[BUGFIX] auth-utils: Use loopback method to fetch authorizaton code | Fix labbots#183

It will use either netcat or python3 to start the http server

Now no need to copy paste the authorizaton ccode manually

https://developers.google.com/identity/protocols/oauth2/native-app#create-code-challenge

Author: Akianonymus

src/common/auth-utils.sh

@@ -336,30 +336,74 @@ _check_refresh_token() {
             "${QUIET:-_print_center}" "normal" " No Refresh token given, follow below steps to generate.. " "-" && unset refresh_token_value_check_refresh_token
         fi
 
+        server_string_check_refresh_token='Now go back to command line..'
+        server_port_check_refresh_token='8079'
+        # run a loop until an open port has been found
+        # check for 50 ports
+        while :; do
+            : "$((server_port_check_refresh_token += 1))"
+            if [ "${server_port_check_refresh_token}" -gt 8130 ]; then
+                "${QUIET:-_print_center}" "normal" "Error: No open ports found ( 8080 to 8130 )." "-"
+                return 1
+            fi
+            { curl -Is "http://localhost:${server_port_check_refresh_token}" && continue; } || break
+        done
+
+        # https://docs.python.org/3/library/http.server.html
+        if command -v python 1> /dev/null && python -V | grep -q 'Python 3'; then
+            python << EOF 1> "${TMPFILE}.code" 2>&1 &
+from http.server import BaseHTTPRequestHandler, HTTPServer
+
+class handler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        self.send_response(200)
+        self.end_headers()
+        if '/?code' in self.path:
+            message = '${server_string_check_refresh_token}'
+            self.wfile.write(bytes(message, "utf8"))
+
+with HTTPServer(('', ${server_port_check_refresh_token}), handler) as server:
+    server.serve_forever()
+EOF
+            _tmp_server_pid="${!}"
+        elif command -v nc 1> /dev/null; then
+            # https://stackoverflow.com/a/58436505
+            printf "%b" "HTTP/1.1 200 OK\nContent-Length: $(printf "%s" "${server_string_check_refresh_token}" | wc -c)\n\n${server_string_check_refresh_token}" | nc -c -l -p "${server_port_check_refresh_token}" 1> "${TMPFILE}.code" 2>&1 &
+            _tmp_server_pid="${!}"
+        else
+            "${QUIET:-_print_center}" "normal" " Error: neither netcat (nc) nor python3 is installed. It is required to required a http server which is used in fetching authorization code. Install and proceed." "-"
+            return 1
+        fi
+
+        # https://developers.google.com/identity/protocols/oauth2/native-app#obtainingaccesstokens
+        code_challenge_check_refresh_token="$(_epoch)authorization_code"
         [ -z "${refresh_token_value_check_refresh_token}" ] && {
-            printf "\n" && "${QUIET:-_print_center}" "normal" "Visit the below URL, tap on allow and then enter the code obtained" " "
-            URL="https://accounts.google.com/o/oauth2/auth?client_id=${CLIENT_ID}&redirect_uri=${REDIRECT_URI}&scope=${SCOPE}&response_type=code&prompt=consent"
+            printf "\n" && "${QUIET:-_print_center}" "normal" "Visit the below URL, follow the instructions and then come back to commandline" " "
+            URL="https://accounts.google.com/o/oauth2/auth?client_id=${CLIENT_ID}&redirect_uri=${REDIRECT_URI}%3A${server_port_check_refresh_token}&scope=${SCOPE}&response_type=code&code_challenge_method=plain&code_challenge=${code_challenge_check_refresh_token}"
             printf "\n%s\n" "${URL}"
-            unset AUTHORIZATION_CODE authorization_code AUTHORIZATION_CODE_VALID response
-            until [ -n "${AUTHORIZATION_CODE}" ] && [ -n "${AUTHORIZATION_CODE_VALID}" ]; do
-                [ -n "${AUTHORIZATION_CODE}" ] && {
-                    if _assert_regex "${authorization_code_regex}" "${AUTHORIZATION_CODE}"; then
-                        AUTHORIZATION_CODE_VALID="true" && continue
-                    else
-                        "${QUIET:-_print_center}" "normal" " Invalid CODE given, try again.. " "-" && unset AUTHORIZATION_CODE authorization_code
-                    fi
-                }
-                { [ -z "${authorization_code}" ] && printf "\n" && "${QUIET:-_print_center}" "normal" " Enter the authorization code " "-"; } || _clear_line 1
-                printf -- "-> \033[?7l"
-                read -r AUTHORIZATION_CODE && authorization_code=1
-                printf '\033[?7h'
-            done
-            response_check_refresh_token="$(curl --compressed "${CURL_PROGRESS}" -X POST \
-                --data "code=${AUTHORIZATION_CODE}&client_id=${CLIENT_ID}&client_secret=${CLIENT_SECRET}&redirect_uri=${REDIRECT_URI}&grant_type=authorization_code" "${TOKEN_URL}")" || :
+
+            "${QUIET:-_print_center}" "normal" " Press enter if you have completed the process in browser" "-"
+            read -r _
+            kill "${_tmp_server_pid}"
+
+            if ! authorization_code="$(grep -m1 'GET.*code.*HTTP/1.1' < "${TMPFILE}.code" | sed -e 's/.*GET.*code=//' -e 's/\&.*//')" &&
+                _assert_regex "${authorization_code_regex}" "${authorization_code}"; then
+                "${QUIET:-_print_center}" "normal" " Code was not fetched properly , here is some info that maybe helpful.. " "-"
+                "${QUIET:-_print_center}" "normal" " Code that was grabbed: ${authorization_code} " "-"
+                printf "Output of http server:\n"
+                cat "${TMPFILE}.code"
+                (rm -f "${TMPFILE}.code" &)
+                return 1
+            fi
+            (rm -f "${TMPFILE}.code" &)
+
+            # https://developers.google.com/identity/protocols/oauth2/native-app#handlingresponse
+            response_check_refresh_token="$(_curl --compressed "${CURL_PROGRESS}" -X POST \
+                --data "code=${authorization_code}&client_id=${CLIENT_ID}&client_secret=${CLIENT_SECRET}&redirect_uri=${REDIRECT_URI}%3A${server_port_check_refresh_token}&grant_type=authorization_code&code_verifier=${code_challenge_check_refresh_token}" "${TOKEN_URL}")" || :
             _clear_line 1 1>&2
 
             refresh_token_value_check_refresh_token="$(printf "%s\n" "${response_check_refresh_token}" | _json_value refresh_token 1 1)" ||
-                { printf "%s\n" "Error: Cannot fetch refresh token, make sure the authorization code was correct." && return 1; }
+                { printf "%s\n" "Error: Cannot fetch refresh token, make sure the authorization code was correct." && printf "%s\n" "${response_check_refresh_token}" && return 1; }
 
             _set_value direct REFRESH_TOKEN "${refresh_token_value_check_refresh_token}"
             { _check_access_token "${account_name_check_refresh_token}" skip_check "${response_check_refresh_token}" &&