Lua

Refresh GMail SMTP OAuth2 Access Token

See more OAuth2 Examples

Demonstrates how to refresh an access token for sending email via GMail (SMTP). Lua

local chilkat = require("chilkat")

-- This example requires the Chilkat API to have been previously unlocked.
-- See Global Unlock Sample for sample code.

-- See Get GMail SMTP Access Token
-- for sample code showing how to obtain a GMail SMTP access token for desktop apps.

-- It is assumed we previously obtained an OAuth2 access token for GMail (one with a scope for sending email).

local jsonToken = chilkat.JsonObject.new()
local success = jsonToken:load_file("qa_data/tokens/_gmailSmtp.json")
if not success then
    print("Failed to load _gmailSmtp.json")
    return
end

-- The access token JSON looks something like this:

--     {
--      "access_token": "abac.Ci-ZabcdF37-NUrmSzxbHxTsMbtlN-uPfabcdAQN_2ekzj0s5ofCzRabcdTDMGaa2Q",
--      "token_type": "Bearer",
--      "expires_in": 3600,
--      "refresh_token": "1/lEe5abcdNJ77eOSDBabcdkQGVmDalkwabcdR2Hatbo"
--     }
--

local oauth2 = chilkat.OAuth2.new()

oauth2.token_endpoint = "https://www.googleapis.com/oauth2/v4/token"

-- Replace these with actual values.
oauth2.client_id = "GOOGLE-CLIENT-ID"
oauth2.client_secret = "GOOGLE-CLIENT-SECRET"

-- Get the "refresh_token"
oauth2.refresh_token = jsonToken:string_of("refresh_token")

-- Send the HTTP POST to refresh the access token..
success = oauth2:refresh_access_token()
if not success then
    print(oauth2.last_error_text)
    return
end

-- The response contains a new access token, but we must keep
-- our existing refresh token for when we need to refresh again in the future.
jsonToken:update_string("access_token", oauth2.access_token)

-- Save the new JSON access token response to a file.
local sbJson = chilkat.StringBuilder.new()
jsonToken.emit_compact = false
jsonToken:emit_sb(sbJson)
sbJson:write_file("qa_data/tokens/_gmailSmtp.json", "utf-8", false)

print("OAuth2 authorization granted!")
print("New Access Token = " .. oauth2.access_token)