fmt.Errorf("could not set permanent page token")
+	}
+
+	return nil
+}
+
+func (mod *FacebookBee) fetchLongLivedUserAccessToken() (string, error) {
+	// See https://developers.facebook.com/docs/pages/access-tokens/#get-a-long-lived-user-access-token
+	baseURL := "https://graph.facebook.com/oauth/access_token"
+	v := url.Values{}
+	v.Set("grant_type", "fb_exchange_token")
+	v.Set("client_id", mod.clientID)
+	v.Set("client_secret", mod.clientSecret)
+	v.Set("fb_exchange_token", mod.accessToken)
+	graphUrl := baseURL + "?" + v.Encode()
+
+	res, err := http.Get(graphUrl)
+
+	if err != nil || res == nil {
+		return "", fmt.Errorf("fetching long lived user access token failed: %w", err)
+	}
+
+	defer res.Body.Close()
+	body, err := ioutil.ReadAll(res.Body)
+
+	if err != nil {
+		return "", fmt.Errorf("reading content while fetching long lived user access token failed: %w", err)
+	}
+
+	// mod.Logf("Long lived user access token result: \"%s\"", body)
+
+	type RequestResult struct {
+		AccessToken string `json:"access_token"`
+	}
+
+	var tokenRes RequestResult
+	err = json.Unmarshal(body, &tokenRes)
+
+	if err != nil {
+		return "", fmt.Errorf("parsing result while fetching long lived user access token failed: %w", err)
+	}
+
+	return tokenRes.AccessToken, nil
+}
+
+func (mod *FacebookBee) fetchAccountID(accessToken string) (string, error) {
+	baseURL := "https://graph.facebook.com/v8.0/me"
+	v := url.Values{}
+	v.Set("access_token", accessToken)
+	v.Set("fields", "id")
+	graphUrl := baseURL + "?" + v.Encode()
+
+	res, err := http.Get(graphUrl)
+
+	if err != nil || res == nil {
+		return "", fmt.Errorf("fetching user id failed: %w", err)
+	}
+
+	defer res.Body.Close()
+	body, err := ioutil.ReadAll(res.Body)
+
+	if err != nil {
+		return "", fmt.Errorf("fetching user id failed: %w", err)
+	}
+
+	// mod.Logf("user id result: \"%s\"", body)
+
+	type RequestResult struct {
+		ID string `json:"id"`
+	}
+
+	var tokenRes RequestResult
+	err = json.Unmarshal(body, &tokenRes)
+
+	if err != nil {
+		return "", fmt.Errorf("parsing result while fetching user id failed: %w", err)
+	}
+
+	return tokenRes.ID, nil
+}
+
+func (mod *FacebookBee) fetchPermanentPageAccessToken(accountID string, accessToken string) (string, error) {
+	// the method in https://developers.facebook.com/docs/pages/access-tokens/#get-a-page-access-token doesn't work!
+	// https://github.com/Bnjis/Facebook-permanent-token-generator/blob/master/src/components/Form.js helped a lot
+	baseURL := "https://graph.facebook.com/v8.0/" + accountID + "/accounts"
+	v := url.Values{}
+	v.Set("access_token", accessToken)
+	graphUrl := baseURL + "?" + v.Encode()
+
+	// var buf io.ReadWriter
+	res, err := http.Get(graphUrl)
+
+	if err != nil || res == nil {
+		return "", fmt.Errorf("fetching page token failed: %w", err)
+	}
+
+	defer res.Body.Close()
+	body, err := ioutil.ReadAll(res.Body)
+
+	if err != nil {
+		return "", fmt.Errorf("reading content while fetching page token failed: %w", err)
+	}
+
+	// mod.Logf("Page token result: \"%s\"", body)
+
+	type RequestResult struct {
+		Data []struct {
+			AccessToken string `json:"access_token"`
+		} `json:"data"`
+	}
+
+	var tokenRes RequestResult
+	err = json.Unmarshal(body, &tokenRes)
+
+	if err != nil {
+		return "", fmt.Errorf("parsing result while fetching page token failed: %w", err)
+	}
+
+	return tokenRes.Data[0].AccessToken, nil
+}
+
 // Action triggers the action passed to it.
 func (mod *FacebookBee) Action(action bees.Action) []bees.Placeholder {
 	outs := []bees.Placeholder{}
 	switch action.Name {
 	case "post":
 		var text string
 		action.Options.Bind("text", &text)
-		mod.Logf("Attempting to post \"%s\" to Facebook", text)
 
-		params := facebook.Params{}
-		params["message"] = text
+		// transform possible html in the text
+		textNoHtml, err := html2text.FromString(text, html2text.Options{PrettyTables: true})
+
+		if err == nil {
+			text = textNoHtml
+		}
+
+		// newline workaround for html2text
+		text = strings.Replace(text, "[NEWLINE]", "\n", -1)
+
+		mod.Logf("Attempting to post \"%s\" to Facebook Page \"%s\"", text, mod.pageID)
+
+		// See https://developers.facebook.com/docs/pages/publishing#before-you-start
+		baseURL := "https://graph.facebook.com/" + mod.pageID + "/feed"
+		v := url.Values{}
+		v.Set("message", text)
+		v.Set("access_token", mod.pageAccessToken)
+		graphUrl := baseURL + "?" + v.Encode()
+
+		//mod.Logf("graphUrl: \"%s\"", graphUrl)
+		//return outs
+
+		var buf io.ReadWriter
+		res, err := http.Post(graphUrl, "", buf)
+
+		if err != nil || res == nil {
+			mod.LogErrorf("Posting to Facebook Page failed: %v", err)
+			return outs
+		}
+
+		defer res.Body.Close()
+		body, err := ioutil.ReadAll(res.Body)
 
