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Basic implementation of the file upload using new slack file api #92

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d10c065
addressed file uploading through new slack api
Voronenko Jan 2, 2026
3967d2f
chore(comments) reverted to original
Voronenko Jan 2, 2026
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190 changes: 170 additions & 20 deletions slacktee.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -22,13 +22,13 @@
# ----------
# Default Configuration
# ----------
webhook_url="" # Incoming Webhooks integration URL. Old way to interact with Slack. (Deprecated)
token="" # The authentication token of the bot user. Used for accessing Slack APIs.
channel="general" # Default channel to post messages. '#' is prepended, if it doesn't start with '#' or '@'.
tmp_dir="/tmp" # Temporary file is created in this directory.
username="slacktee" # Default username to post messages.
icon="ghost" # Default emoji to post messages. Don't wrap it with ':'. See http://www.emoji-cheat-sheet.com; can be a url too.
attachment="" # Default color of the attachments. If an empty string is specified, the attachments are not used.
webhook_url="${SLACKTEE_WEBHOOK_URL:-}" # Incoming Webhooks integration URL. Old way to interact with Slack. (Deprecated)
token="${SLACKTEE_TOKEN:-}" # The authentication token of the bot user. Used for accessing Slack APIs.
channel="${SLACKTEE_CHANNEL:-general}" # Default channel to post messages. '#' is prepended, if it doesn't start with '#' or '@'.
tmp_dir="${SLACKTEE_TMP_DIR:-/tmp}" # Temporary file is created in this directory.
username="${SLACKTEE_USERNAME:-slacktee}" # Default username to post messages.
icon="${SLACKTEE_ICON:-ghost}" # Default emoji to post messages. Don't wrap it with ':'. See http://www.emoji-cheat-sheet.com; can be a url too.
attachment="${SLACKTEE_ATTACHMENT:-}" # Default color of the attachments. If an empty string is specified, the attachments are not used.

# ----------
# Initialization
Expand Down Expand Up @@ -87,6 +87,78 @@ function get_ok_in_response() {
echo "$(echo "$response" | awk 'match($0, /"ok":([^,}]+)/) {print substr($0, RSTART+5, RLENGTH-5)}')"
}

function get_upload_url() {
local filename=$1

# Get file size - try different methods for different OS
local length
length=$(stat -c%s "$filename" 2>/dev/null)
if [[ -z "$length" ]]; then
length=$(stat -f%z "$filename" 2>/dev/null)
fi
if [[ -z "$length" ]]; then
length=$(wc -c < "$filename" 2>/dev/null | tr -d ' ')
fi

local name=$(basename "$filename")

if [[ -z "$name" ]]; then
name="unnamed"
fi
if [[ -z "$length" ]]; then
length=0
fi

# Use form fields, not JSON (Slack API expects -F parameters)
curl --silent \
-H "Authorization: Bearer $token" \
-F "filename=$name" \
-F "length=$length" \
https://slack.com/api/files.getUploadURLExternal
}

function complete_upload() {
local file_id=$1
local channels=$2

# Build files JSON array for form field
local files_json="[{\"id\": \"$file_id\"}]"

if [[ -n "$channels" ]]; then
# Use channel_id for single channel or channels for comma-separated list
curl --silent \
-H "Authorization: Bearer $token" \
-F "files=$files_json" \
-F "channel_id=$channels" \
https://slack.com/api/files.completeUploadExternal
else
curl --silent \
-H "Authorization: Bearer $token" \
-F "files=$files_json" \
https://slack.com/api/files.completeUploadExternal
fi
}

function get_file_id_from_response() {
local response=$1
echo "$response" | grep -o '"file_id":"[^"]*"' | cut -d'"' -f4
}

function get_upload_url_from_response() {
local response=$1
echo "$response" | grep -o '"upload_url":"[^"]*"' | cut -d'"' -f4 | sed 's/\\//g'
}

function get_permalink_from_response() {
local response=$1
echo "$response" | grep -o '"permalink":"[^"]*"' | cut -d'"' -f4 | sed 's/\\//g'
}

function get_url_private_from_response() {
local response=$1
echo "$response" | grep -o '"url_private":"[^"]*"' | cut -d'"' -f4 | sed 's/\\//g'
}

function handle_signal()
{
cleanup
Expand Down Expand Up @@ -253,7 +325,7 @@ function send_message()
\"username\": \"$username\", \
$message_attr \"icon_emoji\": \"$icon_emoji\", \
$parseMode}"
fi
fi

post_result=$(curl -H "Authorization: Bearer $token" -H 'Content-type: application/json; charset=utf-8' -X POST -d "$json" https://slack.com/api/chat.postMessage 2> /dev/null)
if [ $(get_ok_in_response "$post_result") != "true" ]; then
Expand Down Expand Up @@ -789,6 +861,8 @@ function check_configuration()

if [[ $channel == "" ]]; then
err_exit 1 "Please specify a channel."
elif [[ ( "$channel" != "#"* ) && ( "$channel" != "@"* ) ]]; then
channel="#$channel"
fi

