Add support for fetching private channels. Fixes grundleborg#32

cmd/fetch_private_channels.go

@@ -0,0 +1,353 @@
+package cmd
+
+import (
+	"archive/zip"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var (
+	privateChannelsApiToken string
+)
+
+var fetchPrivateChannelsCmd = &cobra.Command{
+	Use:   "fetch-private-channels",
+	Short: "Fetch all private channels accessible to the user",
+	RunE:  fetchPrivateChannels,
+}
+
+func init() {
+	fetchPrivateChannelsCmd.PersistentFlags().StringVar(&privateChannelsApiToken, "api-token", "", "Slack API token. Can be obtained here: https://api.slack.com/docs/oauth-test-tokens")
+	fetchPrivateChannelsCmd.MarkPersistentFlagRequired("api-token")
+}
+
+func fetchPrivateChannels(cmd *cobra.Command, args []string) error {
+	// Open the input archive.
+	r, err := zip.OpenReader(inputArchive)
+	if err != nil {
+		fmt.Printf("Could not open input archive for reading: %s\n", inputArchive)
+		os.Exit(1)
+	}
+	defer r.Close()
+
+	// Open the output archive.
+	f, err := os.Create(outputArchive)
+	if err != nil {
+		fmt.Printf("Could not open the output archive for writing: %s\n\n%s", outputArchive, err)
+		os.Exit(1)
+	}
+	defer f.Close()
+
+	// Create a zip writer on the output archive.
+	w := zip.NewWriter(f)
+
+	groupsFound := false
+	// Run through all the files in the input archive.
+	for _, file := range r.File {
+		verbosePrintln(fmt.Sprintf("Processing file: %s\n", file.Name))
+
+		// Open the file from the input archive.
+		inReader, err := file.Open()
+		if err != nil {
+			fmt.Printf("Failed to open file in input archive: %s\n\n%s", file.Name, err)
+			os.Exit(1)
+		}
+
+		// Copy, because CreateHeader modifies it.
+		header := file.FileHeader
+
+		outFile, err := w.CreateHeader(&header)
+		if err != nil {
+			fmt.Printf("Failed to create file in output archive: %s\n\n%s", file.Name, err)
+			os.Exit(1)
+		}
+
+		if file.Name == "groups.json" {
+			groupsFound = true
+			verbosePrintln("The file groups.json is already present in the dump, we don't fetch it again")
+		}
+		_, err = io.Copy(outFile, inReader)
+		if err != nil {
+			fmt.Printf("Failed to copy file to output archive: %s\n\n%s", file.Name, err)
+			os.Exit(1)
+		}
+	}
+
+	outFile, err := w.Create("groups.json")
+	if err != nil {
+		return err
+	}
+	if !groupsFound {
+		err = createGroupsJson(outFile, privateChannelsApiToken, w)
+		if err != nil {
+			fmt.Printf("Failed to fetch private channels.\n\n%s\n", err)
+			os.Exit(1)
+		}
+	}
+
+	// Close the output zip writer.
+	err = w.Close()
+	if err != nil {
+		fmt.Printf("Failed to close the output archive.\n\n%s", err)
+	}
+
+	return nil
+}
+
+func createGroupsJson(output io.Writer, slackApiToken string, w *zip.Writer) error {
+
+	verbosePrintln("Creating groups.json by fetching private channels.")
+
+	privateChannels, err := fetchPrivateChannelsList(slackApiToken)
+	if err != nil {
+		return err
+	}
+
+	enc := json.NewEncoder(output)
+	// The same indent level as export zip uses.
+	enc.SetIndent("", "    ")
+	var err2 = enc.Encode(&privateChannels)
+	if err2 != nil {
+		return err2
+	}
+
+	verbosePrintln("Fetching the contents of private channels")
+	for _, channel := range privateChannels {
+		var channelId = channel["id"].(string)
+		var channelName = channel["name"].(string)
+		verbosePrintln("Fetching the replies of private channel " + channelName)
+
+		var messageFileName = channelName + "/messages.json"
+
+		outFile, err := w.Create(messageFileName)
+		if err != nil {
+			return err
+		}
+		ts_ids, err := fetchChannelHistory(outFile, slackApiToken, channelId)
+		if err != nil {
+			return err
+		}
+
+		outFileReplies, err := w.Create(channelName + "/replies.json")
+		if err != nil {
+			return err
+		}
+		fetchChannelReplies(outFileReplies, slackApiToken, channelId, ts_ids)
+
+		verbosePrintln("Done with replies of private channel " + channelName)
+
+	}
+	return nil
+}
+
+func fetchChannelHistory(output io.Writer, token string, channelId string) ([]string, error) {
+	client := &http.Client{}
+	res := make([]map[string]interface{}, 0)
+	ts_ids := make([]string, 0)
+	url := "https://slack.com/api/conversations.history"
+
+	cursor := ""
+
+	for {
+		req, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			return nil, fmt.Errorf("got error %s when building the request", err)
+		}
+
+		query := req.URL.Query()
+		query.Add("limit", "200")
+		query.Add("channel", channelId)
+		if cursor != "" {
+			query.Add("cursor", cursor)
+		}
+		req.URL.RawQuery = query.Encode()
+
+		req.Header.Set("Authorization", "Bearer "+token)
+
+		resp, err := client.Do(req)
+		if err != nil {
+			return nil, err
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode != http.StatusOK {
+			return nil, fmt.Errorf("Slack API returned HTTP code %d", resp.StatusCode)
+		}
+
+		var data struct {
