PureBasic

Refresh GMail IMAP OAuth2 Access Token

See more GMail SMTP/IMAP/POP Examples

Demonstrates how to refresh an access token GMail IMAP read/write access. PureBasic

IncludeFile "CkStringBuilder.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkOAuth2.pb"

Procedure ChilkatExample()

    success.i = 0

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

    ; See Get GMail IMAP OAuth2 Access Token for Desktop App 
    ; for sample code showing how to obtain a GMail IMAP read/write access token.

    ; It is assumed we previously obtained an OAuth2 access token for GMail.

    jsonToken.i = CkJsonObject::ckCreate()
    If jsonToken.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkJsonObject::ckLoadFile(jsonToken,"qa_data/tokens/_gmailFullAccess.json")
    If success <> 1
        Debug "Failed to load _gmailFullAccess.json"
        CkJsonObject::ckDispose(jsonToken)
        ProcedureReturn
    EndIf

    ; 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"
    ; 	}
    ; 

    oauth2.i = CkOAuth2::ckCreate()
    If oauth2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkOAuth2::setCkTokenEndpoint(oauth2, "https://www.googleapis.com/oauth2/v4/token")

    ; Replace these with actual values.
    CkOAuth2::setCkClientId(oauth2, "GOOGLE-CLIENT-ID")
    CkOAuth2::setCkClientSecret(oauth2, "GOOGLE-CLIENT-SECRET")

    ; Get the "refresh_token"
    CkOAuth2::setCkRefreshToken(oauth2, CkJsonObject::ckStringOf(jsonToken,"refresh_token"))

    ; Send the HTTP POST to refresh the access token..
    success = CkOAuth2::ckRefreshAccessToken(oauth2)
    If success <> 1
        Debug CkOAuth2::ckLastErrorText(oauth2)
        CkJsonObject::ckDispose(jsonToken)
        CkOAuth2::ckDispose(oauth2)
        ProcedureReturn
    EndIf

    Debug "New access token: " + CkOAuth2::ckAccessToken(oauth2)

    ; 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.
    CkJsonObject::ckUpdateString(jsonToken,"access_token",CkOAuth2::ckAccessToken(oauth2))

    ; Save the new JSON access token response to a file.
    sbJson.i = CkStringBuilder::ckCreate()
    If sbJson.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::setCkEmitCompact(jsonToken, 0)
    CkJsonObject::ckEmitSb(jsonToken,sbJson)
    CkStringBuilder::ckWriteFile(sbJson,"qa_data/tokens/_gmailFullAccess.json","utf-8",0)

    Debug "Access token refreshed!"
    Debug "New Access Token = " + CkOAuth2::ckAccessToken(oauth2)


    CkJsonObject::ckDispose(jsonToken)
    CkOAuth2::ckDispose(oauth2)
    CkStringBuilder::ckDispose(sbJson)


    ProcedureReturn
EndProcedure