gupload: Rewrite logic for access token usage | Fix #113

launch a background service to check access token and update it

checks ACCESS_TOKEN_EXPIRY, try to update before 5 mins of expiry, a fresh token gets 60 mins ( 3600 seconds )

process will be killed when script exits

dont update config in bg service, update at script exit

create a temp file where updated access token will be stored by the bg service

every function that uses access token will source it on every call

make a new function named _api_request for all oauth network calls

decrease a network request ( to fetch expiry of access token, just calculate it locally using remaining time given in json as expires_in )

google-oauth2.[bash|sh]: Apply new changes

README.md

@@ -114,6 +114,7 @@ This repo contains two types of scripts, posix compatible and bash compatible.
 | sed              | Miscellaneous                                          |
 | mktemp           | To generate temporary files ( optional )               |
 | sleep            | Self explanatory                                       |
+| ps               | To manage different processes                          |
 
 <strong>If BASH is not available or BASH is available but version is less tham 4.x, then below programs are also required:</strong>
 
@@ -124,11 +125,10 @@ This repo contains two types of scripts, posix compatible and bash compatible.
 | cat                 | Miscellaneous                              |
 | stty or zsh or tput | To determine column size ( optional )      |
 
-<strong>These programs are needed for synchronisation script:</strong>
+<strong>These are the additional programs needed for synchronisation script:</strong>
 
 | Program       | Role In Script            |
 | ------------- | ------------------------- |
-| ps            | To manage background jobs |
 | tail          | To show indefinite logs   |
 
 ### Installation

bash/google-oauth2.bash

@@ -25,16 +25,21 @@ Usage:
     exit 0
 }
 
+###################################################
 # Method to regenerate access_token ( also updates in config ).
 # Make a request on https://www.googleapis.com/oauth2/""${API_VERSION}""/tokeninfo?access_token=${ACCESS_TOKEN} url and check if the given token is valid, if not generate one.
-# Requirements: Refresh Token
-_get_token_and_update() {
+# Globals: 8 variables, 2 functions
+#   Variables - CLIENT_ID, CLIENT_SECRET, REFRESH_TOKEN, TOKEN_URL, CONFIG, API_URL, API_VERSION and QUIET
+#   Functions - _update_config and _print_center
+# Result: Update access_token and expiry else print error
+###################################################
+_get_access_token_and_update() {
     RESPONSE="${1:-$(curl --compressed -s -X POST --data "client_id=${CLIENT_ID}&client_secret=${CLIENT_SECRET}&refresh_token=${REFRESH_TOKEN}&grant_type=refresh_token" "${TOKEN_URL}")}" || :
     if ACCESS_TOKEN="$(_json_value access_token 1 1 <<< "${RESPONSE}")"; then
-        { [[ -n ${UPDATE} ]] && ACCESS_TOKEN_EXPIRY="$(curl --compressed -s "${API_URL}/oauth2/${API_VERSION}/tokeninfo?access_token=${ACCESS_TOKEN}" | _json_value exp 1 1)" &&
-            _update_config ACCESS_TOKEN_EXPIRY "${ACCESS_TOKEN_EXPIRY}" "${CONFIG}"; } || { "${QUIET:-_print_center}" "justify" "Error: Couldn't update" " access token expiry." 1>&2 && exit 1; }
-        "${UPDATE:-:}" ACCESS_TOKEN "${ACCESS_TOKEN}" "${CONFIG}"
-        "${UPDATE:-:}" ACCESS_TOKEN_EXPIRY "${ACCESS_TOKEN_EXPIRY}" "${CONFIG}"
+        [[ -n ${UPDATE} ]] && {
+            _update_config ACCESS_TOKEN "${ACCESS_TOKEN}" "${CONFIG}"
+            _update_config ACCESS_TOKEN_EXPIRY "$(($(printf "%(%s)T\\n" "-1") + $(_json_value expires_in 1 1 <<< "${RESPONSE}")))" "${CONFIG}"
+        }
     else
         _print_center "justify" "Error: Something went wrong" ", printing error." 1>&2
         printf "%s\n" "${RESPONSE}" 1>&2
@@ -45,19 +50,17 @@ _get_token_and_update() {
 
 [[ ${1} = create ]] || [[ ${1} = refresh ]] || _short_help
 
-[[ ${2} = update ]] && UPDATE="_update_config"
+{ [[ ${2} = update ]] && UPDATE="true"; } || unset UPDATE
 
 UTILS_FOLDER="${UTILS_FOLDER:-$(pwd)}"
-{ . "${UTILS_FOLDER}"/common-utils.sh; } || { printf "Error: Unable to source util files.\n" && exit 1; }
+{ . "${UTILS_FOLDER}"/common-utils.bash; } || { printf "Error: Unable to source util files.\n" && exit 1; }
 
 _check_debug
 
 _print_center "justify" "Starting script.." "-"
 
 CLIENT_ID=""
 CLIENT_SECRET=""
-API_URL="https://www.googleapis.com"
-API_VERSION="v3"
 SCOPE="https://www.googleapis.com/auth/drive"
 REDIRECT_URI="urn:ietf:wg:oauth:2.0:oob"
 TOKEN_URL="https://accounts.google.com/o/oauth2/token"
@@ -68,7 +71,7 @@ CONFIG="${CONFIG:-${HOME}/.googledrive.conf}"
 # shellcheck source=/dev/null
 [[ -f ${CONFIG} ]] && source "${CONFIG}"
 
-! _is_terminal && [[ -z ${CLIENT_ID:+${CLIENT_SECRET:+${REFRESH_TOKEN}}} ]] && {
+! [[ -t 2 ]] && [[ -z ${CLIENT_ID:+${CLIENT_SECRET:+${REFRESH_TOKEN}}} ]] && {
     printf "%s\n" "Error: Script is not running in a terminal, cannot ask for credentials."
     printf "%s\n" "Add in config manually if terminal is not accessible. CLIENT_ID, CLIENT_SECRET and REFRESH_TOKEN is required." && return 1
 }
@@ -103,15 +106,15 @@ if [[ ${1} = create ]]; then
         --data "code=${CODE}&client_id=${CLIENT_ID}&client_secret=${CLIENT_SECRET}&redirect_uri=${REDIRECT_URI}&grant_type=authorization_code" "${TOKEN_URL}")" || :
 
     REFRESH_TOKEN="$(_json_value refresh_token 1 1 <<< "${RESPONSE}" || :)"
-    if _get_token_and_update "${RESPONSE}"; then
+    if _get_access_token_and_update "${RESPONSE}"; then
         "${UPDATE:-:}" REFRESH_TOKEN "${REFRESH_TOKEN}" "${CONFIG}"
         printf "Access Token: %s\n" "${ACCESS_TOKEN}"
         printf "Refresh Token: %s\n" "${REFRESH_TOKEN}"
     fi
 elif [[ ${1} = refresh ]]; then
     if [[ -n ${REFRESH_TOKEN} ]]; then
         _print_center "justify" "Required credentials set." "="
-        _get_token_and_update
+        _get_access_token_and_update
         _clear_line 1
         printf "Access Token: %s\n" "${ACCESS_TOKEN}"
     else