+			Ok               bool                     `json:"ok"`
+			Messages         []map[string]interface{} `json:"messages"`
+			ResponseMetadata struct {
+				NextCursor string `json:"next_cursor"`
+			} `json:"response_metadata"`
+		}
+		err = json.NewDecoder(resp.Body).Decode(&data)
+		if err != nil {
+			return nil, err
+		}
+
+		if !data.Ok {
+			return nil, errors.New("unexpected lack of ok=true in Slack API response. Is access token correct?")
+		}
+
+		res = append(res, data.Messages...)
+		for _, message := range data.Messages {
+			_, has_reply_count := message["reply_count"].(float64)
+			if has_reply_count {
+				id, present := message["ts"].(string)
+				if present {
+					ts_ids = append(ts_ids, id)
+				}
+			}
+		}
+
+		cursor = data.ResponseMetadata.NextCursor
+		verbosePrintln("Processed a batch of messages.")
+
+		if cursor == "" {
+			break // Exit the loop if there's no next cursor
+		}
+	}
+	enc := json.NewEncoder(output)
+	// The same indent level as export zip uses.
+	enc.SetIndent("", "    ")
+	return ts_ids, enc.Encode(&res)
+}
+
+func fetchChannelReplies(output io.Writer, token string, channelId string, tsIds []string) error {
+	client := &http.Client{}
+	res := make([]map[string]interface{}, 0)
+	url := "https://slack.com/api/conversations.replies"
+
+	cursor := ""
+
+	for _, tsId := range tsIds {
+		for {
+			req, err := http.NewRequest("GET", url, nil)
+			if err != nil {
+				return fmt.Errorf("got error %s when building the request", err)
+			}
+
+			query := req.URL.Query()
+			query.Add("limit", "200")
+			query.Add("channel", channelId)
+			query.Add("ts", tsId)
+			if cursor != "" {
+				query.Add("cursor", cursor)
+			}
+			req.URL.RawQuery = query.Encode()
+
+			req.Header.Set("Authorization", "Bearer "+token)
+
+			resp, err := client.Do(req)
+			if err != nil {
+				return err
+			}
+			defer resp.Body.Close()
+
+			if resp.StatusCode != http.StatusOK {
+				return fmt.Errorf("Slack API returned HTTP code %d", resp.StatusCode)
+			}
+
+			var data struct {
+				Ok               bool                     `json:"ok"`
+				Messages         []map[string]interface{} `json:"messages"`
+				ResponseMetadata struct {
+					NextCursor string `json:"next_cursor"`
+				} `json:"response_metadata"`
+			}
+			err = json.NewDecoder(resp.Body).Decode(&data)
+			if err != nil {
+				return err
+			}
+
+			if !data.Ok {
+				return errors.New("unexpected lack of ok=true in Slack API response. Is access token correct?")
+			}
+
+			res = append(res, data.Messages...)
+
+			cursor = data.ResponseMetadata.NextCursor
+			verbosePrintln("Processed a batch of replies.")
+
+			if cursor == "" {
+				break // Exit the loop if there's no next cursor
+			}
+		}
+	}
+	enc := json.NewEncoder(output)
+	// The same indent level as export zip uses.
+	enc.SetIndent("", "    ")
+	return enc.Encode(&res)
+}
+
+func fetchPrivateChannelsList(token string) ([]map[string]interface{}, error) {
+	verbosePrintln("Fetching private channels from Slack API")
+
+	client := &http.Client{}
+	res := make([]map[string]interface{}, 0)
+	url := "https://slack.com/api/conversations.list"
+
+	cursor := ""
+
+	for {
+		req, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			return nil, fmt.Errorf("got error %s when building the request", err)
+		}
+
+		query := req.URL.Query()
+		query.Add("limit", "1000")
+		query.Add("types", "private_channel")
+		if cursor != "" {
+			query.Add("cursor", cursor)
+		}
+		req.URL.RawQuery = query.Encode()
+
+		req.Header.Set("Authorization", "Bearer "+token)
+
+		resp, err := client.Do(req)
+		if err != nil {
+			return nil, err
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode != http.StatusOK {
+			return nil, fmt.Errorf("Slack API returned HTTP code %d", resp.StatusCode)
+		}
+
+		var data struct {
+			Ok               bool                     `json:"ok"`
+			Channels         []map[string]interface{} `json:"channels"`
+			ResponseMetadata struct {
+				NextCursor string `json:"next_cursor"`
+			} `json:"response_metadata"`
+		}
+		err = json.NewDecoder(resp.Body).Decode(&data)
+		if err != nil {
+			return nil, err
+		}
+
+		if !data.Ok {
+			return nil, errors.New("unexpected lack of ok=true in Slack API response. Is access token correct?")
+		}
+
+		res = append(res, data.Channels...)
+
+		cursor = data.ResponseMetadata.NextCursor
+		verbosePrintln("Processed a batch of channels.")
+
+		if cursor == "" {
+			break // Exit the loop if there's no next cursor
+		}
+	}
+
+	verbosePrintln("Fetched all private channels from Slack API.")
+	return res, nil
+}

cmd/root.go

@@ -27,6 +27,7 @@ func init() {
 	rootCmd.MarkPersistentFlagRequired("output-archive")
 	rootCmd.AddCommand(fetchAttachmentsCmd)
 	rootCmd.AddCommand(fetchEmailsCmd)
+	rootCmd.AddCommand(fetchPrivateChannelsCmd)
 }
 
 func Execute() error {