Upload file to Mattermost (API v4)

MattermostUpload.sh

#!/bin/bash

# your mattermost installation url
mattermost="https://example.com"

# bot token, get it in Integrations > Bot Accounts
token=abcdef123456

# set to true for debug output
debug=false

checkDep() {
    for prog in "$@"; do
        command -v $prog >/dev/null 2>&1 || { echo "Please install these dependencies first: $@" && return 1; }
    done
}

checkDep curl jq || exit 1

if [ ! -f "$2" ]; then
	echo "syntax: $0 channel_id path_to_file"
	exit 2
fi

if [ "$debug" == "true" ]; then
	curlParam=''
else
	curlParam='-s'
fi

output=$(curl $curlParam --location --request POST "$mattermost/api/v4/files?channel_id=$1" \
  --header "Authorization: Bearer $token" \
  --header "Content-Type: multipart/form-data" \
  --form "files=@$2")

if [ "$debug" == "true" ]; then
	echo "$output"
fi

file_id=$(echo "$output" | jq -M -c -r '.file_infos[].id' 2>/dev/null)

if [ -z "$file_id" ]; then
	echo "Failed to upload file :("
	exit 3
fi

output=$(curl $curlParam --location --request POST "$mattermost/api/v4/posts" \
  --header "Authorization: Bearer $token" \
  --header "Content-Type: application/json" \
  --data "{\"file_ids\":[\"$file_id\"],\"message\":\"\",\"channel_id\":\"$1\"}")

if [ "$debug" == "true" ]; then
	echo "$output"
fi

post_id=$(echo "$output" | jq -M -c -r '.id' 2>/dev/null)

if [ -z "$post_id" ]; then
	echo "Failed to create post :("
	exit 4
fi

You're welcome!

Thanks. It helped me a lot in CI/CD Deployments