-		_, err := mod.session.Post("/me/feed", params)
 		if err != nil {
-			// err can be an facebook API error.
-			// if so, the Error struct contains error details.
-			if e, ok := err.(*facebook.Error); ok {
-				mod.LogErrorf("Error: [message:%v] [type:%v] [code:%v] [subcode:%v]",
-					e.Message, e.Type, e.Code, e.ErrorSubcode)
-				return outs
-			}
-			mod.LogErrorf(err.Error())
+			mod.LogErrorf("Reading content from post request to Facebook Page failed: %v", err)
+			return outs
 		}
 
+		mod.Logf("Facebook Page post: \"%s\"", body)
+
 	default:
 		panic("Unknown action triggered in " + mod.Name() + ": " + action.Name)
 	}
@@ -190,4 +381,6 @@ func (mod *FacebookBee) ReloadOptions(options bees.BeeOptions) {
 	options.Bind("client_id", &mod.clientID)
 	options.Bind("client_secret", &mod.clientSecret)
 	options.Bind("access_token", &mod.accessToken)
+	options.Bind("page_id", &mod.pageID)
+	options.Bind("page_access_token", &mod.pageAccessToken)
 }

bees/facebookbee/facebookbeefactory.go

@@ -130,6 +130,16 @@ func (factory *FacebookBeeFactory) Options() []bees.BeeOptionDescriptor {
 			Description: "Access token for the Facebook API",
 			Type:        "oauth2:" + u.String(),
 		},
+		{
+			Name:        "page_id",
+			Description: "Page ID of your Facebook page (see wiki)",
+			Type:        "string",
+		},
+		{
+			Name:        "page_access_token",
+			Description: "Page access token for the Facebook API (leave blank to get a permanent token)",
+			Type:        "oauth2:" + u.String(),
+		},
 	}
 	return opts
 }

go.mod

@@ -49,7 +49,6 @@ require (
 	github.com/jpillora/backoff v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.6 // indirect
 	github.com/kelvins/sunrisesunset v0.0.0-20170601204625-14f1915ad4b4
-	github.com/kevinburke/go-bindata v3.21.0+incompatible // indirect
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
 	github.com/kr/pretty v0.1.0
 	github.com/kurrik/oauth1a v0.0.0-20151019171716-cb1b80e32dd4 // indirect
@@ -104,5 +103,6 @@ require (
 	gopkg.in/mail.v2 v2.3.1 // indirect
 	gopkg.in/mgo.v2 v2.0.0-20180705113604-9856a29383ce // indirect
 	gopkg.in/yaml.v2 v2.3.0
+	jaytaylor.com/html2text v0.0.0-20200412013138-3577fbdbcff7
 	layeh.com/gumble v0.0.0-20180508205105-1ea1159c4956
 )

go.sum

@@ -120,8 +120,6 @@ github.com/jtolds/gls v4.20.0+incompatible h1:xdiiI2gbIgH/gLH7ADydsJ1uDOEzR8yvV7
 github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU=
 github.com/kelvins/sunrisesunset v0.0.0-20170601204625-14f1915ad4b4 h1:8GEzGYjqXcb1PW2RFrkbsv7Gzq4v9ykbjy6lUc9nbnM=
 github.com/kelvins/sunrisesunset v0.0.0-20170601204625-14f1915ad4b4/go.mod h1:3oZ7G+fb8Z8KF+KPHxeDO3GWpEjgvk/f+d/yaxmDRT4=
-github.com/kevinburke/go-bindata v3.21.0+incompatible h1:baK7hwFJDlAHrOqmE9U3u8tow1Uc5ihN9E/b7djcK2g=
-github.com/kevinburke/go-bindata v3.21.0+incompatible/go.mod h1:/pEEZ72flUW2p0yi30bslSp9YqD9pysLxunQDdb2CPM=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.2 h1:DB17ag19krx9CFsz4o3enTrPXyIXCl+2iCXH/aMAp9s=
 github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
@@ -320,5 +318,7 @@ gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+jaytaylor.com/html2text v0.0.0-20200412013138-3577fbdbcff7 h1:mub0MmFLOn8XLikZOAhgLD1kXJq8jgftSrrv7m00xFo=
+jaytaylor.com/html2text v0.0.0-20200412013138-3577fbdbcff7/go.mod h1:OxvTsCwKosqQ1q7B+8FwXqg4rKZ/UG9dUW+g/VL2xH4=
 layeh.com/gumble v0.0.0-20180508205105-1ea1159c4956 h1:TaQ2ECrcAom2bkjRvOxhsUkD6l5iiCJ/++lHHZ42zII=
 layeh.com/gumble v0.0.0-20180508205105-1ea1159c4956/go.mod h1:ZWnZxbDNsg1uFq6Zu7mRdCi7xechwiqWYsFdedd0GUc=