if [[ -n "$icon" ]]; then
Expand Down Expand Up @@ -853,7 +927,7 @@ function main()
fi

timestamp="$(date +'%m%d%Y-%H%M%S')"
filename="$tmp_dir/$filetitle$$-$timestamp.log"
filename="$tmp_dir/$filetitle$$-$timestamp.txt"

if [[ "$mode" == "file" ]]; then
touch $filename
Expand All @@ -876,25 +950,101 @@ function main()
send_message "$text"
elif [[ "$mode" == "file" ]]; then
if [[ -s "$filename" ]]; then
channels_param=""
if [[ ( "$channel" == "#"* ) ]]; then
# Set channels for making the file public
channels_param="-F channels=$channel"
# Step 1: Get upload URL from Slack
get_url_result=$(get_upload_url "$filename")

if [ $(get_ok_in_response "$get_url_result") != "true" ]; then
write_to_stderr "Failed to get upload URL."
err_exit 1 "$get_url_result"
fi
upload_result="$(curl -F file=@"$filename" -F token="$token" $channels_param https://slack.com/api/files.upload 2> /dev/null)"
if [ $(get_ok_in_response "$upload_result") != "true" ]; then
write_to_stderr "Upload failed. Please make sure slacktee is a member of $channel."
err_exit 1 $upload_result

file_id=$(get_file_id_from_response "$get_url_result")
upload_url=$(get_upload_url_from_response "$get_url_result")

$debug && printf "Got file_id: $file_id and upload_url: $upload_url\n"

if [[ -z "$file_id" || -z "$upload_url" ]]; then
write_to_stderr "Failed to extract file_id or upload_url from response."
err_exit 1 "$get_url_result"
fi

# Step 2: Upload file to the upload URL
$debug && printf "Uploading file to: $upload_url\n"
upload_result=$(curl --silent -X POST \
-F "file=@$filename" \
"$upload_url")

# The upload URL returns 200 OK on success
if [[ $? -ne 0 ]]; then
write_to_stderr "File upload to upload URL failed."
err_exit 1 "$upload_result"
fi

# Step 3: Complete the upload and optionally share to channel
# Need to convert channel name to channel ID for the API
channel_id=""
if [[ "$channel" == "#"* ]]; then
# For public channels, we need to get the channel ID first
channel_name="${channel#\#}"
channel_lookup=$(curl --silent -H "Authorization: Bearer $token" \
-G \
--data "types=public_channel" \
https://slack.com/api/conversations.list)

if [ $(get_ok_in_response "$channel_lookup") == "true" ]; then
# Find the channel ID matching the channel name
channel_id=$(echo "$channel_lookup" | python3 -c "
import sys, json
data = json.load(sys.stdin)
for channel in data.get('channels', []):
if channel.get('name') == '$channel_name':
print(channel.get('id'))
break
" 2>/dev/null || echo "")

# Fallback: try using grep if python3 is not available
if [[ -z "$channel_id" ]]; then
channel_id=$(echo "$channel_lookup" | grep -o "\"name\":\"$channel_name\"" -A 1 | grep -o '"id":"[^"]*"' | cut -d'"' -f4 | head -1)
fi
fi
elif [[ "$channel" == "@"* ]]; then
# For DMs, we need to get the user ID
username="${channel:1}"
user_lookup=$(curl --silent -H "Authorization: Bearer $token" \
-G \
--data-urlencode "user=$username" \
https://slack.com/api/users.info)

if [ $(get_ok_in_response "$user_lookup") == "true" ]; then
channel_id=$(echo "$user_lookup" | grep -o '"id":"[^"]*"' | cut -d'"' -f4 | head -1)
fi
else
# Channel without # prefix might already be an ID or name
# Try to use it as-is for the API call
channel_id="$channel"
fi
access_url="$(echo "$upload_result" | awk 'match($0, /url_private":"([^"]*)"/) {print substr($0, RSTART+14, RLENGTH-15)}'|sed 's/\\//g')"
download_url="$(echo "$upload_result" | awk 'match($0, /url_private_download":"([^"]*)"/) {print substr($0, RSTART+23, RLENGTH-24)}'|sed 's/\\//g')"

complete_result=$(complete_upload "$file_id" "$channel_id")

if [ $(get_ok_in_response "$complete_result") != "true" ]; then
write_to_stderr "Failed to complete upload."
err_exit 1 "$complete_result"
fi

# Extract file URLs from the response
access_url=$(get_permalink_from_response "$complete_result")
private_url=$(get_url_private_from_response "$complete_result")

if [[ -n "$attachment" ]]; then
text="Input file has been uploaded"
else
if [[ "$title" != "" ]]; then
title=" of $title"
fi
text="Input file$title has been uploaded.\n$access_url\n\nYou can download it from the link below.\n$download_url"
text="Input file$title has been uploaded.\n$access_url"
if [[ -n "$private_url" ]]; then
text="$text\n\nYou can download it from the link below.\n$private_url"
fi
fi
send_message "$text"
fi
Expand Down